Distribution of the timber quality attribute ‘knot surface’ in logs of Fagus sylvatica L. from pure and mixed forest stands

European Journal of Forest Research - Research on mixed forests has mostly focused on tree growth and productivity, or resistance and resilience in changing climate conditions, but only rarely on...     

Quantification of tree species diversity in forest stands—model BIODIVERSS

This paper presents a method for complex evaluation and quantification of tree-layer species diversity in forest ecosystems—model BIODIVERSS. The model was constructed for the assessment of species diversity on a small-scale (forest-stand) level, but may be applied with advantage to regional and large-scale inventories. The probability of correct classification of species diversity degree is relatively high; e.g. with a sampling intensity of only 1.5%, the correctness of the classification by the model is already 90%. Model BIODIVERSS is a simple and practical tool. It can be used directly during fieldwork, since for its application only a pocket calculator is needed.     

Rural household and forest: an evaluation of household’s dependency on community forest in Nepal

The aim of this paper is to analyze the level of dependency of rural households on forests, based on the economic status of the households and the property regimes of forests. The analysis of household-level dependency suggests that large numbers of rural households are benefiting regularly from their community forests. Out of three forest property regimes examined, community forests were found to be the most prominent sources for supplying forest products to local households. Analysis of the degree of forest-products dependency and the economic status of households shows that the low economic status households rely more on the community forest than the economically better-off households. In addition, a ² analysis indicates that the economic status of households affects the degree of forest-product collection activities. The results show three types of property regime with respect to forest management in Chitwan. Each regime holds its own ownership rights, which control the harvesting of forest products and provides incentives to the local households.     

Transpiration of forest trees and stands at different altitude: consistencies rather than contrasts?

Compared to lowland trees and forests, evidence on water relations at mountainous and sub-alpine sites with their climatic and topographic peculiarities is scarce. On such limited grounds, the outcome of three pilot studies is reviewed, intended to launch working hypotheses for initiating integrative research across the altitudinal gradient of the European Alps. Highlighted are tree transpiration and structural differentiation as well as stand water balance of mono-specific and/or mixed forests with Picea abies, Pinus cembra, Larix decidua and Fagus sylvatica at sub-alpine (timberline ecotone), mountainous and colline elevation. Given the preliminary evidence, tree-allometric structures of relevancy for water transport appeared to be independent of elevation and forest type, although timberline trees under open-canopy conditions did not buffer transpiration by internal water storage and had enhanced foliage/sapwood area ratios. Transpiration appeared to depend on site conditions rather than site-dependent adaptation. Canopy transpiration approached 20% of the high seasonal precipitation at the mountainous site, with about 60% being ascribed to run-off, whereas the water budget of the colline site was balanced during summer. The water balance of the subalpine site resembled, at lower precipitation, that of the mountainous site. The derived hypotheses focus on mixed-stand transpiration under altitude-specific topography and moisture regimes, hydraulic adaptation and water demand versus uptake capacity, as this latter ratio is crucial at high altitude in view of expected warming. The clarification of consistencies relative to contrasts indicated by the pilot studies will be challenging across altitudes in view of tree species, forest types and topography.     

‘Climatic factors control rodent seed predation in Pinus pinea L. stands in Central Spain’

? Context

Pinus pinea L. presents serious problems of natural regeneration in managed forest of Central Spain. The species exhibits specific traits linked to frugivore activity. Therefore, information on plant–animal interactions may be crucial to understand regeneration failure.

? Aims

Determining the spatio-temporal pattern of P. pinea seed predation by Apodemus sylvaticus L. and the factors involved. Exploring the importance of A. sylvaticus L. as a disperser of P. pinea. Identifying other frugivores and their seasonal patterns.

? Methods

An intensive 24-month seed predation trial was carried out. The probability of seeds escaping predation was modelled through a zero-inflated binomial mixed model. Experiments on seed dispersal by A. sylvaticus were conducted. Cameras were set up to identify other potential frugivores.

? Results

Decreasing rodent population in summer and masting enhances seed survival. Seeds were exploited more rapidly nearby parent trees and shelters. A. sylvaticus dispersal activity was found to be scarce. Corvids marginally preyed upon P. pinea seeds.

? Conclusions

Survival of P. pinea seeds is climate-controlled through the timing of the dry period together with masting occurrence. Should germination not take place during the survival period, establishment may be limited. A. sylvaticus-mediated dispersal does not modify the seed shadow. Seasonality of corvid activity points to a role of corvids in dispersal.     

A comprehensive framework of forest stand property–density relationships: perspectives for plant population ecology and forest management

? Context

There are many stand property–density relationships in ecology which represent emergent properties of plant populations. Examples include self-thinning, competition–density effect, constant final yield, and age-related decline in stand growth. We suggest that these relationships are different aspects of a general framework of stand property–density relationships.

