Search

Beech (Fagus sylvatica L.) is the most important deciduous tree species in Germany. The wood of beech shows normally a bright colour (white beech) as long as no coloured heartwood has been formed. The facultative heartwood formation is induced when oxygen enters central parts of older trees, where dead or at least less vital parenchyma exist. The coloured heartwood is usually called âred heartwoodâ. Beech without red heartwood can preferably be found in younger trees which show a high water content even in central parts of the stem. The presence of red heartwood is regarded as a severe reduction of timber quality. Numerous studies have investigated opportunities to derive information on the presence and characteristics of red heartwood of standing beech trees. But until now it has not been tested whether such information could be helpful to improve the economics of beech-silviculture. This paper investigates whether complete information on the heartwood of standing beech could be useful to control the proportion of discoloured timber harvested during one rotation. It is also examined, which kind of information on the heartwood could be used to improve the economic results. To verify this, simulations based on simple algorithms were conducted. The general assumption was made that all information on the heartwood would be available. The results show that information which is restricted on the mere existence of red heartwood is neither suited to significantly reduce the amount of coloured timber nor is it possible to improve economic results based on this information. Only based on information on the recent formation of red heartwood of beech, which is actually still white the amount of discoloured timber can be reduced significantly. Consequently the discounted cash flows can only be substantially improved based on information on an expected formation of recent red heartwood.

Forests provide important ecosystem services (ESs), including climate change mitigation, local climate regulation, habitat for biodiversity, wood and non‐wood products, energy, and recreation. Simultaneously, forests are increasingly affected by climate change and need to be adapted to future environmental conditions. Current legislation, including the European Union (EU) Biodiversity Strategy, EU Forest Strategy, and national laws, aims to protect forest landscapes, enhance ESs, adapt forests to climate change, and leverage forest products for climate change mitigation and the bioeconomy. However, reconciling all these competing demands poses a tremendous task for policymakers, forest managers, conservation agencies, and other stakeholders, especially given the uncertainty associated with future climate impacts. Here, we used process‐based ecosystem modeling and robust multi‐criteria optimization to develop forest management portfolios that provide multiple ESs across a wide range of climate scenarios. We included constraints to strictly protect 10% of Europe's land area and to provide stable harvest levels under every climate scenario. The optimization showed only limited options to improve ES provision within these constraints. Consequently, management portfolios suffered from low diversity, which contradicts the goal of multi‐functionality and exposes regions to significant risk due to a lack of risk diversification. Additionally, certain regions, especially those in the north, would need to prioritize timber provision to compensate for reduced harvests elsewhere. This conflicts with EU LULUCF targets for increased forest carbon sinks in all member states and prevents an equal distribution of strictly protected areas, introducing a bias as to which forest ecosystems are more protected than others. Thus, coordinated strategies at the European level are imperative to address these challenges effectively. We suggest that the implementation of the EU Biodiversity Strategy, EU Forest Strategy, and targets for forest carbon sinks require complementary measures to alleviate the conflicting demands on forests. [ABSTRACT FROM AUTHOR]

A shifting focus in forest management from timber production to resilience and multifunctionality in the face of changing disturbance regimes might entail altering the species composition of forests. Although the conifers Douglas fir (Pseudotsuga menziesii) and silver fir (Abies alba) currently comprise only a small proportion of Central European forests, the prospect of widespread planting of these species as a climate adaptation measure is currently widely debated by forest managers. To inform this debate, objective assessments of the multifunctional value of these species are required. Here, we introduce Pareto frontiers to objectively assess the value of tree species under competing objectives and considering an uncertain future. Using these frontiers, we explore trade-offs between financial performance and biodiversity aspects of German tree species portfolios with and without these currently rare conifers. We compare several potential biodiversity indicators (related to herbivores, saproxylic beetles, and deadwood decomposition rates) that can be derived from standard forest inventory data. Our results indicate that optimizing the biodiversity indicators generates gradual decreases in financial performance at first, but after an inflection point soil rent declines sharply. Portfolios excluding Douglas fir and silver fir achieved comparable biodiversity levels, but much weaker financial performance, than portfolios that included these conifers. Our novel approach of generating Pareto frontiers that integrate uncertainty can offer useful insights into ecosystem services trade-offs in contexts where risk is unequally distributed across management alternatives. [ABSTRACT FROM AUTHOR]

Because of the very high complexity of modern optimization models based on single trees, uncertainties are often disregarded. In this study, we present a modelling approach that allows partial harvesting but is still simple enough to consider risk. Our modelling approach investigates whether the inclusion of timber price uncertainty influences the harvesting schedule. The model considers positive growth response to the density reduction that follows harvesting. Testing the impact of uncertainty, we define the discounted net revenues of each harvest operation as random variables. We compare harvest scheduling both with and without the inclusion of uncertainty. We first model growth response based on a partial-harvest schedule, without integrating uncertainty from timber price fluctuations. The results show that harvesting tree cohorts at different times is financially optimal. We run the same model again, including the risk of timber price fluctuations. The inclusion of risk leads to slightly greater differences in recommended harvest timings. Because of the small difference observed, we conclude that it is unlikely that risk arising from fluctuating timber prices would strongly affect the results for more complex forest economic models concerning the optimal harvest schedules. Key words: uncertainty, forest management planning, forest stand optimization, risk integration, portfolio theory. Etant donne la tres grande complexite des modeles d'optimisation modernes bases sur l'arbre individuel, on ignore souvent les incertitudes. Dans cette etude, nous presentons une approche de modelisation qui permet une recolte partielle mais est quand meme assez simple pour tenir compte des risques. Notre approche de modelisation verifie si l'inclusion de l'incertitude au sujet des prix du bois influence la programmation de la recolte. Le modele tient compte de la croissance positive engendree par la reduction de la densite qui resulte de la recolte. Pour tester l'impact de l'incertitude, nous definissons les revenus nets actualises de chaque operation de recolte en tant que variable aleatoire. Nous comparons la programmation de la recolte en incluant ou non l'incertitude. Nous modelisons d'abord la reaction de la croissance sur la base d'une programmation de recolte partielle sans integrer l'incertitude due aux fluctuations du prix du bois. Les resultats montrent que la recolte de cohortes d'arbres a differents moments est financierement optimale. Nous avons utilise le meme modele en incluant les risques associes aux fluctuations du prix du bois. L'inclusion des risques a engendre des differences legerement plus importantes dans les moments recommandes pour la recolte. Etant donne que la difference observee est faible, nous concluons qu'il est peu probable que les risques associes a la fluctuation des prix du bois aient un impact significatif sur les resultats avec des modeles economiques forestiers plus complexes a propos des programmations de recolte optimales. [Traduit par la Redaction] Mots-cles : incertitude, planification de l'amenagement forestier, optimisation des peuplements forestiers, integration des risques, theorie du portefeuille., 1. Introduction There is a long tradition in forest economics to determine the stand rotation based on Faustmann's (1849) land expectation value (LEV). LEV is the present value of an [...]