Search

European forests are threatened by increasing numbers of invasive pests and pathogens. Over the past century, Lecanosticta acicola, a foliar pathogen predominantly of Pinus spp., has expanded its range globally, and is increasing in impact. Lecanosticta acicola causes brown spot needle blight, resulting in premature defoliation, reduced growth, and mortality in some hosts. Originating from southern regions of North American, it devastated forests in the USA's southern states in the early twentieth century, and in 1942 was discovered in Spain. Derived from Euphresco project ‘Brownspotrisk,’ this study aimed to establish the current distribution of Lecanosticta species, and assess the risks of L. acicola to European forests. Pathogen reports from the literature, and new/ unpublished survey data were combined into an open-access geo-database (http://www.portalofforestpathology.com), and used to visualise the pathogen's range, infer its climatic tolerance, and update its host range. Lecanosticta species have now been recorded in 44 countries, mostly in the northern hemisphere. The type species, L. acicola, has increased its range in recent years, and is present in 24 out of the 26 European countries where data were available. Other species of Lecanosticta are largely restricted to Mexico and Central America, and recently Colombia. The geo-database records demonstrate that L. acicola tolerates a wide range of climates across the northern hemisphere, and indicate its potential to colonise Pinus spp. forests across large swathes of the Europe. Preliminary analyses suggest L. acicola could affect 62% of global Pinus species area by the end of this century, under climate change predictions. Although its host range appears slightly narrower than the similar Dothistroma species, Lecanosticta species were recorded on 70 host taxa, mostly Pinus spp., but including, Cedrus and Picea spp. Twenty-three, including species of critical ecological, environmental and economic significance in Europe, are highly susceptible to L. acicola, suffering heavy defoliation and sometimes mortality. Variation in apparent susceptibility between reports could reflect variation between regions in the hosts’ genetic make-up, but could also reflect the significant variation in L. acicola populations and lineages found across Europe. This study served to highlight significant gaps in our understanding of the pathogen's behaviour. Lecanosticta acicola has recently been downgraded from an A1 quarantine pest to a regulated non quarantine pathogen, and is now widely distributed across Europe. With a need to consider disease management, this study also explored global BSNB strategies, and used Case Studies to summarise the tactics employed to date in Europe.

Forest ecosystems provide a wide variety of ecosystem services to society. In harsh mountain environments, the regulating services of forests are of particular importance. Managing mountain forests for regulating services is a cost- and labor intensive endeavor. Yet, also unmanaged forests regulate the environment. In the context of evidence-based decision making it is thus important to scrutinize if current management recommendations improve the supply of regulating ecosystem services over unmanaged development trajectories. A further issue complicating decision making in the context of regulating ecosystem services is their high sensitivity to climate change. Climate-mediated increases in natural disturbances, for instance, could strongly reduce the supply of regulating services from forests in the future. Given the profound environmental changes expected for the coming decades it remains unclear whether forest management will still be able to significantly control the future trajectories of mountain forest development, or whether the management effect will be superseded by a much stronger climate and disturbance effect. Here, our objectives were (i) to quantify the future regulating service supply from a 6456 ha landscape in the Stubai valley in Tyrol, Austria, and (ii) to assess the relative importance of management, climate, and natural disturbances on the future supply of regulating ecosystem services. We focused our analysis on climate regulation, water regulation, and erosion regulation, and used the landscape simulation model iLand to quantify their development under different climate scenarios and management strategies. Our results show that unmanaged forests are efficient in providing regulating ecosystem services. Both climate regulation and erosion regulation were higher in unmanaged systems compared to managed systems, while water regulation was slightly enhanced by management. Overall, direct effects of climate change had a stronger influence on the future supply of regulating services than management and natural disturbances. The ability of management to control ecosystem service supply decreased sharply with the severity of future climate change. This finding highlights that forest management could be severely stymied in the future if climate change continues to proceed at its current rate. An improved quantitative understanding of the drivers of future ecosystem service supply is needed to more effectively combine targeted management efforts and natural ecosystem dynamics towards sustaining the benefits society derives from forests in a rapidly changing world.

Urban forests are threatened by land cover change and invasive species but little is known about how they are changing over time. Furthermore, although management is sometimes used to maintain native communities, we have little information about the long-term outcomes of forest management actions. In this study, we examined current status and long-term changes in 35 urban forest plots in DuPage County, Illinois (USA). From 1979 to 2014, in five-year intervals, presence/absence of all woody species was recorded in the plots. Environmental conditions in and surrounding the plots were measured in the field or with GIS. With these data, we analyzed trends and changes in the community, looked for evidence of biotic homogenization, and examined drivers of non-native species. We found a significant change in community composition over time but no evidence of biotic homogenization in either managed or unmanaged plots. There was a significant increase in non-native species richness over time but no change in richness of other species groups. Vegetation management such as fire prescription and clearing seemed to somewhat decrease the number of non-native species, but did not increase the number of more desirable species. Distance to agriculture and deer control frequency determined the variation in both non-native species abundance and richness. Overall, we conclude that the management activities were able to slow down the spread of some undesirable species but did not prevent their increase over time. More consistent management, as well as collaboration with stakeholders outside the forest preserves, is likely needed to maintain native communities.

A long-distance edge effect influences structure of species-rich plant communities in temperate forest fragments surrounded by an agricultural landscape in Central Europe. Though the edge effect may be an aggregate of many environmental conditions, the thermal gradient from the forest edge to the forest interior deserves particular attention due to increasing ambient air temperature over the past decades. With regard to ongoing climate change, any reliable information about magnitude and distance of thermal gradients in these forest fragments has become of great importance. Therefore, we carried out seasonal measurements of forest air and soil temperature at a total 40 sites in 14 forest fragments in central Bohemia with areas ranging between 0.3 and 255 ha. In addition, we assessed spatial and vertical air temperature variability at two sites, on both south and north facing slopes. We found that differences in daily mean air temperature in these forest fragments is significantly modified by slope aspect (and/or slope inclination) and distance to the forest edge. A negative monotonic edge-related thermal gradient was apparent up to 100 m towards the forest interior with differences in daily mean air temperatures of about 0.3 °C. The magnitude of this edge thermal gradient is comparable to the effect of slope aspect. In addition to mean air temperature, maximum and minimum daily temperatures as well as mean soil temperature inside forest fragments also showed impacts caused by the edge effect and other environmental conditions (e.g. forest structure, elevation). The edge-related area closer than 100 m from the forest edge represents the majority (78%) of forested land in the study area as well as a considerable part of temperate forests in Central Europe (40%), including less fragmented mountain forests. Hence, the edge alteration of forest microclimate should be taken into serious consideration when planning adaptation measures against the consequences of climate change in Central Europe. The edge influence could be partially mitigated by preventing further forest fragmentation and the adoption of timber harvesting methods that avoid creation of clearings, such as single-tree selection. Even if such forest management measures are implemented in the study area, spatial patterns and gradients of environmental heterogeneity may be gradually reduced in the forest fragments as a result of further exposure to the combined effects of climate change and edge influence.

Forest management, including setting aside non-intervention forests, is currently debated as a measure to efficiently mitigate climate change. Temperate, old-growth forests are rare and the long-term effect of setting aside forest reserves, e.g. for habitat conservation, on forest carbon stocks and carbon sequestration remains uncertain. In this study, we assessed the five principal forest carbon pools in a semi-natural, temperate forest in Denmark and evaluated the changes in biomass and dead wood carbon stocks over 20 years. We also benchmarked the current carbon stocks against those in managed beech-dominated forests in the same region. In the most recent inventory, carbon stocks totalled 395 Mg ha−1 of which 47% was in above-ground live biomass, 11% in below-ground biomass, 9% in dead wood, 2% in the forest floor, and 31% in the top 75 cm of the mineral soil. Compared to similar, but managed forests in the same region, carbon stocks in above- and below-ground biomass as well as in dead wood were notably larger. However, analyses of above- and below-ground biomass and dead wood carbon stocks showed remarkable stability during the past 20 years, despite major disturbances in terms of windthrows and various pathogens. Despite the overall stability of carbon stocks we observed some significant spatio-temporal changes. Notably, the observed dynamics illustrate a general retreat of Q. robur and increasing dominance of F. sylvatica under a small-scale disturbance regime. The forest floor and soil carbon stocks averaged 131 ± 4 Mg ha−1 and were very similar to those of managed beech-dominated forests, suggesting little potential for soil carbon sequestration from setting forests aside as unmanaged. Our study has implications for selection of adequate forest management strategies to efficiently mitigate climate change as it confirms the large and persistent carbon stocks in old-growth forests compared to managed forests, but offers no evidence of continued carbon sequestration in old-growth forests.

