Growth Of Beech Research Articles

Growth and resource allocation of juvenile European beech and sycamore maple along light availability gradients in uneven-aged forests

The success of tree regeneration in forests strongly depends on light availability. In structured uneven-aged deciduous forests with continuous cover, radiation regimes in the understorey are typically characterized by low and heterogeneous light transmittance. The competitive ability of juvenile trees in these forests is therefore linked to their shade tolerance and expressed by different growth strategies. The related growth traits result in different morphological responses to light availability and shape recruitment dynamics. In the different light availability niches created by continuous-cover forestry, assessing tree growth patterns is crucially important towards silvicultural optimization, which aims to promote species diversity and the sustainable provision of forest ecosystem services. However, information on growth rates of small trees below the caliper limit of typical inventories or monitoring plots is relatively scarce. In an extensive field campaign, we sampled juvenile European beech (Fagus sylvatica L.) and sycamore maple (Acer pseudoplatanus L.) along light availability gradients and analyzed stem discs to quantify primary and secondary growth. We used linear mixed effects models to explain the annual increments of height, basal area and volume as well as allometric exponents. Beech growth rates were explained well by diffuse light availability and ontogeny. Models predicting sycamore growth were slightly less accurate, as indicated by a higher root mean square error. Compared to beech, light availability had a stronger influence on secondary growth of sycamore stems, and height increment decreased with tree age. Trajectories of height and diameter growth of the two species were different at low light availability, where sycamore invested more in height growth and thus was generally slender than beech. At light availability above 20%, similar growth trajectories but different allocation patterns were observed. Overall, we found markedly different growth strategies and different competitive abilities of beech and sycamore in small gaps in uneven-aged mixed deciduous forests. From a management perspective, sycamore should not be left suppressed in shaded conditions as it loses its height growth potential with increasing age. Tending measures may be needed for sycamore to maintain its stability and low height to diameter ratio, but not for juvenile beech, which benefits from positive effects of crowding on height growth.

Dendroclimatic study of a mixed spruce-fir-beech forest in the Czech Republic

European forests are undergoing an important transition due to the current climate change, as monocultures are being gradually replaced by mixed forests. Understanding tree growth in mixed forests under a changing climate is challenging because of tree species’ adaptation and long-term forest planning. In this study, we evaluate the long-term behaviour of Norway spruce (Picea abies), silver fir (Abies alba) and European beech (Fagus sylvatica) from a low montane range at the Czech-Austrian border. Species-specific tree-ring width chronologies have revealed significantly decreasing growth trends since the 2000s. Temporally unstable climate–growth relationships showed an increasing negative effect of current growing season drought on spruce growth and a positive effect of dormant season temperature on fir and beech growth. Our results suggest that though species’ response to climate change differs in the mixed forest, growth reduction in the last years has been proved for all species, likely due to frequent climate extremes.

Lowest drought sensitivity and decreasing growth synchrony towards the dry distribution margin of European beech

AbstractAimClimate limits the potential distribution ranges of species. Establishment and growth of individuals at range margins is assumed to be more limited by extreme events such as drought or frost events than in the centre of their range. We explore whether the growth of beech is more sensitive to drought towards the dry distribution margin and more sensitive to frost towards the cold distribution margin. Furthermore, we aim to gain insight into the adaptive potential of beech towards both the dry and cold distribution margins.LocationEuropean gradient from the dry (Spain) to the cold (Poland, Sweden) distribution margin of beech.TaxonEuropean beech (Fagus sylvatica L.).MethodsWe applied a range‐wide dendroecological study to analyse spatial and temporal trends in climate–growth relationships. We further investigated negative growth anomalies and growth synchrony towards the range margins.ResultsWe found beech to be drought sensitive across its whole range, except at the dry distribution margin. Furthermore, sensitivity to winter temperature was not found in the centre or at the cold distribution margin, but at the southern distribution margin. Growth synchrony was lower at the dry than at the cold distribution margin.Main conclusionsBeech seems to be adapted to drought at the dry distribution margin with a high adaptive potential indicated by the lowest growth synchrony along the gradient. At the cold distribution margin, cold events in winter and spring were less important for growth than drought. Still, the importance of spring frost for beech growth appears to increase in recent decades. Considering a projected north‐eastward shift of the distribution range, beech is likely facing drought stress in combination with spring frost risk at the cold margin which could lead to a hampered range expansion.

