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Aim: Despite mounting empirical evidence regarding the positive effects of forest structural diversity (STRDIV) on forest functioning, the underlying biotic mechanisms and controlling abiotic factors remain poorly understood. This study provides the first assessment of the interactive effects of STRDIV and diversity in species and functional traits on aboveground biomass (AGB) in natural forests in West and East Africa. Location: West and East Africa. Time period: 2014–2020. Major taxa studied: Woody plants. Methods: Using data from 276 plots and 7993 trees of 207 species distributed across various types of natural forests and major climatic zones of Africa, linear mixed‐effects and structural equation models, we have evaluated how alternative causal relationships between STRDIV and taxonomic and functional diversity attributes influence AGB, while accounting for the effects of environmental covariates. We also assessed the consistency of these relationships across floristically and environmentally homogenous forest types. Results: We found that the positive effects of STRDIV on AGB were underpinned by both the community‐weighted mean (CWM) of trait values (selection effects) and species richness (niche complementarity), but the relative importance of these effects varied depending on forest types. Across the forest types, STRDIV primarily mediated the effects of CWM of traits and species richness on AGB. We also found that STRDIV–AGB relationships were constrained by resource (water and nutrient) availability. Main conclusions: Our findings provide novel insights into the role of functional traits as key determinants of the effects of STRDIV on AGB in tropical forests. We suggest that forest management and climate change mitigation strategies aimed at conserving biodiversity, and fostering biomass storage through increased STRDIV should focus on maintaining high levels of functionally dominant species while also increasing tree species diversity. [ABSTRACT FROM AUTHOR]

Forests mitigate climate change by absorbing CO2. However, N2O emissions in forests, which has 298 times larger global warming potential than CO2, can diminish the climate mitigation role of forests. Thus, it is crucial to project not only CO2 absorption but also N2O emissions in forests to provide a scientific basis for the 1.5 °C Paris Agreement goal. This study used a biogeochemical model, called FBD-CAN, to project CO2 absorption and N2O emissions of South Korean forests from 2021 to 2080 under three climate scenarios, including the current climate, Representative Concentration Pathway (RCP) 4.5, and RCP 8.5. From 2021 to 2080, CO2 absorption decreased from 5.0 to 1.4 Mg CO2 ha—1 year—1 under the current climate with the aging of forests, while N2O emissions increased from 0.25 to 0.33 Mg CO2 eq. ha—1 year—1. Climate change accelerated the decreasing trend in CO2 absorption and the increasing trend in N2O emissions. The subalpine region had a faster decreasing trend in CO2 absorption than the central and southern regions due to its older stand age. These findings provide scientific references for future greenhouse gas reduction plans and broaden our knowledge of the impacts of climate change on the climate mitigation role of forests. [ABSTRACT FROM AUTHOR]

Given recent and projected climate change, the study of adaptation and mitigation strategies which involve ecologically and economically important plant species is urgently needed. Faidherbia albida (Delile) A. Chev. is a species of both economic and ecological importance. We use 229 locational records gathered in the dry highlands of Ethiopia, nineteen environmental variables and the modelling program MaxEnt to model both the present and possible future distributions of this species. To model future distributions, we used two emission scenarios (Representative Concentration Pathways 2.6 and 8.5) for two time slices (2050 and 2070). Mean temperature of wettest quarter was the major factor which determines the species' potential distribution. Suitable habitat for F. albida under the current climatic conditions is the mid-highlands. However, its future distributions would shift upwards in elevation and will likely lead to some decrease in suitable areas, especially towards the end of the century. At the same time, however, other areas would become suitable for colonization, so that, overall, the species does not appear to face a significant reduction in distribution within our study region. Future studies should consider the possible effects of climate extremes, further environmental factors and of evolutionary adaptation of the species to new conditions. [ABSTRACT FROM AUTHOR]