88 results on '"abies alba"'
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2. The interplay between climate and bedrock type determines litter decomposition in temperate forest ecosystems.
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Michalet, Richard and Liancourt, Pierre
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TEMPERATE forest ecology , *FOREST litter decomposition , *BEDROCK , *CALCAREOUS soils , *SILVER fir - Abstract
At regional scale, it is dominantly considered in the European literature that litter decomposition is higher in soils from calcareous than siliceous bedrocks because of higher pH in the former forest ecosystems. We tested the alternative hypothesis that this should rather be due to differences in physical characteristics of the bedrock, with likely higher decomposition on calcareous than siliceous bedrocks in wet climates because of more favourable texture in the former and nutrient leaching in the latter, and the opposite in dry climates because of higher drought stress in calcareous soils. We assessed, four consecutive years with contrasting climates, the litter decomposition of a unified litter of Abies alba needles with the litterbag method in 70 forest sites located on both bedrocks and in wet oceanic and dry continental climates of the European Alps and the Pyrenees. Average and annual climate data were analysed with principal component analyses and the effects of bedrock type, average and annual climate drought stresses on litter decomposition were analysed, separately in the Alps and the Pyrenees, with analyses of variance. We found, in both mountain ranges, a highly significant bedrock type by average climate drought stress interaction on litter decomposition, due to a strong decrease in litter decomposition from wet oceanic to dry continental sites on calcareous bedrocks only. Although litter decomposition did not change over all years in siliceous sites with increasing climate drought stress, it increased during wet years in the dry continental sites only, in particular in the Pyrenees where interannual climate variability was higher. Together our results strongly support the physical hypothesis and not the chemical hypothesis. We argue that the chemical hypothesis was proposed based on studies only conducted in low elevation wet temperate sites comparing mull humus types from deciduous forests on calcareous soils to mor and moder humus types from evergreen forests on highly sandy siliceous bedrocks. Our study conducted on a wider range of climate and bedrock conditions bring strong evidence that litter decomposition is rather dependent on the physical characteristics of the bedrocks. • Litterbag experiment conducted in 70 sites from the Alps and the Pyrenees. • Litter decomposition is higher on siliceous than calcareous soils in dry climates. • Soil pH does not explain differences in litter decomposition. [ABSTRACT FROM AUTHOR] more...
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- 2024
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3. Spatial conservation planning of forest genetic resources in a Mediterranean multi-refugial area.
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Vajana, Elia, Andrello, Marco, Avanzi, Camilla, Bagnoli, Francesca, Vendramin, Giovanni G., and Piotti, Andrea
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ENVIRONMENTAL degradation , *GERMPLASM conservation , *GENETIC variation , *SILVER fir , *ENGLISH oak - Abstract
The Kunming-Montreal Global Biodiversity Framework recognised the urgency of taking action to conserve intraspecific genetic diversity (IGD) as an insurance against habitat degradation and environmental change. Recent work suggests that 90–99 % of IGD should be conserved to safeguard viability of future generations. Here, we addressed such a conservation issue in three forest tree species in Italy: silver fir (Abies alba Mill.), Heldreich's pine (Pinus heldreichii H. Christ), and pedunculate oak (Quercus robur L.). We used microsatellite markers to measure IGD of 36 (A. alba), 15 (P. heldreichii) and 25 (Q. robur) natural sites, including several putative glacial refugia. We developed a spatial conservation planning (SCP) analysis to quantify the genetic irreplaceability of each site and identify the minimum set coverage ensuring IGD protection. Finally, we compared SCP results with the contributions to allelic diversity within and between sites, total allelic diversity and private allelic richness. We found that between 44 % and 73 % of sites were required to conserve 90–99 % of the alleles, and that this conservation effort held even when targeting lower percentages of alleles to protect (50–75 %). Glacial refugia were often included in the minimum set coverage, confirming biogeographical expectations. Finally, sites with high genetic irreplaceability were found to have higher private allelic richness on average. These results are discussed in the light of the biogeographic history of the species studied and the current policies for the conservation of forest genetic resources. • Intraspecific genetic diversity (IGD) must be protected to avoid extirpation. • Spatial conservation planning of IGD in forest trees from a multi-refugial area. • ½ to ¾ of sites are to be conserved to achieve adequate protection for IGD. • Setting unambitious conservation targets has limited impact on conservation costs. • Glacial refugia are priority candidates for maximising IGD conservation. [ABSTRACT FROM AUTHOR] more...
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- 2024
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4. The absence of disturbances promoted Late Holocene expansion of silver fir (Abies alba) in the Bohemian Forest.
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Schafstall, Nick, Svitavská-Svobodová, Helena, Kadlec, Martin, Gałka, Mariusz, Kuneš, Petr, Bobek, Přemysl, Goliáš, Viktor, Pech, Pavel, Nývlt, Daniel, Hubený, Pavel, Kuosmanen, Niina, Carter, Vachel A., and Florescu, Gabriela more...
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SILVER fir , *FORESTS & forestry , *PEAT bogs , *HOLOCENE Epoch , *VEGETATION dynamics , *HUMAN activity recognition - Abstract
Temperate forests in the Northern Hemisphere are strongly affected by increasing annual temperatures and natural disturbances such as droughts, fires, and pest outbreaks. In many regions, alternatives are explored by the forestry industry for previously commercialized tree species which are rapidly declining in areas outside their optimal climatic niches. However, as the current ranges of tree species have been mainly constrained by human activity, their true climatic and ecological niches are likely different from our observations. For example, little is known about environmental niches and population dynamics of tree species with limited dispersal ability, such as silver fir (Abies alba). Long-term (paleo) records of past landscape composition, past climate, and past disturbances can help to reveal the natural environmental niches of tree species. This study focuses on the Bohemian Forest (Šumava) in Czechia, where the human alteration of forests in higher elevations (>1000 m asl) has only been demonstrated from Medieval times onward. We present an interdisciplinary approach of geochemistry, pollen, charcoal, botanical and insect macro remains from a high-elevation peat record for the last seven millennia. Our multi-proxy study aimed to identify episodes of increased fire and other disturbances such as insect outbreaks, which could have influenced forest dynamics and vegetation succession in this montane region. However, the charcoal and macro-fossil records do not indicate any large local fires, insect outbreaks, browsing, or other disturbances (e.g., anthropogenic) for a major part of the record, suggesting that changes in the vegetation after 6500 cal yr BP were mainly caused by climatic fluctuations. Silver fir (Abies alba) expanded from 4300 cal yr BP, and likely became the dominant tree species at this locality for the next 2000 years, with extremely high pollen values up to 60%. During the establishment of silver fir around the peat bog around 5600 cal yr BP and its expansion around 4300 cal yr BP, the geochemical record and low counts of the testate amoeba Archerella flavum indicate drier conditions on the peat bog. Comparison with climatic simulations on a 1 × 1-km scale from the CHELSA database suggests that the local expansion of silver fir possibly coincided with a decrease in precipitation during both the wettest and warmest quarter of the year, related to a decreasing trend in seasonality of annual precipitation; this might confirm the species' higher tolerance to drought. Although silver fir is currently extremely rare in the Bohemian Forest, it has the potential for local expansion if logging, fire, and game browsing are kept to a minimum. • Multi-proxy record from Blatenská slat', Bohemian Forest. • Prominent dominance of Abies alba over Picea abies between ca. 4000–1200 cal yr BP. • Indicators for disturbances (fire, insect outbreaks, browsing) were not found. • Climate simulations match the local geochemical record, suggesting declining precipitation. • Silver fir populations in central Europe could expand in the absence of disturbances. [ABSTRACT FROM AUTHOR] more...
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- 2024
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5. Long-term nutrient imbalances linked to drought-triggered forest dieback.
- Author
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Hevia, Andrea, Sánchez-Salguero, Raúl, Camarero, J. Julio, Querejeta, José I., Sangüesa-Barreda, Gabriel, and Gazol, Antonio
- Abstract
Drought-induced forest dieback is causing reductions in productivity, increasing tree mortality and impairing terrestrial carbon uptake worldwide. However, the role played by long-term nutrient imbalances during drought-induced dieback is still unknown. To improve our knowledge on the relationships between dieback and nutrient imbalances, we analysed wood anatomical traits (tree-ring width and wood density), soil properties and long-term chemical information in tree-ring wood (1900–2010) by non-destructive Micro X-ray fluorescence (μXRF) and destructive (ICP-OES) techniques. We studied two major European conifers with ongoing drought-induced dieback in mesic (Abies alba , silver fir) and xeric (Pinus sylvestris , Scots pine) sites. In each site we compared coexisting declining (D) and non-declining (ND) trees. We used dendrochronology and generalized additive and linear mixed models to analyse trends in tree-ring nutrients and their relationships with wood traits. The D trees presented lower growth and higher minimum wood density than ND trees, corresponding to a smaller lumen area of earlywood tracheids and thus a lower theoretical hydraulic conductivity. These differences in growth and wood-anatomy were more marked in silver fir than in Scots pine. Moreover, most of the chemical elements showed higher concentrations in D than in ND trees during the last two-five decades (e.g., Mn, K and Mg), while Ca and Na increased in the sapwood of ND trees. The Mn concentrations, and related ratios (Ca:Mn, Mn:Al and P:Mn) showed the highest differences between D and ND trees for both tree species. These findings suggest that a reduced hydraulic conductivity, consistent with hydraulic impairment, is affecting the use of P in D trees, making them more prone to drought-induced damage. The retrospective quantifications of Mn ratios may be used as early-warning signals of impending dieback. Unlabelled Image • 110-Year long series of wood-chemistry to understand drought-induced dieback. • Declining trees showed lower growth and higher minimum wood density than non-declining trees. • Alterations in wood nutrient concentrations are coherent with hydraulic failure hypothesis. • Mn, Ca:Mn and P:Mn rings content may serve as early-warning signals of dieback. [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
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6. Quantifying the relative influence of terminal shoot browsing by ungulates on tree regeneration.
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Kupferschmid, Andrea D., Bütikofer, Lukas, Hothorn, Torsten, Schwyzer, Andreas, and Brang, Peter
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FOREST regeneration ,FIR ,UNGULATES ,FOREST canopy gaps ,TREE seedlings ,SOIL acidity - Abstract
• Browsing probability is not linearly related to seedling density. • Regeneration variables decrease until a browsing probability of <10%. • Thus, browsing in the range of 0–9% reduces seedling and sapling densities. • Temporal development of tall:small seedlings is species- and browsing-dependent. • Browsing probability is important in explaining tree species composition. Ungulate densities and browsing in many European forests have increased over the past several decades. However, the extent to which tree regeneration is influenced by leader shoot browsing by ungulates versus other factors, such as light availability and the edaphic properties of different forest types, is unclear. In this study, tree regeneration in response to ungulate browsing and environmental factors was compared in 49 forest areas in Switzerland. The forests were located 500–1400 m a.s.l. and were characterized by a wide range of soil humidities and acidities. Seedlings of the six most frequent Swiss tree species were repeatedly assessed for leader browsing in 1704 permanently marked sampling plots for at least 10 years. Browsing probabilities and seedling outgrowth (ratio between tree seedlings in the tallest and smallest height classes (hc4: 100–130 cm and hc1: 10–40 cm tree height, respectively) were first estimated in a stratum-specific manner (per forest, plot, species and, for the browsing probability, height class as well) based on GLMMs. Random forest models were then used to separately explain seedling density, outgrowth probability, the temporal development of outgrowth and the species composition based on the estimated browsing probabilities and environmental factors. Browsing probability was among the most important variables explaining species composition, but its contribution to explaining seedling density and outgrowth probability was less than that of other variables, such as stand basal area. The densities of all species declined dramatically when annual browsing exceeded a threshold of ca. 5–10%, but there was very little change above this threshold. Forest type and gap size did not influence the relationship between browsing and seedling density, but a considerably larger number of browsed seedlings was found in closed beech forests than in other forests. Tree species palatability was not related to the proportions of seedlings of different size classes, since for Fagus and Fraxinus more tall than small seedlings were present, while the reverse was observed for Abies , Acer, Sorbus and Picea. The pattern identified in this study can be attributed to the coincidence of environments equally favorable to tree regeneration and ungulates in some but not in other forests. In rare cases, such as after a major disturbance, almost no ungulates were present and tree regeneration was abundant, or vice versa. While browsing intensity seemed to correlate with ungulate density, its impact on seedling density and development may be more complex. Further research is therefore needed to correctly estimate the impact of ungulate browsing on tree regeneration in different forest types, [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
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7. Biotic factors and increasing aridity shape the altitudinal shifts of marginal Pyrenean silver fir populations in Europe.
