Retrieval of forest attributes in complex successional forests of Central Indonesia: Modeling and estimation of bitemporal data

Quantification of forest parameters in different successional stages is required because of its importance as a source of global emissions and ecosystem changes. This study focuses on a successional tropical forest under logging practices in East Kalimantan province, Indonesia. We modeled the forest attributes using both a parametric multiple linear regression analysis and neural networks approach, with Landsat ETM data acquired in 2000 (ETM00). We compiled sample plot data using forest inventory data collected from 1997 to 1998. A total of 226 plots were used to train the models and 112 plots were used for the validation. The remote sensing data (spectral values, vegetation indices, texture, etc.) coupled with digital elevation model (DEM) were experimented with and selectively used to model basal area, stem volume and above ground biomass (AGB). We investigated the possibility to estimate the forest attributes from bitemporal ETM data by calibrating radiometric properties of the ETM image from 2003 (ETM03) using the multivariate alteration detection method. The Pearson correlations showed that the mean texture index is strongly correlated with the forest attributes. We show that neural networks resulted in a higher coefficient of determination (r²) and lower RMSE than multiple regressions for predicting the forest attributes. The estimated forest properties increased with the forest succession advancement (i.e. from the open forest to advanced secondary forest classes). The modeled basal area, stem volume and AGB varied from 10.7–15.1 m² ha⁻¹, 123.2–181.9 m³ ha⁻¹, and 132.7–185.3 Mg ha⁻¹, respectively. The RMSE_r values of model fitting ranged from 11.2% to 13.3%, and the test dataset estimated slightly higher RMSE_r which varied from 12% to 14.1%. The ETM03 forest attributes revealed favorable estimates, showing considerably higher estimates than the ETM00. The estimation of forest properties using neural networks makes Landsat data a valuable source of information for forest management, mainly with the recent free access to its historical dataset.     

Epidemiological derivation of flux-based critical levels for visible ozone injury in European forests

The European MOTTLES project set-up a newgeneration network for ozone(O_3) monitoring in 17 plots in France, Italy and Romania. These monitoring stations allowed:(1) estimating the accumulated exposure AOT40 and stomatal O_3 fluxes(PODY) with an hourly threshold of uptake(Y) to represent the detoxifi cation capacity of trees(POD1, with Y = 1 nmol O_3 m~(-2) s~(-1) per leaf area); and(2) collecting data of forest-response indicators, i.e. crown defoliation and visible foliar O_3-like injury over the time period 2017–2019. The soil water content was the most important parameter aff ecting crown defoliation and was a key factor aff ecting the severity of visible foliar O_3-like injury on the dominant tree species in a plot. The soil water content is thus an essential parameter in the PODY estimation, particularly for water-limited environments. An assessment based on stomatal flux-based standard and on real plant symptoms is more appropriated than the exposure-based method for protecting vegetation. From flux-eff ect relationships, we derived flux-based critical levels(CLef) for forest protection against visible foliar O_3-like injury. We recommend CLef of 5 and 12 mmol m~(-2) POD1 for broadleaved species and conifers, respectively. Before using PODY as legislative standard in Europe, we recommend using the CLec for ≥ 25% of crown defoliation in a plot: 17,000 and 19,000 nmol mol~(-1) h AOT40 for conifers and broadleaved species, respectively.     

Mycorrhizas and secondary succession in aspen-conifer forests: Light limitation differentially affects a dominant early and late successional species

Plant succession and mycorrhizal fungi both play crucial roles in shaping the development of forest ecosystems. However, despite the strong potential for interactions between them, few studies have examined how patterns of forest succession affect mycorrhizal associations that a majority of plant species depend on to alleviate soil resource constraints. Fire suppression in subalpine forests over the last century has changed successional patterns in ways that may have important implications for mycorrhizal associations of forest tree species. To better understand these relationships we conducted a field and greenhouse study in which we examined mycorrhizal infection along gradients of light intensity and soil nutrient availability that develop as aspen becomes seral to conifers under longer fire return intervals. We examined whether ectomycorrhizal associations of quaking aspen (Populus tremuloides), a shade intolerant, early succession species, were more sensitive to light and soil resource limitations than subalpine fir (Abies lasiocarpa), a shade tolerant, late succession species. In the field study, ectomycorrhizal infection of aspen roots was reduced by 50% in conifer dominated stands relative to aspen stands. In contrast, subalpine fir maintained its EM associations regardless of the successional status of the stand. The greenhouse results were consistent with field results and indicated that light limitation was the driving force behind reductions in EM infection of aspen roots in later stages of succession. These results suggest that nutrient limitations constraining early successional species may be exacerbated by losses in EM associations via light limitations created by late successional species. This is one potential mechanism by which climax forest species create a competitive advantage over early successional species and these results suggest that it is likely exacerbated by longer fire return intervals.     

