摘要In forests,a few large trees(L-trees)versus small-medium trees(S-trees)are often considered the major reservoir of aboveground carbon stock(AGCS).Here,we hypothesize that tree species'functional stra-tegies regulate AGCS by tree sizes in temperate deciduous forests across local scale environmental gradients.Using data from 99 plots,we modelled the multivariate effects of the tree-based(tree di-versity,stand density and multidimensional tree size inequality)versus the trait-based(multi-trait di-versity and single-trait dominance)attributes of L-trees versus S-trees,along topographic and soil conditions,to predict AGCS through four L-trees threshold size(i.e.,≥ 50 cm fixed-diameter,top 95th percentile,≥ top 50％cumulative AGCS descending-ranked ordered,and mean threshold size)ap-proaches.The tree-based and trait-based attributes of L-trees and S-trees shaped species co-occurrence processes but L-trees regulated AGCS more effectively(31.29-93.20％)than S-trees and abiotic factors across four thereshold size approaches and two concepts.Although L-trees threshold size and tree-based attributes mattered for AGCS,the dominant resource-acquisitive strategy of structurally complex L-trees having higher specific leaf area but lower leaf dry matter content and lesser multi-trait dispersion could promote AGCS better than the resource-conservative strategy(low specific leaf area)of S-trees.Capturing tree species' functional strategies,synergies and trade-offs across tree sizes can enhance our under-standing of how to achieve nature-based carbon neutrality and lessen climate change.Thus,forest management and restoration initiatives should prioritize high-functioning tree species with dominant productive traits while conserving multi-trait diversified species in temperate deciduous forests.