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The study investigates the long-term impact of Lophodermium needle cast on open-pollinated Scots pine progenies in Latvia. A significant impact of cumulative needle cast damage on growth and survival was found. Notably, 51% of trees experienced severe damage after the 4th growing season. Genetic factors played a role in survival at 12 years. Height growth was significantly affected, with height at age 3 and cumulative needle cast damage as key predictors for heights at ages 12 and 16. Genetics demonstrated a substantial impact, with heritability coefficients of 0.25 for cumulative needle cast damage and 0.24 for height, and negative genotypic correlations (rG ≥ -0.71) between the traits. Selecting the top 10% families based on height at 12 years yielded a 14.2% improvement in height and a simultaneous 8.4% reduction in cumulative needle cast damage, enhancing survival by 9.8%. Thinning somewhat mitigated the negative effect of needle cast. The findings highlight the need for adaptive forestry strategies in the Baltic Sea region. [ABSTRACT FROM AUTHOR]

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A wide range of climatic conditions in Ukraine causes significant regional differences in the vulnerability of forests to the current rapid climate change. The mitigation/adaptation strategy should be based on assessments of their vulnerability at the regional level. Phytoindication model by Prof. Y.P. Didukh was used to assess forest vulnerability. The model provides a quantitative estimation of climate as one of the major environmental factors affecting the distribution, condition and productivity of vegetation on the base of climate-related indicators – continentality, humidity and frost. For these indicators climate suitability scales were calculated. The modeling was carried out for the main forest species: Pinus sylvestris L., Quercus robur L., Fagus sylvatica L., Picea abies (L.) H. Karst, Betula pendula Roth., Alnus glutinosa (L.) Gaertn. and Robinia pseudoacacia L. Climate projections based on the Euro CORDEX time series (up to 2100) and 2 scenarios of the Representative Concentration Pathways (RCP 4.5, RCP 8.5) were used. Using Q-GIS, the maps containing zones of suitability to climate for each of the studied species were created for current climate conditions and future time series. The directions for strengthening the mitigation and adaptive capacity of forests are considered. The mainstream for nature-based solutions is adaptive sustainable forest management, which provides: 1) optimization of land use structure and increasing the forested area; 2) development and implementation of a national forestry program considering the priorities of climate change and low-carbon development; 3) using wood to substitute greenhouse gas intensive-materials and fossil fuels; 4) the best forestry practices through the introduction of modern Climate-Smart Forestry principles.

Non-native tree species – defined as those species intentionally or unintentionally introduced by humans – have long been a part of the Alpine Space, providing numerous benefits, but also posing a potential threat to native biodiversity and related ecosystem services. Compared to the urban space where non-native trees comprise most tree species, the number of non-native trees in forests and plantations is relatively low. To evaluate potential risks and benefits of non-native trees in the Alpine Space, a transnational strategy for the responsible use and management of non-native trees is needed. The goals of the strategy are to tailor management practices for a sustainable and responsible use or admixture of non-native trees, to reduce the risks connected with the invasive potential of some non-native tree species, to help forests and urban areas to adapt to climate change, and to improve coordination and cooperation regarding best practices between different regions of the Alpine Space. A proposal was developed in a four-step process including expert-based assessment, stakeholder mapping, an extensive data review, and a public consultation. For implementing the strategy fully, strong collaboration among diverse stakeholders is anticipated and robust governance and an adequate long-term and fair funding scheme is needed.

This study is intended for forest owners considering options to increase the efficiency of the production of forest seedlings in automated nurseries. In the short rotation technology of the Scots pine (Pinus sylvestris L.), the production of seedlings was integrated in the process of grading seeds by spectrometric features, followed by the fall outplanting of containerized seedlings to a restorable post-pyrogenic site. There are studies of the spectrometric effect grading viable seeds, but a negligible amount of testing has been conducted on the seedling's field performance from these seeds. It was very important for us to evaluate the morphogenesis of juvenile Scots pine trees in relation to the change in morphological features—increase in root collar diameter (RCD-increment) and increase in stem height (SH-increment)—in the second and third growing season from the field outplanting. To determine the nature of the interaction between independent (RCD increase), dependent (SH-increment), and categorical (seed spectrometric categories and timespans) variables, a regression analysis was performed using the R statistical software. All coefficients of the linear models are statistically significant at the 1% significance level, and all are positively associated with an increase in seedling height. On average, a RCD increment by 0.1 cm causes a SH-increment by 0.72 ± 0.16 cm (p = 9.779 × 10−6). In addition, in 2020, compared to 2019, the SH-increment was 5.46 ± 0.37 cm (p < 0.001). The seeds' differentiation into spectrometric categories is strongly correlated with the stem height increment (p < 0.001). Thus, in order to improve the plant propagation protocol, it seems advisable to first condition the seeds in accordance with the spectrometric feature, and to then apply a coating (by pelleting or encapsulating) in order to improve the storage and seeding conditions. For a medium-term assessment of the short rotation technology with an integrated seed spectrometric grading in the future, the morphogenesis of Scots pine trees at 5, 7 and 10 growing seasons from the seedlings field outplanting is controlled. [ABSTRACT FROM AUTHOR]