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Hernández, Laura, Camarero, J. Julio, Gil-Peregrín, Eustaquio, Saz Sánchez, Miguel Ángel, Cañellas, Isabel, and Montes, Fernando
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SILVER fir ,LAND use ,CLIMATE change ,PLANT conservation ,SPECIES distribution - Abstract
Highlights • Low-elevation decline but high-elevation expansion of Pyrenean silver fir populations. • Biotic factors after major land use changes drive climatic-mediated shifts in marginal tree populations. • An integral conservation strategy for silver fir in Europe is needed. Abstract Rear-edge tree populations are currently at the forefront of habitat conservation. Understanding the dynamics of such marginal and peripheral populations is necessary to improve their preservation in the face of global change. Focusing on the south-western rear edge populations of silver fir (Abies alba) in Europe (Spanish Pyrenees) and using 763 resampled plots from the Spanish National Forest Inventory (1989–2000 and 2001–2010), we analyzed temporal changes in demographic parameters such as regeneration, growth and mortality as well as changes in diameter distribution and vitality of silver fir to identify shifts in the distribution. For this purpose, montane (900–1600 m a.s.l.) and subalpine (1600–2000 m a.s.l.) silver fir populations were considered separately. We then assessed the relative effects of various biotic and abiotic factors on the observed changes and specifically on each of the studied demographic parameters. In montane forests, early recruitment and the proportion of trees exhibiting high vitality decreased, while the amount of dead trees increased. In subalpine forests, silver fir has become more abundant and displays the highest growth and recruitment rates as well as the lowest mortality rate. The increase in radial growth and saplings were positively related to elevation but negatively associated with warmer and drier conditions, coinciding with the intensified aridification observed in the study area over recent decades. Our findings point to the contraction of montane silver fir forests but also to an upward expansion of subalpine forests. The results also indicate that the dynamics of marginal tree populations are driven not only by climate warming, but particularly, by biotic factors, suggesting a positive impact of interspecific interactions with tree species displaying differentiated ecophysiological traits. Given the singularity of marginal Pyrenean silver fir populations, their importance as regards the conservation of forest biodiversity at European scale, and the demographic changes revealed in this study, an integral conservation strategy to ensure their long-term preservation is necessary. [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
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8. Gap regeneration patterns in Carpathian old-growth mixed beech forests – Interactive effects of spruce bark beetle canopy disturbance and deer herbivory.
- Author
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Orman, Olga, Dobrowolska, Dorota, and Szwagrzyk, Jerzy
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BEECH ,FOREST management - Abstract
Highlights • Tree species' responses to bark beetle induced canopy disturbance were studied in mixed stands. • Saplings and pole-sized trees responded to forest-gap gradient but not small and tall seedlings. • Inter-specific differences in species abundance relative to gap properties were found. • Beech was affected by gap size across all life stages. • Deer browsing has changed regeneration patterns in these forests. Abstract The combined effects of various disturbance types have lasting consequences on forest ecosystems and the services they provide. We examined inter-specific differences in the responses of European beech, silver fir and Norway spruce to canopy disturbance across four life stages (small seedlings, tall seedlings, saplings and pole-sized trees) in two Carpathian old-growth mixed beech forests located in the Gorce National Park (GNP) and Babia Gora National Park (BGNP), Poland. Both study sites were recently affected by spruce bark beetle outbreak. We compared the composition of tree regeneration between forest plots, canopy gaps and expanded areas (i.e. areas located under tree crowns). Moreover, we studied how various gap properties (size, expanded gap to canopy gap size ratio, shape) and other factors (browsing, plant and advanced regeneration cover) shaped regeneration patterns. Inter-specific differences in species abundance relative to gap properties and intra-specific differences in species response across various life stages to gap properties were found. Gap properties had more pronounced effects on saplings and pole-sized trees than on small and tall seedlings. Gap size had the most noticeable effect on beech across all regeneration classes. However, its effect varied from negative to positive depending on life stage. Pole-sized trees of all species responded positively to gap size. Thus, it seems that large gaps provided an opportunity for all species to recruit to canopy. Fir and spruce responded contrastingly to expanded gap to canopy gap size ratio, which reflects differences in their ability to adapt to high-intensity solar radiation. With the exception of beech, the 'forest-gap' gradient only affected trees in the advanced life stages (saplings and pole-sized trees). Beech and fir sapling densities and fir pole-sized tree densities were higher when under forest canopy, but spruce pole-sized trees were slightly more abundant in expanded areas. Browsing rates differed between the two study sites; they were more severe in BGNP, where deer densities in the last twenty years have been significantly higher. This intense deer browsing kept silver fir regeneration below the height of 0.5 m and prevented any recruitment to sapling stage. We conclude that even though the recent spruce mortality caused by bark beetle outbreak improved light conditions in both study areas, thus providing good regeneration opportunities to both beech and fir, deer browsing may have long-lasting effects on successional patterns by hindering fir recruitment in BGNP. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
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9. Seasonality matters—The effects of past and projected seasonal climate change on the growth of native and exotic conifer species in Central Europe.
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Vitali, Valentina, Büntgen, Ulf, and Bauhus, Jürgen
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Norway spruce is one of the economically most important tree species in Central European forestry. However, its high susceptibility to droughts poses a strong challenge to its cultivation under future conditions with likely more frequent and prolonged droughts and shifts in the seasonal climate. To compensate for expected losses of forest areas suitable for the cultivation of spruce, more drought-tolerant species are required. Silver fir and Douglas fir are two potential candidates, which promise lower drought susceptibility and equal or even higher yield when compared to Norway spruce. Using the Black Forest as a regional case study, we assessed the effects of seasonal climate change, including drought stress, on tree-ring width formation of these three economically relevant conifer species over the last 60 years. In addition, we projected potential species-specific growth changes under different climate change scenarios until 2100. Our results suggest that both silver fir and Douglas fir will possibly experience growth increases in a warmer future climate, as predicted under the 4.5 and 8.5 Representative Concentration Pathway (RCP) climate change scenarios, whereas growth of spruce is expected to decline. Moreover, drought susceptibility in silver fir and Douglas fir is lower than in spruce, as shown for past drought events, and their ability to benefit from milder winters and springs could play a major role in their capacity to compensate for drier summers in the near to mid-term future. This study highlights the need to advance our understanding of the processes that drive drought resistance and resilience in tree species to guide management strategies in the face of climate change. [ABSTRACT FROM AUTHOR] more...
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- 2018
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10. Species diversity and competition have minor effects on the growth response of silver fir, European larch and Douglas fir to drought.
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Charlet de Sauvage, Justine, Bugmann, Harald, Bigler, Christof, and Lévesque, Mathieu
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DOUGLAS fir , *SILVER fir , *EUROPEAN larch , *SPECIES diversity , *DENDROCHRONOLOGY , *DROUGHTS , *LEMNA minor - Abstract
• 401 trees were sampled for tree-ring analysis, and their neighborhood was measured. • The growth sensitivity to drought was higher for larch than for the two other species. • No effect of species diversity on tree radial growth over the period 2000–2020. • The drought resilience of Douglas fir was increased in a more diverse neighborhood. • Competition did not always have an effect on tree growth and drought resilience. With climate change, the frequency and duration of droughts are increasing, strongly impacting forest ecosystems. Therefore, a thorough understanding of the factors influencing tree response to drought is needed. Particularly, it remains unclear how competition and species diversity influence the drought sensitivity of tree species. Thinning (i.e., lowering competition) and mixing species (i.e., increasing diversity) are two common forest management practices that are thought to help forests to cope with droughts. However, their actual effects are still controversial. We sampled and measured tree-ring widths of 401 conifer trees with a wide range of competition and species diversity in their neighborhood across a bioclimatic gradient in Switzerland. Based on mixed-effects models and correlations, we examined the climate sensitivity of silver fir, European larch and Douglas fir and analyzed how competition and species diversity affect their radial growth and drought sensitivity. Silver fir was the least sensitive species to temperature, precipitation, and climatic water balance. When we analyzed the combined effects of the climatic water balance, competition and species diversity on tree radial growth over the past 20 years, we found that competition usually had a negative effect on radial growth of the three species, while species diversity had no effect. However, when focusing on drought resilience, competition had a negative effect for silver fir only, and a more mixed neighborhood enhanced the drought resilience of Douglas fir. Larch showed a higher drought sensitivity than silver fir and Douglas fir. At most sites, radial growth of all species recovered within two years after the severe droughts of 2003 and 2018. Overall, our results suggest that competition and species diversity have minor effects on the drought resilience of silver fir, larch and Douglas fir in Switzerland. [Display omitted] [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
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11. Delineating vulnerability to drought using a process-based growth model in Pyrenean silver fir forests.
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Valeriano, Cristina, Tumajer, Jan, Gazol, Antonio, González de Andrés, Ester, Sánchez-Salguero, Raúl, Colangelo, Michele, Linares, Juan C., Valor, Teresa, Sangüesa-Barreda, Gabriel, and Julio Camarero, J. more...
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SILVER fir ,DROUGHTS ,FOREST declines ,CLIMATE change ,GROWING season ,TREE growth - Abstract
• Silver fir forests show different degrees of dieback in the western Pyrenees. • Dieback and growth decline were caused by late-summer drought stress. • The Vaganov-Shashkin (VS) model simulated silver-fir growth and identified its climatic constraints. • Simulated growth series showed a decoupling with respect the climate baseline. • The VS model allows identifying vulnerable forests and early signals of dieback. Assessing tree growth patterns and deviations from expected climate baselines across wide environmental gradients is fundamental to determine forest vulnerability to drought. This need is particularly compelling for the southernmost limit of the tree species distribution where hot droughts often trigger forest dieback processes. This is the case of some silver fir (Abies alba) populations located in southwestern Europe (Spanish Pyrenees) which present ongoing dieback processes since the 1980s. We sampled 21 silver fir stands showing different dieback intensity, assessed using defoliation levels, quantified their growth patterns and characterized their responses to climate. Then, we assessed growth deviations from climatic predictions using the process-based Vaganov-Shashkin (VS) growth model. The forests showing most intense dieback, i.e. highest defoliation levels, were mainly located in low-elevation sites of the western Pyrenees. Trees in these stands displayed the lowest growth rates and the highest year-to-year variability in growth and their growth was limited by late-summer evaporative demand. In eastern and central Pyrenees, we detected a mild growth limitation by low soil moisture during the late growing season and positive growth recovery in recent years with respect to a climate baseline. Decreasing growth trajectories were the most common pattern, while rising trends were common in stands with low dieback in eastern and central Pyrenees. Our results portend systematic spatial variability of growth trends across the Pyrenean silver fir populations forming the south-western distribution limit of the species in Europe. Decoupling of growth between eastern and western populations observed in the recent decades suggests contrasting vulnerability to climate change, and more importantly, the decoupling of growth patterns in western clusters could be used as an early-warning signal of impending dieback. Consequently, we foresee future dieback events to have more detrimental effects in the western compared with the eastern Pyrenees. [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
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12. Tracking the origin of silver fir plantations along the boundary between different genetic clusters in central Apennines: Implications for their management.
