Big-sized trees and forest functioning: Current knowledge and future perspectives

Abstract

Although approximately three decades ago the ecological role of big-sized trees (also known as either large, large-diameter, mega, oversized or big trees) has been recognized in the scientific literature, the reviews synthesizing our current knowledge and perspectives on the ecological influences of big-sized trees on aboveground biomass, productivity, demographic processes, multifunctionality and stability as well as litterfall, decomposition and belowground functions (e.g., soil organic carbon storage) are still largely unavailable. Here, we provide a literature review and find that ample of studies have suggested that big-sized trees contribute much (i.e., nearly half or more) to stand-level aboveground biomass in worldwide forests, but big-sized trees decline globally due to deforestation and climate change. Although several studies have generally assumed that big-sized trees regulate above- and belowground forest functions, there was no strong evidence through the support of data to explicitly show the effects of big-sized trees attributes (in terms of the species, structural, functional trait and phylogenetic diversity and composition of big-sized trees) on forest functions in the integrative ecological models. This review suggests some future research directions (based on integrative ecological modeling) to explore the effects of big-sized trees attributes, in relationships with abiotic and biotic drivers, on forest functioning in the context of natural and anthropogenic changes because big-sized trees are directly linked with many key ecological issues in global forests.

Keywords

• Abiotic conditions
• Aboveground biomass
• Biodiversity
• Demographic processes
• Forest stability
• Global forests