Influence of topography, soil properties and plant community on the biomass of Abies georgei var. smithii seedlings in Southeast Tibet

Biomass of seedlings at different developing stages of growth is important information for studying the response of species to site conditions. The objectives of this study was to explore the distribution characteristics of AGB (above-ground biomass) and BGB (below-ground biomass) of Abies georgei var. smithii seedlings of different ages, and investigate the effects of topography (slope aspect, altitude), plant community characteristics (crown density, species diversity, etc.), and soil properties (soil physical and chemical properties) on the biomass and its allocation. Seedlings in five age classes (1–2, 3–4, 5–6, 7–8, and 9–10 years old) were collected by full excavation from 6 elevations (3800 m, 3900 m, 4000 m, 4100 m, 4200 m, 4300 m) on the north and south slopes of Sejila Mountain in Tibet. 15 seedlings of each age class were investigated at one altitude. The individual effects of seedling age (SA) and the interaction effects of SA, slope aspect (SL), and elevation (EG), namely, SL×EG, SL×SA, EG×SA, and SL×EG×SA, had significant effects on the AGB of the seedlings ( p