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Santini, Filippo, Andrisano, Teodoro, Leonardi, Stefano, Ciaschetti, Giampiero, Labriola, Mariaceleste, Vendramin, Giovanni Giuseppe, and Piotti, Andrea
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SILVER fir ,PLANTATIONS ,PLANT genetics ,REFORESTATION - Abstract
Reforestation with native species determines that autochthonous populations and plantations are often within the reach of gene flow. To address efficient strategies for forest plantation management it is fundamental to track the origin of reforestation material, in order to limit potentially detrimental effects on the adaptive potential of autochthonous populations. The use of genetic information to determine the origin of plantations is very effective when historical data about reforestation programs are absent. The main objectives of our study were to assess the origin of silver fir plantations in the Majella National Park (Central Apennines) and to compare genetic diversity parameters between plantations and natural stands. The latter objective is particularly relevant to evaluate the levels of genetic variation in plantations of local origin and to evaluate their suitability as already established reforestation stands. A comprehensive genetic dataset (1619 individuals from 33 natural silver fir populations genotyped at 16 nuclear microsatellite markers) was built to characterize potential seed sources for 10 plantations from the Majella National Park. Their genetic origin was assessed through combining the results of Bayesian assignment tests and analyses of genetic differentiation. Based on the genetic structure characterizing natural populations, we were able to definitely assess the origin of most of the planted individuals. Five plantations were established using material which most likely originated in natural populations that are only 10–20 km distant. These plantations harbour levels of genetic variation similar to the surrounding natural populations and are, therefore, to be considered valuable local forest genetic resources. The other five plantations consist either partially or entirely of allochthonous individuals which are similar to Alpine and northern Apennine populations. To avoid exotic gene flow to nearby autochthonous populations, we suggest the removal of plantations in which allochthonous individuals are present before they reach sexual maturity. However, before taking such action, we recommend the monitoring of the relative performance of different provenances, i.e. plantations entirely made by either putatively autochthonous or undoubtedly allochthonous material. Such an investigation would allow a thorough ex post evaluation of past reforestation programs. To conclude, our results show that genetic data can provide essential information for general decision-making in forest plantations management and, considering the thorough characterization of silver fir genetic structure in this multi-refugial area, such information can be particularly useful for a correct management of Apennine plantations. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
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13. Wood density of silver fir reflects drought and cold stress across climatic and biogeographic gradients.
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Camarero, J. Julio and Gutiérrez, Emilia
- Abstract
Climate influences wood density and this relationship affects the ability of conifer forests to uptake and store carbon. Some conifer species can show mixed responses to long-term climate variability in their within-ring width and density patterns. Here we analyze if tree-ring width and density differently respond to seasonal climate variability in silver fir ( Abies alba ) forests from the Spanish Pyrenees subjected to cold and Mediterranean influences. In these forests, early growing-season dry conditions increase minimum wood density, possibly by reducing lumen diameter and lowering growth rates. Cold conditions during the late growing season are associated to a decrease in maximum wood density, probably through a reduction in the lignification and thickening rates of latewood tracheids. We test if these associations follow climatic and biogeographic patterns since the Mediterranean influence, characterized by late-summer storms which alleviate drought stress, is prevalent eastwards in this region. Silver-fir intra-annual width and wood density data showed mixed responses to climate. Minimum wood density negatively responded to spring precipitation, particularly in dry sites forming the southernmost distribution limit of the species. Maximum wood density positively responded to mean maximum temperatures and sunshine duration during late summer and early autumn, mainly in eastern sites subjected to a dominant Mediterranean influence where late-summer drought stress is expected to be low. More extreme climate conditions including dry spells could shift minimum wood density and reduce hydraulic conductivity and growth in conifer species as silver fir which dominate mesic sites. Warmer conditions would lead to denser latewood in silver fir if accompanied by longer durations of sunshine. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
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14. Variability of the climate-radial growth relationship among Abies alba trees and populations along altitudinal gradients.
- Author
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Latreille, Anne, Davi, Hendrik, Huard, Frédéric, and Pichot, Christian
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SILVER fir ,WOODY plants ,HUMIDITY ,CLIMATE change ,DENDROCHRONOLOGY - Abstract
Tree ring widths provide very useful information to assess factors controlling tree radial growth and to estimate future growth trajectories under climate change. Radial growth variability has already been largely studied among tree populations that experience different environmental conditions and was most recently analyzed among individuals within populations. In the present study we assessed, over the 1960–2011 period, the growth response of silver fir ( Abies alba Mill.) individuals originating from ten populations located along two altitudinal gradients (1000–1600 m a.s.l.) in the south east of France. Tree ring increments were estimated from wood cores collected from 129 adult trees. Results showed that (i) 30% of the growth variance among individuals was explained by competition; (ii) the climates of both the current and previous years were correlated with growth. Most of the climatic variables affecting growth were consistent with those identified in previous studies and with the known physiology of the species: negative effects of summer drought of the current and past years as well as a positive effect of the spring temperature of the current year. However in our study, fir growth was also enhanced by previous year spring droughts. The growth responses to precipitation, temperature, and, relative humidity of the current and previous years varied between sites and/or altitudinal levels, reflecting population acclimation by plasticity or genetic adaptation to local conditions. By contrast, only summer rainfall induced variable responses between individual trees, result attributed to the edaphic micro local heterogeneity. The recent climate change did not significantly alter the fir growth response to climate. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
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15. Light response of Fagus sylvatica L. and Abies alba Mill. in different categories of forest edge – Vertical abundance in two silvicultural systems.
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Čater, Matjaž and Kobler, Andrej
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EUROPEAN beech ,SILVER fir ,EFFECT of light on plants ,FORESTS & forestry ,SHELTERWOODS - Abstract
In managed Dinaric montane fir ( Abies alba Mill.) and European beech ( Fagus sylvatica L.) forests, the light response of young beech and fir in gap microsites was studied during three consecutive growing periods (2009, 2010, and 2011) under controlled environmental conditions in stands of single-tree and irregular shelterwood silvicultural system. According to maximal quantum yield, the different response between species in microsite light categories was evidenced for silver fir on microsites with predominating diffuse light and for beech on microsites with predominating direct light, respectively. Abundance and change of share in microsite light categories was compared over different elevation belts on comparable sites between two silvicultural systems. The share of forest edge area was bigger in the irregular shelterwood system. Change in width of forest edge (20, 30 and 40 m) did not affect the proportion and share of the microsite in both regions of different silvicultural system. Separation of microsite areas between both silvicultural systems, evident in lower elevation belts was not evident in the most conflict and highest elevation zone, while the absolute values of all categories above 700 m in both systems were almost identical, indicating the same, small-scale irregular shelterwood system, known also as the freestyle silvicultural approach. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
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16. Fire has been an important driver of forest dynamics in the Carpathian Mountains during the Holocene.
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O‘Hara, Robert B., Pfeiffer, Mirjam, Feurdean, Angelica, Florescu, Gabriela, Hickler, Thomas, Tanţău, Ioan, Vannière, Boris, Hutchinson, Simon M., Gałka, Mariusz, and Moskal-del Hoyo, Magdalena
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FOREST management ,FOREST ecology ,SHELTERWOODS ,FORESTS & forestry ,CHARCOAL -- Environmental aspects ,MOUNTAIN environmental conditions - Abstract
Fire frequency and severity are key parameters in evaluating fire-mediated changes in ecosystems, but these metrics are rarely reconstructed at extensive temporal scales. Notably our understanding of the role of fire regime dynamics in the functioning and biodiversity of Central Eastern European temperate forests is limited because investigation of the effect of fire has been neglected. To fill this gap in knowledge, we applied a multi-proxy approach (macrocharcoal, charred remains, pollen, plant macrofossils) to two sedimentary sequences spanning stands of closed canopy Picea abies to the P. abies treeline located in the northern Carpathians, Romania. We found that climate exerts a broad-scale influence, whereas vegetation feedbacks strongly modulate this fire-climate relationship. Fire has been almost continuously present throughout the Holocene with a remarkably stable mean fire rotation (∼250 yr) with fires of mostly low to mid severity and/or small to medium size. Humans have shifted the fire regime during the last 2800 years to slightly longer fire return intervals (mean 300 yr) and more biomass consumption per fire. We found that P. abies was favoured by low to moderate fire severity/area burned. The establishment of late-successional, shade tolerant Fagus sylvatica was facilitated by fire disturbances, but its expansion coincided with major gaps in fire events. This highlights the key role of fire in the expansion of F. sylvatica that seems only possible in a low/small to mixed severity/size fire regime with a sufficiently long fire return interval. High magnitude charcoal peaks negatively affected F. sylvatica . We found more diverse pollen assemblages, especially taxa linked to anthropogenic impact, at times of moderate fire disturbance corroborating the intermediate disturbance hypothesis. In terms of forest management, our results show that, contrary to current understanding, fire is a natural and important driver of vegetation change in this region. The anticipated increase in fire activity with the climate warming and/or augmented fuel accumulation may threaten the dominant forest ecosystems, given that these are adapted to low frequency and severity fires. We advise forestry to consider the effects of fire as part of climate-change conservation strategies. Diversifying the forest tree mixture with more fire-resistant native species is desirable in order to mitigate the effects of increased fire occurrence and severity. [ABSTRACT FROM AUTHOR] more...
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- 2017
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17. The natural disturbance regime in forests of the Dinaric Mountains: A synthesis of evidence.
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Nagel, Thomas A., Mikac, Stjepan, Dolinar, Mojca, Klopcic, Matija, Keren, Srdjan, Svoboda, Miroslav, Diaci, Jurij, Boncina, Andrej, and Paulic, Vinko
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TEMPERATE forest ecology ,ECOLOGICAL disturbances ,LAND use ,SALVAGE logging ,FOREST surveys ,FOREST canopies - Abstract
Quantitative descriptions of natural disturbance regimes are lacking for temperate forest regions in Europe, primarily because a long history of intensive land-use has been the overriding driver of forest structure and composition across the region. The following contribution is the first attempt to comprehensively describe the natural disturbance regime of the dominant forest communities in the Dinaric Mountain range, with an emphasis on the range of natural variability of regime components for the main disturbance agents. Compared to other forest regions in Europe, the mountain range has a history of less intensive forest exploitation and provides a suitable record of natural disturbance processes. Our synthesis is based on multiple types of evidence, including meteorological information, historical documentation, evidence from old-growth remnants, and salvage logging data from National forest inventories. Taken together, the results show that no single disturbance agent dominates the regime in the dominant forest types (i.e. beech and mixed beech-fir forests), and any given agent exhibits remarkable variation in terms of severity and spatial extent both within and among individual disturbance events. Thunderstorm winds cause the most severe damage (i.e. near stand replacement), but blowdown patches are typically limited to stand-scales (e.g. 10s of ha). Ice storms and heavy snow typically cause intermediate severity damage and affect much larger areas (e.g. 100s of km 2 ). A notable exception was the 2014 ice storm, which was nearly an order of magnitude larger and more severe than any other event recorded in the synthesis. Severe and prolonged periods of drought have occurred several times over the past century, and along with secondary insect damage (e.g. bark beetles), have caused episodes of forest decline. Overall, our synthesis indicates that on top of the background of relatively continuous gap dynamics, stand-scale intermediate severity events are an important part of the regime; these events likely have rotation periods that are less than the lifespan of a tree cohort (e.g. several centuries) and create canopy openings large enough to alter successional trajectories. [ABSTRACT FROM AUTHOR] more...
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- 2017
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18. Tree aboveground biomass increment and mortality in temperate mountain forests: Tracing dynamic changes along 25-year monitoring period.