Tree species diversity improves beech growth and alters its physiological response to drought

Beech trees growing in biodiverse patches in Belgium have higher radial growth and are less physiologically sensitive to drought than those in monocultures. Forest diversification therefore alleviates the negative effects of drought on beech. Common beech, a widespread and economically important tree species in Europe, is known to be drought sensitive. For ensuring its survival under increasing future drought conditions, we need to advance our understanding on the relationships between drought and its growth performance. Diversifying forests has been proposed as a management strategy to mitigate the effects of drought, because a more complete use of the available water is expected. We made use of a tree species diversity gradient in Belgium to study if beech trees growing in diverse forest patches are more resistant and resilient to drought than beech trees in monocultures. Combining dendrochronological and stable carbon (δ13C) and oxygen isotope (δ18O) data allowed for studying the effect of tree species diversity on the response of beech growth to drought regarding stem radial growth and physiological performance. Up to 62% enhanced stem radial growth strongly increased growth stability, and higher resistance to drought was observed for beech trees in diverse forest patches. Beech performs best in three-species mixtures, particularly those with oak and maple. In drought years, beech growth is more reduced in monocultures than mixtures. During these drought years, δ13C values increased, and the increase was weaker in beech trees of diverse stands compared to monospecific stands, indicating enhanced stomatal conductance and growth continuation in mixtures. δ18O patterns did not indicate a clear effect of diversity or the response of beech trees to drought. Overall, our results indicate that until now, still the positive effects of diversity on beech growth outperform the negative effects induced by drought.

Growth and mortality of Norway spruce and European beech in monospecific and mixed-species stands under natural episodic and experimentally extended drought. Results of the KROOF throughfall exclusion experiment

Key messageUnder severe drought, growth of Norway spruce suffered much more than European beech. Norway spruce benefited from growing in the environment of beech, and both species acclimated slightly to 5 years of experimentally extended drought.Recent studies show that the detrimental effects of drought on stand growth are mitigated when the stand contains mixed tree species. We analysed the growth responses of Norway spruce and European beech to episodic and experimentally extended drought in intra- and inter-specific mature stands. We used annual diameter growth records dating back to 1998 to determine the impact of the natural episodic drought in 2003 and 2015. To analyse extended drought, spruce and beech trees were exposed to extreme drought under automatic throughfall exclusion roofs from 2014 to 2018. The growth of spruce in an inter-specific environment with beech was 20–50% less affected by natural episodic drought compared with an intra-specific constellation. When beech grew in an inter-specific environment, it was by 23% more affected by drought compared to intra-specific conditions, but seemed to recover faster. The induced drought from 2014 to 2018 resulted in a strong growth reduction in the first year particularly for spruce, followed by a slight acclimation to the dry conditions. Beech acclimated and recovered faster than spruce across all growing conditions, while spruce only acclimatized faster in the environment of beech. Both species showed a higher mortality under induced drought compared with the controls; for spruce, the mortality rate was fivefold higher compared to the long-term mortality. The long-term moderate-growth stabilization and the growth increase after the 5-year exposure to drought suggest a gradual acclimation to drought by beech. The resistance and acclimation to drought of spruce when growing in mixture should be considered when designing resource efficient and productive mixed conifer-broadleaved stands for future climates.

Evidence of elevation-specific growth changes of spruce, fir, and beech in European mixed mountain forests during the last three centuries

In Europe, mixed mountain forests, primarily comprised of Norway spruce (Picea abies (L.) Karst.), silver fir (Abies alba Mill.), and European beech (Fagus sylvatica L.), cover about 10 × 106 ha at elevations between ∼600 and 1600 m a.s.l. These forests provide invaluable ecosystem services. However, the growth of these forests and the competition among their main species are expected to be strongly affected by climate warming. In this study, we analyzed the growth development of spruce, fir, and beech in moist mixed mountain forests in Europe over the last 300 years. Based on tree-ring analyses on long-term observational plots, we found for all three species (i) a nondecelerating, linear diameter growth trend spanning more than 300 years; (ii) increased growth levels and trends, the latter being particularly pronounced for fir and beech; and (iii) an elevation-dependent change of fir and beech growth. Whereas in the past, the growth was highest at lower elevations, today’s growth is superior at higher elevations. This spatiotemporal pattern indicates significant changes in the growth and interspecific competition at the expense of spruce in mixed mountain forests. We discuss possible causes, consequences, and silvicultural implications of these distinct growth changes in mixed mountain forests.

