Outline and examples for integrated evaluations of data from the intensive (Level II) monitoring of forest ecosystems in Germany

Data are collected at plots of the intensive forest monitoring programme (Level II monitoring) in Germany by the federal states and stored in a nation-wide database with the main task of contributing to a better understanding of the impacts of air pollutants and other environmental factors on forest ecosystems. Within this feasibility study these data were screened with the intention of outlining a conclusive concept for integrated evaluations. As a permanent challenge of complexly organised monitoring, the necessity of data control measures is underlined and a transparent documentation of univariate properties of key factors and basic relationships is advocated. Besides different statistical analyses, selected, aggregated, and derivative parameters have to undergo substantial check-ups of their information value with respect to risks associated with chemical or physical stress for trees and other biotic compartments of forest ecosystems. Examples of evaluations of different profundity are taken from the domains: crown condition, foliar element concentrations, increment of trees, ground floor vegetation, and chemical condition of the soil solution. Grounded on subject-specific sectoral considerations, concise sets of relevant (key) factors or composite factors should in future approaches—together with results from amending process-oriented modelling—be passed on to construct integrated models against the background of current hypotheses about stress in forest ecosystems, even on the national scale, and on reasonable sub-scales.     

Concept and feasibility study for the integrated evaluation of environmental monitoring data in forests

In the 1970s unexpected forest damages, called “new type of forest damage” or “forest decline”, were observed in Germany and other European countries. The Federal Republic of Germany and the German Federal States implemented a forest monitoring system in the early 1980s, in order to monitor and assess the forest condition. Due to the growing public awareness of possible adverse effects of air pollution on forests, in 1985 the ICP Forests was launched under the convention on long-range transboundary air pollution (CLRTAP) of the United Nations Economic Commission for Europe (UN-ECE). The German experience in forest monitoring was a base for the implementation of the European monitoring system. In 2001 the interdisciplinary case study “concept and feasibility study for the integrated evaluation of environmental monitoring data in forests”, funded by the German Federal Ministry of Education and Research, concentrated on in-depths evaluations of the German data of forest monitoring. The objectives of the study were: (a) a reliable assessment of the vitality and functioning of forest ecosystems, (b) the identification and quantification of factors influencing forest vitality, and (c) the clarification of cause-effect-relationships leading to leaf/needle loss. For these purposes additional data from external sources were acquired: climate and deposition, for selected level I plots tree growth data, as well as data on groundwater quality. The results show that in particular time series analysis (crown condition, tree growth, and tree ring analysis), in combination with climate and deposition are valuable and informative, as well as integrated evaluation of soil, tree nutrition and crown condition data. Methods to combine information from the extensive and the intensive monitoring, and to transfer process information to the large scale should be elaborated in future.

A leap forward in geographic scale for forest ectomycorrhizal fungi

The functionally critical role of mycorrhizal fungi in forest ecosystems, and the imminent threat of climate change that may act to alter mycorrhizal functional biodiversity, means there is an urgent need for a regional to continental-scale assessment of mycorrhizal distributions. Until recently, it had not been possible to cost-effectively assess mycorrhizas precisely and accurately. A large-scale survey of ICP Forests plots would be only the first stage in answering many of the questions outlined above, but it is essential if future studies are going to address these questions with hypothesis-driven research in a cohesive manner, rather than remain independent for lack of a unified approach. The chance to utilise the vast network of biomonitoring plots at this time is a remarkable opportunity because it minimises the logistics and costs associated with achieving such an enormous effort and provides a rare stable — past and future — ground for forest ecosystem scientific investigation. In the face of rapid global change, we finally have an opportunity to accurately integrate mycorrhizal distribution data with long-term environmental monitoring, providing a basic understanding of functionally crucial organisms, and at the same time creating an invaluable resource for future research.     