Aboveground biomass (AGB) plays an important role in carbon cycle. Assessment of AGB presents a challenge in forest management. Reported studies have explored the potential of synthetic aperture radar (SAR) and multispectral instrument (MSI) data using random forest (RF) approach in AGB mapping. However, how AGB prediction would be affected by using data from different sources based on random forest kriging (RFK), which integrates RF and estimates residuals by ordinary kriging (OK), deserves further exploration. This study reported an assessment of multisensor data from Advanced Land Observing Satellite 2 (ALOS-2) L band and Sentinel-1C band SAR, Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM), and Sentinel-2 MSI for forest AGB mapping using RFK. The effectiveness of 97 predictor variables derived from multisensor data was evaluated for AGB prediction in a temperate continental forest site in northeastern China. The assessment was tested by field-measured data from 1167 forest plots in 2017. The results showed that the RFK model achieved the accuracy with mean error, mean absolute error, root mean square error and correlation coefficient in –0.11, 19.37, 28.15 Mg ha−1 and 0.98, respectively. The study revealed that backscatters and texture features from ALOS-2 L band SAR and vegetation indices from Sentinel-2 MSI were primary contributors for explaining the observed variability of AGB. Topographic indices from SRTM DEM were more important than C band SAR backscatters and texture features. The accuracy improvement on forest AGB mapping by RFK over RF was more distinguished in models using a single sensor than those using multisensors.

The impacts of forest-related land use and management on soil organic carbon (SOC) stocks have been investigated through years of primary research and review articles. This attention is justified given the importance of land use and management to greenhouse gas mitigation, soil and forest productivity, and other ecosystem services. However, there is a gap of scale and scope between site-level studies that control for sources of variation, producing high-confidence results for limited locations, and the broad reviews that offer more general conclusions. The present analysis is intended to fill that gap. Here, we focus on six ecoregions of the eastern United States, and integrate meta-analysis of published literature with synthesis of geo-referenced soil observations to: (1) test whether common land use and management practices quantitatively impact SOC; (2) identify key sources of variation in these effects; (3) assess how sources of variation translate to decisions about land use and management at ecoregional to landscape levels. Results corroborate general trends, such as O horizon SOC losses with harvesting and fire and SOC gains during reforestation, but provide greater detail about the influence of specific practices and site-level controls on SOC stocks and change in the study region. Results also show that: (1) harvest impacts depend upon landform and soil taxonomy; (2) harvesting forests that are recovering on previously cultivated lands decreases SOC; (3) tree biomass and SOC recovery increase concurrently during reforestation; (4) specific harvest, site preparation, and fire management practices affect the magnitude and variability of changes in SOC. Perhaps more importantly, ecoregional classification and soil taxonomy provide spatial frameworks for placing quantitative estimates of SOC stocks and changes in the geographic context of the study region, providing greater detail and specificity for individuals and institutions concerned with SOC management at more localized levels.

Plantations of non-native tree species cover over 50,000 ha in Zambia of which Pinus kesiya accounts for 36% of the main tree species. In order to quantify the growing stock of P. kesiya, updated and reliable height-diameter (h-d) models are required. Therefore, the aim of this study was to develop appropriate h-d models for P. kesiya that are consistent with current forest management practices in the country. Using 7691 measured pairs of diameter and height of P. kesiya from four different forest sites, the following questions were investigated; (i) do frequently used h-d models accurately estimate height of P. kesiya in Zambia?; and (ii) what h-d models account for site and rotation in the country? Predicted h from the frequently used h-d models (Naslund, Modified Logistic and Hossfeld) was significantly lower than the measured h (p ≤ 0.001). This suggests that frequently used h-d models for pine significantly underestimates tree height of P. kesiya in Zambia. The deviations associated with these models varied but generally increased with tree diameter. In this regard, country level h-d model developed using the Weibull function, and tested in this study proved to be more accurate than the frequently used models in predicting tree height of P. kesiya in Zambia. Furthermore, site and rotation were found to influence the overall accuracy and reliability of the country level model (p ≤ 0.001) suggesting the need to refine this model in order to account for site and/or rotation effect. Therefore, the h-d models that are specific to site and in some instances to rotation were derived and increased the accuracy and precision in estimating tree height of P. kesiya in the country. These locally developed h-d models are recommended for future forest plantation inventories, management planning and as a basis for modeling h-d relationships for other Pinus species in the country.

Knowledge regarding tree species dynamics is essential to understand forest responses to the environment, and to evaluate management options in adapting forest ecosystems to future climates. As maintaining tree species diversity and promoting structural stand heterogeneity are among the strategic elements in adapting forest management to climate change, the monitoring tree diversity is an ongoing challenge. Large-scale forest inventories have been proposed as a suitable basis for forest diversity analysis on large spatial and temporal scales. We used Swiss forest inventory data (NFI) to analyse temporal changes in tree species richness on small plots from 1983 to 2006. For two size groups of trees (‘small’ trees with dbh from 12 to 35 cm from plots with 200 m2 area, and ‘large’ trees with dbh ≥ 36 cm from plots with 500 m2 area), we identified the number and the tree species appearing (‘gains’) or disappearing (‘losses’) from each plot during the study period, and related these changes to site, stand and management characteristics. We found that species richness change was size-dependent and varied largely due to regional differences in the past land-use history of the Swiss forests. ‘Gains’ of ‘small’ trees were higher in stands with diverse vertical structure, with less competitive pressure as well as in warm environments, whereas ‘gains’ of ‘large’ trees were mostly related to climate and were highest in warm and moderately moist habitats. ‘Losses’ in both tree-size groups were mainly promoted by management. Our analysis suggests high vulnerability of Picea abies and high competitiveness of Fagus sylvatica, and underlines the potential of Abies alba in forming future Swiss forests. Despite of the silvicultural paradigm to create more species rich forests, most silvicultural interventions decreased small-scale species richness. This calls for further studies on the effect of management on tree species diversity.

One long-standing, unresolved issue in forest management is how to achieve high levels of biodiversity conservation and commercial forestry for timber production. Retaining fallen logs on the forest floor is effective in preserving the habitats essential for many wood-dwelling organisms. However, the contributions of fallen logs toward the plant species diversity of forest understories are less clear, even though the importance of fallen logs on the emergence and survival of coniferous seedlings and saplings is well known, especially in boreal forests. This study aimed to clarify the roles of fallen logs in the maintenance of species diversity of understory vascular plants in forests. We investigated species richness and the composition of vascular plants on 319 fallen logs and in 128 forest-floor quadrats (2 × 2 m) in a 4-ha plot in a mixed coniferous and broad-leaved forest in Hokkaido, northern Japan. We also measured canopy openness in summer, surface area, wood resistance, and moss cover of fallen logs, and soil thickness in forest-floor quadrats. Additive partitioning and permutational multivariate analysis of variance (PERMANOVA) were used to examine differences in composition between quadrats and fallen logs. Generalized linear model (GLM) and canonical correspondence analysis (CCA) were also applied to test the determinants of species richness and composition in quadrats and fallen logs. In total, 83 vascular plant species were identified. For woody and herbaceous plants, several species occurred predominantly on fallen logs in comparison with quadrats. Species richness of woody plants on fallen logs was positively affected by surface area and moss cover, and negatively by wood resistance; although in quadrats it was not significantly associated with any environmental factors. Herbaceous species richness on fallen logs was also negatively influenced by wood resistance. In contrast, herbaceous species richness in quadrats was positively associated with canopy openness. These results suggest that fallen logs promote plant species diversity, including herbaceous plants, by creating habitat conditions favored in forest understory environments. This study implies that leaving fallen logs on the forest floor at logging sites contributes toward plant diversity conservation.

Coastal Alaska forests consist of 2.6 million hectares of productive timberland and constitute the largest terrestrial carbon reservoir in the state. It has become increasingly urgent to understand potential climate-induced changes in forest structural and species composition in this region. Based on in situ data from 544 permanent sample plots (PSPs) for calibration and 244 PSPs for validation, we developed a climate-sensitive density-dependent, species-, and size-specific matrix model (CSMatrix-AK), to predict fine-scale dynamics of coastal Alaska forests from the present to Year 2100 under three climate scenarios – Representative Concentration Pathway (RCP) 4.5, RCP6.0, and RCP8.5. With post-sample validation, we showed that the CSMatrix-AK model was more accurate than other existing models for the region. Under low-intensity and high-frequency stochastic shocks which represented natural disturbances typical for the region, we projected a gradual decline of Sitka spruce, a major commercial species in the region, and a significantly lower level of total stand basal area under all three climate scenarios. The results suggest that timber industry, landowners and managers, policymakers, and local communities will need to prepare for substantial impacts of climate change on Coastal Alaska forests and the regional forestry sector. Our CSMatrix-AK model provides a useful tool to better inform the stakeholders of such changes and lays the foundation for adaptive forest management to sustain forests and associated ecosystem services in the region.

Norway spruce (Picea abies), European beech (Fagus sylvatica), silver fir (Abies alba) and Scots pine (Pinus sylvestris) typically co-occur in European forests, but show contrasting response to climate and environmental change. Sustainable forest management therefore depends on species- and regional-specific information. Here, we use tree-ring width measurements of 334 beech, 280 fir, 144 spruce and 63 pine trees from 75 inventory plots in Slovakia to assess the predominant factors that control radial stem growth of Europe’s economically most important forest species. All four species exhibit significant shifts in stem growth over the past 100 years. Ring width patterns were, however, not significantly affected by tree species diversity and site elevation. The resistance, resilience and recovery of all species to the extreme summer droughts between 1950 and 2003 suggest that spruce is the species most unsuitable for the predicted warmer and drier future. Silver fir may benefit from warmer conditions, although we cannot conclude that it will not suffer from predicted increased frequency of climate extremes. Forest management in this locality should aim to avoid significant loss of forest cover by replacing Norway spruce monocultures with mixed stands of silver fir and European beech.

