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Among the protected sites of the Eastern Carpathians, the Synevyr National Nature Park (NNP) in the Zakarpattia region of Ukraine is one of the most valuable and was created to preserve its unique mountain beech and spruce forest communities. The importance of the conservation of typical natural virgin forest ecosystems of the Central European mountain systemis emphasized. The aim of this article was to determine the state of the naturalness of virgin forests in the territory of Synevyr NNP, to analyse their syntaxonomy, and to establish the floristic and geobotanical characteristics of its virgin forests and to distinguish the existing biodiversity threats. It was established that the studied plots of beech and spruce forests within the territory of the Synevyr NNP have a distinct virgin nature based on their structure, forest valuation parameters, spontaneous dynamics and other features. Syntaxonomically the virgin forests of the park belong to two associations: Symphyto cordati-Fagetum Vida (1959) 1963 (alliance Fagion sylvaticae Luquet 1926, order Fagetalia sylvaticae Pawłowski 1928, class Сarpino-Fagetea sylvaticae Jakucs ex Passarge 1968) and Luzulo luzuloidis-Fagetum (Du Rietz 1923) Markgraf 1932 (alliance Luzulo-Fagion sylvaticae Lohmeyer & Tx. in Tx. 1954, order Luzulo-Fagetalia Scamoni & Passarge 1959, class Quercetea roboripetraeae Br.-Bl. & Tx. ex Oberd. 1957). The natural and anthropogenic biodiversity threats of these virgin forests are summarized. The results of the research formed the basis for the inclusion of the beech virgin forests of Synevyr NNP as a UNESCO World Heritage Site in the list of objects on "Beech virgin forests and ancient forests of the Carpathians and other regions of Europe". [ABSTRACT FROM AUTHOR]

Forest understorey plants are sensitive to light availability, and different species groups can respond differently to changing light conditions. A plant trait tightly linked to light capture is specific leaf area (SLA). Studies considering the relative role of within‐ and among‐species SLA variation across different species groups (e.g. specialists and generalists) are rarely implemented in temperate forest understories varying in their maturity.We examined community‐level SLA patterns of beech forest understories along a light availability gradient, and for habitat specialists and generalists separately. We then disentangled and quantified the contribution of intraspecific trait variability and interspecific trait differences in shaping SLA patterns.We revealed that the increase in community‐level SLA with decreasing light availability was primarily driven by beech forest specialists (and, to a lesser extent, by forest generalists), and this pattern was mainly determined by specialists' high intraspecific variability. Community‐level SLA was therefore formed by different responses at different organizational levels, i.e. within and among species, and for separate species groups.This study provides insights into factors shaping the shade tolerance strategy in beech forest understorey plants; specialists persistence under putative less favourable conditions (i.e. high irradiation) may be fostered by their ability to adjust their light capture strategies intraspecifically. [ABSTRACT FROM AUTHOR]

The concept of plant functional traits has been demonstrated to be very effective in unravelling the ecological mechanisms governing plant community response to disturbance, especially when research is focused on short-term post-disturbance vegetation dynamics. In this study, we established an experiment to quantify how logging intensity affects the trait composition and functional diversity of understory communities in fir-beech forests in the Dinaric Mountains in Slovenia. Three different silvicultural treatments were implemented: control (no logging), 50% of the growing stock removed and 100% of the growing stock removed. Vegetation surveys of vascular plants were made before (in 2012) and two years after (in 2014) logging. Changes in species traits, C-S-R plant strategies (sensu Grime) and community-level functional diversity were analysed. The importance of traits such as small and light diaspores, short life span and anemochory increased with logging intensity. Moreover, species with the ability of both sexual and vegetative reproduction, longer flowering duration and overwintering green leaves increased in abundance after logging. C-S-R strategies mainly shifted from stress-tolerators in pre-logging conditions towards a more ruderal component in post-logging stands. Logging in the short term increased functional diversity, mainly due to newly colonize d species being functionally dissimilar from persistent residents. Results suggest that logging intensity strongly influences the magnitude of change in both functional composition and diversity, which also has important implications for biodiversity conservation. At the landscape scale, increasing spatial heterogeneity by creating a mosaic of forest stands subjected to different logging intensities will likely contribute to the enhancement of plant functional diversity. [ABSTRACT FROM AUTHOR]