Avian use of early successional habitats: Are regenerating forests,utility right-of-ways and reclaimed surface mines the same?

The importance of early successional habitats for breeding and post-breeding birds has received recent attention. Common early successional habitats in the eastern United States are regeneration after timber harvests, utility right-of ways and reclaimed surface mines. Few studies, however, have compared the characteristics of these with regard to avian habitat use. We conducted a passive mist-netting study to assess the breeding and post-breeding avian communities associated with these land uses in the Cumberland Mountains of eastern Tennessee. We used analysis of variance to compare the vegetation structure among these habitat types and discriminant function analyses to illustrate differences in vegetation structure and bird abundance among habitats. We banded 1562 individuals of 40 species (1.08 birds/net-hour). The percent cover of saplings, forbs and grass differed among habitat types, but there was no detectable difference in shrub cover. Vegetation structure allowed good discrimination between habitat types (Wilks’ λ = 0.16), specifically in differentiating clearcuts from surface mines and right-of-ways. Although the three habitat types had several avian species in common, the abundance of 12 species differed substantially among habitat types, and their species abundance patterns allowed for excellent discrimination between these habitat types (Wilks’ λ = 0.08). We conclude that these three early successional habitat types are different with regard to vegetation structure and avian community assemblage. These differences are important for local and landscape-scale conservation planning for both early and late successional avian species.     

Climate change and nature conservation in Central European forests: A review of consequences, concepts and challenges

With a predicted rise in average global surface temperature at an unprecedented rate, as well as changes in precipitation and disturbance regimes, climate change will bring forth new challenges for nature conservation in forest ecosystems. Species and habitats to be protected will be affected as well as related concepts and area specific objectives. Climate change impacts are likely to be aggravated by other anthropogenic stresses such as fragmentation, deposition or habitat destruction. To be reliable and effective, current objectives and guidelines of forest conservation need to be reassessed and improved. Our study analyses possible impacts of climate change on forests and identifies key future challenges for nature conservation in forests and ecosystem research. We reviewed 130 papers on climate change impacts on forest ecosystems and species published between 1995 and 2010. The geographical focus of the study is Central Europe. Papers were analysed accounting for direct and indirect impacts of gradual changes as well as stochastic disturbance events in forest ecosystems and their possible consequences for nature conservation.Even though broader aspects of nature conservation (protected areas, biodiversity) are frequently mentioned, little attention is given to forest-specific nature conservation. Particular aspects are insufficiently represented, such as the influence of climate change on different forest succession stages, the development of dead wood volume and quality, responses of secondary broadleaved species, azonal or extrazonal forests as well as ancient woodlands or remnants of historical silvicultural systems. Challenges arise in the context of great uncertainties about future developments. Nature conservation concepts and objectives in forests need to be adapted either within a permanent evaluation process or through the inclusion of further changes a priori, even if they are to some extent unpredictable. In some cases adaptation measures within nature conservation (e.g. adjusting protected areas) may conflict with interests of other stakeholders. Further research, particularly on interrelations between different impacts and the adaptive capacity of current forest ecosystems, associated species and existing genotypes is urgently needed. The scale and complexity of the task at hand calls for the establishment and further strengthening of international research networks.     

Landscape genetics highlight the importance of sustainable management in European mountain spruce forests: a case study on Western capercaillie

The mountain spruce forests of the Western Carpathians have experienced a dramatic deterioration in the last decades increasing the landscape fragmentation. This considerably affected the Western capercaillie population recently surviving within small habitat patches surrounded by unfavourable habitats. Our study shows that the long-term isolation resulted in genetic differentiation with decreasing trend in allelic richness towards the most adjacent western subpopulations. We evaluated dispersal possibilities within the landscape and identified barriers and the most critical corridors between genetically distinct subpopulations. Landscape genetic analysis confirmed that the isolation by environmental features explains the observed genetic patterns better than straight geographical distance. We highlight the urgent need for an active conservation management in the critical habitats where dispersion might be constrained or “bottlenecked” in order to ensure gene flow within the fragmented capercaillie metapopulation of the Western Carpathian mountain forests.     

