Coverage change of ground and canopy layers in Abies Tsuga forests during the natural regeneration of Bashania faberi

Arrow bamboo (Bashania faberi) is one of the major staple-food species for wild giant panda (Ailuropoda melanoleuca). In the spring of 1983, massive flowering and die-off of arrow bamboos occurred in Wolong, Sichuan. The goal of this study is to understand the natural regen- eration process of arrow bamboo, a dominant understory species beneath the canopy of Abies- Tsuga forests, and the relationship between vegetation layers by analyzing the coverage change during different stages of the regeneration process. We measured the coverage of trees, herbs and moss, and bamboos in seven permanent plots in an old-growth Abies-Tsuga forest in Wolong Na- tional Nature Reserve, Sichuan, China from 1984 to 2013. Arrow bamboo died off in 1983 in six of the seven forest plots. The results showed that, except for two plots, the bamboo coverage in the regenerative bamboo forests was increasing since the die-off, reaching 60% in 2013. The cov- erage change of the remnant bamboo forests exhibited a unimodal pattern. The coverage of the herb and moss layers in subsequent years was lower than that of the bamboo die-off phase in five plots. The results from the Kruskai-Wallis test revealed a significant difference in canopy coverage between 1984 and 2013; however, the difference of canopy coverage was minor between those two years, ranging from 0.60% to 18.89%. The difference in coverage change patterns among the seven forest plots was mainly related to site conditions. In addition, we also tried to visualize the bamboo coverage across different time periods, which helped to intuitively understand the spatial dynamic patterns of bamboo coverage during the regeneration process of bamboo forest.