Questions What are the main floristic patterns in European beech forests? Which classification at the alliance and suballiance level is the most convincing? Location Europe and Asia Minor. Methods We applied a TWINSPAN classification to a data set of 24 605 relevés covering the whole range of Fagus sylvatica forests and the western part of Fagus orientalis forests. We identified 24 'operational phytosociological units' (OPUs), which were used for further analysis. The position of each OPU along the soil pH and temperature gradient was evaluated using Ellenberg Indicator Values. Fidelity of species to OPUs was calculated using the phi coefficient and constancy ratio. We compared alternative alliance concepts, corresponding to groups of OPUs, in terms of number and frequency of diagnostic species. We also established formal definitions for the various alliance concepts based on comparison of the total cover of the diagnostic species groups, and evaluated alternative geographical subdivisions of beech forests. Results The first and second division levels of TWINSPAN followed the temperature and soil pH gradients, while lower divisions were mainly geographical. We grouped the 22 OPUs of Fagus sylvatica forests into acidophytic, meso-basiphytic and thermo-basiphytic beech forests, and separated two OPUs of F. orientalis forests. However, a solution with only two ecologically defined alliances of F. sylvatica forests (acidophytic vs basiphytic) was clearly superior with regard to number and frequency of diagnostic species. In contrast, when comparing groupings with three to six geographical alliances of basiphytic beech forests, respectively, we did not find a strongly superior solution. Conclusions We propose to classify F. sylvatica forests into 15 suballiances - three acidophytic and 12 basiphytic ones. Separating these two groups at alliance or order level was clearly supported by our results. Concerning the grouping of the 12 basiphytic suballiances into ecological or geographical alliances, as advocated by many authors, we failed to find an optimal solution. Therefore, we propose a multi-dimensional classification of basiphytic beech forests, including both ecological and geographical groups as equally valid concepts which may be used alternatively depending on the purpose and context of the classification. [ABSTRACT FROM AUTHOR]

Situated at the interface of Central European and Illyrian vegetation, the mesic forests of southwestern Hungary occupy a special position. Despite their importance in vegetation science and conservation, a comprehensive study of the Illyrian mesic forests of the Villány Mts, the southernmost mountain region in Hungary, has not been provided yet. In this study 60 phytocoenological relevés were prepared in the beech, oak-hornbeam, ravine and scree forests of the Villány Mts. To compare the individual associations, we performed a PCoA-ordination, calculated the per plot species number and the per plot protected species number, computed the percentage constancy values of the protected species, identified significant diagnostic species, and prepared the spectra of the coenological preference groups. We used relative ecological indicator values to assess habitat conditions. The PCoA-ordination, the coenological preference group spectra, and to a certain extent the ecological indicator values suggested that the different mesic forests of the Villány Mts show certain similarities. This is probably due to the fact that beech forests and ravine forests are confined to small and atypical stands by the suboptimal environmental conditions. Nonetheless, the number of diagnostic species and the constancy values of protected plants indicated that significant differences do exist between the four associations, the scree forest being the most distinct. We conclude that oak-hornbeam forests and scree forests of the Villány Mts have a regional conservation importance, while the beech and ravine forests are locally important, enhancing the structural, floristical and habitat diversity of the Villány Mts. [ABSTRACT FROM AUTHOR]

Changes in the woodland extent over the last 200 years were assessed from old maps for a 100 ha woodland nature reserve in southern Britain. More detailed changes in the composition and structure of the tree and shrub layers were measured using data from 95 permanent vegetation plots (10 × 10 m) distributed across the reserve at the intersections of a 100 m grid. These were recorded in 1973, 1992 and 2009. The woodland area has more than doubled since the 18th century, but whereas the pre-1800 woodland was mainly Fagus sylvatica the more recent woodland was initially predominantly conifer plantation. These plantations have since developed into mainly broadleaved high forest of Fraxinus excelsior and Acer pseudoplatanus . Changes on the site are the combination of active interventions through management and natural processes (differential species growth, death from disease, windthrow, herbivore damage). Further changes are likely in future in particular from ash dieback ( Hymenoscyphus fraxineus ) and climate change impacts. Many of the changes seen on this reserve are mirrored in woods elsewhere in Britain and Europe. Over periods of a few decades and at the whole-reserve scale the woods can be considered to be relatively stable; at the plot level, or over time-scales of centuries they are very dynamic. Whether woods are judged to be resilient must include definition of the temporal and spatial scales. [ABSTRACT FROM AUTHOR]