Plot size and shape for the early assessment of post-fire regeneration in Aleppo Pine Stands

Aleppo pine stands account for a third of the burned forests in the Mediterranean basin. The early assessment of post-fire regeneration is essential for the management of such stands. The assessment should be based on reliable and objective methods. In the Mediterranean basin, plot size and shape applied in regeneration survey designs and sampling schemes differ considerably. A study involving twelve stands (7 unharvested and 5 harvested) in the Province of Taranto (southern Italy) was carried out 38 months after a fire, by comparing plots of different shape and size within a plot-count sampling frame. The relative efficiency method was used to compare the efficiency of each size and shape. Early regeneration of Aleppo pine proved to be best assessed by 8m × 2m plots, i.e. by a plot size four times wider than the most commonly used one (2m × 2m). The need for such wide plots depends upon the typical spatial arrangement of the seedlings whose clustering is associated with the presence of seed bearing trees.     

The relative importance of community forests,government forests,and private forests for household-level incomes in the Middle Hills of Nepal

To investigate the household-level economic importance of income from forests under different tenure arrangements, data were collected from 304 stratified randomly sampled households within 10 villages with community forest user groups in Tanahun District, Western Nepal. We observed that forest income contributed 5.8% to total household income, ranging from 3.8% in the top income quartile to 17.4% in the lowest quartile. Analyses of poverty indices and Gini decomposition showed that incorporating forest incomes in total household income reduces measured rural poverty and income inequality. Community forestry income constituted 49.7% of forest income, followed by 27.5% from government-managed forest, and 22.8% from private forests/trees. Community forestry income, however, contributed more than other sources of forest income to income inequality, indicating elite capture. We argue that a full realisation of community forestry's poverty reduction and income equalizing potential requires modifications of rules that govern forest extraction and pricing at community forest user group level.     

Identification of viruses from European beech (Fagus sylvatica L.) of declining forests in Northrhine-Westfalia (FRG)

Five different viruses isolated from degenerating European beech of different forest sites of West Germany could be identified as cherry leaf roll virus, brome mosaic virus, potex and potyviruses.     

Spatial interpolation of in situ data by self-organizing map algorithms (neural networks) for the assessment of carbon stocks in European forests

Self-organizing maps (SOMs) are an advanced neural networks application. SOMs were applied for the spatially explicit estimation of forest carbon stocks for a test region in Thuringia (Germany). The approach utilizes in situ national forest inventory data and satellite remote sensing data (Landsat 7 ETM+) and provides maps showing a high-resolution spatial distribution of forest carbon stocks. The generated maps are compared to alternative estimates obtained by the k-nearest neighbour (kNN) method—a remote sensing based carbon assessment. Beside maps the SOM- and kNN-approaches were utilized to calculate statistical estimates of carbon stock and growing stock. The statistical estimates were validated by calculating bias and mean square errors with reference to in situ assessments.     

A review of habitat thresholds for dead wood: a baseline for management recommendations in European forests

In contemporary forest management, also of commercial forests, threshold values are widely used for consideration of biodiversity conservation. Here, we present various aspects of dead-wood threshold values. We review published and unpublished dead-wood threshold data from European lowland beech–oak, mixed-montane, and boreo-alpine spruce–pine forests separately to provide managers of European forests with a baseline for management decisions for their specific forest type. Our review of dead-wood threshold data from European forests revealed 36 critical values with ranges of 10–80 m³ ha⁻¹ for boreal and lowland forests and 10–150 m³ ha⁻¹ for mixed-montane forests, with peak values at 20–30 m³ ha⁻¹ for boreal coniferous forests, 30–40 m³ ha⁻¹ for mixed-montane forests, and 30–50 m³ ha⁻¹ for lowland oak–beech forests. We then expand the focus of dead-wood threshold analyses to community composition. We exemplify the two major statistical methods applied in ecological threshold analysis to stimulate forest researchers to analyze more of their own data with a focus on thresholds. Finally, we discuss further directions of dead-wood threshold analysis. We anticipate that further investigations of threshold values will provide a more comprehensive picture of critical ranges for dead wood, which is urgently needed for an ecological and sustainable forestry.     

Carbon sequestration capability of Fagus sylvatica forests developing in the Majella National Park (Central Apennines,Italy)

Terrestrial ecosystems represent a major sink for atmospheric carbon(C) and temperate forests play an important role in global C cycling, contributing to lower atmospheric carbon dioxide(CO_2) concentration through photosynthesis. The Intergovernmental Panel of Climate Change highlights that the forestry sector has great potential to decrease atmospheric CO_2 concentration compared to other sectoral mitigation activities. The aim of this study was to evaluate CO_2 sequestration(CO_2 S)capability of Fag us sylvatica(beech) growing in the Orfento Valley within Majella National Park(Abruzzo,Italy). We compared F. sylvatica areas subjected to thinning(one high-forest and one coppice) and no-management areas(two high-forests and two coppices). The results show a mean CO_2 S of 44.3 ± 2.6 Mg CO_2 ha~(-1)a~(-1),corresponding to 12.1 ± 0.7 Mg C ha~(-1) a~(-1) the no-managed areas having a 28% higher value than the managed areas. The results highlight that thinning that allows seed regeneration can support traditional management practices such as civic use in some areas while no management should be carried out in the reserve in order to give priority to the objective of conservation and naturalistic improvement of the forest heritage.     

