<正>利用电子顺磁共振（ESR）技术对竹材热处理至900℃的炭化机理进行了研究。结果表明：（1）600℃左右是竹材炭化的一个非常重要的热处理温度。低于600℃时，为竹材炭化的热解阶段；高于600℃时，为竹材炭化的过渡阶段，并且产生非常显著的硅效应。（2）竹材的热分解历程主要表现为自由基反应。（3）竹炭中的水分和炭化气氛对自旋中心的性质和弛豫机制都产生了比较明显的影响，并且在不同的炭化阶段产生的影响不同。

Based on the investigation and experimental trials for thinning and pruning on same site, planting densities and stand age, the first time for thinning and pruning of Pinus ellottii plantation was at 7～8 years old. While standard degree of closing of the plantation reacl-Ted 0.85, current annual increment of DBH started to decline, and the intensity of thinning should not exceed 30%. The second time of thinning should be based on the silvicultural purpose and management intensity, usually intensity of thinning should not exceed 35%, and thinning interval was about 5～6 years. If the culture aims are for the large diameter of construction commercial forest, the third thinning should be carried out, and 600～680 tree/hm2 should be reserved for harvest. Pruning should be practiced after thinning, and intensity of pruning is 1/3 of tree height for the first time, while 1/2 of tree height is for the second time. The pruning interval is about 3～5 years, and pruning times are the best from early spring to deep autumn.