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Dyderski, Marcin K., Pawlik, Łukasz, Chwistek, Kazimierz, and Czarnota, Paweł
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MOUNTAIN forests ,TEMPERATE forests ,FOREST biomass ,TREE mortality ,BIOMASS ,DEAD trees - Abstract
• We assessed forest biomass dynamics in mountain forests over 25 years. • Spatiotemporal climate variability had a minor effect on tree biomass increment at the scale of individual plots. • We showed that climate, geomorphology, and stand characteristics modify stand dynamics. • Tree species proportion was a significant driver of stand dynamics. • The topographic wetness index indicated sites with higher recruitment and increment and lower mortality. Tree aboveground biomass and its increment are sensitive forest and landscape dynamics indicators. Although various methods can measure forest biomass dynamics, only in situ , direct monitoring can substantially reduce the uncertainty related to unknown or uncontrolled factors. Within the present study, we aimed to isolate drivers of tree biomass increment, mortality, and recruitment in the Gorce National Park (GNP), Outer Western Carpathians, Poland. We used a unique database consisting of information collected between 1992 and 2017 (in 5-year intervals) within 389 permanent monitoring plots regularly distributed in the GNP area. This allowed us to calculate tree biomass and its increments and model them using a set of explanatory variables: proportion of particular tree species, mean temperature of the coldest quarter (bio11), mean precipitation of the warmest quarter (bio18), elevation, topographic wetness index (TWI), stand basal area (BA), diameter heterogeneity expressed by the coefficient of variation (DBH CV), and conservation regime. We applied generalized linear mixed-effects models (GLMMs), assuming the beta distribution of response variables, i.e. biomass proportions of increment, recruitment, and mortality of three main tree species: Norway spruce Picea abies (L.) Karst, European beech Fagus sylvatica L., and silver fir Abies alba Mill. In a large part of the GNP area, tree biomass increased. In the central and southern parts of the park, tree mortality was higher than in other parts, especially between 2002 and 2007, due to bark beetle outbreaks and intense wind damage. Stand dynamics of all species depended mainly on species proportion in stand biomass. The increment of Abies alba increased with TWI but decreased with BA and DBH CV. Recruitment decreased with BA and slope but increased with TWI and DBH CV, while mortality decreased with DBH CV and TWI. For Fagus sylvatica , increment increased with TWI but decreased with BA, elevation, and bio18, while recruitment decreased with BA and increased with TWI. Mortality decreased with DBH CV, bio11, and TWI but increased with BA. Picea abies increment increased with elevation but decreased with BA, slope, and DBH CV and weakly increased with bio11. Recruitment increased with TWI but decreased with BA and DBH CV, while mortality decreased with DBH CV, BA, and bio18. Water retention at the plot level, approximated by TWI, decreased mortality and increased recruitment of the studied species. Therefore, it can serve as an indicator of suitable microsites for their persistence. In addition, the increment was lower in strictly protected forests, while mortality was higher. Our study provided quantitative evidence of how climate, geomorphology, and forest stand characteristics modify stand dynamics. [ABSTRACT FROM AUTHOR] more...
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- 2023
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19. Forest ecology and fire history of the mixed conifer forest belt in the Italian Alps from Late Roman fires to the 20th century under cultural and climate pressure.
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Furlanetto, Giulia, Abu El Khair, Davide, Badino, Federica, Bertuletti, Paolo, Comolli, Roberto, Maggi, Valter, Perego, Renata, and Ravazzi, Cesare
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FOREST fire ecology , *CONIFEROUS forests , *MIXED forests , *CONIFERS , *ALNUS glutinosa , *ITALIAN language , *TWENTIETH century - Abstract
We reconstructed vegetation, fire and watershed history during the Late Roman-Early Middle Ages and in the last three centuries in a mixed conifer forest forming the middle mountain elevational belt in the inner Alpine region, analyzing co-registered micro-botanical data, charcoal particles, sediment lithology, nutrients, and modern pollen deposition from a high-resolution peat record in Valmalenco (Italian Alps). During Late Roman Age the site hosted a dump mixed conifer forest dominated by Picea abies and Abies alba on peaty forest soil, locally affected by fires which also triggered episodes of hillslope denudation. Fire frequency increases during Early Middle Ages dry and warm phases, favoring Alnus viridis and Larix , while Abies alba and Alnus glutinosa type maintained a main role in the pre- and post-fire. Specifically, Abies alba , nowadays eradicated from the Valmalenco watershed, withstood the local regime of low intensity surface fires for more than a millennium, from the Late Roman throughout the Early Middle Ages. Larix , Alnus viridis and Fraxinus excelsior abundance in modern vegetation is ascribed to effects of intensified disturbance in the Early Modern Age, and to further woodland thickening triggered by fire suppression and abandonment after the Second World War. • A multiproxy study yielded a 1750-year long history of a mixed conifer forest. • Changes in forest composition and structure were driven by six events of local fires. • Fir-dominated forest sustained low intensity surface fires during Early Middle Age. • Larch and green alder responded positively to early medieval fire regime. • Nowadays larch abundance is ascribed to effects of intensified disturbance. [ABSTRACT FROM AUTHOR] more...
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- 2023
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20. Nutrient regime modulates drought response patterns of three temperate tree species.
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Schmied, Gerhard, Hilmers, Torben, Mellert, Karl-Heinz, Uhl, Enno, Buness, Vincent, Ambs, Dominik, Steckel, Mathias, Biber, Peter, Šeho, Muhidin, Hoffmann, Yves-Daniel, and Pretzsch, Hans
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- 2023
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21. Spatial determinants of tree recruitment in mixed stands in southeastern Poland- silver fir's interaction with lowland tree species.
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Bolibok, Leszek, Janek, Magdalena, Pawlak, Bogdan, and Dobrowolska, Dorota
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SILVER fir ,ALNUS glutinosa ,SPECIES ,TREES ,COEXISTENCE of species ,MIXED forests - Abstract
• Silver fir occupy sites with raised water table at north-eastern limit of its distribution. • Black alder outcompete silver fir from the most wet parts of forest stand. • In mixed lowland forest fir seedling establishment is limited by seeds availability. • Less intensive cuttings aimed at promotion of fir sapling are better than salvage cuttings. Silver fir (Abies alba Mill.) is a typical mountain tree species, but it can also grow in lowlands below 300 m a.s.l., where it must coexist with a variety of competitors. Much less were studied in the northeastern part of its natural range, where annual precipitation varies between 500 and 600 mm, distinctly less than in the mountains. The general objective of this study was to investigate the regeneration process of silver fir in mixed lowland forests in regions with water shortage. The evaluation of spatial relationships between old, dominant and newly established trees was used to clarify the mechanisms of tree species coexistence. The study was conducted in managed and protected stands in Janów Forests in the southeastern part of Poland. We selected mature forest stands (oldest trees older than 100 years) representing three types of mixed stands in nature reserves, as well as in comparable managed forests. Data was collected on 500 m
2 sample plots established randomly in each stand category (20 sample plots × 6 stands). Silver fir as the target tree showed statistically significant segregation from other species in 15 cases. Small silver fir trees were associated with large pines in two forest types and segregated form large firs in one. The spatial relationships between fir and black alder were negative. Black alder was the second species with the most statistically significant spatial relationships with other tree species (11 cases). Alders separated from large pines and large firs and from medium and small silver firs. Strong segregation of medium-sized hornbeam from the small class of silver fir was observed. Our study showed that silver fir natural regeneration and colonization of new areas at the northeastern limit of its range are limited by low seed rain density, interactions with other competing species, and local site conditions. Areas with moderately high water table are potentially suitable for fir regeneration, but black alder has a competitive advantage in wetter parts of forest stand. The major advantage of such sites is the absence of beech populations, which are an important competitor to fir in the central European mountains, but a likely equally important limitation would be the presence of hornbeam populations. Our results suggest that less intensive cuttings at carefully selected places are more conducive to fir regeneration than more intensive salvage cuttings. [ABSTRACT FROM AUTHOR] more...- Published
- 2023
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22. Recruitment of European beech, Norway spruce and silver fir in uneven-aged forests: optimal and critical stand, site and climatic conditions.
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Trifković, Vasilije, Bončina, Andrej, and Ficko, Andrej
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EUROPEAN beech ,SILVER fir ,NORWAY spruce ,FOREST dynamics ,FOREST surveys ,TREE growth - Abstract
• Recruitment of beech, spruce and fir in uneven-aged stands studied on 200 m
2 plots. • Optimal and critical levels of 18 influential factors determined with the Tobit model. • Stand basal area and the proportion of target tree species are key factors. • Stocking control is efficient for regulating recruitment of spruce and beech. • Fir recruitment is weakly limited by stand density and largely stochastic. Tree recruitment models are important for predicting the dynamics of uneven-aged forests. Previous studies of recruitment of European beech, Norway spruce and silver fir have shown different ecological amplitudes of these species. However, recruitment in uneven-aged stands and the values of environmental factors at which the greatest and poorest recruitment can be expected remain poorly explained. The main objectives of this study were to 1) explain how 39 stand, site and climatic factors and their interactions influence the number of recruited trees in uneven-aged forests; 2) determine the optimal and critical ranges of influential factors, including stand basal area, number of trees, proportion of tree species, shade casting, soil pH, site productivity, temperature and precipitation; and 3) estimate the maximum expected response of recruitment to changes in stand density while controlling for the effect of other limiting factors. A Tobit censored regression model was used to consider that the observed range of the number of recruited trees is censored at zero. The models were parametrized and validated using 30,963 forest inventory plots (200 m2 each) in uneven-aged forests in Slovenia. The models, which used 9 stand, 6 site and 3 climatic factors, explained 15 %, 10 % and 8 % of the total variation of the number of recruited spruce, fir and beech, respectively. Stand structure was the most important factor, with stand basal area (BA) and the proportion of the studied species having the greatest effect. Site factors including soil pH and rockiness were important for fir recruitment. The number of recruited beech and spruce was positively influenced by decadal precipitation. Higher temperatures decreased recruitment of spruce. Beech was the only species sensitive to shade casting. Recruitment of beech was higher if shade was imposed by tree species other than beech. The optimal and critical ranges of limiting factors differ between species. The model suggests that the optimal stand basal area for recruitment of beech is ≤ 19 m2 /ha, which is higher than that for spruce (≤ 16 m2 /ha) but lower than that for fir (≤ 28 m2 /ha). The maximum predicted response of the studied species to changes in stand basal area shows that stand density control is efficient for regulating recruitment of spruce and beech, but not for fir. The suggested sensitivities and threshold values may be used in individual tree growth models or simulation–optimization studies in support of forest management decisions. [ABSTRACT FROM AUTHOR] more...- Published
- 2023
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23. Assessing drought-driven mortality trees with physiological process-based models.
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Hendrik, Davi and Maxime, Cailleret
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TREE mortality , *EFFECT of drought on plants , *TREE physiology , *FOREST plants , *LEAF area index ,ONTOGENY of plants - Abstract
(1) This study describes how physiological process-based models can be used to assess the mortality risk of forest trees under global change. (2) Using the CASTANEA model, we simulated the development over time of tree functioning with different ontogenetic and phenotypic characteristics (age, diameter, Leaf Area Index, leaf traits) and growing in different site conditions (elevation, soil water content). Based on this set of simulations, we determined the carbon and hydraulic physiological thresholds associated with tree mortality that best reproduce the observed mortality rate. (3) We tested this methodology on a long-lasting and patchy drought-induced mortality event of silver fir ( Abies alba Mill.) in South-Eastern France. (4) We found that tree mortality was not caused by a massive summer xylem embolism, but rather by depletion in carbon reserves probably associated with bark beetle attacks. Simulation outputs also revealed that trees with high diameter and Leaf Area Index and growing on shallower soils were more prone to die. (5) This study highlighted that physiological process-based models can be of high interest to determine the factors predisposing and inducing tree death. [ABSTRACT FROM AUTHOR] more...
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- 2017
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24. Evaluating the potential of an individual-tree sampling strategy for dendroecological investigations using the Italian National Forest Inventory data.