Seedling genotype is one of the major factors affecting seedling survival when the rate of damage by natural enemies depends on a host genotype. However, to our knowledge, no previous study has examined the mortality of seedlings adjacent to conspecific adults, considering intraspecific variation in seedling genotypes. On the basis of the assumption that natural enemies adapt to adult trees having a unique genotype, we tested the hypothesis that seedling survival decreases when they are more closely genetically related to neighboring adults, by measuring the mortality rate of seedlings of Fagus crenata growing in a cool-temperate forest in Japan. We estimated the genetic relatedness of seedlings (2 and 6 years old) to the neighboring adult F. crenata using microsatellite analysis and measured seedling survival. We determined that there was a non-significant negative correlation between seedling survival and genetic relatedness in the 2-year-old seedling cohort, and a non-significant but positive correlation in the 6-year-old seedlings. Our results call for further studies on the potential relationship between seedling survival and genetic relatedness to neighboring adults. [ABSTRACT FROM AUTHOR]

The phenology and survival of beech scale, Cryptococcus fagisuga Lindinger (Hemiptera: Eriococcidae), were investigated in part of its native range (Caucasus Mountains, Georgia) and in an invaded area (Massachusetts, USA). Despite nearly identical growing seasons (as measured by cumulative day-degrees), the scale was found to be bivoltine in the Caucasus Mountain region but univoltine in Massachusetts. In Georgia, scales overwintered as adults, whereas in Massachusetts, 1st instar crawlers were the overwintering stage. In Massachusetts, protective cages increased scale survival over a year-long period, but the effect was not great and was presumed to be due to exclusion of generalist predators, not specialized natural enemies. There was no effect of caging on survival in Georgia, and no support was found for the hypothesis that specialized natural enemies might exist in the scale's native range that might be imported for biological control of the pest in the United States. Rather, it appears that selection for resistance in American beech ( Fagus grandifolia Ehrhart; Fagales: Fagaceae) may offer the best chance to restore healthy stands of American beech in North American forests. [ABSTRACT FROM AUTHOR]

Net atmospheric carbon dioxide exchange, total evapotranspiration and net primary production of two neighbouring beech ( Fagus sylvatica L . ) forests in central Germany differing in site management were measured using the eddy covariance technique and biometric methods. The unmanaged site was an old-growth forest with admixtures of ash ( Fraxinus excelsior L.) and sycamore ( Acer pseudoplatanus L.) trees whereas the managed site was a regularly thinned, even-aged (about 130 years old), pure beech stand. Average carbon fluxes measured over seven years did not differ significantly between the two forests. Evapotranspiration was slightly higher (and consequently water use efficiency lower) at the unmanaged site. The maximum rates as well as the interannual variability of both net ecosystem exchange and net primary production were considerably larger at the managed, even-aged stand. The lowest annual carbon sequestration rates were observed in years with high fruit production in beech combined with cold and dry spells during leaf development which affected the carbon balance of the managed forest more than that of the unmanaged forest. In contrast, an extraordinarily dry period in late summer 2003 caused a stronger reduction in net carbon uptake in the old-growth forest which can probably be attributed to the contribution of ash to the ecosystem fluxes. Ash has a different phenology which made it more susceptible to the late summer drought. The relative importance of tree and structural (age, size) diversity, leaf area index and regenerative growth as well as the temporal frame and extent of single weather extremes for the forest–atmosphere exchange is discussed and it is concluded that site management and forest structure needs to be included in soil–vegetation–atmosphere-transfer models as it can often override effects of land use or plant functional type. [ABSTRACT FROM AUTHOR]

