Short-Term Effects of Thinning Intensity on Stand Growth and Species Diversity of Mixed Coniferous and Broad-Leaved Forest in Northeastern China

【Objective】 To explore the best tending measure, the thinning intensity experiment was carried out in the secondary forest of the mixed coniferous and broad-leaved forest to analyze the effect of different thinning intensities on stand growth and species diversity, and to provide a guidance for rational management of forestation activities in the region. 【Method】 Four permanent plots with a size of 1 hm~2 were established for thinning experiment in the secondary forest of the mixed coniferous and broad-leaved forest in Jiaohe Forestry Experimental Bureau of Jilin Province in July 2011. The thinning intensities were set by basal area, which were 0%(control, CK), 17.24%(light thinning, LT), 34.74%(medium thinning, MT), and 51.87%(heavy thinning, HT). Five sample plots( 20 m × 20 m) were selected from each standard plot to determine the actual thinning intensity. 2 and 4 years after thinning, the DBH, tree height, basal area, stock volume, species diversity and community similarity were measured and analyzed, an