Abstract
Key message
Authors have analyzed the possible correlation between measurements/indicators of forest structure and species richness of many taxonomic or functional groups over three regions ...of Germany. Results show the potential to use structural attributes as a surrogate for species richness of most of the analyzed taxonomic and functional groups. This information can be transferred to large-scale forest inventories to support biodiversity monitoring.
Context
We are currently facing a dramatic loss in biodiversity worldwide and this initiated many monitoring programs aiming at documenting further trends. However, monitoring species diversity directly is very resource demanding, in particular in highly diverse forest ecosystems.
Aims
We investigated whether variables applied in an index of stand structural diversity, which was developed based on forest attributes assessed in the German National Forest Inventory, can be calibrated against richness of forest-dwelling species within a wide range of taxonomic and functional groups.
Methods
We used information on forest structure and species richness that has been comprehensively assessed on 150 forest plots of the German biodiversity exploratories project, comprising a large range of management intensities in three regions. We tested, whether the forest structure index calculated for these forest plots well correlate with the number of species across 29 taxonomic and functional groups, assuming that the structural attributes applied in the index represent their habitat requirements.
Results
The strength of correlations between the structural variables applied in the index and number of species within taxonomic or functional groups was highly variable. For some groups such as Aves, Formicidae or vascular plants, structural variables had a high explanatory power for species richness across forest types. Species richness in other taxonomic and functional groups (e.g., soil and root-associated fungi) was not explained by individual structural attributes of the index. Results indicate that some taxonomic and functional groups depend on a high structural diversity, whereas others seem to be insensitive to it or even prefer structurally poor stands.
Conclusion
Therefore, combinations of forest stands with different degrees of structural diversity most likely optimize taxonomic diversity at the landscape level. Our results can support biodiversity monitoring through quantification of forest structure in large-scale forest inventories. Changes in structural variables over inventory periods can indicate changes in habitat quality for individual taxonomic groups and thus points towards national forest inventories being an effective tool to detect unintended effects of changes in forest management on biodiversity.
Background
The global decrease in wildlife populations, especially birds, is mainly due to land use change and increasing intensity of land use (Parmesan and Yohe
2003
). However, impacts of ...management tools to mitigate biodiversity loss at regional and global scales are less apparent in forest regions that have a constant forest area, and which did not suffer from habitat degradation, and where forests are sustainably managed, such as in Central Europe or the northeastern USA. A biodiversity assessment for Germany suggested, for example, that bird populations were constant (Bundesamt für Naturschutz
2015
).
Results
This study shows that changes in the environment and in forest management over the past 45 years have had a significant, positive effect on the abundance of non-migratory forest bird species in Central Europe. Economy (timber prices and GDP), forest management (timber harvest and mixed forest area), and environmental factors (atmospheric CO
2
concentration and nitrogen deposition) were investigated together with changes in abundances of migratory and non-migratory forest birds using partial least squares path modeling. Climate change, resulting in longer seasons and milder winters, and forest management, promoting tree diversity, were significantly positively related to the abundance of non-migratory forest birds and explained 92% of the variation in their abundance in Europe. Regionally-migrating forest birds had stable populations with large variation, while birds migrating across continents declined in recent decades, suggesting significant, contrasting changes in bird populations in Europe. In northeastern North America we also found evidence that non-migratory forests have experienced long-term increases in abundance, and this increase was related to management. The increase of populations of non-migratory forest birds in Europe and North America is associated with an increase in structural diversity and disturbances at the landscape level.
Conclusions
Our results suggest that reports about bird decline in forests should separate between migratory and non-migratory bird species. Efforts to mitigate the general decline in bird abundance should focus on land-use systems other than forests and support sustainable forest management independent of economic conditions.
Wood product models have often been used to estimate the carbon dynamics of wood products and evaluate their effects on the mitigation of climate change. Their increasing complexity allows for ...advanced analysis of industrial product conversion efficiency, product lifespan and recycling rate, although data availability for such analyses is very often problematic. In spite of the widely recognised importance of cascade chains from one wood product to another, some wood product models represent them with recycling parameters that allocate part of the recycled wood to the same product category. Consequently, the infinite repetition of these loops overestimates carbon stock.