In southeast Europe, silvicultural measures for improving forest protective effects against rockfall are often based on unsystematic observation and experience. We compared formalised expert assessment of forest protective effects and silvicultural decision-making with an approach supported by modelling (Rockyfor3D, Rockfor.NET, shadow angle method). The case study was conducted in Fagus sylvatica dominated Alpine forests above the regional road leading to the Ljubelj pass, in Slovenia. We analysed rock sources, silent witnesses, forest structure and regeneration. Expert assessment indicated acceptable protection effects of the forest and their decline in the future. Modelling revealed several road sections endangered by rockfalls. It also indicated subtle differences between silvicultural alternatives: current forest, current forest with cable crane lines, selection forest and non-forested slope. This outcome may be due to short transition zones, small rock sizes, low rock source heights and low resolution of the digital elevation model. Modelling requires more initial input than formalised expert assessment but gives spatially explicit results that enable comparison of silvicultural alternatives, coordination of silviculture and forest operations, and delineation of protection forests. Modelling also supported prioritising of silvicultural measures, where the necessity of silvicultural measures increases with increasing rockfall susceptibility and decreasing long-term stability of stands. [ABSTRACT FROM AUTHOR]

Protection forests play an important role in mitigating the influence of natural hazards. Despite the growing need for protective functions due to aging forests and increased risk of natural disturbances, active forest management has become increasingly uncommon across the Alps. Active management of protection forests can be facilitated by state subsidies. This requires an objective delineation of forests with a direct protection function and the development of silvicultural techniques that mitigate natural hazards. A study of protection efficiency of beech-dominated forests was performed in the Soteska gorge in NW Slovenia, where a main state road and railway are at risk from debris flows and rockfall. We assessed the starting points of debris-flow hazard based on a small-scale geological survey of the terrain characteristics and a local debris flow susceptibility map. We applied the TopRunDF model for determination of the run-out zones. Forest structure data were obtained from 26 sample plots. A detailed description and delineation of forest stands was performed. The results showed that these forests play an important role in the protection of infrastructure. Forest protection efficiency can be improved by stand thinning for stability and careful planning of regeneration patches over time and space. In areas where silvicultural measures cannot provide sufficient protection, technical measures are needed. Since these forests have not been managed for several decades, natural disturbances (windthrow) are frequent. Research findings suggest that regular assessment and management of these beech-dominated protection forests are necessary, contrary to the current practice of non-management in protection forests in Slovenia. [ABSTRACT FROM AUTHOR]

Forests in our country are a very important component for the environment, considering the fact that they cover more then 1 031 000 ha or 36% of total Albania surface. 47% of the total timber volume comes from the utilization of beech forests. In our country beech forests are located in steep and very steep terrain. Taking into account the above facts silviculture and utilization study of these forests is of great interest to identify different conservation and development technologies. Is very important for the future the evaluation of new utilization technologies in the context of a sustainable forestry and silviculture considering the experience we have had in the past has not been very generous. This study has compared different utilization methodologies of beech forest in Albania and Italy. To identify the weak points of utilization works in Albania and the possibility of their improvement has also been of interest to evaluate the productivity of various working sub phases. This study aimed also the study of the actual infrastructure of Albanian beech forest which is very defective and needs maintenance. [ABSTRACT FROM AUTHOR]

Various disturbances in forests often result in the formation of open habitats with characteristics that are distinctly different from those of the original forest (microclimate, illumination, stand age and composition). These disturbances affect the habitat heterogeneity in time and space and seem to drive forest succession and changes in biodiversity in forests. Little is known about how the colonization of deforested habitats by Orthoptera is influenced by environmental factors. We studied the association between the structure of orthopteran assemblages and the age of clear-cuts, vegetation structure and other environmental parameters (size, elevation, altitude). This involved 33 clear-cuts of three age categories in broadleaved forests dominated by European beech. The Orthoptera were sampled using sweep netting and by counting individuals recorded along transects that ran parallel to those used for recording the structure of the vegetation. We recorded significant differences in the number and abundance of species in the three age categories of clear-cuts. Grasshopper species were more abundant than bush-crickets in first year clear-cuts. Species capable of flight occured in all three age categories of clear-cuts (> 62% of the 27 species recorded). All the species of Orthoptera identified were present in two year-old clear-cuts. The species composition and abundance of Ensifera and Caelifera differed in their association with the six vegetation parameters studied. While the Caelifera occurred in habitats with bare ground the Ensifera mainly occurred in those with a higher proportion of shrubs and trees. There was also a positive correlation between number of species of Orthoptera and area of the clear-cut regardless of its age as well between the number of species of Orthoptera and elevation. [ABSTRACT FROM AUTHOR]