Fungal fruitbodies and soil macrofauna as indicators of land use practices on soil biodiversity in Montado

The impacts of land use on soil biodiversity are still poorly understood, although soil fungi and macrofauna are recognized to provide benefits to ecosystems. Here, we tested whether land use practices used to control shrub density influences the fruiting macromycetes (ectomycorrhizal-forming fungi—ECMF—and saprobes) and soil macrofauna diversity and abundance in Montado ecosystems. To address this influence, we conducted a 2-years’ period monitoring of fungi fruitbodies and macrofauna in sixteen experimental plots in Montado landscape in southern Portugal. A total of 4,881 frutibodies (57 taxa of ECMF and 64 taxa of saprobic fungi) and 3,667 soil invertebrates (73 species and morphospecies) were monitored in the experimental plots. There was greater losses in sporocarps production and taxa composition, particularly the ECMF, in plots where shrub density was controlled by permanent grazing (Ca) or involving cutting practices followed by soil tillage (M), in comparison with cutting practices with no soil tillage (Cu) and the control (C). The ECMF Laccaria laccata and Xerocomus subtomentosus exhibited a close relation with C and Cu plots while the saprobes, e.g., Entoloma conferendum, were associated to Ca and M plots. Most species associated to Cu plots were present in C plots during the 2 years, but not in Cu after the cutting practices (in the second year of sampling). Regarding soil macrofauna, higher values of taxa and species richness were observed in C and Cu plots in the first year of sampling. The ant species Aphaenogaster senilis and several Staphylinid morphospecies exhibited a close relation with M plots, whilst most spider families were directly associated to C and Cu plots. After the shrub cutting practices, higher values of taxa and species richness of soil macrofauna were observed in M and Ca plots; the presence of species with a high competitive ability to colonize disturbed areas faster might explain the results. Contrary to the frutibodies production and diversity, species richness and abundance within soil macrofauna were identical between Cu and C in 2004. Thus, fruiting macromycetes and soil macrofauna diversity and abundance in Montado’s, appear highly sensitive to land use and somewhat reflected a trend of severity to the current shrub management practices.     

Farms in the black forest of Baden-Württemberg: A historical review

Today the Black Forest is an internationally renowned tourist region in Germany. For centuries the Black Forest remained as a low mountain range regarded as not suitable for settlement due to its unfavourable climatic conditions and difficult terrain. Clearing the dense forests and settlement therefore started at a historically late stage compared to other regions of Germany, about 1000 years ago. Due to the special conditions in this area, the structure of the settlement had to be quite different to those landscapes with more favourable conditions for agriculture. A single-farm settlement developed, farms situated 200 to 400 m away from each other, surrounded by meadows, agricultural land and forests and owned by the farmer’s family. This structure has remained in some areas until today; in other areas different types of settlement took place, and great changes occurred during history. A special type of agroforestry — a slash-and-burn-management of forests — also took place 150 to 200 years ago.     

An aerial photograph auto-interpretation system for forest resource inventory

Aerial photographs arc important information sources for forest inventory. With the development of science and technology, an automated approach to aerial photograph interpretation has been sought. This paper introduces an experimental computer system for the auto-interpretation of aerial photographs. On thebasis of the experimental system, several algorithms are developed for the interpretation of density, crown closure, working groups and species composition of forest stands. Experiments show that auto—interpretation works well for some forest inventory data.     

国家森林资源与生态状况综合监测理念及其技术体系——以2007年广东省试点为例

介绍了2007年广东省开展国家森林资源与生态状况综合监测试点时所采用的监测理念与方法体系,供全国开展此类工作借鉴参考。试点以连清固定样地体系为依托,构建了融植被监测系统、林地土壤监测系统、物种多样性监测系统于一体的样地调查体系;设计了森林资源、湿地资源、石漠化土地资源以及森林健康、森林土壤状况、森林景观、森林固碳、涵养水源、保育土壤、生物多样性保护等功能效益的指标体系;形成了以固定样地调查为主体,地面调查结合实验测定,以及遥感监测、模型测算结合指数分析的综合评定技术体系。     

Factors affecting runoff and soil erosion: plot-level soil loss monitoring for assessing sustainability of forest management