? Aims

We aim to illustrate the generalities and ecological implications of stand property–density relationships, and organize them in a comprehensive framework.

? Methods

We illustrate relationships between stand property and density (1) at one point in time, (2) over time, and (3) independent of time. We review the consequences of considering different variables to characterize stand property (mean tree size, mean tree growth, stand growth, stand yield, stand leaf area).

? Results

We provide a framework that integrates the broad categories of stand property–density relationships and individual expressions of these relationships. For example, we conclude that constant final yield is a special case of the growth–growing stock relationship for life forms were yield is a reasonable approximation of growth (non-woody plants).

? Conclusion

There is support in the literature for leaf area being broadly integrative with respect to various expressions of stand property–density relationships. We show how this is and suggest implications for plant population ecology and forest management.     

The mean tree mass–stand density index relationship for forest stands in China

Most traditional studies of mean tree mass (MTM)– density relationships focus on crowded stands, without considering stands characterized with canopy gaps. We developed a model to estimate MTM of closed and unclosed forest stands based on stand density index (SDI). Data were obtained from eight forest stands in China to test the generality of this model. MTM was accurately expressed in terms of SDI by combining the equations for SDI and Yoda's model, and exponents of the MTM–SDI relationship ranged from –2.23 to 1.93. Compared with density, SDI is a better predictor of MTM, regardless of the degree of canopy closure in the stands.     

Relationships of climate change and tree ring of Betula ermanii tree line forest in Changbai Mountain

Based on the tree-ring growth characteristics of Erman＇s birch （Betula ermanii charm.） and the relationships between it and climatic ）＇actors at elevation of 1950m, the sensitivity of tree lines in Changbai Mountain to climatic factors was assessed. The results indicated tree line forest in Changbai Mountain had an obvious sensitivity to climate factors. However, difference from other study sits is that the main climatic control factor on tree-ring growth was not current growth season temperatures, as might be expected, but previous winter and current March temperature. Although the precipitation in the region was quite abundant, the tree-ring growth was still significantly correlated with the precipitation during previous winter and current spring. Additionally, climatic factors which influenced the Erman＇s birch growth were not the yearly variables, but seasonal and monthly variables. Therefore, the reported increase in yearly mean temperature and total yearly precipitation since 1980s was not responded by sustained increase in ring widths in recent decades.     

Future orientation and planning in forestry: a comparison of forest managers’ planning horizons in Germany and the Netherlands

Long range (or strategic) planning is an important tool for forest management to deal with the complex and unpredictable future. However, it is the ability to make meaningful predictions about the rapidly changing future that is questioned. What appears to be particularly neglected is the question of the length of time horizons and the limits (if any) to these horizons, despite being considered one of the most critical factors in strategic planning. As the future creation of values lies within individual responsibility, this research empirically explored the limits (if any) of individual foresters’ time horizons. To draw comparisons between countries with different traditions in forest management planning, data were collected through telephone surveys of forest managers in the state/national forest services of the Netherlands and Germany. In order to minimize other cultural differences, the research in Germany concentrated on the federal state of Nordrhein-Westfalen, which has considerable similarities with the Netherlands, e.g. in topography, forest types and forest functions. The results show that, in practice, 15 years appears to be the most distant horizon that foresters can identify with. This is in sharp contrast to the time horizons spanning decades and even generations that are always said to exist in forestry. The “doctrine of the long run”—the faith in the capacity of foresters to overcome the barriers of the uncertain future and look ahead and plan for long-range goals—which in many countries still underlies traditional forest management, can therefore be rejected.

Toward forest ‘‘sprawl':monitoring and planning a changing landscape for urban sustainability

The present study analyzes the structure and dynamics of the forest landscape in a peri-urban area(Rome, Italy) during the city's expansion from 1949 to2008 using landscape metrics and change detection analysis of digital maps of the area(1500 km2). While urban settlements increased continuously from 6.5 to 27.5 % of the study area, woodlands changed less clearly, with a moderate increase(from 11.2 to 11.9 % of the total area)and a higher fragmentation as a consequence of Rome's expansion. The structure of forest landscape changed along the urban-to-rural gradient with patch size increasing with the distance to the inner city in 1949 and substantial landscape homogeneity in 2008. The indicators proposed in this study inform dedicated measures for conserving forest and maintaining landscape diversity. Measures adopted in Rome's forestation plan to counteract woodlandffragmentation were analyzed and discussed. Based on the complex landscape dynamics found for Rome, an integrated multiscale planning approach targeting forest conservation is considered a key contribution to urban sustainability.     