In 2008 we compared the terrestrial isopod assemblages from two different habitats, a beech forest and a mixed beech and spruce forest, from north western Romania (Huta Certeze locality). The samples were taken from April to September using pitfall traps. We identified a total of 7 species: Ligidium germanicum, Trichoniscus sp., Hyloniscus transsilvanicus, Protracheoniscus politus, Porcellium collicola, Trachelipus difficilis and Porcellio scaber. A greater diversity and species richness were noticed in the beech forest. The poverty of species in the mixed forest was a consequence of the forest type, the anthropogenic impact and the dry environment. High surface activity of individuals was noticed in the summer months. Even if the species compositions of the two compared isopod assemblages were not identical, there weren't statistically significant differences between them. [ABSTRACT FROM AUTHOR]

We monitored variation in seasonal and annual net ecosystem production (NEP), gross primary production (GPP), and ecosystem respiration ( R) based on 7-year eddy covariance measurements above a cool-temperate deciduous broad-leaved forest (Japanese beech forest). The 7-year means (±SD) of annual NEP, GPP, and R were 312 ± 64, 1250 ± 62, and 938 ± 36 g C m year, respectively. Variation in NEP was much larger than variation in GPP and R. During the growing season, the main factor controlling carbon balance was air temperature; variation in seasonal integrated NEP was regulated by accumulated air temperature (degree-day) with a significant negative correlation, whereas the seasonal ratio of R to GPP was correlated positively with accumulated air temperature. Because the deviation of seasonal NEP was also significantly correlated with seasonal R/GPP, NEP was controlled by R/GPP, depending on air temperature during the growing season. Seasonal R in the defoliation and snow seasons was also important for evaluating the annual carbon balance, because the total number of days in the two seasons was quite large owing to a long snowy winter. In the defoliation and snow seasons, we found defoliation season length was a major factor determining seasonal integrated R, illustrating the positive correlation between R and defoliation season length. The major factors controlling interannual variations in forest carbon balance are discussed. [ABSTRACT FROM AUTHOR]

Extra-zonal beech forests in Tuscany: structure, diversity and synecologic features. The present paper focuses on the structural, synecological and floristic diversity features of beech-dominated forest communities in four major areas of the Antiapenninic Tyrrhenian system in Tuscany: Metalliferous hills, mountains to the south of Mt. Amiata, volcanic area of the upper Lente valley and Mt. Cetona. These are relict woodlands of Holo-Pleistocene origin with a special ecological and conservation value due to their extrazonal location in lowland submediterranean areas. Results show substantial among-area differences in structure, synecology and plant species composition, but in general a potential for coppices to reach the tall forest stage, as demonstrated by the old-growth stands of Pietraporciana and Sassoforte. Compared with montane Apenninic beechwoods, the relatively rich flora of the studied communities include thermophilous species with a southern Apennine-Balkan distribution, making their syntaxonomical position unclear. Closer affinities are found with the calcicolous Beech Forests of the Lathyro veneti-Fagetum association and with the silicicolous ones of the Fraxino orni-Fagetum. Based on the Natura 2000 system, all the examined communities belong to the priority Habitat "Apennine beech forests with Taxus and Ilex" (code: 9210*). Due their relict nature, these biotopes appear vulnerable to climate changes and to a production-oriented forest management. Criteria of naturalistic silviculture should instead promote the dynamic development of these communities towards tall forests and their natural regeneration. INSET: Schema sintassonomico. [ABSTRACT FROM AUTHOR]

The article discusses the study on the attraction and antennal reaction of Vespula vulgaris, a common wasp, to chosen synthetic chemicals in New Zealand beech forests. Vespid wasps are a major problem for it affects the biodiversity of native birds and invertebrates. Seven recognized wasp attractants including acetic acid, isobutanol, and heptyl butyrate were field tested but only heptyl butyrate and octyl butyrate pulled in higher number of wasps than a trap which is non-baited.