The assessment on key ecological factors affecting runoff and soil erosion and the usefulness of plot-level monitoring of soil erosion was conducted by collecting runoff and soil loss records from 14 runoff plots. The runoff plots were set up in two catchments in Central Kalimantan, Indonesia, where conventional logging and Reduced Impact Logging (RIL) took place. Runoff plots were set up in forest areas with different levels of logging disturbances, i.e. harvesting areas (four plots), skid trails (six plots), and undisturbed/control areas (four plots). The magnitude of runoff and soil loss from skid trail plots were found to be the highest, followed by control plots and harvest plots. Canopy cover, sapling density, litter depth and woody debris appeared to be important ecological factors that determine the magnitude of soil loss. Tree canopy determines the size and erosive power of the raindrops. Sapling, litter layer, and woody debris protected soil surface, thus preventing soil detachment, and provided surface roughness that minimised soil particle movement down the slope. The roles of these ecological factors were less significant compared to rainfall in determining the magnitude of runoff.

Canopy cover, sapling density, litter depth and woody debris can be measured quantitatively or qualitatively without complicated equipment and methods. Furthermore, they are sensitive to logging disturbance which make them suitable verifiers of soil erosion. Forest managers need to limit disturbance to these factors in order to minimise soil erosion in their logging operation areas. Monitoring of soil loss using runoff plots was cost-effective and provided valuable information about soil erosion risks caused by logging operations. Runoff plots clearly demonstrated site disturbances where the plots are located. Monitoring allowed more direct linkages to be made between management practices and their impacts on runoff and soil erosion, thereby enabling forest managers to identify problems and take appropriate preventive measures to improve their management practices.     

以现代林业理论指导林业跨越式发展

林业跨越式发展是我国建设现代林业的重要途径,现代林业是跨越式发展战略的目标。以现代林业理论指导我国林业跨越式发展是我国林业健康发展的根本要求。因此,我们要深刻领会现代林业理论的内涵,以可持续林业理论为指导,从林业的多目标经营入手,采取多种经营方式,依靠科学技术进步,动员全社会力量,实现林业的跨越式发展。     

The effect of participatory forest management on the livelihood and poverty of settlers in a rehabilitation program of degraded forest in Bangladesh

The sal forest is the only plainland forest in Bangladesh, and is of national economic and environmental importance. High population and ever increasing poverty has stimulated exploitation of the forest alarmingly and brought it near extinction. In facing this situation, the Bangladesh Forest Department implemented a participatory management approach, involving the householders living in and around the forests, for forest maintenance and protection. This study examines the effectiveness of practicing participatory forestry on the settlers’ livelihood in the encorached area of the sal forest. The settlers were given degraded and encroached forest land through the program. Two major social forestry models — namely agroforestry and woodlots — are included in the study. Participation in the resettlement increased household income, employment opportunities and financial and non-land assets. It was found that the participatory management regime could attain the sustainability of the forest and accelerate the standard of settlers’ livelihood, hence the program is an efficient management option towards sustainability of the forest resources. These findings suggest that there is a role for extending the approach to rehabilitate other degraded and encroached forest lands in Bangladesh.     

Spatial prediction of forest stand variables

This study aims at the development of a model to predict forest stand variables in management units (stands) from sample plot inventory data. For this purpose we apply a non-parametric most similar neighbour (MSN) approach. The study area is the municipal forest of Waldkirch, 13 km north-east of Freiburg, Germany, which comprises 328 forest stands and 834 sample plots. Low-resolution laser scanning data, classification variables as well rough estimations from the forest management planning serve as auxiliary variables. In order to avoid common problems of k-NN-approaches caused by asymmetry at the boundaries of the regression spaces and distorted distributions, forest stands are tessellated into subunits with an area approximately equivalent to an inventory sample plot. For each subunit only the one nearest neighbour is consulted. Predictions for target variables in stands are obtained by averaging the predictions for all subunits. After formulating a random parameter model with variance components, we calibrate the prior predictions by means of sample plot data within the forest stands via BLUPs (best linear unbiased predictors). Based on bootstrap simulations, prediction errors for most management units finally prove to be smaller than the design-based sampling error of the mean. The calibration approach shows superiority compared with pure non-parametric MSN predictions.     