Spatio-temporal assessment of beech growth in relation to climate extremes in Slovenia – An integrated approach using remote sensing and tree-ring data

Climate change is predicted to affect tree growth due to increased frequency and intensity of extreme events such as ice storms, droughts and heatwaves. Yet, there is still a lot of uncertainty on how trees respond to an increase in frequency of extreme events. Use of both ground-based wood increment (i.e. ring width) and remotely sensed data (i.e. vegetation indices) can be used to scale-up ground measurements, where there is a link between the two, but this has only been demonstrated in a few studies. We used tree-ring data together with crown features derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) to assess the effect of extreme climate events on the growth of beech (Fagus sylvatica L.) in Slovenia. We found evidence that years with climate extremes during the growing season (drought, high temperatures) had a lower ring width index (RWI) but we could not find such evidence for the remotely sensed EVI (Enhanced Vegetation Index). However, when assessing specific events where leaf burning or wilting has been reported (e.g. August 2011) we did see large EVI anomalies. This implies that the impact of drought or heatwave events cannot be captured by EVI anomalies until physical damage on the canopy is caused. This also means that upscaling the effect of climate extremes on RWI by using EVI anomalies is not straightforward. An exception is the 2014 ice storm that caused a large decline in both RWI and EVI. Extreme climatic parameters explained just a small part of the variation in both RWI and EVI by, which could indicate an effect of other climate variables (e.g. late frost) or biotic stressors such as insect outbreaks. Furthermore, we found that RWI was lower in the year after a climate extreme occurred in the late summer. Most likely due to the gradual increase in temperature and more frequent drought we found negative trends in RWI and EVI. EVI maps could indicate where beech is sensitive to climate changes and could be used for planning mitigation interventions. Logical next steps should focus on a tree-based understanding of the short -and long-term effects of climate extremes on tree growth and survival, taking into account differential carbon allocation to the crown (EVI) and to wood-based variables. This research highlights the value of an integrated approach for upscaling tree-based knowledge to the forest level.

Interactive effects of elevated CO2 and neighbourhood competition on the radial growth of European beech (Fagus sylvatica L.) seedlings

This paper explores the effects of three types of admixture treatments: (1) monospecific (M: European beech surrounded by six European beech seedlings), (2) single-admixture (S: European beech surrounded by six Norway spruce seedlings), and (3) group-admixture (G: European beech surrounded by three Norway spruce and three European beech seedlings), and two different CO2 concentrations ([CO2]): ambient [AMBCO2, 385 μmol (CO2) mol−1] and elevated [ELECO2, 770 μmol (CO2) mol−1] on the stem diameter increment (DI), based on a 7-year monitoring of the diameter growth of European beech (Fagus sylvatica L.) seedlings. Furthermore, to improve our understanding of the influence of climatic variables, we assessed the effects of precipitation and temperature on radial growth. After 7 years’ experience (irrespective of admixture treatment), our data were not able to confirm the effect of elevated CO2 on the diameter growth (p value = 0.35), but the result was changed when the effect of elevated CO2 was considered under the different types of admixture. Elevated CO2 along with single-admixture increased the diameter increment significantly (p value = 0.001). In contrast, we characterized a significant effect of AMBCO2 × G interaction on DI (p value = 0.002). But DI was unaffected by elevated CO2 in M (p value = 0.77). In both [CO2], inter-specific competition with spruce resulted in the highest radial growth. The inter-specific interaction was most pronounced in the lower proportion with spruce (S) in ELECO2, while in ambient CO2, the higher proportion with spruce (G) had the greatest effect on the radial growth. With respect to the climatic factors, our observations showed that temperature had a stronger influence than precipitation in ELECO2, but in AMBCO2, precipitation had the strongest effect on the radial growth as indicated by the statistically significant correlation between climatic variables and radial growth. Overall, our result suggested that seedlings growth was more under the control of climate and edaphic factors than dependent on tree species diversity and CO2 concentrations.