Intensively managed forests are expected to play an increasingly important role in meeting future global demand for wood products. To meet this challenge, a key focus will be on lifting yields from these forests along with economic returns. In this study, we used data from a long-term series of trials that were established in radiata pine (Pinus radiata D. Don) to examine the effect that stand density, deployment of genetically-improved seedlots, and site have on economic returns. This dataset comprised end-of-rotation assessments of eight installations of a trial series in New Zealand that spanned a wide range of site productivity. Each installation typically contained four seedlots with differing levels of genetic improvement growing at three levels of stand density. Mixed effects models were used to examine the effects of stand density, site, seedlot genetic rating, and their interactions on Total Value (NZ$ ha−1) and Relative Value (NZ$ m−3). There was a strong positive relationship between stand density and Total Value, but there was generally no significant relationship between stand density and Relative Value. Of the variation in Total Value not explained by the fixed effect of stand density, approximately 60% was due to differences among trial installations (i.e. site) and 5–7% was due to seedlot genetic worth. There were significant first order interactions between seedlot and site, and between site and stand density. Seedlot genetic worth was able to explain a higher proportion of the variation in Relative Value (between 10 and 18% depending on the genetic trait under consideration). The genetic worth of a seedlot in terms of stem straightness rating was able to explain the greatest proportion of variation in Relative Value. These results highlight the importance of the choice of location and stand density management have on the economic returns from intensively-managed forests. While seedlot genetic rating has a smaller effect on economic returns, improvements in traits such as stem straightness and branch characteristics also make an important contribution. As silvicultural practices move towards higher stand densities, and the next generation of genetically improved trees are deployed, a more precise understanding of the interactions of site, silviculture and genetics will be needed. New ways of testing and modelling these interactions will be required but will ensure the delivery of a more informed approach to forest management.

Wind is a natural disturbance factor in boreal and temperate forests having large ecological and economic consequences. We investigated recovery processes in forests severely damaged by windthrow, by conducting a systematic quantitative literature review of 34 case studies. We addressed three questions on forest ecosystem recovery: (1) Which forest regeneration processes dominate forest recovery after windthrow? (2) Which structures and processes enhance or impede forest recovery after windthrow? (3) Does salvage logging after windthrow influence forest recovery? Our analyses showed that the main focus of the reviewed studies was on post storm seedling regeneration and survival. Advanced regeneration from suppressed seedlings or saplings also played an important role in the studies, especially for shade tolerant species and in the boreal biome. Pits and mounds and coarse woody debris played an important role for the establishment of Picea sp., especially in the studies from the boreal biome, whereas in the temperate biome game interference and competition from ground vegetation seemed to be the most important influencing processes. Salvage logging mostly acted as a subsequent disturbance after the windthrow, pushing the forest ecosystem towards an earlier successional stage, hereby impeding recovery. In none of the studies however, did the windthrow nor the consequent salvaging halt recovery completely, confirming the resilience of forests as the dominant vegetation type in these biomes. Based on our results forest management implications are discussed.

Wildlife conservation in multi-use landscapes requires identifying and conserving critical resources that may otherwise be destroyed or degraded by human activity. Summer day-roost sites are critical resources for bats, so conserving roost sites is thus a focus of many bat conservation plans. Studies quantifying day-roost characteristics typically focus on female bats due to their relative importance for reproduction, but large areas of species’ ranges can be occupied predominantly by male bats due to sexual segregation. We used VHF telemetry to identify and characterize summer day-roost selection by male northern long-eared bats (Myotis septentrionalis) in a ponderosa pine (Pinus ponderosa) forest in South Dakota, USA. We tracked 18 bats to 43 tree roosts and used an information theoretic approach to determine the relative importance of tree- and plot-level characteristics on roost site selection. Bats selected roost trees that were larger in diameter, more decayed, and under denser canopy than other trees available on the landscape. Much like studies of female northern long-eared bats have shown, protecting large-diameter snags within intact forest is important for the conservation of male northern longeared bats. Unlike female-specific studies, however, many roosts in our study (39.5%) were located in short (≤ 3 m) snags. Protecting short snags may be a low-risk, high-reward strategy for conservation of resources important to male northern long-eared bats. Other tree-roosting bat species in fire-prone forests are likely to benefit from forest management practices that promote these tree characteristics, particularly in high-elevation areas where populations largely consist of males.

Prescribed burning has become more common for the management of eastern forests in North America, so understanding if and how foraging bats respond to structural changes generated by fire is of increasing importance. Our objective was to investigate the effects of post-fire landscape conditions on the occurrence of foraging bats in mixed forests of the Cumberland Plateau physiographic region. We deployed Anabat II bat detectors in 164 paired burned and unburned forest sites for ≥2 nights from mid-May through August 2014 and 2015 to monitor bat foraging and commuting habitat use. We conducted vegetation surveys to quantify site-specific structural characteristics, which indicated that measures of structure were significantly lower in burned sites than unburned sites. We used Program Presence to test a priori hypotheses of species-specific probability of detection and site occupancy related to weather, burn history (i.e., site burned within the past 10 years or unburned), and site and landscape characteristics. Bats were detected at 94% of burned sites and 83% of unburned sites. Probability of detection was affected by weather conditions, vegetative structure, and burn history for most species. Occupancy for all species/species groups examined was positively associated with burning and generally associated with lower vegetative structure. Although burn severity did not affect most species groups, occupancy of Myotis species and tri-colored bats (Perimyotis subflavus) was lower in sites that received moderate severity burns than in sites that received low severity burns. Therefore, while prescribed fire may provide vegetative structure conducive to efficient foraging for all bats of the Cumberland Plateau, our results demonstrate that retaining some unburned forests while creating mosaics of lower and higher severity burns across the landscape will result in favorable foraging conditions for all resident bat species.

Natural Mediterranean forest ecosystems, especially pine plantations, are severely affected by human disturbances and global change consequences. To achieve an appropriate and complete management of these areas, key species beyond dominant ones that would support vulnerable ecosystem functions should be considered. Dianthus inoxianus Gallego is a rare and endemic species with unique traits that occurs in southwestern Iberian pine forests. Thus, the development of an efficient translocation protocol disentangling the factors that affect the establishment of this species, its physiological status and long-term survival is crucial to the future integrated forest management. In this study, we aimed to assess several influential treatments and their cost trade-offs by monitoring survival and stomatal conductance (gs) of D. inoxianus transplants for a short period. We performed an experimental translocation of individuals from exploitation areas to a fenced reserve site, subjecting them to the interaction of three treatments: transplant time (January or March), transplant source (in situ direct translocation or ex situ rooted cuttings) and water supply (constant drip irrigation or no irrigation). Benign environmental conditions (winter) during the establishment phase and additional irrigation until the end of the dry season were revealed as key factors determining survival through the stressing periods (i.e., transplant shock and first summer). This survival pattern was characterised by two major peaks (resprouting), which correspond to gs increases after these stressing events. The source treatment also played a significant role by interacting with transplant time: direct transplants showed a higher survival in January and those from cuttings in March. However, survival results were evaluated with respect to the costs of each treatment combination: direct transplants in January without irrigation and those from cuttings in March with irrigation were identified as the best choices. Moreover, radiation and minimum temperature were the two climatic variables with the greatest effects on survival and gs. Overall, our results suggest that the success of D. inoxianus translocation is constrained by climatic conditions and characterised by its great stress tolerance to root damage, drought and high temperatures. We suggest that the inclusion of this type of species in ecosystem management strategies would provide an enhanced stability as well as long-term resilience to Mediterranean forests.

The negative biodiversity effects of timber- and biofuel-oriented forestry practices can be alleviated by leaving retention trees and logging residues following clear-cut harvests and occasionally including prescribed burns. Such measures can potentially maintain substrates especially for dead-wood-associated species during young, post-harvest successional stages. However, the availability and temporal patterns of different types of dead wood substrates after cutting are largely unknown, yet these patterns may have a major influence on fungal diversity. We sampled dead wood and the associated polypore fungi - a key wood decomposer group - in a large-scale field experiment with 24 sites, before logging and 2, 4 and 10 years after logging (clear-cut with and without retention trees) and burning. We investigated all old natural dead wood, stumps, slash and retention trees on each site, totaling 98,136 dead wood items. The data include 22,150 records of 122 polypore species collected across all sampling years. Ten years after treatments, we found no differences in the number of species between unlogged and logged or burned and unburned treatment categories, but on the treated sites, the numbers were higher than before treatments. Furthermore, the composition of species assemblages differed as the substrate types available varied between treatments. All dead wood substrate types hosted diverse polypore assemblages. The highest numbers of species were found on slash and retention trees. Furthermore, the polypore assemblages differed between dead wood types. Burning increased the number of species on stumps and red-listed species seemed to increase on burned sites. Our results show that dead wood can host diverse polypore assemblages also in managed forests after timber harvests. However, the pre-requisite for maintaining fungal diversity appears to be that – in addition to sufficient amount of substrates - also qualitative variation in dead wood substrates is maintained, including stumps and slash.