广西森林资源连续清查角规样地体系评价

广西森林资源连续清查(以下简称"广西连清)"角规样地体系,是我国唯一的以点抽样理论为基础,以固定角规样地为监测载体的省(区)级森林资源连续清查体系。广西连清第7次复查,除了增设的方形样地调查以外,还对原有的角规样地进行了复查,因此本文得以用同时进行调查的方形样地调查结果作为参照对象,对角规样地体系的优点和存在的问题进行定性和定量相结合的综合分析评价。分析评价结果表明,与方形样地比较,角规样地除了具有显著的隐蔽性外,外业工作量只相当于方形样地的53%,两套体系的活立木蓄积量差异仅为3.16%,角规样地和方形样地体系总蓄积量抽样精度分别为94.47%与94.57%,均达到国家森林资源连续清查技术规定要求(≥90%)。角规样地复位率大于规定的98%,样木复位率远大于规定的95%,达97%以上,能满足林木蓄积生长量和消耗量监测的要求。角规样地体系的不足主要是由于漏测木和进测木的存在,导致森林资源的现状估计值偏低,且动态估计精度明显低于方形样地体系。     

Ground floor vegetation assessment within the intensive (Level II) monitoring of forest ecosystems in Germany: chances and challenges

As a part of the ‘Intensive Forest Monitoring Programme’ of ICP Forests, ground floor vegetation has been surveyed along with parameters of other relevant components of the forest ecosystems and their environment at 80 permanent plots all over Germany. Its floristic composition and their changes can therefore be linked to a wide variety of potentially influencing factors, scrutinising recent hypotheses on floristic changes, mainly soil eutrophication and acidification due to air pollutants. Results of a broad-scaled feasibility study are presented and critically discussed with regard to future in-depth evaluations. After an overview on the most abundant species, the syntaxonomic allocation of the plots is given. An ordination reveals a gradient from nutrient and base rich soils to poor acidic soils. Floristic dynamics are mainly aligned with the main axis, but conclusions about the medium-term development cannot be stated yet. Ordination and subsequent statistics are recommended to open up a wide field for explorative investigations. Indicator values for soil acidity and nutrient supply corroborate the main floristic gradient. Based on an empirical species–area relationship (SAR), species numbers for a common plot size of 400 m² were calculated. Basic relationships among different diversity measures and between diversity measures and basic stand and site-related parameters were elaborated. Recommendations focus on enhancements of the assessment of ground floor vegetation within the context of the Level II monitoring like annual sampling or harmonisation of the plot sizes.     

Estimating forest biomass increment based on permanent sample plots in relation to woodfuel consumption: a case study in Kampong Thom Province,Cambodia

To assess the sustainability of forest use for woodfuel, above ground biomass increment must be examined against woodfuel consumption. However, reliable data on the biomass increment of tropical forests are very limited. In this study, we estimated above ground forest biomass increment in Kampong Thom Province, Cambodia, using two consecutive measurements of 32 permanent sample plots in 1998 and 2000, and forest inventory data of 540 plots collected in 1997. The permanent sampling plot data were used to determine the relationship between initial biomass and subsequent biomass increment over a 2-year period. This relationship was applied to the inventory data to obtain a robust estimate of biomass increment across the major forest types for the entire province. The weighted average annual above ground biomass increment for the whole province was 4.77Mg/ha, or 2.3% of biomass. Woodfuel consumption was estimated to be about 2% of biomass increment for the province, suggesting that deficiency of woodfuel may not occur in this province. However, localized variation needs to be taken into account and there is a need to examine the effects of stand age and factors such as soil type, microtopography, and species composition on biomass increment and to consider woodfuel collection rate in specific forest areas with respect to accessibility for firewood collection.     