Precommercial thinning could be a valuable tool for climate change adaptation, as it can promote stand diversity while increasing productivity. Softwood and hardwood stands are usually thinned following different methods, and we lack recommendations for application in mixedwood stands. We evaluated the effects of precommercial thinning on the growth and composition of balsam fir (Abies balsameaL.)–birch stands dominated by paper and yellow birch (Betula papyrifera Marsh. and Betula alleghaniensis Britt.), comparing methods and production objectives (systematic release-softwood, systematic release-mixedwood, crop-tree release-mixedwood, and crop-tree release-hardwood) in Québec (Canada). Precommercial thinning increased tree-level and stand-level growth, especially for both birches. Compared to the non-thinned control, thinning increased tree diameter at breast height annual increments by 60%–107%, with similar results among modalities. Thinning changed initial stand composition, but mixedwood production plots composition was similar to that of the control 15 years after treatment. Promoting diversity is often perceived to be made at the expense of wood production. Our results suggest that we can obtain both increased growth and maintain diversity. Precommercial thinning is currently suggested as an adaptation tool that can foster drought resistance. Based on our study, we suggest it could serve another purpose in climate-adapted forest management, that is, maintaining diversity and thus increasing resilience to disturbances. [ABSTRACT FROM AUTHOR]

Snowstorms are disturbance agents that have received relatively little research attention rather than significant disturbances that they pose to forest ecosystems. In this study, we modeled the interactions between snowstorms and different characteristics of a forest stand in northern Iran and spatially visualized the susceptibility of the stand to damage caused by snowstorms using the random forest (RF) and logistic regression (LR) methods. After a severe snowstorm in November 2021 that caused stem breakage and uprooting of individual trees, the location of 185 damaged trees was identified via field surveys and used for generating an inventory map of snowstorm damage. The thematic maps of fourteen explanatory variables representing the characteristics of damaged trees and the study forest were produced. The models were trained with 70% of the damaged trees and validated with the remaining 30% based on the area under the receiver operating characteristic curve (AUC). The results indicated the better performance of RF compared to LR in both training (0.934 vs. 0.896) and validation (0.925 vs. 0.894) phases. The RF model identified slope, aspect, and wind effect as the variables with the greatest impacts on the forest stand sustainability to snowstorm damage. Approximately 30% of the study area was categorized as high and very high susceptible to snowstorms. Our results can enable forest managers to tailor more informed adaptive forest management plans in readiness for snowstorm seasons and recovery from their damage. [ABSTRACT FROM AUTHOR]

Climate-adaptive forest management aims to sustain the provision of multiple forest ecosystem services and biodiversity (ESB). However, it remains largely unknown how changes in adaptive silvicultural interventions affect trade-offs and synergies among ESB in the long term. We used a simulation-based sensitivity analysis to evaluate popular adaptive forest management interventions in representative Swiss low- to mid-elevation beech- and spruce-dominated forest stands. We predicted stand development across the twenty-first century using a novel empirical and temperature-sensitive single-tree forest stand simulator in a fully crossed experimental design to analyse the effects of (1) planting mixtures of Douglas-fir, oak and silver fir, (2) thinning intensity, and (3) harvesting intensity on timber production, carbon storage and biodiversity under three climate scenarios. Simulation results were evaluated in terms of multiple ESB provision, trade-offs and synergies, and individual effects of the adaptive interventions. Timber production increased on average by 45% in scenarios that included tree planting. Tree planting led to pronounced synergies among all ESBs towards the end of the twenty-first century. Increasing the thinning and harvesting intensity affected ESB provision negatively. Our simulations indicated a temperature-driven increase in growth in beech- (+ 12.5%) and spruce-dominated stands (+ 3.7%), but could not account for drought effects on forest dynamics. Our study demonstrates the advantages of multi-scenario sensitivity analysis that enables quantifying effect sizes and directions of management impacts. We showed that admixing new tree species is promising to enhance future ESB provision and synergies among them. These results support strategic decision making in forestry. [ABSTRACT FROM AUTHOR]

Warming climate and resulting declines in seasonal snowpack have been associated with drought stress and tree mortality in seasonally snow‐covered watersheds worldwide. Meanwhile, increasing forest density has further exacerbated drought stress due to intensified tree–tree competition. Using a uniquely detailed data set of population‐level forest growth (n = 2,495 sampled trees), we examined how inter‐annual variability in growth relates to snow volume across a range of forest densities (e.g., competitive environments) in sites spanning a broad aridity gradient across the United States. Forest growth was positively related to snowpack in water‐limited forests located at low latitude, and this relationship was intensified by forest density. However, forest growth was negatively related to snowpack in a higher latitude more energy‐limited forest, and this relationship did not interact with forest density. Future reductions in snowpack may have contrasting consequences, as growth may respond positively in energy‐limited forests and negatively in water‐limited forests; however, these declines may be mitigated by reducing stand density through forest thinning. [ABSTRACT FROM AUTHOR]