Understory vegetation biomass (UVB) is necessary for forest stability and supply of numerous forest ecosystem services (FES). However, UVB is often ignored in traditionally managed overly dense plantations. A tradeoff approach between the overstory biomass (OB) and UVB, based on the quantitative evaluation of overstory stand structure effects on UVB, was examined using 82 sample plots of larch (Larix Principis-rupprechetii) plantation in the Liupan Mountains (LPM), northwest China. Results showed that with rising tree density at given age, the single tree biomass decreased, but the OB increased. The UVB decreased significantly with rising OB. The optimal canopy density of 0.7 was suggested to balance OB and UVB. The corresponding proper tree densities calculated using fitted model were about 2600, 2000, 1600, 1250, 1000 trees/ha for the ages of 15, 20, 25, 30, 35 years, respectively. These proper tree densities lead to an increase of single tree biomass by 0.8%, 4.1%, 3.9%, 4.1%, 5.5%, an increase of UVB by 0.9%, 10.1%, 16.1%, 32.2%, 88.5%, but a decrease of OB by 2.9%, 13.26%, 12.5%, 13.3%, 18.5%, compared with the stands having the maximum tree densities of 2700, 2400, 1900, 1500 and 1300 trees/ha. The study can help to guide the multifunctional forest management and to uplift FES of degraded plantation.

The utilisation of non-timber forest products (NTFPs) is an important way to realize sustainable forest utilisation. Wild edible fungi (WEF) are frequently collected, sold, and consumed by households because of their high nutritional and economic value. Rational utilisation of WEF is imperative in balancing ecological protection and household livelihood development. Most existing studies concerning NTFPs or WEF utilisation combine collecting, selling, and reselling behaviours, but few studies focus on single behaviours, such as selling, that provide direct household income. Based on questionnaire survey data obtained from 193 households that collect WEF in nearby forests in the Wanzhou district of the Three Gorges Reservoir Area, this study employed a logistic regression model to analyse the factors determining whether households sold the WEF they had collected. Results indicated that the decision to sell WEF was influenced by the amount of WEF collected, mastery of market information, distance from residence to main roadside selling points, and household income. Education, number of women in the household, and distance from collection points to residence were not influential. Based on the findings, this study suggests that implementing changes to the WEF market and local forest management system could improve household livelihood and reduce area poverty by enabling efficient use of WEF to generate greater sales revenue.

Forests in the interior of British Columbia, Canada have seen a substantial change in age class structure caused by a mountain pine beetle outbreak that instigated high tree mortality, and consequently, large scale salvage operations. The current age class structure in affected regions implies a midterm timber supply shortage that has the potential to negatively impact the forest industry in affected timber supply areas in the near future. A spatially explicit landscape level forest model for Bulkley timber supply area (TSA), a typical TSA facing these challenges, was developed. Using landscape level planning software we modelled future timber supply as well as age class structure over a 250-year planning horizon for (a) current single entry forest management practices focusing mainly on clearcutting; and (b) alternative management scenarios using multi-entry (thinning) approaches. Alternative scenarios were designed to determine economically viable forest management alternatives while mitigating midterm timber supply shortage, and converting the forest structure in the region towards a more even age-class distribution. Implementing commercial thinnings in stands located within 300 m of existing roads showed the highest potential to successfully mitigate midterm timber supply shortage if entries were scheduled based on culmination of mean annual increment rather than on a fixed minimum harvestable volume. The use of thinnings shortened the overall duration of the midterm timber supply shortage, reaching sustainable harvest levels sooner than if conventional approaches were used, and higher overall timber volumes available for harvest. Alternative approaches to current forest management practices in BC prove to be promising and should be considered where possible.

Many tree species worldwide are suffering from slow or failed natural regeneration with dramatic consequences for biodiversity and ecosystem services. However, it is difficult to disentangle the complex effects of factors influencing regeneration processes on long-lived tree species at large scales. In this study, we use long-term data from the Swedish National Forest Inventory (1953–2015) combined with deer hunting data (1960–2015) to reveal experimentally-intractable processes impeding oak (Quercus spp.) regeneration in southern Sweden. Oak-dominated ecosystems are widespread in northern temperate regions, where oaks are foundation species with disproportionate importance for biodiversity and ecosystem functions. Our study reveals that during the last six decades, oak tree numbers and standing volume have continuously increased, while natural regeneration of oak declined steeply after the early 1980s. We connect this decline to denser and darker forests, combined with increased abundance of deer. Land use changes during the six decades, such as abandonment of traditional practices and large-scale introduction of forest management oriented towards high volume production, led to continuously denser forests and thereby reduced the oak regeneration niche. In addition, the impact of changed game management was evident. This was particularly clear from a natural experiment on Gotland, a large island free of deer until roe deer were introduced in the late 20th century, at which point oak regeneration began a steep decline. At the stand level, natural oak regeneration could be expected to mainly occur in pulses after disturbance events, followed by a period of low regeneration success as the cohort ages. However, at a landscape scale one would expect a mix of successional stages that would even out such demographic patterns. A prolonged period of low regeneration at a landscape scale will eventually lead to a large gap in the oak size distribution as was observed in this study. This could eventually hurt the many species dependent on old and large oak trees. Active management to restore the oak regeneration niche, i.e. forest habitats with more light and less browsing pressure, therefore seems essential. The latter includes developing strategies that manage both deer populations and their available food across landscapes. Our study is the first to link oak regeneration failure to long-term changes in land use and increased deer populations at a landscape scale in this region. Furthermore, our study show how historical data can clarify confounded processes impacting long-lived forest species.

Intensive forest management (fertilization, weed control) and the planting of fast-growing families of loblolly pine (Pinus taeda L.) can dramatically increase the rate of tree biomass accumulation, but it is unclear how tree genetics and management intensity interact to affect belowground processes. For 2.5 years in a 10–12-year-old plantation in north central Florida, we examined ecosystem carbon (C) accumulation, soil respiration (SR), total belowground C flux (TBCF), and litterfall in forests receiving different levels and types of fertilizer and weed control treatments that effectively reflected a contrast in ‘high’ vs. ‘operational’ management intensity. A fast-growing family was compared with a slower-growing family using single-family block plots. Applying high intensity silviculture treatments significantly (p 0.05) for either annual increment or organic horizon C. In contrast, the response of belowground C dynamics to silvicultural intensity were family specific, with the fast-growing family having significantly (p

Prescribed fires are becoming more widely used forest management tool to reduce both fuel load for fire prevention and high-severity wildfires. However, alterations to site conditions and influence on the natural regeneration of these fires in Mediterranean pine forests are still poorly known. Our study investigates how using prescribed fires before or after natural pine seed release could influence changes in germination and individuals’ early survival by altering the composition and structure of these Mediterranean habitats. We ran a seed-sowing experiment to analyse the recruitment patterns of three Mediterranean pine species (Pinus halepensis, Pinus pinaster and Pinus nigra) in three sites where prescribed fires were carried out. In each site, we sowed one representative pine species according to natural habitats. Three treatments (control: sowing without intervention; pre-fire: sowing before prescribed fires; and post-fire: sowing after prescribed fires) were established. In the sown experiment, we tested two biogeographical seed provenances (wetter and drier regions) per species to observe different capabilities of adaptation. Germination and survival of individuals were monitored during one year. We observed that the provenances from drier areas had higher germination and survival rates than those from the wetter ones. The three species seemed to undergo a negative effect in the burned plots. Within the burned area, the pre-fire seeds presented higher germination and early survival rates than post-fire. These outcomes could be useful in fire management planning as a tool to influence forest regeneration.

From a forest management stand point, it is crucial to know which ecological processes are most likely to drive changes in tree species distributions and abundance under warming climate conditions. In this study, we simulated forest dynamics in a 703,580 km2 territory that straddles the boreal and temperate broadleaved forest biomes in the province of Quebec (Canada), under a RCP 8.5 climate change scenario. The objective was to evaluate how future forest composition is sensitive to variation in four potential drivers: fire regimes, harvesting regimes, the capacity of tree species to persist under warmer climate conditions, and species capabilities for long-distance colonization. The results indicate that forest composition in 2100 is most sensitive to variation in the parameters controlling species persistence when conditions become warmer or dryer than the conditions found in their current range. Concretely, this points to avenues of research to improve the accuracy of our predictions regarding the impacts of climate change on forest composition. For instance, we should further investigate the underlying ecological (competition) or physiological (drought stresses) processes that influence tree species persistence at the receding edge of their current distributions.

To better understand natural regeneration of trees and forest dynamics it is important to gain insight into the drivers of invertebrate herbivory. In mature forests, associational resistance of trees resulting from a high diversity of neighbouring trees is common, and can have cascading effects on tree growth through resource concentration effects or through changes in top-down control. While the underlying biological processes are known to be influenced by the forest’s spatial properties, we lack insights on how resource concentration, top-down control and fragmentation jointly affect sapling performance in fragmented landscapes. We therefore experimentally quantified effects of the proportion of conspecific trees in the overstorey (resource concentration), avian top-down control (natural enemies) and distance to the forest edge on invertebrate herbivory levels and sapling growth. The assessments were made on planted saplings of Fagus sylvatica, Quercus robur and Quercus rubra in 53 experimental plots and birds were excluded by means of exclosures from a subset of these saplings. Excluding avian top-down control increased herbivory on each tree species. Increased herbivory led to decreased sapling growth in F. sylvatica and Q. rubra. On Q. robur saplings, top-down control was stronger closer to the forest edge. Furthermore, in this species, herbivory inside the exclosures increased with an increasing proportion of conspecific trees in the overstorey, while such a resource concentration effect was not observed outside the exclosures. Our results show the importance for forest management of conserving insectivorous birds and promoting a mixed overstorey, which can decrease sapling herbivory when bird abundance is low. More generally, our study provides insight into the complex, multitrophic interactions that drive sapling growth in forest stands located within fragmented landscapes.