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Bosela, Michal, Gasparini, Patrizia, Di Cosmo, Lucio, Parisse, Barbara, De Natale, Flora, Esposito, Stanislao, and Scheer, Ľubomír
- Abstract
European National Forest Inventories (NFIs) are well established in most of the European countries. In some NFIs, core samples are taken to estimate volume increments at annual resolution. However, the potential of the NFI for dendroecological investigations has not been evaluated so far. Therefore, the aim of this study was to test the potential of dendrochronological data collected during the Italian NFI in 2006. Silver fir was selected as a test species. Core samples were taken from eighty-one trees including one sample per inventory plot (IP). The 81 IPs were distributed across the Italian Alps and the northern Apennine thus well representing the site conditions of the study area. The effects of the detrending method and sample size on detecting middle- to long-term growth trends and high-frequency climate signals were tested. Further, cluster analysis was applied to find dissimilarities among tree-ring width (TRW) series. Results suggest the detrending method to be the most important factor for detecting growth trends, but not for identification of high-frequency climate signals. Sample size essentially influences the final mean chronology, but it does not bring new information when larger than 30 series. Two groups of trees were recognised with distinct middle-term TRW patterns, although being the same in terms of climate sensitivity. Results are mostly in line with recent findings of other authors, which suggest the potential of the NFI data for dendroecological investigations. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
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25. Tree and timberline shifts in the northern Romanian Carpathians during the Holocene and the responses to environmental changes.
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Feurdean, Angelica, Gałka, Mariusz, Tanţău, Ioan, Geantă, Anca, Hutchinson, Simon M., and Hickler, Thomas
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- *
TIMBERLINE , *GLOBAL environmental change , *HOLOCENE Epoch , *EFFECT of altitude on plants , *ATMOSPHERIC temperature - Abstract
High altitude environments are experiencing more rapid changes in temperature than the global average with the risk of losing essential ecosystem services in mountain environments. The Carpathians Mountains are regarded as hosting Europe's most pristine mountain ecosystems, yet the paucity of past environmental records limits our understanding of their sensitivity to the various drivers of change. A multi-proxy palaeoecological approach (plant macro-remains, pollen, charcoal) applied to three Holocene sediment sequences (between 1540 and 1810 m a.s.l.) in the Rodna Mountains documents past treeline and timberline shifts in response to climate change and human impact to anticipate the likely future responses. Our results indicate that forest reacted sensitively to past climate conditions. The timberline had exceeded an elevation of 1540 m a.s.l. by 10,200 cal. yr BP, when summers were warmer than today. The treeline remained below 1810 m a.s.l. at this time and reached its maximum elevation after 8500 cal. yr BP, when winter temperatures became milder. Cool summer conditions probably caused a lowering of the timberline and an extension of the treeline ecotone from 4900 cal. yr BP, a process accentuated by human impact from the Bronze Age (3500 cal. yr BP) onwards. The anticipated upslope tree movements as a consequence ongoing global warming are not yet clearly visible in our records, but will more probably take place in abandoned agricultural areas and be counter-balanced by re-enforced anthropogenic pressure elsewhere. Pinus sylvestris was the dominant tree species in the timberline under a warm and dry climate, when fires were frequent, during the early Holocene (11,250–10,200 cal. yr BP), while Picea abies became dominant in the timberline and Pinus mugo in the treeline ecotone, respectively from 10,200 cal. yr BP to the present. Abies alba became a significant component of the timber over the last four millennia. The anticipated future warmer and moister climatic conditions will favour the persistence of P. abies as well as A . alba . However, A. alba is more sensitive to anthropogenic disturbance, which implies that in places with continuing farmland pressure, A. alba may be less prevalent than P. abies in the future. Anthropogenic pressure is expected to increase the proportion of tree species characteristic of more disturbed forests and consequently threaten biodiversity with important implications for mountain ecosystem services. [ABSTRACT FROM AUTHOR] more...
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- 2016
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26. Later growth onsets or reduced growth rates: What characterises legacy effects at the tree-ring level in conifers after the severe 2018 drought?
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Miller, Tobias Walter, Stangler, Dominik Florian, Larysch, Elena, Honer, Harald, Puhlmann, Heike, Schindler, Dirk, Jung, Christopher, Seifert, Thomas, Rigling, Andreas, and Kahle, Hans-Peter
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- 2023
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27. Characterization of condensed tannins and carbohydrates in hot water bark extracts of European softwood species.
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Bianchi, Sauro, Kroslakova, Ivana, Janzon, Ron, Mayer, Ingo, Saake, Bodo, and Pichelin, Frédéric
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TANNINS , *CARBOHYDRATES , *HOT water heating , *BARK , *SOFTWOOD , *EXTRACTION (Chemistry) - Abstract
Condensed tannins extracted from European softwood bark are recognized as alternatives to synthetic phenolics. The extraction is generally performed in hot water, leading to simultaneous extraction of other bark constituents such as carbohydrates, phenolic monomers and salts. Characterization of the extract’s composition and identification of the extracted tannins’ molecular structure are needed to better identify potential applications. Bark from Silver fir ( Abies alba [Mill.]), European larch ( Larix decidua [Mill.]), Norway spruce ( Picea abies [Karst.]), Douglas fir ( Pseudotsuga menziesii [Mirb.]) and Scots pine ( Pinus sylvestris [L.]) were extracted in water at 60 °C. The amounts of phenolic monomers, condensed tannins, carbohydrates, and inorganic compounds in the extract were determined. The molecular structures of condensed tannins and carbohydrates were also investigated (HPLC-UV combined with thiolysis, MALDI-TOF mass spectrometry, anion exchange chromatography). Distinct extract compositions and tannin structures were found in each of the analysed species. Procyanidins were the most ubiquitous tannins. The presence of phenolic glucosides in the tannin oligomers was suggested. Polysaccharides such as arabinans, arabinogalactans and glucans represented an important fraction of all extracts. Compared to traditionally used species (Mimosa and Quebracho) higher viscosities as well as faster chemical reactivities are expected in the analysed species. The most promising species for a bark tannin extraction was found to be larch, while the least encouraging results were detected in pine. A better knowledge of the interaction between the various extracted compounds is deemed an important matter for investigation in the context of industrial applications of such extracts. [ABSTRACT FROM AUTHOR] more...
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- 2015
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28. Structural patterns of beech and silver fir suggest stability and resilience of the virgin forest Sinca in the Southern Carpathians, Romania.
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Petritan, Ion Catalin, Commarmot, Brigitte, Hobi, Martina Lena, Petritan, Any Mary, Bigler, Christof, Abrudan, Ioan Vasile, and Rigling, Andreas
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SILVER fir ,OLD growth forests ,FOREST dynamics ,FOREST regeneration ,COEXISTENCE of species - Abstract
The structural patterns and dynamics of a primeval silver fir ( Abies alba ) – European beech ( Fagus sylvatica ) forest in the Southern Carpathians (Romania) were assessed to gain deeper insight into species interactions and mechanisms of coexistence, and to study the influence of species composition on forest structure. At 21 sample plots, each covering 0.123 ha within an area of 240 ha, all living and dead trees ⩾6 cm dbh (diameter at breast height) were mapped and measured. Regeneration was assessed on four sub-plots per plot. Additionally, a 1-ha permanent plot established in 2003 was re-measured in 2013 to obtain information on stand dynamics. Point pattern analyses were conducted to study the spatial patterns and tree-to-tree interactions. The overall dbh distributions of beech and fir tended to indicate sustainable population structures. The share of beech varying from 24.8% to 95% (average 58%) in stand basal area did not influence stand parameters such as basal area or volume, nor the distribution of growing stock to different canopy layers. We found fir to dominate the lowest dbh classes in plots that were strongly dominated by beech in the top layer and vice versa, locally indicating species alternation. The regeneration density of fir was lower than of beech, although browsing by ungulates was negligible. In contrast to its share among living trees, fir contributed two-thirds to the deadwood volume. The 10-year changes in forest structure and mortality rate on the 1-ha plot were very small, suggesting the absence of recent intermediate or severe disturbances. The spatial patterns of the dead trees and of the living beech and fir in different canopy layers agreed with a disturbance regime dominated by stochastic small-scale events. Although the spatial patterns of beech and fir were similar, the tree-to-tree interactions indicated a higher intraspecific competition of beech than of fir and a higher shade tolerance of fir particularly in later stages of development. Both could be important factors for the coexistence of the two species. We conclude that the primeval fir–beech forest Sinca shows under the present small scale disturbance regime a high stability and structural resilience. Temporal changes in species composition only lead to small fluctuations in stand parameters and do not threaten the long-term coexistence of beech and fir. Forest managers may vary the species composition of fir–beech forests without substantially influencing the overall forest structure or productivity. [ABSTRACT FROM AUTHOR] more...
- Published
- 2015
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29. Past logging, drought and pathogens interact and contribute to forest dieback.
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Sangüesa-Barreda, Gabriel, Camarero, J. Julio, Oliva, Jonàs, Montes, Fernando, and Gazol, Antonio
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LOGGING , *FOREST declines , *EFFECT of drought on plants , *PATHOGENIC microorganisms , *GLOBAL warming , *SILVER fir - Abstract
Forest dieback is one of the most widespread responses to global-change drivers, such as climate warming-related drought stress and the spread of pathogens. Although both climatic and biotic stressors have been studied separately, much less is known on how drought and pathogens interact and induce dieback, particularly in formerly used forests. We determine the roles played by each of those drivers as factors causing recent dieback in three Pyrenean silver fir stands: a managed site subjected to past logging and two unmanaged sites not logged for the past 50 years. The age, size, recent competition, and basal-area increment (BAI) trends of non-declining and declining trees, and the presence of fungal pathogens were investigated. Growth patterns at yearly to decadal time scales were compared to distinguish the roles and interactions played by the different stressors. In the managed site, declining trees displayed low growth already before logging (1950–1970s). In both unmanaged sites, declining and non-declining trees displayed divergent growth patterns after extreme droughts, indicating that dieback was triggered by severe water deficit. We did not find indications that fungal pathogens are the primary drivers of dieback, since a low proportion of declining trees were infested by primary pathogens (10%). However, trees with the primary fungal pathogen Heterobasidion showed lower BAI than non-declining trees. On the other hand, the secondary fungal pathogen Amylostereum was isolated from a higher number of trees than expected by chance. These findings highlight the importance of legacies, such as the past use in driving recent forest dieback. Past forest use could predispose to dieback by selecting slow-growing trees and thus, making some them more vulnerable to drought and fungal pathogens. [ABSTRACT FROM AUTHOR] more...
- Published
- 2015
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30. Evapotranspiration deficit controls net primary production and growth of silver fir: Implications for Circum-Mediterranean forests under forecasted warmer and drier conditions.
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Vicente-Serrano, S.M., Camarero, J.J., Zabalza, J., Sangüesa-Barreda, G., López-Moreno, J.I., and Tague, C.L.
- Subjects
- *
EVAPOTRANSPIRATION , *PRIMARY productivity (Biology) , *SILVER fir , *PLANT growth , *WEATHER forecasting , *FORESTS & forestry - Abstract
Warming-induced drought stress has been hypothesized as a major driver of forest net primary production (NPP) reduction, but we lack reliable field data to assess if higher temperatures lead to forest NPP reduction, particularly in humid sites and at basin to landscape spatial scales. The use of a landscape approach would allow considering the feedbacks operating between climate, topography, soil vegetation and water resources. Here we follow that approach by simulating NPP using the regional hydro-ecologic simulation system (RHESSys) model and by comparing the results with radial growth data (tree-ring widths and intrinsic water-use efficiency – iWUE). We evaluate the relationships between climate, growth, NPP, atmospheric CO 2 concentrations ( c a ) and iWUE in xeric and mesic silver fir forests subjected to contrasting water balances. The growth data successfully validated the 11-month NPP cumulated until spring. The main negative climatic driver of growth and NPP was the summer evapotranspiration deficit, which shows a negative association with tree-ring width indices. Sensitivity analyses indicate that rising c a do not compensate the severe NPP reduction associated to warmer and drier conditions. The positive effect of rising c a on NPP is mediated by climatic site conditions being detected only in mesic sites, whereas the negative effects of drought on NPP override any c a -related enhancement of NPP in xeric sites. Future warmer and drier conditions causing a higher evaporative demand by the atmosphere could lead to a NPP decline in temperate conifer forests subjected to episodic droughts. [ABSTRACT FROM AUTHOR] more...
