Wood Anatomical Traits and Their Influence on Carbon Sequestration, Hydraulic Efficiency and Climate Resilience of Indigenous Tree Species in Southern Africa: A Systematic Review and Meta-Analysis

Climate change is increasingly affecting forest ecosystems worldwide through rising temperatures, prolonged droughts, altered precipitation patterns, and increasing frequencies of extreme climatic events. These environmental changes influence tree growth, mortality, carbon sequestration, water relations, and ecosystem resilience. Understanding the biological traits that enable tree species to adapt to climatic stress has therefore become a major priority in forestry and ecological research. Among these traits, wood anatomical characteristics play a critical role in regulating hydraulic conductivity, carbon storage, mechanical support, and drought tolerance. Anatomical features such as vessel diameter, vessel density, vessel arrangement, fibre morphology, ray dimensions, and parenchyma abundance influence how trees transport water, store carbon, and respond to environmental disturbances. Southern Africa contains extensive woodland and forest ecosystems, including miombo, mopane, Kalahari, and dry evergreen forests, which support numerous indigenous tree species of ecological, economic, and conservation importance. However, information linking wood anatomical traits to carbon sequestration, hydraulic efficiency, and climate resilience remains fragmented across multiple disciplines and geographic regions. Consequently, there is limited synthesis of how anatomical adaptations influence forest responses to climate change and their implications for climate-smart forestry and sustainable forest management. This systematic review and meta-analysis synthesizes available evidence on the influence of wood anatomical traits on carbon sequestration, hydraulic efficiency, and climate resilience among indigenous tree species in Southern Africa. Following the PRISMA framework, published journal articles, forestry reports, dissertations, conference proceedings, and institutional publications were reviewed. Data were extracted on vessel characteristics, fibre properties, ray dimensions, parenchyma abundance, wood density, biomass accumulation, carbon storage, hydraulic conductivity, cavitation resistance, drought tolerance, and climate adaptation indicators. The review demonstrates that wood anatomical traits are strong predictors of ecosystem functioning and climate adaptation. Vessel architecture emerged as a primary determinant of hydraulic efficiency and drought resistance, while fibre characteristics and wood density were strongly associated with biomass accumulation and long-term carbon sequestration. Species possessing narrow vessels, high vessel density, thick fibre walls, abundant parenchyma, and dense wood generally exhibited greater hydraulic safety, drought tolerance, and carbon storage potential. The findings highlight the importance of integrating wood anatomical information into climate-smart forestry, forest landscape restoration, carbon accounting systems, species selection programmes, and sustainable forest management strategies. The review further identifies critical research gaps, including limited species-specific anatomical databases, inadequate long-term hydraulic monitoring, and insufficient integration of anatomical traits into climate adaptation models.