The effect of climate on the radial growth of Oriental Beech in the Southern limit of its distribution area

The effect of climate on the radial growth of Oriental Beech in the Southern limit of its distribution area

Annual Beech (Fagus sylvatica) Growth Rings and Solar-Related Climate Variations in the Central and Western Balkans in the 18th–21st Centuries

Abstract—This work analyzes a time series of annual growth ring widths for beech trees (Fagus sylvatica) in the western and central Balkans (Stara Planina, Bulgaria) to identify solar-related climate cycles. The effects of solar activity on beech growth during the Dalton Grand Solar Minimum (1793/98–1833) are studied based on samples ≥200 years of age. Two different methods (T–R periodogram analysis and wavelet analysis) are used to identify statistically significant variations with periods of 20–22, ~40, 60–70, and 210–220 years in most of the samples. Two samples are found to have a cycle of about 110 years. Statistically significant correlations between the ring widths and precipitation amounts and the temperatures from data of the nearest weather stations for 1899–2012 confidently manifest themselves in all four central Balkan samples and one western Balkan sample. Based on the results, it is concluded that a period of cooling and increased precipitation has likely begun in the climate of Bulgaria. The process is proceeding slowly, having begun approximately in 2007–2010, but it may noticeably accelerate after the end of solar cycle 25 and during cycles 26 and 27. It is concluded that cycle 26 is likely to be delayed in development.

The soil conditions of the forests of Zala County and their impact on the growth of beech

Summary During the research, we studied the soil conditions in Zala County's forests and examined the effect on the growth of beech forests on these conditions. Data of National Forest Data Base (NFDB) were analysed for investigation. Most of the forests in Zala County are situated less than 150 m above sea level, their location and topography is very diverse. In most of the forests the groundwater level is deeply beneath the surface so the forests can utilize only the amount of precipitation. In accordance with the geological and climatic conditions, Luvisols were formed predominantly, especially the clayic Luvisols and the gleyic Luvisols are the most typical. In addition, there are still Cambisols and stagnic Luvisols as well. In a small percentage, there are forest stands on rendzinic Leptosols, Vertisol, Regosol and Histosol. According to the favourable parent material, forests have got a deep or medium thickness of soil and the typical texture is loam. Based on the research, soil layer thickness and texture had significant impact on the growth of beech forest stands in terms of soil properties.

Disturbances and Climate Drive Structure, Stability, and Growth in Mixed Temperate Old-growth Rainforests in the Caucasus

The Colchic rainforest of the Western Caucasus is one of the few temperate rainforests dominated by broadleaf deciduous trees. Understanding natural dynamics of broadleaf-dominated temperate rainforests is essential for their conservation and management. Here, we investigate for the first time the structure, natural disturbance, and recruitment dynamics of a mixed Colchic old-growth rainforest, dominated by Fagus orientalis and Picea orientalis. We used forest inventories and dendrochronological analysis of tree growth in five 30-m-radius plots to quantify forest structure, growth, and disturbances. For the last 400 years, the forest experienced a mixed disturbance regime dominated by frequent small gaps superimposed onto medium disturbances with about a 25-year recurrence period, with no evidences of stand-replacing disturbances. This disturbance regime favored the dominance of shade-tolerant, late successional species with slow tree canopy access through multiple growth releases. These dynamics impose low growth rates and continuous recruitment of spruce and beech, and contributed to a high heterogeneity of tree ages and sizes that result in stable forest structure, as suggested by the low stand slenderness. Spruces were the oldest (up to 427 years) and fastest growing trees in the forest, suggesting that their low presence in the forest is due to low disturbance rates that limit their recruitment. Spring climate conditions that promoted beech growth were detrimental for spruce growth, suggesting that interspecies interactions may condition the effect of climate on forest growth and development. The dynamic equilibrium state we reconstructed in this old-growth forest could likely be disrupted by anthropogenic disturbances or management.