Influence of forest clearing methods on nutrient uptake of some tropical food crops

The adverse effects of forest clearing on crop yield have often been directly ascribed to decline in soil fertility. However, the effect of various forest clearing methods on crop nutrient uptake as reflected by the content in the leaf tissues has been the subject of few scientific investigations. A study to determine the effect of forest clearing on nutrient content of some arable crops was, therefore, carried out in the tropical rainforest of south-western Nigeria. Three forest clearing methods—mechanical, semi-mechanical and manual clearing—were used, while maize, cowpea, and cassava were the test crops. Nutrient content in the tissues of these crops was assessed by sampling maize ear leaves at silking, youngest mature leaves (YML) of cowpea at flowering and YML of 3-month-old cassava for analysis. Correlation analysis was carried out to establish the relationship between nutrient content and crop yield. The method of forest clearing had no significant effect on the nutrient content of maize and cowpea during the first cropping cycle. However, nutrient content of maize in the manually cleared plots was higher than those in the semi- and mechanically cleared plots for all elements analyzed except Mg. Nitrogen content of cowpea was much higher than that of maize. Except for P and K, the nutrient content of cassava was not markedly different among the forest clearing methods. Calcium and P content in the leaves of maize and cassava varied inversely with their levels in the soil, implying that crop uptake could have accounted for the differences in their availability within the soil. Nitrogen, P and K had significant positive correlations with maize yield (r = 0.77, 0.89, and 0.71). Potassium content also had significant positive correlation with cassava root yield (r = 0.69). This is not surprising because compared with other crops, cassava requires large amounts of K for starch formation and root development. It is concluded that differences observed in crop yields under different forest clearing methods are a function of nutrient uptake and availability within the soil. However, the uptake of some nutrients does not seem to be determined by the level of soil availability alone. This study was supported with a research grant from the International Foundation for Science (IFS), Sweden.     

Estimating forest carbon fluxes for large regions based on process-based modelling, NFI data and Landsat satellite images

The aim of this study was to develop and evaluate a new approach for estimating forest carbon fluxes for large regions based on climate-sensitive process-based model, national forest inventory (NFI) data and satellite images. The approach was tested for Central Finland and Lapland with NFI field data and daily weather data from 2004 to 2008.The approach combines (1) a light use efficiency (LUE) model, (2) a process-based summary model for estimating gross primary production (GPP) and net primary production (NPP), and (3) the Yasso07 soil carbon model, which together allow the estimation of net ecosystem exchange (NEE). Landsat TM 5 satellite images were utilized to generalize the carbon fluxes obtained for field sample plots for all forested areas using the k-NN imputation method. The accuracy of the imputations was examined by leave-one-out cross validation and by comparing the imputed and simulated values with Eddy covariance (EC) measurements.RMSE of the k-NN imputations was slightly better in Central Finland than in Lapland, the bias staying at a similar level. Based on the EC comparisons, the approach seemed to work rather well with GPP estimates in both areas, but in the north the NEE estimates were remarkably biased. The main advantages of the approach include its applicability to basic NFI data and a high output resolution (30 m).The method proved to be a promising way to produce carbon flux estimates based on large-scale forest inventory data and could therefore be easily applied to the whole of Northern Europe. However, there are still drawbacks to the approach, such as lacking parameters for peat lands. One of the future goals is to integrate the approach with an interactive mapping framework, which could thereafter be utilized, for example, in climate change research.     

Types of bark beetle (Coleoptera: Scolytidae) infestation in spruce forest stands affected by air pollution, bark beetle outbreak and honey fungus (Armillaria mellea)

583 spruce stands in an area affected by air pollution and bark beetle outbreak in Eastern Slovakia were studied in 1996. According to bark beetle infestation of dominant and codominant trees, stands were classified into following types of spruce stand decline:Ips typographus-A,Ips typographus-B,Polygraphus poligraphus, I. typographus/P. poligraphus—A,I. typographus/P. poligraphus—B. The presence of attacked trees in forest edges, bark beetle spots and forest interior was the key important factor for the classification. Data from forest inventory and forest management evidence together with data on types of spruce stands decline were used in further analyses. Results shows that the distribution of forest stands classified into different types or uninfested stands is related mainly to host size and site quality. The percentage of spruce, exposition of stands and stand density showed significant effects. The mechanisms of spreading of studied bark beetle outbreak could be explained by direct effects of stress of trees caused by an abrupt increase of level of solar irradiation and by weakening of trees by the honey fungus.     

