Effects of different planting approaches and site conditions on aboveground carbon storage along a 10-year chronosequence after moso bamboo reforestation

Abstract

Moso bamboo (Phyllostachys pubescens) is widely used for afforestation and reforestation in subtropical China because of its high carbon (C) sequestration rate and ability to control soil erosion in degraded areas; it also plays an important role in mitigating climate change. To satisfy the requirements of carbon trading systems, methodologies for estimating changes in C storage under different planting approaches and site conditions are needed. A 10-year field monitoring study of a moso bamboo reforestation area was carried out to research the effects of different planting approaches and site conditions on stand structure dynamics and aboveground C storage accumulation (AGCSA). The bamboo was transplanted in groups of 3 plants (3-PG) or as individual plants (IP). The site conditions were classified into three categories (poor, fair and excellent). The bamboo diameter at breast height (DBH) and height exhibited a slow-fast-slow growth rate trend under both planting approaches. The DBH and height peaked in the 9th year under the 3-PG approach, but maximum DBH and height values were not reached under the IP approach during the study period. The density (D) of new culms (NCs) peaked at five years after reforestation under both planting approaches, and the aboveground C storage (AGCS) of NCs peaked seven years after reforestation. Both planting approaches exhibited clear on-year and off-year plant growth characteristics. The different planting approaches and site conditions significantly influenced AGCSA. Growth models for DBH, height and AGCSA under the specific silvicultural approaches and site conditions were established on the basis of the identified correlations. Ten years after reforestation under the 3-PG approach, the AGCSA was only 3.71 Mg C ha−1 under poor site conditions, while under excellent site conditions, the AGCSA reached 14.71 Mg C ha−1. An optimized management model that considers soil factors has great potential for improving C sequestration in moso bamboo forests.