间伐补植对马尾松低效林生长及林分碳密度的短期影响

以马尾松低效林为研究对象，根据其林分特征等因素采用20%间伐强度及补植措施，通过对2013—2017年连续4年的样地调查与样品测定获取数据，分析间伐补植措施对其林木生长以及林分碳密度的短期影响。结果表明：间伐补植措施实施4年后，林木平均胸径、平均单株材积的生长均得到显著提高（P<0.05），且分别比对照样地提高了77.78%、109.68%。间伐补植后乔木层碳密度的增量呈显著减慢趋势（P<0.05）；林下植被层、凋落物层碳密度分别表现为极显著减少（P<0.01）和显著增加（P<0.05）；土壤层碳密度的增量则为对照样地大于作业样地，且差异显著（P<0.05）。林分总碳密度4年增长量显著低于对照样地（P<0.05），且作业样地的增量比对照样地减少4.91 t/hm²。本研究可为低效林的质量提升提供参考。

Short-term Effects of Thinning and Replanting Measures on Tree Growth and Stand Carbon Density of Low-efficiency Pinus massoniana Forest

Taking Pinus massoniana low-efficiency forest as the research object, 20% thinning intensity and replanting measures were adopted according to the characteristics of its stand characteristics and other factors. Data were obtained from plot surveys and sample measurements for four consecutive years from 2013 to 2017, and the short-term effects of thinning replanting measures on tree growth and forest carbon density were analyzed. Results show that the growth of individual tree in average DBH and average individual volume are significantly improved after thinning and replanting measures for 4 years（P<0.05）, and respectively increase by 77.78% and 109.68% to be compared with control plots. Carbon density of tree layer decreased significantly after thinning and replanting（P<0.05）. The carbon density of understory vegetation layer and litter layer shows a significant decrease （P<0.01）and significant increase（P<0.05）. The increase in carbon density in the soil layer is greater than that of the control plot, and the difference is significant（P<0.05）. The 4-year increase in total carbon density of the stand is significantly lower than that of the control plot（P<0.05）, and the increment of the plot is reduced by 4.91 t/hm2 compared to the control plot. This study can provide a reference for the quality improvement of low-efficiency forests.