Growth, components of growth, and biomass allocation were quantified for eight species in two commercially important genera, Pinus and Picea, grown in a 2 × 2 factorial of atmospheric CO2 and soil moisture stress. Four of the pines and three of the spruces are native to eastern North America; a fourth spruce, Norway spruce (NS: P. abies), is native to Europe but is used for reforestation in northeastern North America. Height, basal diameter (BD), and total biomass response of pines were often more than two times greater than that of spruces under elevated CO2 (eCO2). A significant species × CO2 interaction for total biomass was a result of species’ differential response to eCO2: Pinus rigida had the greatest biomass stimulation (59%), followed by P. resinosa (39%), P. strobus (26%), and P. banksiana (19%). Among spruces, Picea glauca showed the greatest response (30%), and P. mariana the least response under eCO2 (5%). Overall, soil moisture stress reduced total productivity by 12%. Most pines did have greater growth under moisture stress, and NS and BS grew well. Percent needle mass was lower under eCO2, but this was not due directly to eCO2 but to ontological changes. Controlling for size, pines had 20% greater needle biomass than spruces, while having a negative relationship to total biomass. A comparison of total biomass under eCO2 in relation to aCO2 by species showed that overall, the greater the species mass, the greater the mass gain under eCO2, and the greater the mass loss under drought conditions. In addition, our results for spruces lend strong support to the theory that late-successional species have greater growth response under eCO2 than early to mid-successional species. A diverse portfolio of tree species for artificial reforestation would help forest management adapt to the many uncertainties over future environments and markets, but our results on responses in spruces and pines to eCO2 and soil moisture stress support a shift toward increased use of pines in forest management and artificial reforestation.

Height is a key variable for forest management. However, tree height measurements are expensive and timeconsuming, requiring more effort to measure in the forest than diameter breast height measurements. Indeed, height-diameter (h-d) models are increasingly used to overcome the difficulty in measuring tree heights. Therefore, more accurate h-d models are increasingly needed. The mixed-effects modeling approach is a mainstream method to estimate h-d models. This technique was used to model the h-d relationship in the first 24 years of growth of sweet chestnut (Castanea sativa Mill.) high-forest stands for timber production. A dataset of 10,868 h-d observations and 57 plots of local-inventory data were considered individually. Simple mixed-effects models considering a grouping structure in the data (plot-level) were obtained, and generalized mixed-effects models were developed by expanding the fixed structure of simple mixed-effects models with stand-level variables. Several alternative model forms were tested in terms of accuracy, applicability and measurement effort. Different alternatives for calibrated predictions of tree height at plot level were analyzed, and considerations on the tradeoff between easy-to-use equations in the field practice and high-accuracy equations for forest inventory were tested. The selected Richards M1a generalized mixed-effects model simultaneously provides fixed and random parameters to estimate the chestnut tree height from tree diameter and stand-level variables using the same model. The analysis showed that the inclusion of dominant height and dominant diameter as predictors improved the accuracy of the Richards model. The Draudt method was one of the best approaches to improve tree-level height prediction accuracy using mixed-effects. The applied approach is quite feasible in 100–500 m2 plots. The use of these models and the suggested calibration process will significantly reduce the effort and costs of fieldwork teams to measure heights for forest management planning while ensuring high accuracy. This effort is greater the greater the forest density and, therefore, greater for young stands than for adult stands. Conception of the study, data analysis, drafting of the manuscript and critical revision: MSP, LN, CRGD. Contributed materials: MSP, LN. The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support by national funds FCT/ MCTES to CIMO (UIDB/00690/2020); AGRO Program, Project 267: Sustainable Management of Chestnut Forested Areas in High-Forest and Coppice Systems; Project PTDC/AGRCFL/68186/Mixed forests: Modeling, dynamics and geographical distribution of productivity and carbon storage in mixed forest ecosystems in Portugal; Project PDR2020-101-031671 GO_FTA: Afforestation of agricultural lands with + value, financial support of FEADER and Portuguese Government. info:eu-repo/semantics/publishedVersion

1. Forest landscape restoration (FLR) has gained momentum globally and guidance is needed to identify those species, sites and planting methods that increase restoration success. Incorporating native Non-Timber Forest Product (NTFP) species in FLR approaches provides an opportunity to simultaneously deliver ecological and economic benefits. The Brazil nut tree is one of the most valuable Amazonian NTFP species and could fulfil a cornerstone role in Amazon FLR. However, the factors defining establishment success within Brazil nut restoration activities remain unknown. 2. Here, we evaluate the effect of management practices, restoration site (pastures, agroforestry, secondary forest and canopy gaps in old growth forest) and environmental conditions on the establishment success (tree growth, survival and fruit production) of Brazil nut restoration projects implemented by smallholders in the Peruvian Amazon. We performed a field study at 25 restoration sites of 1–38 years in age, where we conducted measurements on 481 trees and interviewed 21 smallholders. We used mixed effect models to identify drivers of performance. 3. Twenty years after planting, diameter growth in secondary forests was 38%, 34%, and 24% higher than in canopy gaps, pastures, and agroforestry sites, respectively. Survival rate was similar for trees planted in pastures and secondary forests, but 15–20% higher there than trees planted in agroforestry sites, and 7–12% higher than in canopy gaps. Fruit production was 262% higher for reproductive trees in secondary forest sites compared to pastures, but production probability did not differ between restoration sites. These results show that secondary forests are the most suitable sites for planting Brazil nut trees. 4. In addition to restoration site effects, we also found significant effects of management practices. Survival rate increased with application of fire for clearing and weeding and economic investments and decreased with potentially inefficient herbivore protection. Fruit production was lower for trees planted further away from smallholders’ homes. These results show that smallholders’ management has a substantial effect on establishment success. 5. Our findings suggest a significant importance of post-planting maintenance of trees to increase success of FLR projects. Further, our study shows that evaluation of past restoration activities can guide future forest restoration in tropical landscapes., Forest Ecology and Management, 498, ISSN:0378-1127, ISSN:1872-7042

Many long-term forestry water quality studies focus on the impact of the harvesting phase of forestry operations. As a result, the water quality impacts of other activities such as forest (re)planting, thinning and fertilising are less well understood. Here we report the results from 23 years of monthly water quality monitoring from a steep headwater catchment within the Waikato region, New Zealand. Three experimental sub-catchments were planted in different proportions of Pinus radiata (PW2 = 100%, K-Pine 57%; PW3 = 36%). PW2 and PW3 were historical pastoral sites in the first rotation of plantation forestry and K-Pine was harvested and subsequently planted in a second rotation of forestry. All sites underwent two phases of stand thinning six and eight years after planting. The most significant effect of forestry was the increase in nitrate-N (NO3-N) and total nitrogen (TN) concentrations in response to both stand planting and stand thinning operations. Planting resulted in significant increases in NO3-N, TN and DRP over a four-year planting period at PW2. Significant increases in NO3-N and TN were detected over a four-year thinning period, at all three experimental sites. We propose that stream NO3-N and TN concentrations increased in response to stand planting at PW2 because of the change in physical conditions (e.g. increased stream shading, proliferation of nitrogen fixing weeds and decreased spatial extent of seepage wetlands) caused by the change in land use. Increasing nitrogen concentrations due to decreasing stream runoff could also be contributing a factor. Any decrease in NO3-N and TN concentrations in response to increased uptake by the rapidly growing P. radiata appears to have been masked by these other factors. However, the increase in NO3-N and TN concentrations in response to stand thinning at all three experimental sites suggests that NO3-N uptake by growing trees is an important process. Over the entire forestry period, median NO3-N concentrations at PW2 (first rotation site) increased by a factor four (400–1590 µg l−1). The median NO3-N during the post-thinning period was also one order of magnitude higher than those measured at K-Pine (second rotation site) during the post-thinning period. We attribute these differences to the NO3-N legacy within soil and/or groundwater of the previous sheep and beef cattle grazing land use. Long-term use of the PW2 catchment for forestry may eventually reduce NO3-N concentrations to the lower levels measured at K-Pine. Therefore, while NO3-N concentrations and loads may increase in response to the establishment of plantation forestry we envisage that these will decline if plantation forestry continues beyond the first rotation. This research highlights: (i) the complex nature of the response of stream water quality to catchment land use changes, and (ii) the value of studies that monitor the impact of land use/cover change over the long-term.