Growth response of mixed beech forests to climate change, various management and game pressure in Central Europe

The growth, structure and production of mixed beech (Fagus sylvatica L.) forests were analysed in the Broumovsko Protected Landscape Area, Czech Republic. The objective of the paper was to evaluate stand structure, timber production and dynamics of forests with historically different silvicultural practices in relation to climate conditions, management and game damage. The results indicate that scree forests (coppices and coppices with standards) were stands with high-rich species diversity and structure compared to herb-rich beech forests (high forests) with higher timber production. The Norway spruce (Picea abies [L.] Karst.) was the most sensitive tree species compared to low growth variability in European beech. The climate factors had the highest effect on radial growth from June to August. Natural regeneration showed great density potential (13,880–186,462 recruits·ha<sup>–1</sup>), especially in expansion of maples and European ash (Fraxinus excelsior L.). However, recruits were seriously limiting by damage caused by hoofed game, especially in silver fir (Abies alba Mill.; 53% browsing damage), wych elm (Ulmus glabra Hudson; 51%) and rowan (Sorbus aucuparia L.; 50%).

Morphology, Growth and Architecture Response of Beech (Fagus orientalis Lipsky) and Maple Tree (Acer velutinum Boiss.) Seedlings to Soil Compaction Stress Caused by Mechanized Logging Operations

The Caspian forests of Iran were monitored and evaluated for forest natural regeneration after logging activities for more than a decade. This large area has a substantial ecological, environmental and socio-economic importance. Ground based skidding is the most common logging method in these forests and soil compaction is the most critical consequence of this method. One of the current main topics and important emerging issue in forest research of the last decade are discussed in this study. Soil compaction has major influences on growth and/or mortality rates of forest seedlings. This study has lasted for over ten years so as to have a clear overview related to forest natural regeneration after logging activities. We monitored and evaluated physical soil properties (bulk density, penetration resistance and total porosity) and their effects on maple and beech seedlings on 10-year-old skid trails in the Iranian Caspian forests. Results obtained from evaluating the impact of skid trails within the aforementioned three soil physical parameters were significant; bulk density increased by 12.6% on log skidded routes (between two skidder tires on skid trail) and 36.1% on tire tracks, compared to non-skid trails (1.19 g/cm3), penetration resistance increased by 68% on log skidded routes and 220% on tire tracks, compared to non-skid trails (0.25 MPa), total porosity decreased by 12.8% on log skidded routes and 30.9% on tire tracks, compared to non-skid trails (54%). Among the morphological parameters, lateral root length (LRL) and root penetration depth (RPD) showed the highest decrease at soil compaction compared to the control (decrease in LRL: 60% in maple and 44% in beech; decrease in RPD: 56% in both maple and beech); the main response of growth parameters to soil compaction was found in roots (decrease in dry mass of 36% both in maple and beech); architectural parameters were also influenced by soil compaction, and the response of both seedling species was more evident in the ratio of main root to stem length (RRS) (reduction in RRS 42% in maple, 33% in beech); the ratio of RPD to main root length (RPL) also showed a great reduction (reduction in RPL 20% in maple 33% in beech). Physical soil properties, changes in other environmental properties of skid trails, created differences in beech and maple seedling growth between the skid trails and non-skid trails. This was closely related to the physiological characteristics of the two species studied. Beech seedlings reacted well to a moderate uncovering but they needed little disturbed soil, even if there was a very mixed bedding. Maple seedlings reacted better than beech seedlings to the uncovering and soil disturbance. The effects of the skid trail on morphology, growth and architecture of maple seedlings in the Hyrcanian beech forests showed that the maple, as a seedling, is a suitable species for maintaining the physical properties of skid trails after logging operations in the beech stands in the Caspian forests of Iran.

SEASONAL DYNAMICS OF TOTAL SOLUBLE PROTEINS IN ADULT TREES OF Quercus petraea (Matts.) Liebl. AND Fagus sylvatica L.