The biggest challenge for forest management in the near future will be the silvicultural adaptation of forests on sites where climate change will increase the risk for drought induced tree mortality and for a decrease of the growth performance. One management option is the diversification by promoting climate change adapted non-native tree species. Currently, we have in depth experience with only a few non-native tree species in Central Europe. Other tree species that may complement the species pool in Central Europe need to be carefully selected by a range of criteria. Before establishing larger silvicultural experiments at stand-level, the suitability of species to grow well with a low risk of failure under expected future climatic conditions as well as a good performance already today should be tested, amongst other aspects. We present results of a multi-site common garden experiment where growth and survival of five non-native tree species (Abies bornmuelleriana , Cedrus libani , Fagus orientalis , Tilia tomentosa , and Tsuga heterophylla) and one climate adapted local native species per site are tested in five field trials in Austria, Germany and Switzerland along a temperature (7.9–10.4 °C mean annual Temperature) and precipitation (490–1147 mm annual precipitation) gradient. Each species was replicated on three plots per site using a block-wise design. Lower survival and growth of the non-native species as the native reference on most sites indicate that the studied non-native species are today not as well adapted to current climatic conditions as native species. However, the performance of the non-native species was sufficiently high to justify further trials. Survival and growth rates were mostly equally high on the two sites at the opposing ends of the temperature and humidity gradient and lower on all other sites. Height growth and survival were only marginally affected by the strong summer drought in 2018 in all except one site, presumably due to the low water storage capacity of the sandy soils on this site. This indicates that the tested non-native tree species grow well in the wide range of climatically changing weather conditions from our transnational study sites across Central Europe. So far, the tested tree species did not reach their climatic growth limitation. However, edaphic site conditions may have influenced the performance of the tested non-native species as well and must be considered when discussing the suitability of these tree species. • Satisfactory six-year performance of five non-native tree species. • No relationship between tree performance and drought during the growing season. • Tree performance in comparison with native tree species depends on site conditions. [ABSTRACT FROM AUTHOR]

Given the steady decline in the genetic health of tree species populations as adaptation is being outpaced by the speed of human-induced climate change, forest management measures are urgently required. In this context, human translocation of pre-adapted genotypes from source populations whose current climatic conditions are closer to those that recipient populations will experience in the future, the so-called Assisted Gene Flow (AGF), has the potential to reduce the risk of maladaptation and to make more resilient communities. Here, we introduce a metric we call the Mean Offset Ratio (MOR), which is a population pre-adaption measurement useful for AGF as it aims to increase adaptive genetic variation and decrease the risk in maladaptation of recipient populations. We applied MOR to the iconic South American conifer Araucaria araucana and found that populations having the highest risk of maladaptation in the southern Andean piedmonts could benefit from the introduction of genotypes coming from the northern higher elevation Andean populations, which are at the lowest risk of maladaptation. For one metapopulation (Coastal), no translocation possibilities were observed, both as donor and recipient populations. Despite some limitations, we assert that MOR is a useful tool for AGF purposes and could be applied to other tree species. This is the first study to use a genomic approach to inform adaptive forest management actions such as AGF in a long-lived and endangered South American conifer in the face of ongoing climate change. • We proposed a genome offset-based metric (Mean Offset Ratio, MOR) to search for pre-adapted populations to future environmental conditions (RCP 4.5, year 2070) to support assisted gene flow (AGF) in trees, and then we applied it to Araucaria araucana. • Results suggest that AGF is partially possible to implement for Andes Mountain range metapopulation. Maps of pre-adapted populations and AGF-based translocations are presented. • For Coastal metapopulation, AGF would not be possible to implement due to the lack of both donor and recipient populations. • Spatial and climate complexity of local adaptation and evolutionary responses to environmental changes could be better understood and modeled harnessing landscape genomic tools. However, field trials to validate these predictions are needed. [ABSTRACT FROM AUTHOR]

Increased forest vulnerability is being reflected as more widespread and severe drought-induced decline episodes. In particular, the Mediterranean area is revealing a high susceptibility to phenomena of loss in tree vitality across species. Within tree species, oaks (Quercus spp.) are experiencing extensive decline in many countries. However, in the wake of the so-called “oak decline phenomenon”, the attention on these species has generally been limited. In this paper, we review the current available literature on oak-decline cases reported within the Mediterranean Basin, with particular remark for those occurred in Italy and Spain. More specifically our main aims were to: (i) provide an update on the patterns and mechanisms of decline by focusing on tree-ring and wood-anatomical variables; (ii) provide some hints for improving the resistance and resilience of oak stands experiencing decline. Our review reveals that drought is reported as the main driver triggering oak decline within the Mediterranean Basin, although other causes (i.e., increasing temperature, pathogens attack or excessive stand density) could exacerbate decline. In most reported cases, drought induced a substantial reduction of growth and changes in some wood anatomical properties. Indeed, growth decline prior death is also indicated as an early-warning signal of impending death. In ring-porous oak species, declining trees were often characterized by a very low production of latewood and a decrease in lumen area of the widest earlywood vessels, suggesting a potential reduction of hydraulic conductivity. Moreover, hydraulic dysfunction is reported as the main cause of decline. Finally, regarding management actions that should be considered for improving the resilience of declining stands and preserve the species-specific stand composition, it could be useful to shorten the rotation period of coppice stands or promoting their gradual conversion towards high forests, and favoring more drought-resistant species should also be considered. In addition, regeneration prior to regeneration cuts should be improved by anticipating seed dispersal or by planting oak seedlings obtained from local germoplasm.

