• Energy Research

Intensification of forest management is seen as one important measure to increase carbon sequestration and contribute to balance CO2 emissions and mitigate climate change. Potential measures for forest management intensification include increasing the percentage of the area that is actively reforested after felling, planting at higher densities and with genetically improved material, nitrogen fertilization, and pre-commercial thinning. Here we assessed the mitigation potential of these practices in Norwegian forests from 2018 until the end of the 21st century. As a result, when these management practices were intensified, separately and simultaneously, carbon sequestration over the 80-year simulation period was larger than under current practices. Pre-commercial thinning gave the largest additional 80-year carbon dioxide removal increment and fertilization the smallest. The largest accumulated carbon dioxide removal potential occurred when intensifying all the proposed measures in one scenario and was estimated to be around 329.9 Tg CO2 by the end of the century, corresponding to offset more than six times Norway's total GHG emissions in 2022. If the intensification of these practices is considered separately, our results suggested that pre-commercial thinning and active reforestation after felling, in that order, should be prioritized as climate change mitigation measures, followed by genetic improvement, planting density and fertilization.

Le gradient de diversité latitudinale (LDG) est l'un des modèles mondiaux de richesse en espèces les plus reconnus dans un large éventail de taxons. De nombreuses hypothèses ont été proposées au cours des deux derniers siècles pour expliquer le LDG, mais des tests rigoureux des facteurs de LDG ont été limités par un manque de données mondiales de haute qualité sur la richesse en espèces. Ici, nous produisons une carte à haute résolution (0,025° × 0,025°) de la richesse des espèces d'arbres locales à l'aide d'une base de données d'inventaire forestier mondial avec des informations sur les arbres individuels et des caractéristiques biophysiques locales à partir d'environ 1,3 million de placettes-échantillons. Nous quantifions ensuite les moteurs des modèles de richesse des espèces d'arbres locales à travers les latitudes. En général, la température moyenne annuelle était un prédicteur dominant de la richesse des espèces d'arbres, ce qui est le plus conforme à la théorie métabolique de la biodiversité (MTB). Cependant, le MTB a sous-estimé le LDG sous les tropiques, où la richesse élevée en espèces a également été modérée par des facteurs topographiques, pédologiques et anthropiques opérant à l'échelle locale. Étant donné que les variables locales du paysage agissent en synergie avec les facteurs bioclimatiques dans la formation du modèle mondial de LDG, nous suggérons que le MTB soit étendu pour tenir compte de la co-limitation par les conducteurs subordonnés. En examinant les facteurs du gradient latitudinal de biodiversité dans une base de données mondiale sur la richesse des espèces locales d'arbres, les auteurs montrent que la co-limitation par de multiples facteurs environnementaux et anthropiques provoque des augmentations plus importantes de la richesse avec la latitude dans les zones tropicales par rapport aux zones tempérées et boréales. El gradiente de diversidad latitudinal (LDG) es uno de los patrones globales más reconocidos de riqueza de especies que se exhiben en una amplia gama de taxones. Se han propuesto numerosas hipótesis en los últimos dos siglos para explicar la LDG, pero las pruebas rigurosas de los impulsores de las LDG se han visto limitadas por la falta de datos globales de alta calidad sobre la riqueza de especies. Aquí producimos un mapa de alta resolución (0.025° × 0.025°) de la riqueza de especies de árboles locales utilizando una base de datos de inventario forestal global con información de árboles individuales y características biofísicas locales de ~ 1.3 millones de parcelas de muestra. A continuación, cuantificamos los impulsores de los patrones de riqueza de especies arbóreas locales en todas las latitudes. En general, la temperatura media anual fue un predictor dominante de la riqueza de especies de árboles, lo que es más consistente con la teoría metabólica de la biodiversidad (MTB). Sin embargo, el MTB subestimó el LDG en los trópicos, donde la alta riqueza de especies también fue moderada por factores topográficos, del suelo y antropogénicos que operan a escala local. Dado que las variables del paisaje local operan sinérgicamente con factores bioclimáticos en la configuración del patrón global de LDG, sugerimos que el MTB se extienda para tener en cuenta la co-limitación por parte de los conductores subordinados. Al examinar los impulsores del gradiente de biodiversidad latitudinal en una base de datos global de la riqueza de especies de árboles locales, los autores muestran que la co-limitación por múltiples factores ambientales y antropogénicos causa aumentos más pronunciados en la riqueza con latitud en zonas tropicales versus templadas y boreales. The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we produce a high-resolution (0.025° × 0.025°) map of local tree species richness using a global forest inventory database with individual tree information and local biophysical characteristics from ~1.3 million sample plots. We then quantify drivers of local tree species richness patterns across latitudes. Generally, annual mean temperature was a dominant predictor of tree species richness, which is most consistent with the metabolic theory of biodiversity (MTB). However, MTB underestimated LDG in the tropics, where high species richness was also moderated by topographic, soil and anthropogenic factors operating at local scales. Given that local landscape variables operate synergistically with bioclimatic factors in shaping the global LDG pattern, we suggest that MTB be extended to account for co-limitation by subordinate drivers. Examining drivers of the latitudinal biodiversity gradient in a global database of local tree species richness, the authors show that co-limitation by multiple environmental and anthropogenic factors causes steeper increases in richness with latitude in tropical versus temperate and boreal zones. يعد تدرج التنوع العرضي (LDG) أحد أكثر الأنماط العالمية المعترف بها لثراء الأنواع المعروضة عبر مجموعة واسعة من الأصناف. تم اقتراح العديد من الفرضيات في القرنين الماضيين لشرح غاز الديزل منخفض الكثافة، لكن الاختبارات الصارمة لمحركات غازات الديزل منخفض الكثافة كانت محدودة بسبب نقص بيانات ثراء الأنواع العالمية عالية الجودة. هنا ننتج خريطة عالية الدقة (0.025درجة × 0.025درجة) لثراء أنواع الأشجار المحلية باستخدام قاعدة بيانات جرد الغابات العالمية مع معلومات الأشجار الفردية والخصائص الفيزيائية الحيوية المحلية من حوالي 1.3 مليون قطعة عينة. ثم نحدد العوامل المحركة لأنماط ثراء أنواع الأشجار المحلية عبر خطوط العرض. بشكل عام، كان متوسط درجة الحرارة السنوية مؤشراً مهيمناً على ثراء أنواع الأشجار، وهو الأكثر اتساقاً مع نظرية التمثيل الغذائي للتنوع البيولوجي (MTB). ومع ذلك، قلل MTB من تقدير غاز التدهور المنخفض في المناطق المدارية، حيث كان ثراء الأنواع المرتفع معتدلاً أيضًا بسبب العوامل الطبوغرافية والتربة والعوامل البشرية المنشأ التي تعمل على المستويات المحلية. بالنظر إلى أن متغيرات المناظر الطبيعية المحلية تعمل بشكل تآزري مع العوامل المناخية الحيوية في تشكيل نمط الغازات المتدهورة عالميًا، فإننا نقترح توسيع نطاق الحد الأقصى للمناظر الطبيعية لمراعاة الحد المشترك من قبل الدوافع الثانوية. عند دراسة دوافع تدرج التنوع البيولوجي العرضي في قاعدة بيانات عالمية لثراء أنواع الأشجار المحلية، يوضح المؤلفون أن الحد المشترك من خلال عوامل بيئية وبشرية متعددة يسبب زيادات أكثر حدة في الثراء مع خط العرض في المناطق الاستوائية مقابل المناطق المعتدلة والشمالية.