Revisiting the relationship between common weather variables and loblolly–shortleaf pine seed crops in natural stands

Seed production was monitored during24 years using seed-collection traps inloblolly–shortleaf pine (Pinus taeda L.–P.echinata Mill.) stands located in southeast Arkansas,north-central Louisiana, and southwest Mississippi onthe southeastern Coastal Plain, USA. Sound seedproduction was correlated with mean monthlyprecipitation and temperature from National Oceanicand Atmospheric Administration weather stationslocated near the seed-collection areas to determinethe potential of weather factors in forecasting pineseed crops. Correlations were restricted to threecritical periods in the pine reproductive cycle –strobili primordia differentiation, pollination, andfertilization. The most important (P 0.05)variables correlated with pine seed production for combined locations were cumulative precipitation (r = +0.60) during July, August, and September at 27 to 25 months before seed dispersal and mean temperature (r = –0.45) in August at 26 months before seed dispersal. Because multiple environmental factors can negatively impact pine seed development during the two yearsfollowing strobili primordia differentiation,seed-production forecasts based on weather variablesshould be verified by on-site cone counts during thesummer preceding autumn seed dispersal.     

Photosynthetic Characteristics of Ash and Larch in Mixture and Pure stands

IntroductionDuringthepasttwodecades,studieshaverevealedthatgrowingash(Fnainusmandshurica)andlarch(LarlksPP.)togetherinaproperwaycanincreasetheproduc-tivityQfthestandsI"'}'-'].Theyieldimprovementmechanismsattributetotwoaspects,i.e.,theabovegroundandundergr…     

Plant β-diversity in human-altered forest ecosystems: the importance of the structural,spatial, and topographical characteristics of stands in patterning plant species assemblages

An understanding of spatial patterns of plant species diversity and the factors that drive those patterns is critical for the development of appropriate biodiversity management in forest ecosystems. We studied the spatial organization of plant species in human-modified and managed oak forests (primarily, Quercus faginea) in the Central Pre-Pyrenees, Spain. To test whether plant community assemblages varied non-randomly across the spatial scales, we used multiplicative diversity partitioning based on a nested hierarchical design of three increasingly coarser spatial scales (transect, stand, region). To quantify the importance of the structural, spatial, and topographical characteristics of stands in patterning plant species assemblages and identify the determinants of plant diversity patterns, we used canonical ordination. We observed a high contribution of β-diversity to total γ-diversity and found β-diversity to be higher and α-diversity to be lower than expected by random distributions of individuals at different spatial scales. Results, however, partly depended on the weighting of rare and abundant species. Variables expressing the historical management intensities of the stand such as mean stand age, the abundance of the dominant tree species (Q. faginea), age structure of the stand, and stand size were the main factors that explained the compositional variation in plant communities. The results indicate that (1) the structural, spatial, and topographical characteristics of the forest stands have the greatest effect on diversity patterns, (2) forests in landscapes that have different land use histories are environmentally heterogeneous and, therefore, can experience high levels of compositional differentiation, even at local scales (e.g., within the same stand). Maintaining habitat heterogeneity at multiple spatial scales should be considered in the development of management plans for enhancing plant diversity and related functions in human-altered forests.     

Characteristics of bird communities between slope and valley in natural deciduous forest, South Korea

本研究在弄清韩国桂坊山(374030N,128301E)天然落叶阔叶林斜坡和山谷中鸟类群落间的特征差异。调查结果表明:两地鸟类群落的种类组成、丰富度、鸟种多样性及群落结构都有不同。森林的垂直结构特别是林下覆被度及胸高直径分布多显不同。两地生境结构的不同必然影响着鸟类对可利用生境的选择。表6图2参19。     

Distribution of cranes in Hulunber Grassland and Daxing’an mountains forest region in inner Mongolia

The Daxing’an Mountains and Hulunber Grassland are located in the northeastern border area of China. This region covers a large area of rich biodiversity. The natural environment here is well protected because of low pressure of human activity. There are 5 species of cranes here. They are Red-crowned crane (Grus japonensis), White-napped crane (Grus vipio), Siberian White crane (Grus leucogeranus), Grey crane (Grus lifordi) and Demoiselle crane (Anthropoides virgo). Red-crowned crane is a breeding species that is widely distributed in this area. The main breeding population of this species is in Heilongjiang Province. They migrate to the south of China in winter. White-napped crane, Grey crane, Demoiselle crane are also summer birds. It remains unknown if Siberian White crane breeds here. Since the population of Red-crowned crane, White-napped crane, Siberian White crane in China are at the edge of endangering, so they are listed in the namelist of national protected species. But Grey crane, Demoiselle crane have a larger population, and are widely distributed. (Responsible Editor: Zhu Hong)