Tree species mixing has become a crucial tool in European forest management as positive interactions between species have been found to promote the provision of multiple ecosystem services, while at the same time reducing the risks associated with climate change. However, mixing effects have proven to be strongly context-dependant and some species combinations have still not been studied in detail. Here we focus on mixed forests of Scots pine and oak, which are likely to become increasingly popular for balancing wood production and other ecosystem services under climate change. Using 20-year growth data from newly established triplets in Germany and Denmark, this study investigates how mean tree and stand characteristics as well as productivity in mixed Scots pine-oak stands compare with adjacent monocultures and how stable the observed productivity relation is, considering inter-annual variations in local climate. Species mixing on average resulted in 15% higher standing volume and 14% higher volume productivity compared with the weighted mean of the adjacent monocultures. Oak profited most in mixture, showing overyielding of 19%. Overyielding on the stand and species level increased in years with higher water supply. In mixture, standing volume of Scots pine was 25% higher than in monocultures. Both species were found to modify their morphology in mixture. Oak in mixture showed a significantly higher inequality in stem volume compared with monocultures. We hypothesise that the observed overyielding of Scots pine-oak mixtures mainly results from complementary light use, where differences in shade tolerance, crown architecture and leaf phenology may be contributing factors.

Central European temperate oak woodlands are highly valued for their rich biodiversity. They are also of great economic importance and forest management aims to produce high quality timber, which demands high investments. The aim of this literature review is to identify management options for forestry and nature conservation that sustain both the ecological value of oak forests and the economic viability of oak silviculture. We addressed three main questions: (a) Oaks and close-to-nature forestry – what are the key silvicultural challenges and options?, (b) What is the particular significance of ecological continuity and which structural features are of importance for biodiversity conservation in oak forests?, (c) What are the key elements and possible strategies of forest management that sustain the ecological values in oak forests in combination with viable forestry? Light availability appeared to be a conspicuous link connecting the conservation and the silvicultural aspects of multifunctional oak forest management: Both young oak trees and multiple oak woodland specialist species are characterized by their need for increased sunlight exposure. This common denominator provides a sound basis for integrative management practices for forestry and nature conservation. The concept of retention forestry offers purposeful approaches. So the harvest of valuable timber oaks or the creation of canopy gaps for oak regeneration can be used to release the crowns and trunks of habitat oaks from shading and competition. When looking at the management of oak woodland biodiversity hotspots, the re-establishment of (modified) historical forest management techniques, which increase stand openness and create transitional habitats that provide suitable oak regeneration niches, seems to be necessary. Not only the continuity of oak woodland cover and natural site conditions, but also the uninterrupted temporal continuity and availability of wood-related structural features turned out to be of particular importance for oak woodland specialist species. We identified an urgent need for systematic forest planning approaches that secure the long-term availability of these structural features within areas or “sustainability units” that are large enough to maintain viable populations of oak woodland specialist species. In particular, conservation-oriented forestry measures should mainly be implemented in those areas, where the greatest effectiveness is to be expected. In the sustainability units, oak regeneration measures ought to take place either in close vicinity to old oak stands or directly in these stands. The choice of one of these options should be based on a careful consideration of the needs and possibilities of both silvicultural and nature conservation management.

Understanding the impacts of large-scale disturbances on forest conditions is necessary to support forest management, planning, and policy decision making. National forest inventories (NFIs) are an important information source that provide consistent data encompassing large areas, covering all ownerships, and extending through time. Here we compare how temporal aggregation approaches with NFI data affects estimates of standing dead trees as these respond to extreme disturbance events. East Texas was selected for this study owing to the occurrence of three significant disturbance events in a short span: Hurricane Rita in 2005, Hurricane Ike in 2008, and a historic drought in 2011. Wide-spread tree damage and mortality were reported after each disturbance and estimates of standing dead trees were used as the inventory variable for assessment. In the NFI of the US, the plot network is systematically divided into panels and one panel is measured each year. A measurement cycle is completed when all panels have been measured, which varies between 5 and 10 years depending on the region. Using the standard estimation approach of the US NFI, we computed population estimates using data from the full set of panels (FSP), multiple sets of panels (MSP), and single set of panels (SSP). For estimation, a single plot observation is computed from the most recent measurement of the plot that does not exceed the estimate year. Because one panel is measured per year, FSP and MSP estimates will necessarily consist of plot observations whose measurements were collected over a number of years. The SSP estimate is computed from one panel and thus all the plot observations are based on measurements collected over one year. We found that interpretations of disturbance event impacts varied depending on which sets of estimates were considered. All sets of estimates suggested a large and significant drought impact. However, differences existed among the estimates in the timing and magnitude of the impacts. The FSP estimates showed clear lag bias and smoothing of trends relative to the SSP estimates. MSP estimates were intermediate between FSP and SSP estimates. Differences in Hurricane Rita impacts were also observed between sets of estimates. Evidence of a net impact on standing dead trees following Hurricane Ike was weak among all sets of estimates. Given the potential for lag bias and smoothing, we recommend that SSP and MSP estimates be considered along with FSP estimates in assessments of large-scale disturbance impacts on forest conditions.

Despite all efforts to promote sustainable use of timber resources in tropical forests, the current management criteria still require adjustments at a species level, considering specific growth patterns and ecological features. Forest management in upland forests (terra firme) of the Brazilian Amazon region generally applies for all commercial tree species a common minimum logging diameter (MLD) of 50 cm and a felling cycle (FC) varying according to the harvest intensity between 25 and 35 years.. In this study, we define species-specific FCs and MLDs for the two commercial tree species Hymenaea courbaril L. (Fabaceae) and Handroanthus serratifolius (Vahl) S.O. Grose (Bignoniaceae) from the terra firme of the Southern Brazilian Amazon, applying growth models based on the relationships between estimated tree age, diameter, height and volume. A total of 37 transversal cross-sections (20 stem discs from Hymenaea and 17 from Handroanthus) were obtained at a height of 20–60 cm above soil level in a private forest concession close to the municipality of Novo Aripuana in the southern region of the Amazonas state. The two species are common in terra firme forests and have high wood densities of 0.76–0.96 g cm−3 (H. courbaril) and 0.85–1.08 g cm−3 (H. serratifolius). The mean age of H. courbaril and H. serratifolius, estimated by ring counting, varied from 104 to 241 years and both species had similar mean diameter increments of 3.9 ± 0.5 mm year−1 and 4.1 ± 0.6 mm year−1, respectively. Both species present similar tree growth in diameter, height and volume resulting in a FC of 24.2 years and a MLD of 64.9 cm for H. courbaril, and a FC of 26.0 years and a MLD of 69.5 cm for H. serratifolius. These results demonstrate the need to adjust the selective logging systems practiced in the Brazilian Amazon region towards a species-specific management of timber species to increase the sustainability of selective logging.

The use of tree height to estimate forest volume allows the calculation of forest biomass at large scales, and this calculation is of great importance in forest management and carbon accounting for temperate forests. Additionally, LiDAR (Light Detecting and Ranging) shows an increasing dependence on tree height in large-scale forest volume or biomass estimation and carbon accounting. However, the extent to which tree height determines forest volume remains controversial. Additionally, how the relationship between stand volume and tree height is modulated by canopy density has seldom been quantified at large scales across different forest types. This relationship may be important for improving large-scale forest volume or biomass estimations based on LiDAR technology. In this study, based on national forestry inventory data from China containing 34,130 forest plots, we examined the effect of canopy density on the relationship between tree height and stand volume across different forest types. The results showed forest height alone explained 72.9% of variation in stand volume across China and was far more powerful than canopy density (R2 = 49.7%). However, the relationship between stand volume and forest height was significantly affected by canopy density. When the effect of canopy density was included in the model, stand volume could be well predicted from forest height, with an R2 of 0.863. In closed-canopy stands, tree height could explain 91.5% of stand volume at a canopy density of 1.0. In conclusion, we provided the first national-scale model for estimating stand volume from forest height and canopy density across China with a large number of field-measured plots. The results were a robust predicted combination for forest volume, regardless of biotic and abiotic factors, in national scales across different forest types in China. Therefore, they can be utilized by LiDAR or other remote-sensing studies in the future.

In many European countries, recent policies and forest management have been striving to restore and increase forest biodiversity. One of the ways to achieve this goal is by increased planting of admixture tree species, such as birch, hornbeam or lime, after clearcutting or in older, otherwise homogenous forest stands. However, because admixture forest tree species present less economical value than trees such as pine or oak, they are object of fewer studies, and in this context their mycorrhizal relations are not fully known. Describing them would further aid the use of such trees in forest management. This study focused on the ectomycorrhizal (ECM) fungal communities of two-years-old silver birch (B. pendula L.), European hornbeam (C. betulus L.) and small-leaved lime (T. cordata Mill.) seedlings under bare-root forest nursery conditions. The ECM fungal partners of the studied trees were identified based on the molecular approach, and the uncovered community structure was analyzed in context of the local soil chemical parameters. We found that the ECM fungal communities of admixture tree species in bare-root nurseries are of high diversity, and contain a wide array of fungal species. Our study identified the highest taxa richness (23 taxa) associated with the roots of hornbeams and limes, followed closely (21 taxa) by birch. Surprisingly, ECM fungal communities of lime (family Malvaceae) were more similar to hornbeam and birch (family Betulaceae) than the two were to each other. The lime ECM fungal communities were also the least divergent across the five tested nurseries, showing little response to differences in the soil chemistry. The most abundant and frequent fungi found in the study were Tuber (average relative abundance: 18.9%) and Hebeloma (average relative abundance: 18.4%) species. Some of the fungal taxa we recorded have never before been identified under nursery conditions (e.g., Lactarius pubescens, Leccinum holopus, Pachyphloeus melanoxantha, Russula grata). Pachyphloeus melanoxantha is a rare species in Europe, and this study recorded one of its first records in Poland. Our results present not only a description of ECM associations of tested trees (providing the first ever description of young hornbeam ECM communities), but also may have practical implications both for producing planting stock of these admixture trees, and for the later replanting of those into forest stands.

