Effects of selective thinning and residue removal on ground layer structure and diversity in a mixed pine–oak stand of the Qinling Mountains, China

Abstract

Plant species in the forest ground layer are the main food resources for animals and other organisms in the Qinling Mountains, China. To optimise forest thinning programs, we examined how different selective thinning and thinning residue removal regimes influence ground layer diversity and cover. We explored these factors for 2 years in a mixed pine–oak stand. Results indicate the treatments resulted in an increase in the numbers of species, genus and family by 10, 10 and six, respectively, after 1 year thinning and by 14, 10 and four, respectively, after 2 years thinning, compared with the starting point. The highest richness index was achieved at a selective thinning intensity of 17% and a residue removal rate of 57% concurrently. The highest evenness index was achieved at a selective thinning intensity and residue removal rate of 25 and 43% concurrently. The highest ground cover layer was achieved at a selective thinning intensity and residue removal rate of 25 and 69% concurrently. Our results suggest medium thinning intensity and thinning residual removal rate may benefit ground layer richness, whereas a high thinning intensity and medium thinning residual removal rate may maximise evenness and ground layer cover in current forest.