The "Izvorul Bigãr" Nature Reserve is located in south-western Romania. The aim of the present paper is to describe some aspects of the flora and vegetation around Bigãr spring. The analysis of the vegetal association was carried out using the method of the Central-European phytocoenological school. The vegetation around the Bigãr spring and waterfall is dominated by compact beech forests with a frequently reduced grassy layer and soil rich in humus. On the banks of the watercourse and on the rocks around the spring there are species specific to flooding plains of the beech sub-stratum and also thermophilous and xerophilous species, many of them Balkan, Pontic or Mediterranean elements. The phytocoenoses we analysed belong to the Phyllitidi - Fagetum Vida (1959) 1963 association. The association is characteristic to shady and moist slopes with soils rich in humus and formed on a lime substratum sometimes with surface rocks. The species with high abundance-dominance values are: Fagus sylvatica, Fraxinus ornus, Acer pseudoplatanus, Tilia cordata, Hedera helix, Asplenium scolopendrium, Arum orientale, Asarum europaeum, Cardamine bulbifera, Lunaria annua, Polypodium vulgare. Such species as Carpinus orientalis, Cotinus coggygria, Fraxinus ornus, Ruscus hypoglossum, Syringa vulgaris point out the thermophilous character of the forests in southern Banat. [ABSTRACT FROM AUTHOR]

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Abstract: Forests are complex ecological systems, characterised by multiple-scale structural and dynamical patterns which are not inferable from a system description that spans only a narrow window of resolution; this makes their investigation a difficult task using standard field sampling protocols. We segment a QuickBird image covering a beech forest in an initial stage of old-growthness – showing, accordingly, a good degree of structural complexity – into three segmentation levels. We apply field-based diversity indices of tree size, spacing, species assemblage to quantify structural heterogeneity amongst forest regions delineated by segmentation. The aim of the study is to evaluate, on a statistical basis, the relationships between spectrally delineated image segments and observed spatial heterogeneity in forest structure, including gaps in the outer canopy. Results show that: some 45% of the segments generated at the coarser segmentation scale (level 1) are surrounded by structurally different neighbours; level 2 segments distinguish spatial heterogeneity in forest structure in about 63% of level 1 segments; level 3 image segments detect better canopy gaps, rather than differences in the spatial pattern of the investigated structural indices. Results support also the idea of a mixture of macro and micro structural heterogeneity within the beech forest: large size populations of trees homogeneous for the examined structural indices at the coarser segmentation level, when analysed at a finer scale, are internally heterogeneous; and vice versa. Findings from this study demonstrate that multiresolution segmentation is able to delineate scale-dependent patterns of forest structural heterogeneity, even in an initial stage of old-growth structural differentiation. This tool has therefore a potential to improve the sampling design of field surveys aimed at characterizing forest structural complexity across multiple spatio-temporal scales. [Copyright &y& Elsevier]

Leaf-fall phenology was studied in a cool–temperate deciduous broad-leaved forest in central Japan in relation to the topographic environmental gradients that occur along a short mountain slope. Leaf-fall phenology was described quantitatively using data from leaf litter collected along the slope. In autumn, leaf fall at the study site tended to occur slightly earlier on the upper slope than on the lower slope. This pattern was found at both the stand and the species levels. Our results suggest that leaf-fall phenology may be affected by difference in microclimatic conditions, because environmental conditions are thought to be more severe on the upper slope than on the lower slope. The less intensive methods used in this study, the litter trap method, and Dixon’s model succeeded in quantifying the phenological patterns of leaf fall within stands and within species along the short mountain slope. [ABSTRACT FROM AUTHOR]