ContentsSummary50I.Introduction50II.Drivers of the diversity–productivity relationship51III.Patterns of the diversity–productivity relationship55IV.Responses of mixed stands to climate change57V.Conclusions60Acknowledgements61References61 Summary: Although the relationship between species diversity and biomass productivity has been extensively studied in grasslands, the impact of tree species diversity on forest productivity, as well as the main drivers of this relationship, are still under discussion. It is widely accepted that the magnitude of the relationship between tree diversity and forest stand productivity is context specific and depends on environmental conditions, but the underlying mechanisms of this relationship are still not fully understood. Competition reduction and facilitation have been identified as key mechanisms driving the diversity–productivity relationship. However, contrasting results have been reported with respect to the extent to which competition reduction and facilitation determine the diversity–productivity relationship. They appear to depend on regional climate, soil fertility, functional diversity of the tree species involved, and developmental stage of the forest. The purpose of this review is to summarize current knowledge and to suggest a conceptual framework to explain the various processes leading to higher productivity of species‐rich forests compared with average yields of their respective monocultures. This framework provides three pathways for possible development of the diversity–productivity relationship under a changing climate. [ABSTRACT FROM AUTHOR]

Pure and even-aged (PEA) forests of fast-growing conifer species have for a long time been key providers of industrial raw material. Despite recent concerns regarding their greater sensitivity to major natural disturbances, their impacts on biodiversity and their funding efficiency, PEA conifer forests could remain a major economic target given the ongoing European strategy for bioeconomy. These forests are encountered in contrasted climates and in both native and introduced contexts across Europe, giving rise to high uncertainties regarding their growth responses to current climate change. Using the French National Forest Inventory data, we studied the radial growth of eight major conifer species in European forestry across 16 regional native and introduced PEA forest systems ( n > 10 000 trees). Growth trends over the 2006–2016 period exhibited a significant negative association with the absolute growth level in 2006, with the strongest negative growth trends found for emblematic PEA forestry species (e.g. Norway spruce and Douglas fir), and the strongest positive trends for pine species (e.g. Scots pine). While the greater growth rate advantage of some species may shorten rotation and lower risk exposures for future decades, their recent lowered productivity may affect the forest sector in the long run. The prevalence of PEA forests across European forest landscapes and their increasingly reported lower resilience to climate change compared to more complex forest systems call for the establishment of a long-term European forest policy strategy. Maintaining the environmental, social and economic benefits of forests should remain a priority in the European agenda, regardless of the financial costs at stake.

Estimating forest transpiration is of great importance for Adaptive Forest Management (AFM) in the scope of climate change prediction. AFM in the Mediterranean region usually generates a mosaic of different canopy covers within the same forest. Several models and methods are available to estimate forest transpiration, but most require a homogeneous forest cover, or an individual calibration/validation process for each cover stand. Hence, a model capable of reproducing accurately the transpiration of the whole canopy-cover mosaic is necessary. In this paper, the use of Artificial Neural Network (ANN) is proposed as a flexible tool for estimating forest transpiration using the forest cover as an input variable. To that end, sap flow, soil water content and other environmental variables were experimentally collected under five Aleppo pine stands of different canopy covers for two years. These sets of inputs were then used for the ANN training. Stand transpiration was accurately estimated using climate data, soil water content and forest cover through the ANN approach (correlation coefficient R = 0.95; Nash-Sutcliffe coefficient E = 0.90; root-mean-square error RMSE = 0.078 mm day-1). Finally, the input value for soil water content (when not available) was computed using the process-based model Gotilwa+. Then, this computed soil water content was used as input in the proposed ANN. This combination predicted the forest transpiration with values of R = 0.90, E = 0.63, and RMSE = 0.068 mm day-1. Artificial Neural Network proved to be a useful and flexible tool to predict the transpiration dynamics of an Aleppo pine stand regardless of the heterogeneity of the forest cover produced by adaptive forest management.

Aim of study: Use the SUBER model to evaluate the influence of the cork debarking rotation period (CDR) on equivalent annual annuity (EAA) value. Area of study: Nine simulated stands, varying in site index (14.4, 15.6, 17.1) and cork quality characteristics (high, medium, low). Material and methods: EAA values were computed considering CDR periods varying from 9 to 14 years, two contrasting structures of cork prices (high and low cork price scenarios), and three discount rate values (0.5%, 2% and 5%). Main results: For discount rates of 0.5% and 2% the impact of different CDR on the EAA is similar. In stands characterized by high to average site index values or high to medium cork quality characteristics, CDR of 9 and 11 years are associated with similar values of EAA. The variation of the CDR in stands characterized by low site index values and/or low cork quality characteristics did not have a relevant effect on the variation of EAA. For the simulations carried out with a discount rate of 5% the EAA decreases with the increase of CDR, indicating that the minimum legal value of 9 years for CDR should be applied. Research highlights: In stands characterized by high to average site index values or high to medium cork quality characteristics, a delay in the debarking may result in a significant increase of cork thickness and, as a result, of cork price. Detailed knowledge of cork and stand characteristics and updated information on cork prices structure and values are essential for the best usage of management tools such as the SUBER model, which can contribute to the decision-making process concerning the debarking operation.