AbstractForest structural properties largely govern surface fluxes of moisture, energy, and momentum that strongly affect regional climate and hydrology. Forest structural properties are greatly shaped by forest management activities, especially in the Fennoscandia (Norway, Sweden, and Finland). Insight into transient developments in forest structure in response to management intervention is therefore essential to understanding the role of forest management in mitigating regional climate change. The aim of this study is to present a simple grid-based framework – the Fennoscandic Forest State Simulator (F2S2) -- for predicting time-dependent forest structural trajectories in a manner compatible with land models employed in offline or asynchronously coupled climate and hydrological research. F2S2 enables the prescription of future regional forest structure as a function of: i) exogenously defined scenarios of forest harvest intensity; ii) forest management intensity; iii) climate forcing. We demonstrate its application when applied as a stand-alone tool for forecasting three alternative future forest states in Norway that differ with respect to background climate forcing, forest harvest intensity (linked to two Shared Socio-economic Pathways (SSPs)), and forest management intensity. F2S2 captures impacts of climate forcing and forest management on general trends in forest structural development over time, and while climate is the main driver of longer-term forest structural dynamics, the role of harvests and other management-driven effects cannot be overlooked. To our knowledge this is the first paper presenting a method to map forest structure in space and time in a way that is compatible with land surface or hydrological models employing sub-grid tiling.