This study analyses and benchmarks the effect on carbon stock in wood products for the German wood sector, when infinite recycling loops in wood product models are replaced by cascade chains. Different scenarios were simulated to analyse the effect of enhanced cascade chains. We estimated the carbon stock in the German wood product sector at 22.17 ± 3.82 t C per hectare of forest in the most realistic current scenario, an amount that is overestimated by 15.8% if infinite recycling loops were used instead. The deviation on the estimated carbon stock was derived from the uncertainty of allocation parameters. Then we estimated the carbon stock in the European wood product sector (EU-28) at 1231.76 t C, representing 9.16 t C per hectare of forest. The carbon stock in German wood product sector estimated for the high quality wood benchmark scenario (103.17 t C per hectare of forest) indicated that strategies to promote the development of new product designs and material technologies to enhance cascading may have the highest impact on carbon stock in the wood product sector. Studies aiming at reducing uncertainty on results are urgent, because the use of wood products is becoming an important strategy of the international community to mitigate climate change. At the same time, a correct representation of cascade use in wood product models is important because cascade practices are being promoted by governments and will probably become more common in the near future.
•Cascade chains are used to evaluate the inaccuracy of infinite loops and explore the potential of optimized cascading use.•Wood product models including infinite recycling loops overestimate 15.8% carbon stock of the German wood product sector.•The current carbon stock in the wood product sector amounts to 22.17 t C per ha of productive forest in Germany.•The current carbon stock in the wood product sector amounts to 9.16 t C per ha of productive forest in EU-28.•Improving cascade use of harvested wood products has an important potential to increase carbon stock.
Background: The global decrease in wildlife populations, especially birds, is mainly due to land use change and increasing intensity of land use (Parmesan and Yohe 2003). However, impacts of ...management tools to mitigate biodiversity loss at regional and global scales are less apparent in forest regions that have a constant forest area, and which did not suffer from habitat degradation, and where forests are sustainably managed, such as in Central Europe or the northeastern USA. A biodiversity assessment for Germany suggested, for example, that bird populations were constant (Bundesamt für Naturschutz 2015). Results: This study shows that changes in the environment and in forest management over the past 45 years have had a significant, positive effect on the abundance of non-migratory forest bird species in Central Europe. Economy (timber prices and GDP), forest management (timber harvest and mixed forest area), and environmental factors (atmospheric CO2 concentration and nitrogen deposition) were investigated together with changes in abundances of migratory and non-migratory forest birds using partial least squares path modeling. Climate change, resulting in longer seasons and milder winters, and forest management, promoting tree diversity, were significantly positively related to the abundance of non-migratory forest birds and explained 92% of the variation in their abundance in Europe. Regionally-migrating forest birds had stable populations with large variation, while birds migrating across continents declined in recent decades, suggesting significant, contrasting changes in bird populations in Europe. In northeastern North America we also found evidence that non-migratory forests have experienced long-term increases in abundance, and this increase was related to management. The increase of populations of non-migratory forest birds in Europe and North America is associated with an increase in structural diversity and disturbances at the landscape level. Conclusions: Our results suggest that reports about bird decline in forests should separate between migratory and non-migratory bird species. Efforts to mitigate the general decline in bird abundance should focus on land-use systems other than forests and support sustainable forest management independent of economic conditions.
