Suchergebnisse

Abstract
Linking individual and stand-level dynamics during forest development reveals a scaling relationship between mean tree size and tree density in forest stands, which integrates forest structure and function. However, the nature of this so-called scaling law and its variation across broad spatial scales remain unquantified, and its linkage with forest demographic processes and carbon dynamics remains elusive. In this study, we develop a theoretical framework and compile a broad-scale dataset of long-term sample forest stands (n = 1,433) from largely undisturbed forests to examine the association of temporal mean tree size vs. density scaling trajectories (slopes) with biomass accumulation rates and the sensitivity of scaling slopes to environmental and demographic drivers. The results empirically demonstrate a large variation of scaling slopes, ranging from −4 to −0.2, across forest stands in tropical, temperate, and boreal forest biomes. Steeper scaling slopes are associated with higher rates of biomass accumulation, resulting from a lower offset of forest growth by biomass loss from mortality. In North America, scaling slopes are positively correlated with forest stand age and rainfall seasonality, thus suggesting a higher rate of biomass accumulation in younger forests with lower rainfall seasonality. These results demonstrate the strong association of the transient mean tree size vs. density scaling trajectories with forest demography and biomass accumulation rates, thus highlighting the potential of leveraging forest structure properties to predict forest demography, carbon fluxes, and dynamics at broad spatial scales.

The biodiversity-productivity relationship (BPR) is foundational to our understanding of the global extinction crisis and its impacts on ecosystem functioning. Understanding BPR is critical for the accurate valuation and effective conservation of biodiversity. Using ground-sourced data from 777,126 permanent plots, spanning 44 countries and most terrestrial biomes, we reveal a globally consistent positive concave-down BPR, showing that continued biodiversity loss would result in an accelerating decline in forest productivity worldwide.The value of biodiversity in maintaining commercial forest productivity alone—US$166 billion to 490 billion per year according to our estimation—is more than twice what it would cost to implement effective global conservation.This highlights the need for a worldwide reassessment of biodiversity values, forest management strategies, and conservation priorities. ; This work was supported in part by West Virginia University under the United States Department of Agriculture (USDA) McIntire-Stennis Funds WVA00104 and WVA00105; U.S. National Science Foundation (NSF) Long-Term Ecological Research Program at Cedar Creek (DEB-1234162); the University of Minnesota Department of Forest Resources and Institute on the Environment; the Architecture and Environment Department of Italcementi Group, Bergamo (Italy); a Marie Skłodowska Curie fellowship; Polish National Science Center grant 2011/02/A/NZ9/00108; the French L'Agence Nationale de la Recherche (ANR) (Centre d'Étude de la Biodiversité Amazonienne: ANR-10-LABX-0025); the General Directory of State Forest National Holding DB; General Directorate of State Forests, Warsaw, Poland (Research Projects 1/07 and OR/2717/3/11); the 12th Five-Year Science and Technology Support Project (grant 2012BAD22B02) of China; the U.S. Geological Survey and the Bonanza Creek Long Term Ecological Research Program funded by NSF and the U.S. Forest Service (any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. government); National Research Foundation of Korea (grant NRF-2015R1C1A1A02037721), Korea Forest Service (grants S111215L020110, S211315L020120 and S111415L080120) and Promising-Pioneering Researcher Program through Seoul National University (SNU) in 2015; Core funding for Crown Research Institutes from the New Zealand Ministry of Business, Innovation and Employment's Science and Innovation Group; the Deutsche Forschungsgemeinschaft (DFG) Priority Program 1374 Biodiversity Exploratories; Chilean research grants Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT) 1151495 and 11110270; Natural Sciences and Engineering Research Council of Canada (grant RGPIN-2014-04181); Brazilian Research grants CNPq 312075/2013 and FAPESC 2013/TR441 supporting Santa Catarina State Forest Inventory (IFFSC); the General Directorate of State Forests, Warsaw, Poland; the Bavarian State Ministry for Nutrition, Agriculture, and Forestry project W07; the Bavarian State Forest Enterprise (Bayerische Staatsforsten AöR); German Science Foundation for project PR 292/12-1; the European Union for funding the COST Action FP1206 EuMIXFOR; FEDER/ COMPETE/POCI under Project POCI-01-0145-FEDER-006958 and FCT–Portuguese Foundation for Science and Technology under the project UID/AGR/04033/2013; Swiss National Science Foundation grant 310030B_147092; the EU H2020 PEGASUS project (no 633814), EU H2020 Simwood project (no 613762); and the European Union's Horizon 2020 research and innovation program within the framework of the MultiFUNGtionality Marie Skłodowska-Curie Individual Fellowship (IF-EF) under grant agreement 655815. The expeditions in Cameroon to collect the data were partly funded by a grant from the Royal Society and the Natural Environment Research Council (UK) to Simon L. Lewis.

The biodiversity-productivity relationship (BPR) is foundational to our understanding of the global extinction crisis and its impacts on ecosystem functioning. Understanding BPR is critical for the accurate valuation and effective conservation of biodiversity. Using ground-sourced data from 777,126 permanent plots, spanning 44 countries and most terrestrial biomes, we reveal a globally consistent positive concave-down BPR, showing that continued biodiversity loss would result in an accelerating decline in forest productivity worldwide. The value of biodiversity in maintaining commercial forest productivity alone—US$166 billion to 490 billion per year according to our estimation—is more than twice what it would cost to implement effective global conservation. This highlights the need for a worldwide reassessment of biodiversity values, forest management strategies, and conservation priorities.