- Published
- 2015
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31. Palaeoecological study of Pyrenean lowland fir forests: Exploring mid–late Holocene history of Abies alba in Montbrun (Ariège, France).
- Author
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Cunill, Raquel, Métailié, Jean-Paul, Galop, Didier, Poublanc, Sébastien, and de Munnik, Nicolas
- Subjects
- *
ABIES grandis , *HOLOCENE paleoecology , *SILVER fir , *MOUNTAIN plants , *HISTORY of forestry , *ANTHRACOLOGY - Abstract
Fir ( Abies alba Mill.) occupies an important place in the Pyrenean context, where the species finds its optimal conditions in this mountain zone (800–1800 m a.s.l.). In the Pyrenees, the fir woods of Volvestre (Ariège, France) are of particular interest because of two peculiarities of its location: its northern latitude with respect to the usual location of fir in the Pyrenean axis, and its lower altitude (330–440 m a.s.l.). This has given rise to various theories, some considering the silver fir forests as a glacial relic and others pointing to anthropogenic interference and possible plantings during the Middle Ages. Pedoanthracological and palynological studies have been performed to establish the origin and history of this ancient forest, and both approaches show an ancient anthropized landscape with a continuous presence of Abies alba throughout the mid- and late-Holocene. The fir woodlands of Volvestre are testimonies to the ancient and significant presence of fir on the northeast slope of the Pyrenees and the current suitability of this species for lowland areas. Pedoanthracological sampling inside the forest has shown differences in vegetation dynamics at different valley points (north slope, south slope, and valley bottom). [ABSTRACT FROM AUTHOR] more...
- Published
- 2015
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32. Analysis of the structure of condensed tannins in water extracts from bark tissues of Norway spruce (Picea abies [Karst.]) and Silver fir (Abies alba [Mill.]) using MALDI-TOF mass spectrometry.
- Author
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Bianchi, Sauro, Gloess, Alexia N., Kroslakova, Ivana, Mayer, Ingo, and Pichelin, Frédéric
- Subjects
- *
NORWAY spruce , *MOLECULAR structure , *TANNINS , *PLANT extracts , *BARK , *PLANT cells & tissues , *SILVER fir , *TIME-of-flight mass spectrometry - Abstract
Condensed tannins extracted from the bark of softwoods have been proven to be suitable compounds in the formulation of environmentally friendly adhesives and resins. Their chemical structure has been shown to significantly influence their properties and possible applications. Condensed tannins extracted from the bark of Norway spruce ( Picea abies [Karst.]) and Silver fir ( Abies alba [Mill.]) still lack a detail characterization of their chemical structure. In an effort to address this deficiency, barks from these species were collected and extracted in water at 60 °C. The dried extracts were analyzed by MALDI-TOF mass spectrometry to identify the building blocks and to determine the degree of polymerization of the tannin oligomers. The condensed tannins extracted from spruce bark at the used conditions were mainly composed of procyanidins with a polymerization degree up to 13. Silver fir extracts revealed a predominance of prodelphinidins with a polymerization degree up to 9. The presence of less common building blocks such as stilbene glucosides and flavan-3-ols gallates was also hinted. Different curing times and viscosities in resin formulations are expected between the two studied species, as well as in comparison to the most known and available tannins from tropical species. [ABSTRACT FROM AUTHOR] more...
- Published
- 2014
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33. Social status-mediated tree-ring responses to climate of Abies alba and Fagus sylvatica shift in importance with increasing stand basal area.
- Author
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Lebourgeois, F., Eberlé, P., Mérian, P., and Seynave, I.
- Subjects
SILVER fir ,TREE-rings ,EUROPEAN beech ,CLIMATE change ,PLANT ecology ,PLANT competition ,PLANT growth - Abstract
The aim of the study was to assess the effects of competition at both stand and tree levels on climate tree-growth relationships of 414 Abies alba and 243 Fagus sylvatica trees growing in 2 contrasting ecological conditions (north- and south-facing) under mountainous continental climate (mean altitude: 886 m). Stand level competition was considered through three stand basal area (SBA) modalities (Low: 32 m²/ha, Medium: 41 and High: 49) while tree level competition was assessed through three social statuses (SST, Dominant, Codominant and Suppressed trees). A strong specific response to climate was pointed out with different key periods; growth of Abies being mainly driven by previous and current late summer temperatures, while that of Fagus was controlled by April and June ones. No obvious difference between facing sides was evidenced. Competition at stand level prevailed on competition at tree level. In Low and Medium SBA, trees exhibited similar responses to climate whatever their social statuses. On the opposite, sensitivity to summer drought increased with dominancy in high SBA. Inter-specific differences and consequences for forest management are discussed. [ABSTRACT FROM AUTHOR] more...
- Published
- 2014
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34. Gap size and position influence variable response of Fagus sylvatica L. and Abies alba Mill.
- Author
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Čater, Matjaž, Diaci, J., and Roženbergar, D.
- Subjects
EUROPEAN beech ,SILVER fir ,FORESTS & forestry ,PLANT species diversity - Abstract
Highlights: [•] We compared silver fir and beech in managed Dinaric karst forests during three years. [•] Quantum yield was studied in same four light microsites and three different gaps. [•] Response of species within same microsites was different between gaps. [•] With gap size quantum yield increased for beech and decreased for silver fir. [•] Gaps with low direct light or extended towards the southern gap edge favour fir. [Copyright &y& Elsevier] more...
- Published
- 2014
- Full Text
- View/download PDF
35. Longer and faster: Intra-annual growth dynamics of Douglas fir outperform Norway spruce and silver fir over wide climatic gradients.
- Author
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Miller, Tobias Walter, Stangler, Dominik Florian, Larysch, Elena, Honer, Harald, Seifert, Thomas, Puhlmann, Heike, von Arx, Georg, Fonti, Patrick, Fonti, Marina V., Rathgeber, Cyrille B.K., and Kahle, Hans-Peter more...
- Subjects
- *
DOUGLAS fir , *SILVER fir , *NORWAY spruce , *SPECIES distribution , *SOIL moisture , *CELL division - Abstract
Climate change is expected to have significant impacts on European forests, causing changes in the geographic distribution of species and ecosystem functioning. Douglas fir (Pseudotsuga menziesii) and silver fir (Abies alba) are considered potential alternatives to the drought endangered Norway spruce (Picea abies). However, still little is known about differences in their intra-annual growth dynamics, an important characteristic determining the adaptive capacity of each species. Here we make use of more than 5000 microcores from 132 trees of the three species distributed along three elevational transects (370–1125 m a.s.l.) spanning a temperature gradient of 5 °C in South-Western Germany to compare their intra-annual growth dynamics in a context of changing climate. Results indicate an earlier onset of cambial cell production of about 5.1 days per °C temperature increase for all tree species. Douglas fir produced the highest number of cells and exhibited the longest seasonal period of wood formation, starting two and four weeks earlier and ceasing about two and three weeks later than silver fir and Norway spruce, respectively. Additionally, Douglas fir displayed the highest maximum cell production rate and a 20% higher average cell production rate than Norway spruce and even 50% higher rate than silver fir. We found that soil moisture, but even more the number of produced cells were significantly correlated with the date of growth cessation, compared to a negligible correlation with mean annual temperature (MAT). The superior growth performance of Douglas fir resulting from a longer growth duration with higher rates of cambial cell division was consistent across our climatic gradient. These results corroborate that Douglas fir could be a high-performance alternative to the more climate-change-endangered Norway spruce. [ABSTRACT FROM AUTHOR] more...
- Published
- 2022
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36. Mixed stands reduce Abies alba tree-ring sensitivity to summer drought in the Vosges mountains, western Europe.
- Author
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Lebourgeois, F., Gomez, N., Pinto, P., and Mérian, P.
- Subjects
TREE-rings ,SUMMER ,EFFECT of drought on plants ,MIXTURES ,CLIMATE change ,EFFECT of temperature on plants ,SENSITIVITY analysis - Abstract
Highlights: [•] We study tree-ring responses to climate of Abies alba in western European mountains. [•] We compare responses of pure stands to those of three different mixtures. [•] Climatic drivers are temperature at high elevation and drought at low altitude. [•] Mixture reduces A. alba sensitivity to summer drought. [•] Mixture effects depend on local climatic conditions. [ABSTRACT FROM AUTHOR] more...
- Published
- 2013
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37. Pollen percentage thresholds of Abies alba based on 13-year annual records of pollen deposition in modified Tauber traps: perspectives of application to fossil situations.
- Author
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Pidek, Irena Agnieszka, Svitavská-Svobodová, Helena, Van der Knaap, Willem O., and Magyari, Eniko
- Subjects
- *
SILVER fir , *FOSSIL pollen , *ESTIMATES ,ROZTOCZE Range (Poland & Ukraine) - Abstract
Abstract: Abies alba (fir), a submontane tree from Central European mountains and uplands, is of special interest for palaeoecological and palaeoclimate interpretations due to its sensitivity to air and soil humidity. Its present distribution limit in the uplands of SE Poland is still a matter of debate. In the Holocene fir expanded to Poland very late, but early fir populations are supposed to occur in the Šumava Mts (Czech Republic). The study aims: to estimate pollen thresholds for fir presence/absence in Bohemia (Czech Republic) and Poland on the basis of modified Tauber pollen traps; to use these thresholds for tracing fir presence in two pollen diagrams from Poland (Słone and Bezedna lakes) in the border zone between the Roztocze region (with fir forest stands today) and Polesie (where fir has never played an important role); and to investigate how the percentage presence/absence threshold can be used to trace the occurrence and abundance of fir trees in the Šumava Mts based on the pollen diagrams of Rokytecká slat' and Mrtvý luh. The fir pollen thresholds estimated in terms of PAR (pollen accumulation rates or pollen influx) range from 843 (grainscm−2 year−1) (Roztocze) to 61 (Krkonoše) and 49 (Šumava). Percentage thresholds range from 0.3% in Krkonoše where fir trees are not present within 4km to 22% in fir-dominated woodland of the Roztocze, providing evidence of strong underrepresentation of fir in the pollen deposition. Application of these percentage thresholds to the Słone and Bezedna pollen diagrams indicates that occurrence of fir in the region is possible from 3.5calky BP onwards, though the evidence is not decisive. In the Šumava, a low representation of fir pollen (1–2%) reflecting presence of scattered fir trees was detected as early as ca. 7.0calky BP. [Copyright &y& Elsevier] more...
