Abandonment lead to structural degradation and changes in carbon allocation patterns in Moso bamboo forests

Abstract

Moso bamboo (Phyllostachys pubescens) has high carbon sequestration capacity and plays an important role in mitigating climate change. With the decrease in bamboo prices and the increase in labor costs, many Moso bamboo forests have been abandoned. How the abandonment affects the forest structural factors and carbon stocks has not been studied. 50 Moso bamboo forest plots with different abandonment times were investigated in the subtropical region of the southeast coast of China, and we analyzed the effects of abandonment time on the structural factors and carbon storage allocation pattern. Abandonment affected the forest structural factors, especially after 6 years of abandonment. Compared with general management, the culm density was nearly 3 times as normal, the mean age rose from 2.33 ± 1.14 du to 3.23 ± 1.04 du, and the diameter at breast (DBH) decreased by 15.7% after 15–18 years of abandonment. The carbon storage of the individual culm was reduced by 25% due to the smaller DBH, but the bamboo stand carbon stocks were about 2.5 times normal due to the excessive density. Correspondingly, the proportion of vegetation C in ecosystems has increased from 21.69% to 35.95%, even though the understory carbon stocks were lowest in the forests abandoned for eleven or more years. The soil organic carbon (SOC) in the topsoil layer was higher with the extension of the abandonment time while there was no significant difference in the deep. Litter and understory vegetation account for only a small fraction of the entire ecosystem's carbon stocks, especially in the Moso bamboo forest for a longer abandonment time. These results enrich our understanding of the structure and carbon allocation pattern of abandoned Moso bamboo forests and provide a significant support for Moso bamboo forest management or future recovery.