This study investigated the relationship between δ13C of ecosystem components, soluble plant carbohydrates and the isotopic signature of ecosystem respired CO2 (δ13CR) during seasonal changes in soil and atmospheric moisture in a beech (Fagus sylvatica L.) forest in the central Apennine mountains, Italy. Decrease in soil moisture and increase in air vapour pressure deficit during summer correlated with substantial increase in δ13C of leaf and phloem sap soluble sugars. Increases in δ13C of ecosystem respired CO2 were linearly related to increases in phloem sugar δ13C (r2=0.99, P≤0.001) and leaf sugar δ13C (r2=0.981, P≤0.01), indicating that a major proportion of ecosystem respired CO2 was derived from recent assimilates. The slopes of the best-fit lines differed significantly (P≤0.05), however, and were about 0.86 (SE=0.04) for phloem sugars and about 1.63 (SE=0.16) for leaf sugars. Hence, changes in isotopic signature in phloem sugars were transferred to ecosystem respiration in the beech forest, while leaf sugars, with relatively small seasonal changes in δ13C, must have a slower turnover rate or a significant storage component. No significant variation in δ13C was observed in bulk dry matter of various plant and ecosystem components (including leaves, bark, wood, litter and soil organics). The apparent coupling between the δ13C of soluble sugars and ecosystem respiration was associated with large apparent isotopic disequilibria. Values of δ13CR were consistently more depleted by about 4‰ relative to phloem sugars, and by about 2‰ compared to leaf sugars. Since no combination of the measured pools could produce the observed δ13CR signal over the entire season, a significant isotopic discrimination against 13C might be associated with short-term ecosystem respiration. However, these differences might also be explained by substantial contributions of other not measured carbon pools (e.show $132#g., lipids) to ecosystem respiration or contributions linked to differences in footprint area between Keeling plots and carbohydrate sampling. Linking the seasonal and inter-annual variations in carbon isotope composition of carbohydrates and respiratory CO2 should be applicable in carbon cycle models and help the understanding of inter-annual variation in biospheric sink strength. [ABSTRACT FROM AUTHOR]

Without humans, large areas of central Europe would be covered by forests dominated by beech (Fagus silvatica). The spatiotemporal dynamics of natural beech forests are hence a subject of interest for both forest management and conservation. However, since in most regions there are no longer any natural beech forests, their structure and dynamics cannot routinely be analysed and compared to managed forests. The forest model BEech FOREst (BEFORE) is therefore, designed to reconstruct the spatiotemporal dynamics of natural beech forests. BEFORE is a grid-based and partly individual-based model which divides beeches into four different height classes. Changes to the forest structure due to growth, mortality and storm disturbances are entirely described by empirical ‘if-then’ rules. BEFORE is capable of reproducing two patterns which have been observed in remnants of natural beech forests: beech forests consist of a mosaic pattern of small areas (on average 0.3 ha) which are at different developmental stages; at the scale of these small areas, a cyclic succession of three developmental stages occurs, which are characterised by different vertical structures. One typical feature of natural beech forests is hence their very high structural diversity. Gaps in the canopy induce a local pulse of vitality and growth for younger beech trees. These pulses are spread into the vicinity by two mechanisms. Firstly, windfalls affect not only the site of the tree knocked over itself but also neighbouring sites due to the damage caused by the tree falling over. Moreover, since the light is diffuse and oblique, canopy gaps affect also vitality and growth in the neighbourhood of a gap. The results obtained with BEFORE show that natural beech forests achieve quasi-stationary dynamics, demonstrating considerable fluctuations in the forest structure. For example, the percentage of forest area at the optimal stage, which is characterised by a closed canopy and almost no understorey, varies between 10 and 40%, and after extreme storm events even between 0 and 60%. Beech forests with an inner area larger than 40 ha (corresponding to a total area of 70 ha) develop spatiotemporal dynamics which do not differ qualitatively or quantitatively from larger forests, but even very small natural beech forests would exhibit very high temporal and structural diversity. Thus, even small ‘islands’ of unmanaged stands within larger, managed forests would contribute significantly to providing structures typical of natural beech forests. [Copyright &y& Elsevier]

We investigated the patterns of soil nitrogen (N) and forest floor light availability, forest structure and tree species distribution along a topographic gradient on a 200-m mountain slope in a cool-temperate deciduous broad-leaved forest in Japan. Rates of soil N mineralization and nitrification decreased from lower to upper slope positions, revealing that N availability decreased up the slope. Maximum tree height and above-ground biomass were greater on the lower than the upper parts of the slope. Canopy openness, an index of light availability at the forest floor, increased up the slope. Tree species could be placed into three groups according to their distribution patterns on the slope. ‘Ridge’ and ‘valley’ species were distributed on the upper and lower parts of the slope, respectively, whereas ‘uniform’ species were distributed over the entire slope. Topography-mediated resource gradients of soil N and light may be important determinants of species distribution patterns and forest regeneration, and the results of this study imply that the determinants of the regeneration process differ between the lower and upper parts of a slope. The former may be relatively light limited and the latter may be soil N limited. Valley species may have a greater ability to compete for light, whereas ridge species have a greater ability to compete for soil N. The broad distribution of uniform species probably reflects an ability to effectively compete for both light and soil N. [ABSTRACT FROM AUTHOR]