- Published
- 2013
- Full Text
- View/download PDF
38. Response of Fagus sylvatica L. and Abies alba Mill. in different silvicultural systems of the high Dinaric karst.
- Author
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Čater, Matjaž and Levanič, Tom
- Subjects
EUROPEAN beech ,SILVER fir ,SILVICULTURAL systems ,ATMOSPHERIC carbon dioxide ,PHOTOSYNTHESIS - Abstract
Abstract: Among all silver fir forest types in Slovenia, most changes in forest composition are evident in Dinaric silver fir and beech forests, in which ageing and reduction of silver fir populations compared to European beech is evident. The situation has worsened due to a high browsing rate and environmental changes, causing a decline in abundance and a shift in silver fir′s spatio-temporal distribution. The photosynthesis response to different light and CO
2 (max. photosynthetic rate –Amax , compensation points –Ic , quantum yield –Φ), the morphological response in young beech and fir to shade, and the growth response of adult trees were compared on sites with a single selection method, group selection method and old growth, during three consecutive vegetation periods (2009, 2010 and 2011). Three plots were established on each site, each with comparable light conditions according to the indirect site factor – ISF (%) under mature shelter, forest edge and open light conditions. In the old growth forest, beech and fir were more shade-tolerant and had a greater reaction to different light levels or elevated CO2 concentrations, compared to managed forest sites. Fir and beech express more physiological and morphological shade-tolerant characteristics on sites with single selection treatment, and differences are also evident in the growth responses of the two species. To establish conditions under which fir would be able to compete with beech, longer regeneration periods should be applied, with a gradual opening of the mature canopy, similar to conditions in old growth. In our study, group selection treatment proved more effective under the present environmental conditions. [Copyright &y& Elsevier] more...- Published
- 2013
- Full Text
- View/download PDF
39. Isoprene and terpenoid emissions from Abies alba: Identification and emission rates under ambient conditions
- Author
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Pokorska, Olga, Dewulf, Jo, Amelynck, Crist, Schoon, Niels, Šimpraga, Maja, Steppe, Kathy, and Van Langenhove, Herman
- Subjects
- *
ISOPRENE , *TERPENES , *EMISSIONS (Air pollution) , *SILVER fir , *VOLATILE organic compounds & the environment , *LIMONENE , *ALGORITHMS - Abstract
Abstract: In this study, biogenic volatile organic compound (BVOC) emissions from Abies alba were studied under ambient conditions in Flanders (Belgium). Emission patterns and rates were investigated from April till November 2010 by using the dynamic branch enclosure technique. The present work revealed that A. alba is an isoprene emitter, with isoprene accounting for 86–93% of total BVOC emissions, except during budburst (67%) in May. The emission spectrum of A. alba consisted of 27 compounds. Next to isoprene, the main emitted compounds were α-pinene, β-pinene, camphene and limonene. BVOC emissions showed a peak in June after development of the young needles, followed by a constant emission during summer months and September and a decrease in October. In all the samples isoprene was the most abundant compound with standardized emission rates between 27 μg g(dw) −1 h−1 in June and 4.6 μg g(dw) −1 h−1 in October, while the total standardized terpenoid emission rates ranged from 2.85 μg g(dw) −1 h−1 in June to 0.26 μg g(dw) −1 h−1 in October. The obtained average β coefficients according to the temperature dependent algorithm of during April–June, July, August and September–October were as follows: for terpenoids 0.12 ± 0.03, 0.11 ± 0.05, 0.12 ± 0.04, 0.24 ± 0.01 K−1 and sesquiterpenes (SQTs) 0.09 ± 0.02, 0.11 ± 0.01, 0.10 ± 0.05, 0 K−1, respectively. Overall, isoprene detected in this study was never quantified in previous studies on A. alba and this finding could have a significant impact on the regional BVOCs budget. Therefore, the result of this study is very important for modeling and local air quality. [Copyright &y& Elsevier] more...
- Published
- 2012
- Full Text
- View/download PDF
40. Shade-tolerant tree species from temperate forests differ in their competitive abilities: A case study from Roztocze, south-eastern Poland.
- Author
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Szwagrzyk, Jerzy, Szewczyk, Janusz, and Maciejewski, Zbigniew
- Subjects
SHADE-tolerant plants ,PLANT species ,FORESTS & forestry ,COMPARATIVE studies ,COMPETITION (Biology) ,CASE studies ,ROZTOCZE Range (Poland & Ukraine) - Abstract
Abstract: The objective of this study was to compare the relationship between the competition intensity and performance of three shade-tolerant species: European beech, silver fir and European hornbeam. The competition intensity was calculated using two different competition indices, and the tree performance was represented by diameter growth, height growth and mortality. Our research was based on data collected in the years 1993 and 2003 in four permanent sample plots of 0.5ha each located in old-growth stands of the Roztocze National Park. The competition index, which included the height of a target tree relative to its neighbors, yielded higher correlations with the diameter and basal area increments than Hegyi’s competition index for both hornbeam and fir, but the correlation was lower for beech. The importance of the height difference between the target silver fir and its competitors was also confirmed by a strong relationship between the competition intensity and the relative crown length, indicating that the increase was strongly related to the height advantage over neighbors. In contrast, beech appears to be a successful competitor even when shorter than its neighbors. Hornbeam, which was very abundant in a stage of advanced regeneration, was notably less numerous among the shorter trees, suggesting a limited recruitment to the tree layer. The growth rate of hornbeam was much lower than beech and silver fir and was relatively weakly related to the competition intensity: even the hornbeams relatively free of competition did not respond with vigorous growth. No relationship between the indices and height increases was found for the analyzed tree species. In the case of silver fir and hornbeam, the trees that died during the study had higher values of competition indices compared to the trees that survived; the opposite tendency was found for beech, yet the number of dead beeches was very low. The results suggest that, in mixed stands, hornbeam is a weaker competitor than beech, and the most likely explanation for its high abundance in these analyzed stands is the occurrence of natural disturbances, particularly strong winds. [Copyright &y& Elsevier] more...
- Published
- 2012
- Full Text
- View/download PDF
41. Automatic knot detection and measurements from X-ray CT images of wood: A review and validation of an improved algorithm on softwood samples
- Author
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Longuetaud, F., Mothe, F., Kerautret, B., Krähenbühl, A., Hory, L., Leban, J.M., and Debled-Rennesson, I.
- Subjects
- *
TOMOGRAPHY , *SOFTWOOD , *TREE growth , *QUANTITATIVE research , *ALGORITHMS , *NORWAY spruce , *SILVER fir , *FALSE alarms , *X-rays - Abstract
Abstract: An algorithm to automatically detect and measure knots in CT images of softwood beams was developed. The algorithm is based on the use of 3D connex components and a 3D distance transform constituting a new approach for knot diameter measurements. The present work was undertaken with the objective to automatically and non-destructively extract the distributions of knot characteristics within trees. These data are valuable for further studies related to tree development and tree architecture, and could even contribute to satisfying the current demand for automatic species identification on the basis of CT images. A review of the literature about automatic knot detection in X-ray CT images is provided. Relatively few references give quantitatively accurate results of knot measurements (i.e., not only knot localisation but knot size and inclination as well). The method was tested on a set of seven beams of Norway spruce and silver fir. The outputs were compared with manual measurements of knots performed on the same images. The results obtained are promising, with detection rates varying from 71% to 100%, depending on the beams, and no false alarms were reported. Particular attention was paid to the accuracy obtained for automatic measurements of knot size and inclination. Comparison with manual measurements led to a mean R 2 of 0.86, 0.87, 0.59 and 0.86 for inclination, maximum diameter, length and volume, respectively. [Copyright &y& Elsevier] more...
- Published
- 2012
- Full Text
- View/download PDF
42. Comparing Norway spruce and silver fir regarding impact of bark wounds.
- Author
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Metzler, Berthold, Hecht, Ulrike, Nill, Michael, Brüchert, Franka, Fink, Siegfried, and Kohnle, Ulrich
- Subjects
COMPARATIVE studies ,SPRUCE ,SILVER fir ,FUNGAL colonies ,BARK ,DISCOLORATION ,COLONIZATION (Ecology) ,SAPWOOD ,WOOD discoloration - Abstract
Abstract: In order to compare Norway spruce (Picea abies) and silver fir (Abies alba) with respect to susceptibility to wound colonizing fungi, wood stains and rots, experimental cortical lesions were created in situ on mature trees. The study was performed with 40 Norway spruce and 39 silver fir. Two years after the infliction of the lesions the experiment was evaluated with respect to fungal colonization. The most common fungi isolated from xylem beneath the wound area of Norway spruce were Neonectria fuckeliana, Stereum sanguinolentum and Leptodontium beauverioides. Overall, fungal wound infection rate of Norway spruce was 4.6-fold higher compared to silver fir. Only 7% of the Norway spruce stems were sterile in opposite to 67% sterile silver fir trees. Wood decay fungi were isolated from 28% of Norway spruce trees compared to only 8% of silver fir. Accordingly, discolorations in the wood of Norway spruce were clearly larger in their extent. Silver fir mostly displayed only superficial discoloration. On the other hand, the impact on xylem of both tree species was only slightly influenced by the season of wounding (May versus October). Histological examination revealed that in Norway spruce fungal infections occurred through regular resin channels which appeared to be easily colonized by fungi facilitating long distance growth of fungal hyphae. In contrast, traumatic resin ducts formed by both tree species were not found to be infected by fungi. Very obviously, silver fir – being void of primary resin channels – was able to seal injuries by deposition of accessory substances close to the surface of the exposed xylem, thus inhibiting sapwood dehydration and impeding xylem colonization by fungi. For Norway spruce, computer tomography strongly indicated specific sapwood desiccation in the wound region, while in silver fir no such desiccation could be found. [Copyright &y& Elsevier] more...
- Published
- 2012
- Full Text
- View/download PDF
43. Localisation and mobility of trace metal in silver fir needles
- Author
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Gandois, L. and Probst, A.
- Subjects
- *
TRACE metals , *PARTICULATE matter , *ATMOSPHERIC chemistry , *SILVER fir , *FOREST soils , *ATMOSPHERIC deposition ,ENVIRONMENTAL aspects - Abstract
Abstract: Trace metals (TM: Co, Ni, Cu, Zn, Cd, and Pb) as well as Al, Mn, and Fe content was measured in needles of a remote silver fir stand in the south of France. TM localisation and behaviour in needles was evaluated by measuring total and internal content of needles of different ages. Measured concentrations fell within background values. Al, Fe, Co, and Pb were trapped in wax following atmospheric particulate deposition. Contrasting accumulation and migration behaviours of the different elements studied were observed. The wax contained less than 10% Mn, Al, Ni, Co, and Zn and 15–45% Fe, Cu, and Cd in the young needles. Lead was mostly located in the wax (50–80%), and this proportion decreased with needle age. Only the internal content of Pb and Fe increased significantly with needle age. Finally, due to atmospheric deposition accumulation, higher input fluxes of Fe, Cu, Cd, and Pb can be expected in forest soil. [Copyright &y& Elsevier] more...
- Published
- 2012
- Full Text
- View/download PDF
44. Coexistence of Abies alba (Mill.) –Fagus sylvatica (L.) and climate change impact in the Iberian Peninsula: A climatic-niche perspective approach
- Author
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Serra-Diaz, Josep M., Ninyerola, Miquel, and Lloret, Francisco
- Subjects
- *
SILVER fir , *EUROPEAN beech , *CLIMATE change , *SYMBIOSIS , *TOPOCLIMATOLOGY - Abstract
Abstract: Abies alba Mill. (European silver fir) and Fagus sylvatica L. (beech) are Eurosiberian species dispersed over the Iberian Peninsula. Climate change predictions indicate a rise in temperature and a decrease in precipitation in this region, threatening the future existence of these species. In the present study we analyzed the future topo-climatic suitability of Abies alba and Fagus sylvatica and the mixed forests of these two species, using the General Linear Models technique and data from the third National Forest Inventory (). We considered two modeling approaches based on niche theory: modeling community (Abieti-Fagetum) and overlapping individual species models. General trends showed an overall decrease in both species’ topo-climatic suitability and indicated that the Pyrenees will play a crucial role as a climatic refuge. The modeling approaches markedly differed, however, in their current and future spatial agreement. Despite good accuracy results, community modeling through co-occurrence does not encompass the environmental space of individual species prejudicing future assessments in new environmental situations, suggesting a need for future studies in community modeling. [Copyright &y& Elsevier] more...