Aim of study: The paper is a scientific commented discussion with the aim of defining a framework which allows both a comprehensive vision of forest dynamics, as well as an adaptive management approach and policy procedures more suited to a changing and inherently unpredictable world. Main results: We identify the main challenges facing forestry in relation to recent developments in forestry thinking, i.e. the paradox of aiming at sustainability in a changing environment, a shifting perception of the relationship between ecological and social systems, the recognition of forest ecosystems as complex adaptive systems, the need for integrating the social and ecological dimensions of forestry into a single framework, and the growing awareness of the importance of the ethical approach to the forest. We propose the concept of “systemic forestry” as a paradigm for better understanding forest dynamics and for guiding management and public actions at various levels. We compare the systemic approach with different silvicultural and forest management approaches which have been proposed in the last decades. Research highlights: Our analysis shows that a systemic approach to forestry has five main consequences: 1. forestry is viewed as a part of landscape dynamics through a multi-sectoral coordination, 2. the logic of action changes from norm to process, 3. conservation is a dynamic search for resilience, 4. multi-functionality is achieved through a multi-entries approach integrating ecological, social and economic components of sustainability, 5. forestry institutions are reframed to address the issue of changing interactions among actors, 6. a change in the ethical approach to the forest is needed.

Indicators are increasingly required to support a fine-tuning between sustainable forestry and multiple environmental targets. A data mining strategy was implemented in this study to assess the overall impact of traditional and innovative silviculture on stand structure in a sample of beech forests with varying dominant age, management history and stand structure in Italy. Harvesting intensity and stand sensitivity to treatment were investigated using a principal component analysis (PCA) run on a set of dendrometric and stand-structure variables measured before and after practice implementation at the scale of forest compartment. The PCA decomposed the overall impact of silviculture on forest structure in two manipulative effects: (i) structural changes between control and treatments, and (ii) the net manipulative effect of innovative versus traditional treatment. Our approach informs the sustainable management of forests, outlining between-site differences in stand structure and identifying a diversity gradient shaped by silvicultural practices. Multivariate analysis of forest indicators following practice's implementation is a promising tool to design innovative silviculture coherent with conservation of forests' structural diversity. [ABSTRACT FROM AUTHOR]

• Large uncertainties are associated with the future magnitude and stability of the forest carbon sink. • Business-as-usual management practices might already be close-to-optimum for supporting forest carbon uptake and storage. • Increases in management intensity have the potential to lower forest carbon sequestration and stocking capacity. • Forest management practices are as important as climate change to regulatethe carbon sink and stock size. Forest management practices might act as nature-based methods to remove CO 2 from the atmosphere and slow anthropogenic climate change and thus support an EU forest-based climate change mitigation strategy. However, the extent to which diversified management actions could lead to quantitatively important changes in carbon sequestration and stocking capacity at the tree level remains to be thoroughly assessed. To that end, we used a state-of-the-science bio-geochemically based forest growth model to simulate effects of multiple forest management scenarios on net primary productivity (NPP) and potential carbon woody stocks (pCWS) under twenty scenarios of climate change in a suite of observed and virtual forest stands in temperate and boreal European forests. Previous modelling experiments indicated that the capacity of forests to assimilate and store atmospheric CO 2 in woody biomass is already being attained under business-as-usual forest management practices across a range of climate change scenarios. Nevertheless, we find that on the long-term, with increasing atmospheric CO 2 concentration and warming, managed forests show both higher productivity capacity and a larger potential pool size of stored carbon than unmanaged forests as long as thinning and tree harvesting are of moderate intensity. [Display omitted] [ABSTRACT FROM AUTHOR]

The suitability of alternative tree species to replace species that are either threatened by pests/disease or at risk from climate change is commonly assessed by their ability to grow in a predicted future climate, their resistance to disease and their production potential. The ecological implications of a change in tree species are seldom considered. Here, we develop and test 3 methods to assess the ecological suitability of alternative trees. We use as our case study the systematic search for an alternative tree species to Fraxinus excelsior (currently declining throughout Europe due to Hymenoscyphus fraxineus). Those trees assessed as most similar to F. excelsior in selected ecosystem functions (decomposition, leaf litter and soil chemistry) (Method A) were least similar when assessed by the number of ash-associated species that also use them (Method B) and vice versa. Method C simultaneously assessed ecosystem functions and species use, allowing trade-offs between supporting ecosystem function and species use to be identified. Using Method C to develop hypothetical scenarios of different tree species mixtures showed that prioritising ecosystem function and then increasing the mixture of tree species to support the greatest number of ash-associated species possible, results in a mixture of trees more ecologically similar to F. excelsior than by simply mixing tree species together to support the greatest number of ash-associated species. We conclude that establishing alternative tree species results in changes in both ecosystem function and species supported and have developed a general method to assess suitability that simultaneously integrates both ecosystem function and the 'number of species supported'. [ABSTRACT FROM AUTHOR]

The more and more diffused multifunctional role addressed nowadays to public forests, calls for targeted analysis aimed at highlighting the overall outcome of different practices implemented on the same forest compartment, according to the locally prevailing function. This study was carried out in four Italian beech forests across a latitudinal gradient representative of multiple management history, stand structure, and dominant stand age. We analyze forest structure at the compartment scale before and after silvicultural practices. We aim to explore relationships and similarities between 10 stand attributes (mensurational and structural variables) to identify relevant indicators for the monitoring and management of forest ecosystems. Results indicate changing patterns of correlation and similarity among mensurational variables following practice implementation. A sensitivity gradient to silvicultural practice was finally identified within the four sites investigated as a result of the diverging stand structure. Our approach suggests a way and provides an insight for the design of adaptive forestry management practices required to meet environmental targets, in addition to the already acknowledged supply of primary goods and services. [ABSTRACT FROM AUTHOR]

