Tree species richness increases ecosystem carbon storage in subtropical forests

Forest ecosystems are an integral component of the global carbon cycle as they take up and release large amounts of C in short time (C flux) or accumulate it over longer time (C stock). However, there remains uncertainty about whether and in which direction C fluxes and in particular C stocks may differ between forests of high vs. low species richness. Based on a comprehensive dataset derived from field-based measurements, we tested the effect of species richness (3–20 tree species) and stand age (22–116 years) on six compartments of above- and belowground C stocks and four components of C fluxes in subtropical forests in south-east China. Across forest stands, total C stock was 149 ± 12 Mg ha-1 with richness explaining 28.5% and age explaining 29.4% of variation in this measure. Species-rich stands had higher C stocks and fluxes than stands with low richness; and, in addition, old stands had higher C stocks than young ones. Overall, for each additional tree species the total C stock in...

森林生态系统是全球碳循环的核心组成部分，因其可在短时间内吸收与释放大量碳（碳通量，C flux），或在更长周期中固存碳（碳储量，C stock）。然而，针对物种丰富度高低不同的森林，其碳通量尤其是碳储量是否存在差异、差异方向如何，目前仍存在不确定性。本研究基于野外实测获取的综合数据集，针对中国东南部亚热带森林，检验了物种丰富度（3~20种乔木）与林分年龄（22~116年）对6种地上、地下碳储量组分，以及4种碳通量组分的影响。在所有受试林分中，总碳储量为149 ± 12 Mg·ha⁻¹，其中物种丰富度可解释该指标28.5%的变异，林分年龄可解释29.4%的变异。物种丰富度更高的林分，其碳储量与碳通量均高于低丰富度林分；此外，成熟林分的碳储量也高于幼龄林分。总体而言，每增加1种乔木，总碳储量……