- Published
- 2012
- Full Text
- View/download PDF
45. Phenology of wood formation: Data processing, analysis and visualisation using R (package CAVIAR).
- Author
-
Rathgeber, Cyrille B.K., Longuetaud, Fleur, Mothe, Frédéric, Cuny, Henri, and Le Moguédec, Gilles
- Subjects
PLANT growth regulation ,ELECTRONIC data processing ,DATA analysis ,DATA visualization ,INTEGRATED software ,SILVER fir ,PHENOLOGY - Abstract
Abstract: Studies of intra-annual dynamics of cambial activity and wood formation share very similar data because they are based on classic concepts of xylem development and well-documented techniques of sample preparation. However, the way the data are produced is specific to each study or group of authors because there is not a real agreement or consensus about critical variable definitions and data processing. The consequence is that despite very similar data, these studies are difficult to compare. In order to improve this point, we proposed objective definitions of the main phenological events (critical dates) occurring during wood formation, i.e. the beginning and ending of the cell enlarging and maturing phases and the beginning of the cell mature phase. The beginning of a given phase was defined as the date at which 50% of the observed radial files show at least one first cell in this phase, while the end of a given phase was defined as the date at which 50% of the observed radial files show at most one last cell in this phase. Dedicated R package CAVIAR was developed in order to apply these definitions to the computation of critical dates, as well as to their visualisation and analysis. Several statistical tests (Student''s t-test, Wilcoxon''s rank sum test and bootstrap tests on means and medians) were evaluated for comparing critical dates between two groups. Based on theoretical considerations and on study case analyses, it was shown that the bootstrap test on median is the best-suited statistical test for comparing critical dates when considering the peculiarities of the data at hand. Finally, the application of the presented definitions and methods was illustrated by the study of a real dataset obtained from five silver firs and five Scots pines grown under the same conditions and sampled weekly during the 2006 vegetation period. The results of this application showed that wood formation in pines started earlier, finished later and lasted longer than in firs, as documented by previous studies. We believe that the development of such objective definitions accompanied by ready-to-use tools for data processing, analysis and visualisation will reinforce the discipline by contributing efficiently to standardise concepts and methodologies. [Copyright &y& Elsevier] more...
- Published
- 2011
- Full Text
- View/download PDF
46. Long-term dynamics of a mixed conifer stand in Slovenia managed with a farmer selection system.
- Author
-
Diaci, Jurij and Firm, Dejan
- Subjects
FOREST dynamics ,FOREST management ,FOREST regeneration ,SELECTION (Plant breeding) ,CONIFERS ,NORWAY spruce ,SILVER fir ,PLANT species ,AGRICULTURAL climatology - Abstract
Abstract: The single-tree selection system is an important option for management of Norway spruce (Picea abies (L.) Karst.) and silver fir (Abies alba Mill.) forests because it provides continuous cover, requires low investments for tending, and promotes natural regeneration as well as high stand resistance and elasticity. It is often regarded as a very conservative system that usually results in only minor spatiotemporal changes in forest structure and composition. We studied management history, structural changes, regeneration dynamics, and light climate of a traditional single-tree farmer selection silver fir-Norway spruce forest (site typology Bazzanio-Abietetum). Stand structure was analyzed on five 0.25ha permanent plots in 1994, 2001, and 2008. Regeneration density and height growth, forest floor vegetation, and light climate were also assessed on 1.5×1.5m regeneration subplots in 2001 and 2008. Tree cores extracted from dominant trees from both species in two plots were used for reconstructing stand history and age structure of the canopy layer. We documented the forest response to three types of selection management regimes: excessive, normal, and conservative. Excessive management with harvest intensity significantly above the increment was documented until the late 1950s, including two peaks of heavy fellings (diameter limit cut) in the 1880s and 1930s, which favoured establishment of Norway spruce and released regeneration. The period that followed was characterized by normal selection management, but was nevertheless marked by a decline of silver fir as a result of air pollution and several droughts. This led to sanitary fellings that were carried out from the late 1970s to the early 1990s. In the last two decades conservative management followed, which led to suppression and decline of regeneration, especially of Norway spruce, and loss of selection structure. Although we recorded lower regeneration potential of silver fir compared with Norway spruce within the seedling category, silver fir outcompeted Norway spruce within the small-sized tree category (1cm
more... - Published
- 2011
- Full Text
- View/download PDF
47. Synergistic effects of past historical logging and drought on the decline of Pyrenean silver fir forests.
- Author
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Camarero, Jesús Julio, Bigler, Christof, Linares, Juan Carlos, and Gil-Pelegrín, Eustaquio
- Subjects
SILVER fir ,LOGGING ,FOREST declines ,ECOLOGY ,CLIMATE change ,VEGETATION & climate ,TREE growth ,EFFECT of drought on plants ,EFFECT of stress on plants - Abstract
Abstract: The causal factors and effects of forest declines are not well understood in temperate conifer forests. Most studies have focused on climatic and environmental stressors and have obviated the potential role of historical forest management as a predisposing factor of decline. Here, we assess if the recent silver fir (Abies alba) decline observed in the Spanish Pyrenees was predisposed by historical logging and incited by warming-induced drought stress. We analysed a dataset of environmental, structural, and historical variables at the tree and stand level including 32 sites with contrasting degrees of defoliation distributed over 5600km
2 . We followed a dendroecological approach to reconstruct historical logging and to infer the effects of warming-induced drought stress on growth. The silver fir decline was more severe and widespread in western low-elevation mixed forests dominated by trees of small size and slow growth. These sites were subject to higher water deficits than eastern sites, where late-summer rainfall as the key climatic variable controlling silver fir growth was higher. Declining sites showed more frequent growth releases induced by historical logging than non-declining sites. Historical logging and warming-induced drought acted as long-term predisposing and short-term inciting factors of silver fir decline in the Pyrenees, respectively. We suggest that biomass increases caused by past intense logging affected the vulnerability of silver fir against late-summer water deficit. Future research in declining temperate conifer forests should consider the interacting role of predisposing historical management and inducing climatic stressors such as droughts. [Copyright &y& Elsevier] more...- Published
- 2011
- Full Text
- View/download PDF
48. Do changes in spatial distribution, structure and abundance of silver fir (Abies alba Mill.) indicate its decline?
- Author
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Ficko, Andrej, Poljanec, Ales, and Boncina, Andrej
- Subjects
DISTRIBUTION (Probability theory) ,SILVER fir ,INFORMATION theory ,FORESTS & forestry ,ARTIFICIAL neural networks ,NONPARAMETRIC statistics ,VEGETATION & climate - Abstract
Abstract: Silver fir decline was investigated based on changes in spatial distribution of fir, fir abundance in forest stands, dbh (age) structure of fir, and abundance of fir regeneration. The authors used a large-scale approach to study the dynamics of silver fir over nearly 40 years. Based on Silva-SI, a spatial information system, the majority of total forest area in Slovenia was analysed for changes in the distribution of silver fir in the period 1970–2008 using artificial neural networks (ANNs), with respect to site, stand, and forest management variables. Additionally, changes in abundance of silver fir (hereafter fir) in the same period were analysed with a general linear model, while changes in the dbh structure of fir and fir regeneration were analysed with non-parametric tests. Most selected indicators confirmed the hypothesis of fir decline in the period 1970–2008, as evidenced by a reduction in the area of forests with a share of fir in the total growing stock >25% (from 18.9% to 9.5% of total area), a reduction in the share of fir in the growing stock of forest stands (from 17.5% to 7.5%), ageing of the fir population, and a disproportionate share of fir saplings in the total saplings relative to fir''s share in the growing stock of forest stands. A 1.5% increase in fir distribution area in the observed period contradicts the decline hypothesis. ANNs showed that the spatiotemporal dynamics of fir was most affected by four variables: forest type, share of fir in the potential natural vegetation, mean annual precipitation, and mean annual temperature. The latter two, together with the growing stock at the start of study period, the degree of connectivity between fir stands, and bedrock type, were significant predictors of decline of fir abundance in forest stands. Significant differences in spatiotemporal dynamics and changes in fir abundance were found between forest types representing a complex of site conditions and past forest management. A further decline of abundance of fir on a large spatial scale in the next decades is expected. Conservation of fir in forest stands will depend mainly on the successful regeneration of fir and sufficient recruitment. [Copyright &y& Elsevier] more...
- Published
- 2011
- Full Text
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49. Late-Glacial and Holocene vegetation history of Pavullo nel Frignano (Northern Apennines, Italy)
- Author
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Vescovi, Elisa, Kaltenrieder, Petra, and Tinner, Willy
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HOLOCENE stratigraphic geology , *GLACIAL Epoch , *HOLOCENE palynology , *CHRONOLOGY , *RADIOCARBON dating , *VEGETATION & climate - Abstract
Abstract: Until recently, pollen-stratigraphic research in the Northern Apennines (Northern Italy) provided only generalized pollen diagrams that lacked reliable chronologies, and few records provided complete and detailed postglacial sequences equipped with radiocarbon dates. We present a new Late-Glacial and Holocene pollen sequence from Pavullo nel Frignano in the Emilian Apennines (Modena, Italy). The chronology relies on AMS-radiocarbon-dated samples of terrestrial plant origin. Our pollen record suggests that open Late-Glacial Pinus and Juniperus dominated woodlands were established at the site before 14,000cal. BP. Thermophilous trees such as Quercus, Ulmus, and Tilia as well as Abies alba expanded already during the Late-Glacial (ca. 14,000–13,000cal. BP), but did not form closed forests. After climate cooling of the Younger Dryas A. alba re-expanded at the onset of the Holocene at ca. 11,500cal. BP and remained the dominant species until at ca. 6000–5500cal. BP. The decline of A. alba was associated with a marked opening of forests, and the expansion of deciduous trees such as Fagus and Quercus. Vegetational composition did not change substantially during the past 5000years, and cultivated tree taxa such as Juglans and Castanea played only a transient or marginal role. Although the vegetation history of Pavullo is consistent with previous investigations in the study area, comparison is hampered by the absence of other records from the same vegetational (colline) belt. Our pollen-inferred human-impact history is in agreement with archaeological evidence. In addition, our results suggest a rather close link between vegetational change in the Northern Apennines and the Southern Alps. Common features between these two climatically-similar regions are the initial expansion of thermophilous trees and Abies alba at ca. 13,000cal. BP, the mid-Holocene collapse of A. alba (probably as a consequence of human disturbance) as well as the subsequent expansions of Quercus and Fagus. [Copyright &y& Elsevier] more...
- Published
- 2010
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50. Landscape dynamics of Abies and Fagus in the southern Pyrenees during the last 2200 years as a result of anthropogenic impacts
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Pèlachs, Albert, Pérez-Obiol, Ramon, Ninyerola, Miquel, and Nadal, Jordi
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PALYNOLOGY , *SILVER fir , *LANDSCAPES , *POLLEN , *BEECH , *GEOLOGICAL time scales , *EFFECT of human beings on climate change - Abstract
Abstract: The vegetation landscape dynamic is derived from the relationship established between a society and its environment through time, and the current landscape has never been seen in the previous 2000 years. The pollen study of a core from a peat bog in València d''Àneu (Lleida, NE Iberian Peninsula) shows a maximum extension of Abies alba forest about 2200–2000 cal. yr BP. Later on, there is evidence of selective actions affecting this forest and the expansion of Fagus sylvatica at about 2000–1300 cal. yr BP. Beginning in 1300 cal. yr BP, deforestation due to agricultural activities expanded and beech definitively disappeared at 800 cal. yr BP. Natural and human disturbances affected the dynamics of A. alba and F. sylvatica from their first appearance to the current vegetation landscape. Human impact on the silver fir forest, which reached its maximum in the last millennium, favoured the beech population. Pollen data from this region support our finding that human impact, not climate, is the most important influential factor in the development of beech forests. [Copyright &y& Elsevier] more...
- Published
- 2009
- Full Text
- View/download PDF
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