Nearly 25% of world’s poor are dependent on forests, with 0.5–1 billion smallholders managing trees. This extensive human use of forests points to the need for sustainable timber management (STM) at smallholder scales. Similar to other tropical regions, households in the Amazon Estuary have harvested timber informally with minimal management for decades. This research provides a comprehensive look at the ecological and economic sustainability of forest use by local smallholders by integrating detailed plant demography, microeconomic, management and land use models at a whole watershed and community scale. In terms of conservation outcomes, resulting models show that forest management results in extensive harvests that allow for faster tree population recovery. In terms of economic outcomes, management also improves the long-term viability of the local timber industry in all scenarios considered. However, with respect to harvest regulations, given the costs of legalizing these small informal operations, legalization may indirectly lead to heavier ecological impacts as households need to harvest more to keep economic returns similar to the predominant alternative land use in the region (acai palm fruit agroforestry). Despite a fast-growing and resource-rich forest, an increasing extent of degraded forest area reduces the ecological and economic prospects for long-term management. Consequently, for this and other similar tropical forests, the viability of STM should not be evaluated as a binary and static yes or no response but instead as a moving window of opportunity that occurs when ecological, economic and policy conditions are met. Integrated model projections show that regionally-derived and ecologically-based sustainable management guidelines widen this window of opportunity by delivering the best ecological and economic outcomes under a range of scenarios considered.

Connecting forest management with the conservation of forest-associated animals requires an understanding of habitat quality, as well as identifying long-term silvicultural strategies that align with high quality habitat. It is, therefore, essential to characterize the spatio-temporal dimensions of habitat quality. Here, we leveraged multiple datasets to assess high quality habitat for female Canada lynx (Lynx canadensis), a federally threatened forest carnivore in the contiguous U.S. Our datasets included a spatially extensive sample of snowshoe hares (Lepus americanus) collected in 2013 (n = 1340 plots), an expansive time-series (i.e., 1972–2013) of forest structural classes derived from remote sensing, and a longitudinal dataset where we monitored habitat use and the reproductive success (i.e., litter of kittens present or absent) of female Canada lynx during 1999–2013 (n = 32 female lynx over 92 lynx years). Our results indicated that the probability of a female producing kittens was most associated with the connectivity of mature, multistoried forests (composed of mostly spruce-fir). However, the variation among female lynx accounted for ≈62% of the total variation explained in litter production, suggesting substantial individual-level variation. Thus, managers can contribute to increased reproductive success of female Canada lynx by facilitating the development of mature forests, but measuring that success will be difficult given the individual variation. In core areas of high quality females (i.e., produced kittens frequently), mature forest was 17% more abundant (i.e., ≈60% of the total core area), more connected, less clumpy, and exhibited 2.25-times larger patch sizes than the core areas of low quality females. At the home-range extent, patterns were less pronounced while the abundance of mature forests remained high (≈50%) for high quality females. Additionally, we demonstrated that the relative density of snowshoe hares was ≥2.8 times higher in advanced regenerating forests compared to all other structural classes, including mature forest. Advanced regenerating forests accounted for ≈18–19% of the core area and home range of high quality female lynx. Combined, our results suggest that a high quality mosaic for female Canada lynx contains ≈50–60% mature forest and ≈18–19% advanced regenerating forest. Furthermore, we used Forest Inventory and Analysis data to characterize the approximate age distribution of advanced regeneration and mature forest, which was relevant for rotation schedules of forest silviculture. Results indicated that advanced regeneration was ≈20 to 80 years old while mature forest was ≈50 to ≥200 years old. Our results provide novel insight into how forest management could increase habitat quality for female Canada lynx, and suggest that multiple silvicultural methods (e.g., intermediate treatments, regeneration harvests) could be employed to maintain a forest mosaic that enhances the ability of females to produce kittens. We concluded by providing a framework that integrates our new insights into a management context with the aim of conserving Canada lynx on multiple-use lands.

The sustainability of the polycyclic logging system in tropical forests has been increasingly questioned for a variety of reasons, and particularly in central Africa as commercial species, mostly light-demanding long-lived pioneer species, usually fail to recover a stable number of large trees after exploitation. Several factors are known to affect tropical tree demographic processes, like tree growth, survival and recruitment. Tree growth has particularly been showed to depend on ecological conditions, tree genetics, and competition with surrounding vegetation, as well as tree size or ontogeny. Yet, due to the paucity of available data, the importance of such factors is unclear and usually ignored when estimating future timber yields. To fill this gap, we chose to evaluate the variability in growth of one African long-lived pioneer and commercially very important species: Triplochiton scleroxylon K. Schum, gathering a broad dataset composed of tree ring data recorded in one site in Cameroon and periodic field inventory data recorded in seven sites across central Africa. In total, we analyzed 13,225 records of annual tree diameter increments recorded over 920 trees from seven sites in Cameroon, Republic of the Congo and Central African Republic. We evaluated (i) to what extent the average growth of trees that reach harvestable dimensions differs from population average and (ii) to what extent past perturbations influence the growth of remaining trees. We found the diameter growth of T. scleroxylon to be remarkably variable and this study provided an unprecedented quantification of the magnitude of some key growth determinants. In unlogged forests, the diameter increment of T. scleroxylon ranged between 0.40 cm year−1 in Southern Cameroon and 0.83 cm year−1 in South-Eastern Cameroon. The diameter increment was weakly related to tree size but increased twofold from unlogged to logged forests. Perturbation caused by logging stimulates growth of T. scleroxylon for at least 10–15 years. Finally, harvestable timber stock of large-sized T. scleroxylon was found to be constituted by trees that grew in average twice faster than trees of the entire extant population. As more and more inventory data become available, quantifying these effects could be replicated for other timber species and in other sites, to improve the accuracy of future timber resource estimates and improve forest management guidelines.

Determining the factors that influence the regeneration of pine in oak-pine forests is crucial for understanding natural regeneration dynamics and for planning forest management strategies. We investigated the vegetation structure and seedling dynamics of shortleaf, slash, and longleaf pine in oak-pine forest types of the southeastern United States. We used logistic regression with penalized maximum likelihood estimation because of the rarity of the regeneration from these pines. We performed canonical correlation, analysis of variance, and community structure analysis to produce multivariate relationships and statistical inferences. The classification accuracy of the logistic regression models for shortleaf, slash, and shortleaf pine were 96.0%, 96.7%, and 97.7%, respectively. The models indicated that environmental, climatic, stand, site productivity, and disturbance factors, or their combinations, had a significant influence on seedling occurrence. The probability of occurrence of seedlings of the three pine species increased with the increase in the overstory basal area from these species: one unit increase in overstory purity ratio of shortleaf, slash, and longleaf pine increased the odds of occurrence of their seedlings by approximately 51, 24, and 7 times, respectively. The probability of occurrence of shortleaf pine seedlings increased with increasing canopy openness in stands with a substantial proportion of shortleaf pine in the overstory. The increase in mean annual temperature and overstory basal area of slash pine increased the probability of occurrence of slash pine seedlings on wetter sites that had disturbance through harvesting and silvicultural treatments. The chances of occurrence of longleaf pine seedlings increased with increasing overstory basal area of longleaf pine, species diversity, and mean annual temperature in low density stands on low productive sites. The findings can help forest managers in designing and implementing silvicultural treatments to promote the natural regeneration of the three pines in oak-pine forests.

Land-use intensification has been shown to negatively affect biodiversity and ecosystem functioning. Because higher trophic levels are expected to suffer most strongly from intensification, negative consequences for ecosystem services, such as biological pest control by natural enemies, are likely. In European beech forests ambrosia beetles are common secondary pests of freshly cut wood and stored timber, but they may also infest living trees that are highly stressed. We examined whether forest management intensity, ranging from unmanaged beech forests to non-natural conifer plantations, affects the abundance, attack rate, and breeding success of ambrosia beetles across three regions of Germany. We applied pheromone trapping to estimate the abundance of ambrosia beetles and exposed experimental beech logs to measure infestation rates and breeding success. In general, we found decreasing abundance and attack probability by ambrosia beetles with increasing management intensity, which is most likely related to the availability of suitable breeding substrate. However, the abundance of the invasive species Xylosandrus germanus increased with increasing management intensity in one region, where high management intensity was represented by pine forests; the drier and warmer conditions in this forest type most likely increased population densities. Breeding success of Trypodendron domesticum increased with increasing management intensity, suggesting less effective pest control by natural antagonists, in particular by specialised parasitoids, at high management intensities. We conclude that the availability of breeding substrate, in combination with microclimate and antagonist effectiveness, shape ambrosia beetle populations in Central European forests. Forest management strategies should thus reduce the availability of breeding substrate in production forests, in particular where microclimatic conditions are favourable for beetle reproduction (i.e. warm, moist). Moreover, unmanaged forest patches should be maintained to promote parasitoid abundance and thus to mitigate negative effects of climate change, such as increasing drought stress of trees.

