枝叶采收对人工云南红豆杉叶构件种群特性的影响

本研究对云南省马关县的6年生云南红豆杉人工林进行了采收主干及其上部枝叶、保留主干采收其上部枝叶、保留主干采收其下部枝叶3种采收方式下3个采收强度的试验,通过1年的持续观察,以不采收枝叶的植株为对照,分析了枝叶采收对云南红豆杉叶构件数量及动态变化的影响。结果表明:3种采收方式均有随着采收强度的增加落叶量增多的现象,同时老叶落叶率随时间的推移呈递增趋势;采收可以促进新叶数量的增加,但是采收上部枝叶比采收下部枝叶对促进新叶数量增加的效果更明显;采收降低春叶密度,提高秋叶密度,新叶总体密度并没有随采收处理的不同而表现出显著差异;叶净增加量随3种采收方式的采收强度增强而增加。为收获更多的枝叶,提高来年枝叶的叶净增加量,采收主干及上部3/4树冠长度的枝叶和保留主干采收上部3/4树冠长度的枝叶较好,叶净增加量分别是对照的2.96倍和3.00倍。为使人工林持续发展,采收主干及上部3/4的枝叶处理是最佳的枝叶采收方案。

Leaf Modular Population Characteristics of Taxus yunnanensis Plantation under Different Branches and Leaves Harvesting Models

Three harvesting models (cutting the trunk and harvesting upper branches and leaves, retaining the trunk and harvesting upper branches and leaves, retaining the trunk and harvesting lower branches and leaves) were tested to harvest six-years-old Taxus yunnanensis plantation in Maguan County of Yunnan Province. Each model consisted 3 harvesting intensities. Through one-year's continuous observation, the amount and dynamics of T. yunnanensis plantation leaves were analyzed. The results showed that with the increase of harvesting intensity, the amount of falling leaves increased for all the 3 harvesting models, and at the same time, the defoliation rate of older leaves showed an increasing trend over time. Harvesting can promote the increase in the amount of new leaves, but compared with harvesting the lower branches, harvesting the upper branches was more effective to promote the increase of new leaves. Harvesting would reduce spring leaf density, and improve autumn density. The overall density of new leaves showed no significant difference with different harvesting models. The leaf net amount increased with the recovery strength of 3 harvesting models. In order to harvest more branches and increase the net yield of leaves in the coming year, it is suitable to cut the trunk and harvest upper 3/4 branches and leaves of crown length, retain the trunk and harvesting upper 3/4 branches and leaves of crown length. The net amount of leave increment was 2.96 times and 3.00 time that of the control. Simultaneously, if the trunk is harvested, there would be more sprouts in the rest of crown. To sum up, cutting trunk and harvesting upper 3/4 branches and leaves of crown length would be the best harvesting model.