The effects of forest thinning on understory diversity in China: A meta‐analysis

Abstract

Abstract Forest management has been widely used to maintain and improve multiple ecosystem services. However, large‐scale synthesis of the effects of forest management on understory diversity, especially regarding the effects of thinning, has not been well represented in China. Therefore, we synthesized 146 peer‐reviewed publications and conducted a meta‐analysis to evaluate the response of understory diversity (species richness) and seven related variables to forest thinning in China. Overall, forest thinning significantly increased shrub diversity by 28% and herb diversity by 24%. Unthinned diversity and recovery time were the two most important drivers of understory diversity. When the unthinned diversity was low, a decline of understory species richness in managed stands could occur, which may be related to the size of the regional species pool. Rather than the recovery time of 1–2 years after forest thinning, the period of 3–5 years after thinning found the greatest diversity improvement. The northern arid and semiarid ecological domains observed the greatest diversity improvement, which may be due to the specific characteristics in this ecological domain. The coniferous forest was more favorable for understory improvement than in the broadleaved forest. Specific mechanisms on how disturbance (thinning intensity) affect understory diversity need to be further explored. No significant influences of stand stage or sampling quadrat area could be identified. Our study provides a synthetic review of the effects of forest thinning on understory diversity in China and may benefit forest management strategies. Future studies should address changes in compositional or functional diversity after thinning.