The coalition agreement of the German government stipulates that logging in old, near-natural beech forests in public ownership should be stopped (SPD/Grüne/FDP 2021, line 1219-1220). In this Thünen ...Working Paper, possible definitions and their occurrence are presented for old, near-natural beech forests, central inventory key figures for these forests are presented, possible threats are described and economic evaluations are carried out. We propose the following definition to operationalise the term "old, near-natural beech forests": forests with (1) >75 % beech share of the basal area, (2) a minimum age of 140 years, (3) occurrence at sites currently suitable for beech (inclusive risk area) and (4) a minimum area of 1 ha. More detailed explanations of the criteria can be found in section 3.1. Without the minimum area criterion, the area of old, near-natural beech forests comprises 205,200 ha; if all four of the above criteria are considered, then a rough estimate of 168,300 ha with a minimum area of 1 ha remains Waldfläche ha (ohne Kleinstflächen130 J.) 1.500 *Staatswald zusammengefasst, weil wegen der geringen Flächen im Bundeswald keine abgesicherten getrennten Schätzungen möglich sind. ** Die verfügbaren Nutzenschätzungen können der Fläche der über 130-jährigen Bestände im öffentlichen Wald mit einem Buchenanteil von mindestens 50 % zugerechne
Der Koalitionsvertrag der Bundesregierung sieht vor, dass der Einschlag in alten, naturnahen Buchenwäldern im öffentlichen Besitz gestoppt werden soll (SPD/Grüne/FDP 2021, Zeile 1219-1220). Im ...vorliegenden Thünen Working Paper werde für alte, naturnahe Buchenwälder mögliche Definitionen und deren Vorkommen aufgezeigt, zentrale Inventur-Kennzahlen zu diesen Wäldern vorgestellt, mögliche Gefährdungen beschrieben und ökonomische Bewertungen durchgeführt. Wir schlagen folgende Definition vor, um den Begriff 'alter, naturnaher Buchenwälder' zu operationalisieren: Wälder mit (1) >75 % Buchenanteil an der Grundfläche, (2) einem Mindestalter von 140 Jahren, (3) Vorkommen auf heute buchengeeigneten Standorten (inklusive Risikostandorte) und (4) einer Mindestfläche von 1 ha. Nähere Erläuterungen zu den Kriterien findet sich in Abschnitt 3.1. Ohne das Mindestflächen-Kriterium umfasst die Fläche alter, naturnaher Buchenwälder 205.200 ha; zieht man alle vier obengenannten Kriterien heran, dann verbleiben grob geschätzt 168.300 ha mit einer Mindestfläche von 1 ha.
Am 2. und 3. November 2021 trafen sich in Braunschweig Fachleute aus der waldbezogenen Biodiversitätsforschung und dem Monitoring, um fundierte Ideen und Vorschläge zur Erstellung eines nationalen ...Biodiversitätsmonitorings im Wald (NaBioWald) zu sammeln und einen Überblick über das diesbezügliche Meinungsspektrum zu erlangen. Impulsreferate zeigten Ansprüche, Potenziale und Grenzen bestehender und neuer Walderhebungen in Deutschland aus Sicht der Waldpolitik, dem Nationalen Monitoringzentrum zur Biodiversität (NMZB), den Forstlichen Versuchsanstalten und der Schweiz, die bereits auf Erfahrungen eines etablierten Biodiversitätsmonitorings zurückgreifen kann. In den Fachdiskussionen wurden die möglichen Voraussetzungen, Erfolgsfaktoren, Barrieren und Methoden, sowie das potentielle Erfassungsdesign eines nationalen Biodiversitätsmonitorings im Wald diskutiert. Es wurden Entwicklungsoptionen und Lücken bestehender Flächennetze/Erhebungen analysiert und Akteure für die Qualitätssicherung und Akzeptanz der Konzeption definiert. Ein Monitoring ist notwendig und soll repräsentativ und robust relevante Entwicklungen der verschiedenen Ebenen der Biodiversität aufzeigen. Es soll bestehende nationale Walderhebungen einbinden, andere Erhebungen zur Biodiversität ergänzen sowie die aus ihnen resultierenden Erkenntnisse nutzen und - wo notwendig - neue Erhebungen integrieren. Neben der Biodiversität selbst sollen auch natürliche und anthropogene Einflussgrößen ('Treiber') erfasst werden. Genutzt werden soll es für ein biodiversitätsorientiertes Waldmanagement, für die Politik(-beratung) und Maßnahmensteuerung des Bundes und der Länder und für die Erfüllung von Berichtspflichten. Das Biodiversitätsmonitoring benötigt langfristig gesicherte Ressourcen und klare Verantwortlichkeiten. Als nächstes Ziel soll ein NaBioWald-Konzept ausgearbeitet werden. Die Monitoringaufgabe ist wegen der Komplexität, des Aufwands und der großen räumlichen Abdeckung von Bund und Ländern nur gemeinsam un
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