In water-limited regions, adaptive management of forest and water relationships has been put forward, to implement hydrology-oriented silviculture to reduce stand evapotranspiration and, at the tree level, to improve growth and water use efficiency (WUE). The main goal of this study was to evaluate the effect of thinning in the short and medium term on tree growth, climate (drought) sensitivity, WUE performed using growth and sap flow measurements and WUEi performed using δ 13 C and δ 18 O isotopes, in a typical semiarid forest. This approach also evaluated the reliability of isotopes as indicators of the effects of adaptive forest management. A stagnated Aleppo pine plantation was experimentally thinned at high intensity (H98) in 1998 and at High (H), Medium (M) and Low (L) intensities in 2008, along with a control (C). Substantial limitation of tree growth was observed in C. Thinning not only increased growth, but also changed the tree growth–precipitation relationships, with C trees depending more on precipitation than thinned trees did. WUEi after thinning was significantly affected only in the medium term, with C trees being more efficient (94.4 μmolCO 2 /molH 2 O) than H98 trees (88.7), especially in dry spells (100.7). WUEi was found to increase when precipitation decreased, regardless of the treatment. However, WUE increased sharply from C (1.26 g biomass/L H 2 O) to H (3.20 g/L), showing a clear difference with WUEi observed in the same years. Thinning caused an increase in δ 18 O in the short term, but no relationship was found between δ 18 O and tree water use. It can be concluded that forest management improved WUE in spite of higher tree transpiration, but WUEi remained unchanged, probably due to an underestimate of photosynthetic capacity. The dual isotope (δ 13 C and δ 18 O) conceptual model was not consistent with our experimental data. Thus, the question of whether stable isotopes can be used as a tool for addressing the ecophysiological impacts of thinning remains open. [ABSTRACT FROM AUTHOR]

Disruption of species interactions is a key issue in climate change biology. Interactions involving forest trees may be particularly vulnerable due to evolutionary rate limitations imposed by long generation times. One mitigation strategy for such impacts is Climate matching - the augmentation of local native tree populations by input from nonlocal populations currently experiencing predicted future climates. This strategy is controversial because of potential cascading impacts on locally adapted animal communities. We explored these impacts using abundance data for local native gallwasp herbivores sampled from 20 provenances of sessile oak ( Quercus petraea) planted in a common garden trial. We hypothesized that non-native provenances would show (i) declining growth performance with increasing distance between provenance origin and trial site, and (ii) phenological differences to local oaks that increased with latitudinal differences between origin and trial site. Under a local adaptation hypothesis, we predicted declining gallwasp abundance with increasing phenological mismatch between native and climate-matched trees. Both hypotheses for oaks were supported. Provenance explained significant variation in gallwasp abundance, but no gall type showed the relationship between abundance and phenological mismatch predicted by a local adaptation hypothesis. Our results show that climate matching would have complex and variable impacts on oak gall communities. [ABSTRACT FROM AUTHOR]

Biomass and species composition of a forest district in the North-Eastern Carpathian Mountains were simulated until 2100 using the forest landscape model LandClim, driven by climate data from three general circulation models that projected the local climate change under the A1B emission scenario. Four different management scenarios were used: business as usual and three adaptive management scenarios characterized by an intensification of interventions: more intense thinnings and shorter rotations. The total biomass at the end of the simulation differed greatly according to the climate scenario but was comparatively much less influenced by the management scenarios. Forest biomass was projected to increase markedly under the model which forecast the lowest climate change (CCSM3), remained approximately constant in the intermediate climate model (ECHAM5) but decreased severely in the hypothesis of the largest climate changes (HadCM3). Our results showed that developments in species composition differed much more between climate change scenarios than between management scenarios. Under moderate and intermediate climate scenarios, changes in species composition occurred principally in harvested stands, while stands not harvested did not display species replacements. Under extreme climate change (HadCM3) on the other hand, the species change occurred even before harvest. The model projections highlight the inadequacy of some species for the new growing and regeneration conditions that accompany the extreme climate scenario. Harvesting can be seen as a chance to undergo active adaptation with respect to species composition. [ABSTRACT FROM AUTHOR]

We present for the first time a study on alternative forest management at the European scale to account for climate change impacts. We combine insights into detailed studies at high resolution with the actual status of the forest and a realistic estimate of the current management practices at large scale. Results show that the European forest system is very inert and that it takes a long time to influence the species distribution by replacing species after final felling. By 2070, on average about 36 % of the area expected to have decreased species suitability will have changed species following business as usual management. Alternative management, consisting of shorter rotations for those species and species planting based on expected trends, will have increased this species transition to 40 %. The simulated forward-looking alternative management leads to some reduction in increment, but does not influence the amount of wood removed from the forest. Northern Europe is projected to show the highest production increases under climate change and can also adapt faster to the new (proposed) species distribution. Southwest Europe is expected to face the greatest challenge by a combination of a predicted loss of production and a slow rate of management alteration under climate change. [ABSTRACT FROM AUTHOR]