To estimate carbon emissions from selective logging in Central Africa, we employed the reduced-impact logging for carbon emissions reductions (RIL-C) protocol to quantify baseline carbon emissions from legal timber harvests by source (i.e., hauling, skidding, and felling). We modeled the relationships between emissions and biophysical conditions, logging practices, and forest policies and then used these models to estimate potential emission reductions from full implementation of RIL-C practices. We applied the method in 8 forest management enterprises (FMEs; i.e., concessions) in the Democratic Republic of Congo (DRC), 9 in Gabon, and 6 in the Republic of Congo (RoC). Committed logging emissions expressed per cubic meter of timber harvested (to control for differences in logging intensities) ranged from 0.63 Mg C m−3 in a FME in RoC to 4.8 Mg C m−3 in a FME in Gabon, with an overall average of 2.1 Mg C m−3. Logging emissions were dominated by damage caused by road and log landing construction (i.e., hauling; 50%) and felling (43%; includes carbon in extracted logs). Total emissions represented only about 9% of unlogged forest biomass carbon stocks. Average emissions were highest in Gabon (2.65 Mg C m−3) followed by DRC (1.84 Mg C m−3) and RoC (1.54 Mg C m−3). Emissions from concessions certified by the Forest Stewardship Council (FSC, N = 6) and those that were not certified (N = 17) did not differ. Nearly half (51%) of logging emissions could be avoided without reducing timber yields if all best examples of RIL-C logging practices observed were applied in the same FME. At the country level, if all FMEs were to utilize these practices, emissions reductions would be 34% in RoC, 45% in DRC, and 62% in Gabon. When combined with country-level logging statistics, emissions from selective logging as currently practiced in the six countries of the Congo Basin are equivalent to 40% of the region’s total emissions from deforestation.

We followed how forest thinning, repeated twice during a period of 93 years, altered understorey plant community composition, affected the succession of forest understorey vegetation and the accumulation of logs in the long-term. The study was carried out in northern Finland by resampling 20 permanent experimental plots, established after a wildfire in 1920. Understorey vegetation was inventoried in 1961, 1986 and 2013 with forest thinning treatments done in 1953 and 1987, using four and three different harvesting intensities, respectively. We found succession to override the effects of forest logging until the latest study period (2013). We observed negligible long-term effects of logging on understorey communities during the two mid-successional stages (1961, 1986), when the forest was 41 and 66 years old respectively. The impacts of logging on understorey vegetation were strongest in the latest successional stage (2013), the forest being at the age of 93 years. In the latest successional stage (2013) logged plots had less coarse woody debris than unlogged plots. Forest management thus influenced the key feature for forest biodiversity and potential habitats for endangered species. These findings are of major interest since the studies of long-term impacts of less intensive forest management practices are scarce. Our results suggest that in addition to possible immediate impacts, harvesting treatments have legacy effects (subtle or delayed inherited effects of forestry in the past) that influence the forest understorey vegetation community composition and the amount of coarse woody debris. This finding deserves special attention when planning of species conservation, multiple use of forests and sustainable forestry.

Insights into the underlying ecological mechanisms for diversity-biomass relationships across forest strata (i.e., overstorey and understorey) are crucial to understand the importance of vertical stratification on ecosystem function in natural forests. Yet, it remains unclear how multiple abiotic (i.e., soil nutrients) and biotic (i.e., biodiversity, functional identity and stand structural complexity) factors simultaneously determine aboveground biomass in each individual forest stratum and whole-community. To address this knowledge gap, we disentangled the relative effects of soil nutrients (soil fertility hypothesis), taxonomic, functional trait and evolutionary diversity (niche complementarity hypothesis), stand structural complexity (niche differentiation hypothesis based on tree sizes), and community-weighted mean trait values (mass ratio hypothesis) on aboveground biomass across forest strata and whole-community. We used forest inventory, functional traits and environmental factors datasets from 125 subtropical forest plots in Eastern China. Multiple linear regression models were performed for the selection of best predictors within each biotic group, and structural equation modelling was used to evaluating how multiple abiotic and biotic drivers determine aboveground biomass. In the overstorey, aboveground biomass was positively related to the community-weighted mean of tree height (i.e., functional dominance) and stand density but was negatively related to functional evenness on nutrient-rich soils. In the understorey, aboveground biomass was positively related to phylogenetic species richness and stand-level tree mean diameter (i.e., a proxy for forest growth) but was negatively related to Shannon’s species diversity on nutrient-poor soils. Understorey aboveground biomass was also determined by overstorey stand structure and functional dominance through direct and indirect effects via understorey biotic drivers. These results suggest that functional dominance and stand structural complexity are the main biotic drivers of overstorey aboveground biomass. Whereas, functional dominance and stand structural complexity of overstorey, soil nutrients, and niche complementarity among understorey species with the conservative strategy determine understorey aboveground biomass. Whole-community aboveground biomass might be resulting from the superior role of overstorey functional dominance. This study highlights that the niche complementarity, mass ratio and soil nutrients effects are important for driving aboveground biomass, but in different ways across overstorey and understorey strata in natural subtropical forests. We argue that the relative effect of biodiversity loss on aboveground biomass depends critically on the functional and evolutionary identity of the lost species in the specific forest stratum. Better insights can be gained into forest management and biodiversity conservation by considering overstorey and understorey strata separately in complex natural forests.

Species rarity is often an important driver of conservation priorities in lieu of greater knowledge of extinction risk. Land management agencies often prioritize management based in part on the commonness of a species, yet identifying what constitutes where a species lies on the commonness-rarity continuum is difficult. Given limited resources, incorrect classification may have detrimental effects on species conservation. In a large area of the Northwest Forest Plan, which guides management of 9.1 million ha of federal forests in the Pacific Northwest, USA, forest management is closely tied to mitigation for the red tree vole (Arborimus longicaudus), a species considered uncommon due in part to its association with older forests. I explore the ability to provide insight into where a species lies along the commonness-rarity continuum by a multi-species comparison. I compared the relative distribution, abundance, and extrinsic conservation threats of red tree voles to western red-backed voles (Myodes californicus), a similar species considered common. Both species occur in younger forests with legacy components of older forests, but reach their greatest densities within older forests. Densities of the two vole species were qualitatively similar. If assignment of a species along a commonness-rarity continuum is a goal of species surveys, their value may be enhanced by including in the survey a set of similar species whose level of rarity is better understood. Although management of the red-tree vole was intended to be guided by adaptive management, challenging policy and legal issues have made that difficult; rarity as a criterion for prioritizing management is partly responsible.

US public land management agencies are faced with multiple, often conflicting objectives to meet management targets and produce a wide range of ecosystem services expected from public lands. One example is managing the growing wildfire risk to human and ecological values while meeting programmatic harvest targets for economic outputs mandated in agency budgets. Studies examining strategic management tradeoffs on federal lands and program efficiencies are rare. In this study we used the 79 western US national forests to examine tradeoffs between forest management scenarios targeting wildfire risk to the wildland urban interface (WUI) and those meeting agency convertible volume production targets. We quantified production frontiers to measure how the efficiency of meeting harvest volume targets is affected by prioritizing treatments to areas that transmit fire to the WUI. The results showed strong tradeoffs and scale effects on production frontiers, and more importantly substantial variation among planning areas and national forests. Prioritizing treatments to reduce fire transmission to the WUI resulted in an average harvest volume reduction of about 248 m3 per ha treated. The analysis also identified opportunities where both management objectives can be achieved. This work represents the first large-scale tradeoff analysis for key management goals in forest and fuel management programs on national forests.

Forest management practices that influence mast production in oaks (Quercus spp.) are ecologically and economically important for regeneration of future oak forests, timber products, and wildlife that consume acorns. We conducted a 10-year experiment in upland oak-hickory forests of eastern Tennessee to determine the influence of canopy release, fertilization (addition of nitrogen, phosphorus, and potassium), and their combined influence on white oak (Quercus alba) acorn production, acorn size and quality, and acorn depredation. We used a robust before-after-control-impact design where we collected pre-treatment acorn production (acorns/m2 of crown) data from 120 white oaks for 5 years, applied canopy release and fertilizer treatments and then monitored post-treatment acorn production on the same trees for an additional 5 years. Acorn production was temporally variable with 6 of 10 years being near complete mast failures (≤3.67 ± 8.52 acorns/m2 of crown). Also, production varied greatly among individual trees with 11% of trees classified as excellent producers accounting for 31% of all acorns produced, and 41% of trees classified as poor producers accounting for only 17% of all acorns produced. Canopy-released and canopy-released-and-fertilized trees increased acorn production 65% and 47%, respectively, following treatment relative to control trees, with effects greatest in trees classified as poor producers. Fertilization did not influence acorn production or size and did not consistently influence acorn quality. Furthermore, acorn depredation rates did not differ among treatments. Our results indicate crown release is an important management practice when management objectives include increasing white oak acorn production in closed-canopy conditions, whereas fertilization does not influence acorn production.