Forests provide a range of vital services to society and are critical habitats for biodiversity, holding inherent multifunctionality. While traditionally viewed as a byproduct of production-focused forestry, today's forest ecosystem services and biodiversity (FESB) play an essential role in several sectoral policies’ needs. Achieving policy objectives requires careful management considering the interplay of services, influenced by regional aspects and climate. Here, we examined the multifunctionality gap caused by these factors through simulation of forest management and multi-objective optimization methods across different regions - Finland, Norway, Sweden and Germany (Bavaria). To accomplish this, we tested diverse management regimes (productivity-oriented silviculture, several continuous cover forestry regimes and set asides), two climate scenarios (current and RCP 4.5) and three policy strategies (National Forest, Biodiversity and Bioeconomy Strategies). For each combination we calculated a multifunctionality metric at the landscape scale based on 5 FESB classes (biodiversity conservation, bioenergy, climate regulation, wood, water and recreation). In Germany and Norway, maximum multifunctionality was achieved by increasing the proportion of set-asides and proportionally decreasing the rest of management regimes. In Finland, maximum MF would instead require that policies address greater diversity in management, while in Sweden, the pattern was slightly different but similar to Finland. Regarding the climate scenarios, we observed that only for Sweden the difference in the provision of FESB was significant. Finally, the highest overall potential multifunctionality was observed for Sweden (National Forest scenario, with a value of 0.94 for the normalized multifunctionality metric), followed by Germany (National Forest scenario, 0.83), Finland (Bioeconomy scenario, 0.81) and Norway (National Forest scenario, 0.71). The results highlight the challenges of maximizing multifunctionality and underscore the significant influence of country-specific policies and climate change on forest management. To achieve the highest multifunctionality, strategies must be tailored to specific national landscapes, acknowledging both synergistic and conflicting FESB.

The repository contains the data and codes supporting the findings of the study: Climate targets in European timber-producing countries conflict with goals on forest ecosystem services and biodiversity, which can be found in the zip file "euclimate_vs_natpolicy-main.zip". Further, the repository includes the raw forest simulation data used as input for the multi-objective optimizations and the raw optimization outputs of each study region. The codes to run the national optimization can be retrieved from https://doi.org/10.5281/zenodo.6631109. Abstract: The European Union (EU) set clear climate change mitigation targets to reach climate neutrality, accounting for forests and their woody biomass resources. We investigated the consequences of increased harvest demands resulting from EU climate targets. We analysed the impacts on national policy objectives for forest ecosystem services and biodiversity through empirical forest simulation and multi-objective optimization methods. We show that key European timber-producing countries – Finland, Sweden, Germany (Bavaria) – cannot fulfil the increased harvest demands linked to the ambitious 1.5°C target. Potentials for harvest increase only exists in the studied region Norway. However, focusing on EU climate targets conflicts with several national policies and causes adverse effects on multiple ecosystem services and biodiversity. We argue that the role of forests and their timber resources in achieving climate targets and societal decarbonization should not be overstated. Our study provides insight for other European countries challenged by conflicting policies and supports policymakers.

AbstractForests are a substantial terrestrial carbon sink, but anthropogenic changes in land use and climate have considerably reduced the scale of this system1. Remote-sensing estimates to quantify carbon losses from global forests2–5 are characterized by considerable uncertainty and we lack a comprehensive ground-sourced evaluation to benchmark these estimates. Here we combine several ground-sourced6 and satellite-derived approaches2,7,8 to evaluate the scale of the global forest carbon potential outside agricultural and urban lands. Despite regional variation, the predictions demonstrated remarkable consistency at a global scale, with only a 12% difference between the ground-sourced and satellite-derived estimates. At present, global forest carbon storage is markedly under the natural potential, with a total deficit of 226 Gt (model range = 151–363 Gt) in areas with low human footprint. Most (61%, 139 Gt C) of this potential is in areas with existing forests, in which ecosystem protection can allow forests to recover to maturity. The remaining 39% (87 Gt C) of potential lies in regions in which forests have been removed or fragmented. Although forests cannot be a substitute for emissions reductions, our results support the idea2,3,9 that the conservation, restoration and sustainable management of diverse forests offer valuable contributions to meeting global climate and biodiversity targets.