Mehrstufige Stichprobeverfahren in den Tropen—Erfahrungen der philippinischen Nationalwaldinventur

Zusammenfassung Für die komplexe Problematik der philippinischen Nationalwaldinventur erwies sich ein zweistufiges Inventurdesign, gestützt auf kleinma?st?bige Luftbilder und Landsat False Color Composites als Fl?chenrahmen und Relaskopstichproben zur Ermittlung von Bestandesdaten, als operationelles Verfahren. Das Gesamtvorhaben umfa?t die forstliche Kartierung von 30 Millionen Hektar Landesfl?che, verteilt auf 7100 Inseln, die Vorratsaufnahme von etwa 7 Millionen Hektar Wald sowie die Erfassung forstlicher Nebennutzungen wie Rattan und Bambus. Für die Substratifizierung von Landsat-Daten in Gebieten ohne vorhandene Luftbilder und als permanente Stichproben zur überwachung von Fl?chenentwicklungen zeigten Videokamera-Luftaufnahmen neue Wege auf für tropische Gro?rauminventuren.

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Multi-storied sampling methods in the tropics—experiences from the Philippine national forest inventory

Summary For the complex tasks of the Philippine National Forest Inventory, a two-stage inventory design has been successfully applied using small-scale aerial photographs and Landsat False Color Composites for the area delineation and relascope samples to determine the volume per hectare and other stand parameters. The inventory includes forest and landuse mapping of the whole country (30 million ha), distributed over 7100 islands, volume sampling of about 7 million ha of forests and the recording of minor forest products like rattan and bamboo. For the sub-stratification of Landsat data in areas without available aerial photographs and for continuous monitoring of area developments, airborne video recordings have shown new ways for large area forest inventories in the tropics.

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Der Autor ist deutscher Teamleiter des Projektes “Nationale Forstinventur Philippinen”, das die DFS Deutsche Forstinventur-Service GmbH im Auftrag der Deutschen Gesellschaft für Technische Zusammenarbeit (GTZ), GmbH durchführt.     

Signals of summer drought in crown condition data from the German Level I network

Crown transparency estimates of Scots pine, Norway spruce, common beech, pedunculate and sessile oak, annually surveyed between 1990 and 2004 within a grid over Germany, provide a suitable response variable to study drought effects on forest trees. Major climatic factors, available on a monthly basis as plot-specifically interpolated values and parameters of site and stand conditions, biotic and other relevant factors were used as predictors in different cross- and length-sectional, and longitudinal models. Stand age is a considerable and most constant driver of crown transparency in all species. Pine, spruce and beech responded—mainly with a delay of 1 year—with some foliar loss in areas where there was a surplus of temperature after the generally hot and dry summer of 2003. Parallel time-series analyses delivered species-specific geographic large-scale patterns with delayed or recent precipitation deficits or temperature surpluses. Even if beech is partly responding in current years with leaf loss towards precipitation surpluses, defoliation is especially high 1 year after hot summers, partly a result of high seed sets after such summers. Crown condition of oak responds in dry and warm areas according to the drought stress hypothesis, however, in cool and wet mountainous ranges oak responds after wet summers with higher defoliation. Longitudinal approaches revealed for all 4-tree species significant relationships between crown condition and deviations from the long-term means of temperature, precipitation but also global radiation and wind speed. Results do not always match the drought stress hypothesis, however, this is not to expect considering the heterogeneous site, stand and climatic conditions across Germany. Complex interactions of climatic and biotic factors also impede simple relationships. Soil-related clusters reveal higher sensitivity of spruce and beech towards climatic drought factors on more acid soils with thin humus layers. Also clusters constructed from plot-specific courses of defoliation reveal groups with rather closer relationships like a group of pine plots in the Oberpfalz, which seems to be especially sensitive to summer drought.