We investigate the patterns of variation of plant community diversity along a silvicultural cycle in a managed beech forest. A statistical model of the silvicultural cycle is constructed in order to identify: (i) the relationships between species and environmental factors, and (ii) species assemblages occurring along the successional gradient. We measure six diversity indices accounting for the structural (species richness (SR), Shannon index, evenness index), the functional (factorial diversity, FD) and the compositional dimension (similarity index within and between records) of biodiversity. We compare their patterns of variation along the succession in order to understand the different information provided by each index.The model reveals that species assemblages occurring in regeneration stands have the highest SR along the cycle. Species coexistence in these assemblages appears to be based on non-equilibrium mechanisms. On the other hand, mature stands with closed canopy seem to host the more organised communities reflecting true coexistence based on equilibrium mechanisms.We discuss the indicative values of the different diversity measures and their interest for the development of sustainable forest management. We advocate that conservation priorities should thus be defined in reference to the processes controlling biodiversity and to the taxonomic groups responding to these processes. [Copyright &y& Elsevier]

Abstract Global warming and changes in rainfall amount and distribution may affect soil respiration as a major carbon flux between the biosphere and the atmosphere. The objectives of this study were to investigate the site to site and interannual variation in soil respiration of six temperate forest sites. Soil respiration was measured using closed chambers over 2 years under mature beech, spruce and pine stands at both Solling and Unterlüß, Germany, which have distinct climates and soils. Cumulative annual CO2 fluxes varied from 4.9 to 5.4 Mg C ha-1 yr-1 at Solling with silty soils and from 4.0 to 5.9 Mg C ha-1 yr-1 at Unterlüß with sandy soils. With one exception soil respiration rates were not significantly different among the six forest sites (site to site variation) and between the years within the same forest site (interannual variation). Only the respiration rate in the spruce stand at Unterlüß was significant lower than the beech stand at Unterlüß in both years. Soil respiration rates of the sandy sites at Unterlüß were limited by soil moisture during the rather dry and warm summer 1999 while soil respiration at the silty Solling site tended to increase. We found a threshold of -80 kPa at 10 cm depth below which soil respiration decreased with increasing drought. Subsequent wetting of sandy soils revealed high CO2 effluxes in the stands at Unterlüß. However, dry periods were infrequent, and our results suggest that temporal variation in soil moisture generally had little effect on annual soil respiration rates. Soil temperature at 5 cm and 10 cm depth explained 83% of the temporal variation in soil respiration using the Arrhenius function. The correlations were weaker using temperature at 0 cm (r 2 = 0.63) and 2.5 cm depth (r 2 = 0.81). Mean Q 10 values for the range from 5 to 15 °C increased... [ABSTRACT FROM AUTHOR]

Following a full mast production in autumn 1995 in the old-growth beech forest of la Tillaie (France), cupules, live and dead 1-yr old seedlings were counted in September 1996 in 40 plots, representing a wide range of ecological conditions. The influence of geomorphology andforest stage on mast production and on seedling establishment and survival was studied. Maximum seedling abundance did not occur in areaswith the largest cupule abundance, but this result was not statistically significant. The presence of a shallow sandstone table under Fontainebleau sand, where beech is far from its ecological optimum, positively influenced the production of mast but negatively influenced seedling survival. Contrary to expectation, the early biostatic rather than the late biostatic phase seemed to be the best stage for beech regeneration. Gaps also provide good environmental conditions for seedling establishment. Humus and light conditions, water availability and competition between beech individuals may explain the results. Light was the main factor influencing mast production in mature stages, and drought was an important factor causing seedling mortality. This study points out the importance of seedling survival for regeneration patterns in beech forests [ABSTRACT FROM AUTHOR]