Restoration of dry tropical forests in Central America: A review of pattern and process

Much information on restoration and management exists for wet tropical forests of Central America but comparatively little work has been done in the dry forests of this region. Such information is critical for reforestation efforts that are now occurring throughout Central America. This paper describes processes of degradation due to land use and provides a conceptual framework for the restoration of dry tropical forest. Most of this forest type was initially harvested for timber and then cleared for cattle in the last century (1930-1970). Only 1.7% remains largely restricted to infertile soils and remote areas on the Pacific coastal side of Panama, Costa Rica, Nicaragua and Mexico. These cleared areas are again in a state of transition due to a combination of decreasing land productivity, and land speculation for tourism development. Some farms have been sold to new landowners who are interested in reforesting to increase biodiversity and forest cover. Attempts have therefore been made to reforest by protecting the land from fire and cattle, by supplementing natural regrowth with enrichment planting, or through use of tree plantations. Experimental studies have demonstrated the ability of these lands to grow back to forests because of native species ability to sprout after cutting, and the capacity of remnant trees in field and riparian zones to provide seeds and to moderate edge environment for seed germination and seedling establishment. However, research also shows that on sites with long histories of land clearance, species diversity will remain low with functional groups missing unless some active management occurs. Under-planting with late-successional native tree species can add structure and diversity; enrichment planting with large-fruited shade-intolerant species can initiate new islands of more diverse regeneration beneath their canopies; and plantings of fast-growing, nitrogen-fixing trees that provide light canopy shade can moderate the environment below, promoting regeneration establishment of late-successional species. Plantations are the only option for lands that have lost almost all remnants of native forest, and where soils and vegetation have changed to new states of structure and function. Conversion of pastures to tree plantations that can facilitate natural regeneration beneath them is appropriate when pastures are prone to fire and/or lack immediate seed sources nearby. After the grasses have been shaded out, natural recruitment can slowly occur over a 10-15 years period. Under-planting of shade-tolerant late-successional species can supplement species composition and structure.     

中国窄腹细蜂属的研究

本文记述了膜翅目窄腹细蜂科窄腹细蜂属（ＲｏｐｒｏｎｉａＰｒｏｖａｎｃｈｅｒ１８８６）的４个新种，建立了一个新异名．同时，首次描述了红腹窄腹细蜂（Ｒ．ｒｕｆｉａｂｄｏｍｉｎａｌｉｓＨｅｅｔＺｈｕ）的雄性．研究标本均采自湖南省，模式标本保存于中南林学院林学系昆虫标本室．     

基叶蜂亚科一新属新种(膜翅目:蔺叶蜂科)

报道了中国基叶蜂亚科一新属新种：棕股合室叶蜂Ｄｏｌｅｒｏｉｄｅｓｆｕｓｃｏｕｓｇｅｎ．ｅｔｓｐ．ｎｏｖ．．该属隶属于大片叶蜂族Ａｔｅｌｏｚｉｎｉ,但前翅１ｒ－ｍ脉缺失,１Ｒｓ与２Ｒｓ合并,可与该族已知各属鉴别．     

A new sampling method in the Zagros forests using GIS(case study: Ilam forests of Iran)

One of the basic parameters in forest management planning is detailed knowledge of growing stock,information collected by forest inventory. Sampling methods must be accurate, inexpensive, and be easy to implement in the field. This study presents a new sampling method called branching transect for use in the Iranian Zagros forests and similar forests. Features of the new method include greater accuracy, easy implementation in nature, simplicity of statistical calculations, and low cost.In this method, transect is used, which includes some subtransects(side branches). The length of the main transect,side branches, number of trees measured in each side branch, and the number of sub-branches in this method are changeable based on homogeneity, heterogeneity, and density of a forest. In this study, based on the density and heterogeneity of the forest area studied, 20-m transects with four and eight side branches were used. Sampling plots(Transects) in four inventory networks(100 m × 100 m, 100 m × 150 m, 150 m × 150 m and 100 m × 200 m) were implemented in the GIS environment. The results of this sampling method were compared to the results of total inventory(100% count) in terms of accuracy, precision(t-test), and inventory error percentage.Branching transect results were statistially similar to total inventory counts in all cases. The results show that this method of estimating density and canopy per hectare can be used in Zagros forests and similar forests.