 
 
 The complete distribution of total soluble proteins was investigated in 40-year-old oak and beech trees, felled at two dates (October 1999 and June 2000), to estimate seasonal variations in protein content at tree level. The concentration of total soluble proteins was nearly twice as high in oak compared to beech (755 mg.g-1 Dry Mass vs. 4.2 mg.g-1 Dry Mass, respectively) and 10 times lower than total non structural carbohydrates. Scaling from samples to total tree biomass, the contribution of C stored as total soluble proteins accounted for 500 gC in oak trees and only for 250 gC in beech trees. The stem was the major storage compartment in both species. Soluble proteins made up most of nitrogen at the stem and roots of oaks, while in its branches and in all beech organs, several N compounds predominated. These concentrations varied before bud break and stem growth in oak and beech. The seasonal progression of total soluble proteins in twigs of both species showed opposite patterns, especially during Spring, probably due to internal redistribution of proteins from upper stem and large branches. The dates of minimum and maximum concentrations were different for total soluble proteins and total non structural carbohydrates.
 
 
 

Summer drought and spring frost, but not their interaction, constrain European beech and Silver fir growth in their southern distribution limits

Climate warming has lengthened the growing season by advancing leaf unfolding in many temperate tree species. However, an earlier leaf unfolding increases also the risk of frost damage in spring which may reduce tree radial growth. In equatorward populations of temperate tree species, both late frosts and summer droughts impose two constraints to tree growth, but their effects on growth are understudied. We used a tree-ring network of 71 forests to evaluate the potential influence of late frosts and summer droughts on growth in two tree species that reach their southern distribution limits in north-eastern Spain: the deciduous European beech (Fagus sylvatica L.) and the evergreen Silver fir (Abies alba Mill). The occurrence of late frost events and summer drought was quantified by using a high-resolution daily temperature and precipitation dataset considering the period 1950–2012. Late frosts were defined as days with average temperature below 0 °C in the site-specific frost-free period, whereas drought was quantified using the 18 month-long August Standardized Precipitation Evapotranspiration Index (SPEI). The growth of European beech and Silver fir was reduced by the occurrence of both late frost events and summer drought. However, we did not find a significant interaction on growth of these two climate extremes. Beech was more negatively impacted by late frosts, whereas Silver fir was more impacted by summer drought. Further studies could use remote-sensing information or in situ phenological records to refine our frost index and better elucidate how late frosts affect growth, whether they interact with drought to constrain growth, and how resilience mechanisms related to post-frost refoliation operate in beech.

Less is more: Effects of competition reduction and facilitation on intra-annual (basal area) growth of mature European beech

KEY MESSAGE: Species-specific neighborhood identity effects such as competition reduction or facilitation can positively influence growth patterns of Fagus sylvatica at a given site, but are not strong enough to overcome fundamental growth–environment interactions of European beech. Competition and growth dynamics operating within multi-species tree stands are more complex than interactions within evenly aged monocultures. In three major geographic regions of Germany, we used electronic dendrometers to analyze the impact of neighborhood identity effects such as competition reduction or facilitation on the intra-annual stem growth patterns of Fagus sylvatica (European beech) on various time scales (day to year). Although not consistently significant, within the same study site average basal area growth relative to initial values was always higher at the ends of the growing seasons if subject tree beeches were exposed exclusively to interspecific competition. Weibull growth curves were fitted to rescaled dendrometer profiles. Analysis of the resulting Weibull scale (T) and shape (m) parameter estimates indicated the following: within the same growing area, initial growth trends of beeches in either con- or allo-specific competitive neighborhoods did not differ significantly, but subject trees exclusively surrounded by Pinus sylvestris benefited through extended duration of growth. These findings are reflected in the results for onset, cessation and total duration of wood formation calculated from inverse Weibull functions. Results of this study tend to confirm the assumption that interspecific interference induces higher daily stem growth rates of beech throughout the entire growing season. However, although particular species-specific neighborhood identity or mixing effects can indeed positively influence growth patterns of Fagus sylvatica at a given site, they are not strong enough to overcome fundamental growth–environment interactions of European beech.

