Biomass:N:K:Ca:Mg:P ratios in forest stands world‐wide: Biogeographical variations and environmental controls
Kerong Zhang, Xiaoli Cheng, Haishan Dang, Quanfa Zhang
Abstract
Abstract Aim Community‐level biomass‐to‐nutrient ratios and elemental stoichiometry of forests can provide insights for understanding the efficiency of nutrient use and the adaptation strategies of trees. However, the global‐scale pattern of biomass:N:K:Ca:Mg:P ratios in forest stands and its responses to environmental drivers remain unknown. Location World‐wide. Time period 1959–2015. Major taxa studied Trees in forests. Methods We synthesized data from 356 forests distributed globally to study the biogeographical variations in biomass‐to‐nutrient ratios and elemental stoichiometry. Results Our results revealed that the biomass:N, biomass:P, biomass:K, biomass:Ca and biomass:Mg ratios of living trees in forests averaged 330.2 ± 11.1, 3847.1 ± 164.6, 615.3 ± 26.1, 393.2 ± 15.0 and 2221.5 ± 92.0, respectively. The biomass:N, biomass:K, biomass:Mg, P:K, P:Mg and Ca:Mg ratios decreased with mean annual temperature and increased from low to high latitude, whereas the N:P and K:Ca ratios displayed the opposite trends. The biomass:P, N:P and K:Ca ratios increased significantly with increasing mean annual precipitation (MAP), whereas the P:K, P:Mg and Ca:Mg ratios decreased with the MAP. The biomass:N and biomass:Ca ratios decreased significantly with increasing soil N and Ca stocks, respectively. Forest stand age significantly affected biomass‐to‐nutrient ratios, with the older forests displaying higher biomass:N and biomass:P. The scaling relationships indicated that, on average, as biomass increased, biomass:N would increase, because N rose more slowly than linearly with biomass, whereas the Ca and Mg increased proportionally with biomass. Main conclusions Our findings proved that the community‐level biomass‐to‐nutrient ratios and stoichiometry were affected by climate, soil, stand age and taxonomy of trees.