Cork oak stands are one of the major sources of income from Portuguese Mediterranean forests. Future climate is projected to increase temperatures, reduce precipitation and decrease current forests' productivity and therefore, adapting management, is a key strategy to mitigate impacts of future climate on cork supply. The central objective of this research was to compare conventional and adaptive management regimes under scenarios of climate change. The adaptive management focussed on adopting optimal harvest schedules while considering different management objectives. The study focused on the Chamusca region, one of the most productive areas of cork, and considered four distinct spatial scales for analysis. For each scale, the management objective was defined according to field information and considered the maximization of cork production while targeting different cork harvesting flows: (a) more frequent and regular or (b) less frequent and concentrated. A forest growth model was used to simulate climate change impact on future yield of cork oak stands under different forest management alternatives. A mixed integer programming model was developed to find the most adequate cork debarking cycle calendar for cork oak stands. Our results suggest that (1) business as usual management under climate change scenarios could decrease cork supply and carbon stock in the tree component of the forests by up to 20 and 30 %, respectively, (2) the development of adaptive management strategies, including cork extraction schedule optimization, to address climate change has advantages over traditional practices and (3) may contribute further to increase cork production (up to double productivity in mid-long term) while addressing concerns with the regulation of cork extraction flows through the adaptation of debarking periods. The mixed integer programming allowed the spatial visualization of the debarking cycle delay. Furthermore, results underline the relevance of an approach to develop adaptive management strategies that can consider different management goals, with different constraints to address climate change. [ABSTRACT FROM AUTHOR]

Adaptive forest management (AFM) aims to adapt a forest to water availability by means of an artificial regulation of the forest structure and density. Areas vulnerable to water scarcity situations, such as the Mediterranean region, might require AFM to optimize the hydrological cycle under normal and future global change conditions. This study uses the process based model (PBM) BIOME-BGC to predict the effects of AFM in an unmanaged semi-arid Mediterranean Aleppo pine plantation. At the same time, it seeking to increase the spatially explicit information to initialize the model runs. To this end, the model has been slightly modified, and canopy average specific leaf area and canopy water interception coefficient have both been introduced as functions of canopy coverage, which was obtained using airborne laser scanning (LiDAR) technology. The model was then calibrated and evaluated using sap flow, soil moisture and throughfall field data obtained during one year from three forest coverages (85, 73 and 26%, respectively). Calibration and evaluation of the model show acceptable accuracy, with the Nash–Sutcliffe coefficient ranging between 0.39 and 0.76 for calibration and 0.35 and 0.75 for evaluation. The model was then applied to analyze and predict the need for forest management in a Mediterranean public forest indicated a possible optimization of the hydrological cycle to establish a new equilibrium between blue and green water. This new scenario reduced water interception and plant transpiration (green water), and increased water runoff and/or percolation (blue water). [ABSTRACT FROM AUTHOR]

Forests play an important role in the mitigation of global warming, acting as carbon sinks. However, the effects of forest management on the carbon pools over the rotation period in Mediterranean areas are scarcely understood. The objective of this work is to assess the way in which two alternative management systems; one more intensive and the other more moderate (with less severe harvesting and more spread over time) affect the carbon stocks in the living tree biomass, coarse woody debris, forest floor and mineral soil in Mediterranean forests. For this purpose, two chronosequences were established covering the whole rotation period in two Pinus sylvestris L. forests. We conducted four forest inventories over a period of 15 years, measuring the diameter and the height of all the trees higher than 1.3 m in order to calculate the carbon stored in the living parts of the tree. Soil pits were excavated and we collected soil samples to estimate the soil organic carbon. We found that the temporal trends for living tree biomass were similar in both forests. However, the total living tree carbon stored at the end of the rotation period was greater in the forest with the longer rotation period and lighter thinning regime (345.5 Mg ha −1 of carbon) than in the intensively-managed forest (223.8 Mg ha −1 of carbon). On average, more carbon was found to be stored in the forest floor under the more intensive management system, whereas more carbon was present in the first 20 cm of mineral soil under the moderate management system. Moreover, in each forest, the carbon stocks of the forest floor and in the uppermost cm of the soil remained constant over the rotation period. Therefore, management systems with longer rotation periods and moderate harvesting intensities are recommended to increase carbon fixation in Mediterranean forests. [ABSTRACT FROM AUTHOR]

• Key message: To implement adaptive management in post-fire-regenerated Aleppo pine forests, we developed specific biomass equations in two early-thinned climatically contrasting stands. We found thinning enlarged biomass components, although climate primarily constrained biomass accumulation and biomass allocation. • Context: The increase in burnt surface by wildfires in the Mediterranean Basin has triggered the proliferation of large unmanaged forested areas, particularly Aleppo pine stands in drier and lower altitudinal areas. These young naturally regenerated stands require specific biomass models for accurate carbon stock quantification. • Aims: The aim of this study is to analyse the effects of climate (dry vs. semiarid), age and forest management (early thinning) on biomass accumulation and biomass allocation of young Pinus halepensis components: stem, crown (crown wood, needles and cones) and roots. • Methods: We sampled 251 individual Aleppo pine trees across an age sequence of 5-16 years old to develop component biomass equations. • Results: We observed that biomass allocation differed with climate, age and tree density. The crown was the largest biomass fraction, followed by root fraction and stem fraction. At the most limiting site (semiarid climate), we found major reproductive efforts, which may be shaped by adaptive traits to recurrent fires or recurrent drought episodes. • Conclusion: Climate was the first limiting factor to constrain biomass accumulation and biomass allocation. Thinning played a key role in promoting positive effects on biomass components at both sites, which were enlarged under less stressful site conditions (dry climate). These results may help managers understand how altering stand density promotes more resilient forests. [ABSTRACT FROM AUTHOR]