Uncertainty of Carbon Economy Using the Faustmann Model

Forest growth predictions are used to build expectations about the future economic performance of management decisions. Faustmann land expectation value (LEV) is a widely used criterion in forestry to evaluate a diversity of decision parameters, such as rotation age and thinning regimes. Most of the predictions and, consequently, expectations are based on emperical knowledge, assuming a steady state in climate and a deterministic forest growth approach. However, the climate may change to potentially different degrees in the coming decades, causing a dynamic and uncertain forest growth and carbon budget. Moreover, carbon economy in forestry, defined as opportunity cost of in situ carbon sequestration, can hardly be analysed using empirical models and calls for process-based forest biomass production models. Process-based models include numerous parameters and processes that embody some degree of uncertainty. The uncertainty of these parameters and climate state propagates over time to the final decision about carbon economy and optimal management solutions. Here we quantify this uncertainty using Bayesian inference and apply twelve different climate change scenarios to evaluate the forecasts of the process-based forest model 3-PG, to predict the growth of European beech (Fagus Sylvatica) in central european conditions as an example. The results show a strong influence of the model’s parameters uncertainty on the final decisions about timber based and carbon economy. The uncertainty triples if different climate change scenarios are applied as a source of deep uncertainty where no probability can be assigned to any scenario. To deal with deep uncertainty, a robust decision-making approach has been applied to find solutions with minimum regret or maximum value at risk regarding all scenarios. We conclude that communicating uncertainty is a fundamental issue for forestry economics under changing climate conditions, especially if carbon sequestration is an asset. The key message for designing global forest governance policy in the uncertain times of climate change will be the necessity to take into account both the uncertainty on the demand side, that is, socio-economic developments and regional population needs for forest ecosystem services such as wood, but also the uncertainty of the supply side and the inherent ecological uncertainties in predicting the forests’ growth, resources, and climatic conditions.

Impacts of Multiple Environmental Change Drivers on Growth of European Beech (Fagus sylvatica): Forest History Matters

Revealing the interactive effects of multiple environmental change drivers (water deficits, nitrogen (N) deposition, land-use change) is crucial for evaluating actual and possible future changes in forest ecosystem functioning. Here, we analyse whether and to what extent combined effects of spring and summer water deficits and variable amounts of N deposition affect radial growth of beech trees growing on forest sites with a different forest history. Dendrochronological data showed that trees growing on ancient forest sites (forest continuity > 200 years) exhibit a higher negative growth response under high N deposition and simultaneous spring water deficits than trees growing on recent (post-agricultural) forest sites. Based on additional analyses of the fine root system and masting behaviour, we propose two different mechanisms to explain differing influences of N deposition and water deficits on negative radial growth responses in recent and ancient forests: (1) for both forest history types, growth reductions during summer water deficits result from the antagonistic effects of elevated N deposition according to the ‘resource optimization hypothesis’. The tendency towards higher negative growth responses in recent forests seems to be caused by a higher fine root mortality and lower standing fine root biomass compared to ancient forests; (2) higher growth reductions in ancient forests during spring water deficits are likely the result of mass fructification, which is enhanced by N deposition. We conclude that nutrient cycling may differ between forests with contrasting forest history, which can modulate the growth trajectories of forests in response to multiple, co-occurring environmental changes.

Exploring Nonlinear Intra-Annual Growth Dynamics in Fagus sylvatica L. Trees at the Italian ICP-Forests Level II Network

The European beech (Fagus sylvatica L.) is a widely distributed tree species across Europe, highly sensitive to climate change and global warming. This study illustrates results of a 5-year monitoring time period from eight sites of the ICP-Forests Level II (intensive monitoring network) along the Italian latitudinal gradient. The tree-level relationship between tree growth dynamics and environmental factors, including seasonal climate fluctuations were investigated by means of tree-level Generalized Additive Mixed Models (GAMMs). Model results revealed that climate was responsible for just a portion of the variability in beech growth dynamics. Even if climatic predictors were highly significant in almost all sites, the model explained nearly 30% of the total variance (with just a maximum value of 71.6%), leaving the remaining variance unexplained and likely connected with forest management trajectories applied to each site (e.g., aged coppice and fully grown high forest). Climate change scenarios were then applied to predict site-specific future responses. By applying climate change scenarios, it was predicted that central and northern Italy would face similar climatic conditions to those currently detected at southern latitudes. A special case study was represented by VEN1 plot (Veneto, Northern Italy) whose current and future climate regimes were grouped in a unique and separated cluster.