Salvage logging is the commonest post-fire emergency action, but has unclear ecological effects. In the Mediterranean Basin, drought periods and fire regimes are changing and forest management should be adapted. In summer 2009, a mid-high severity fire burned 968 ha of Aleppo pine (Pinus halepensis Mill.) forest in southeast Spain, which was submitted to salvage logging six months later. In spring 2010, plots were set in untreated and logged areas to monitor the recruitment and survival of the main tree species and three companion species: Stipa tenacissima L. (resprouter), Cistus clusii Dunal and Rosmarinus officinalis L. (obligate seeders). We evaluated responses to different scenarios in relation to intensification of summer droughts and forest management to obtain differences in water stress, growth, and gas exchange to cope with summer drought. Drought was induced by using rain-exclusion shelters and recorded ecophysiological characteristics were obtained with a portable gas exchange system. The main tree species recruitment was poor, but companion species showed a high survival ratio. Lower water stress was found for obligate seeder seedlings, which was higher in logged areas with induced drought. The initial post-fire stage was similar for the studied areas. However, after two drought periods (2010 and 2011), significant differences were found in the morphological and ecophysiological responses. In the unmanaged area, the biggest size of individuals due to the most marked increases in height and coverage were observed mainly in resprouter S. tenacissima. In the area submitted to salvage logging, the growth ratios in plots with induced drought were lower, mainly for seeders. Greater productivity was related to higher transpiration, stomatal conductance, and net photosynthetic ratio, but lower water use efficiency was found in obligate seeders with no drought induction, and S. tenacissima obtained higher values in untreated areas. Our results confirm that both forest management and intensification of summer droughts influenced the resilience and productivity of the ecosystems in the short term. Adaptive forest management after fire can imply successful survival and recovery of plant communities in the mid to long term. This study provide a scientific basis to develop tools for the post-fire restoration of serotinous pine forests occurring in low-altitudinal areas of the Mediterranean Basin, prone to summer droughts and fire events. [ABSTRACT FROM AUTHOR]

Context: We develop a modelling concept that updates knowledge and beliefs about future climate changes, to model a decision-maker's choice of forest management alternatives, the outcomes of which depend on the climate condition. Aims: Applying Bayes' updating, we show that while the true climate trajectory is initially unknown, it will eventually be revealed as novel information become available. How fast the decision-maker will form firm beliefs about future climate depends on the divergence among climate trajectories, the long-term speed of change, and the short-term climate variability. Methods: We simplify climate change outcomes to three possible trajectories of low, medium and high changes. We solve a hypothetical decision-making problem of tree species choice aiming at maximising the land expectation value (LEV) and based on the updated beliefs at each time step. Results: The economic value of an adaptive approach would be positive and higher than a non-adaptive approach if a large change in climate state occurs and may influence forest decisions. Conclusion: Updating knowledge to handle climate change uncertainty is a valuable addition to the study of adaptive forest management in general and the analysis of forest decision-making, in particular for irreversible or costly decisions of long-term impact. [ABSTRACT FROM AUTHOR]

Abstract: Forestry worldwide has a history of relying upon quantification, drawing on science and economics to compute core concepts such as the relationship between tree-based stand descriptors and marketable timber volumes. This number-oriented approach is grounded in rationalisation and sustained yield objectives that emerged in the eighteenth century and persisted throughout most of the twentieth century. With the rise of Sustainable Forest Management (SFM) as a governing idea in the 1990s, forest policy and management broadened its orientation to encompass different values, including biodiversity and cultural values. Adaptive Forest Management (AFM) has emerged as a more recent paradigm, responding to the complexity of forest ecosystems by building on systematic learning from operational practice, making space for more qualitative approaches. With the development of climate change policy and carbon accounting, the balance changes once again towards the role of numbers in forestry management. In both Australia and the UK, international politics, policy and national debate linking climate change to forests prioritise one public good – carbon sequestration – over others. The quantifiability of carbon makes mitigation more easily communicated and translated into other sectors and across levels of government, so when policy actors attempt to promote the role of forestry in climate change, its contribution to mitigation is receiving more recognition than adaption. At the sub-national level, there is a growing awareness of the urgency of adaptation, but advocates struggle with the challenges of making adaptation legible in the absence of widely recognised forms in which to express results. Our analysis suggests that ways need to be found to combine the historically strong language of number with other, more qualitative languages, to realise the full potential of forestry in climate change policy. [Copyright &y& Elsevier]

Forest bioenergy feedstock production and harvesting systems range from small-scale fuelwood gathering to large-scale industrial plantations and the potential removal of all available aboveground and belowground biomass from intensively managed forests. Across this wide range of options for production and extraction, there is an equally wide range of potential impacts. It is critical that forest biomass procurement systems do not adversely impact forests or the environment; therefore, effective standards and planning tools, based on the best available scientific knowledge, must be in place to prevent these impacts from being realized, and hence ensure a sustainable industry. Sustainable forest management (SFM) certification schemes are one mechanism for applying measurable environmental standards (in the form of criteria and indicators, or C&I) to forest management systems. How existing SFM certification schemes and frameworks, such as C&I and Adaptive Forest Management, can be used to help guide sustainable biomass operations is discussed. The potential impacts of biomass production and harvesting on soil and water resources, site productivity and biodiversity in the forest, as well as issues related to greenhouse gas balances and global and supply-chain impacts, are evaluated. An example is then given of how principles and criteria for sustainable biomass production can be used to address these potential impacts. [ABSTRACT FROM PUBLISHER]