带状采伐对毛竹地上生物量分配及异速生长的影响

【目的】 毛竹林带状采伐可实现竹林机械化经营,研究不同采伐宽度毛竹立竹生物量分配及其异速生长,为毛竹林带状采伐经营提供科学依据。【方法】 2019年12月模拟机械采伐对不同宽度条带内的毛竹林实施全林皆伐,2020年8月统计试验毛竹林不同采伐宽度带(0、3、9、15 m)内新竹数量、胸径、枝下高和竹高。调查新竹枝、叶、秆生物量,分析伐后新竹地上构件生物量分配特征及其异速生长关系。【结果】 随着带状采伐宽度的增加,新竹数量先增加后减少,9 m采伐宽度带新竹数量最多,新竹竹高降低,胸径减小,枝下高及相对枝下高降低,立竹鲜枝质量、鲜叶质量、鲜秆质量及总生物量均显著降低。带状采伐可以提高立竹出叶强度、相对竹高,尤其增加叶分配占比和叶相对生物量。带状采伐未改变立竹秆-总生物量的等速生长关系,但对枝-总生物量、叶-总生物量相对生长速率产生显著影响,由异速生长关系转变为等速生长关系。【结论】 带状采伐致使毛竹通过生理整合作用权衡各构件资源分配关系,改变其异速生长关系,诱发新竹形态可塑性变化,9 m采伐宽度的新竹数量达到最大值。

Effects of strip cutting on aboveground biomass accumulation and allocation,and allometric growth of Phyllostachys edulis

【Objective】 Strip cutting of moso bamboo forests can realize their mechanized management. We aimed to provide a scientific basis for the reasonable management of bamboo strip cutting, biomass allocation and allometric growth of Phyllostachys edulis with different cutting widths. 【Method】 Whole forest clear-cutting of P. edulis forests of different widths was conducted in December 2019. The number of new bamboos, diameter at breast height (DBH), clear bole height and height of the bamboo at different cutting widths (0, 3, 9 and 15 m) were counted in August 2020. The biomass of branches, leaves and stems of new bamboo were investigated, and the biomass allocation characteristics and allometric growth relationship of aboveground components were analyzed. 【Result】 Strip cutting increased the number of new bamboos: the trend was first increase and then decrease, and the number reached the maximum value in the 9 m cutting width. With the increase in cutting width, the bamboo height (CBH), DBH, clear bole height, and ratio of CBH to DBH of new bamboo decreased, and the fresh branch, leaf, stem weight and total biomass decreased significantly. Strip cutting could improve the leaf strength and ratio of bamboo height to DBH of P. edulis, especially the proportion of leaf distribution and leaf relative biomass. Strip cutting did not change the isokinetic growth relationship between the stem-total biomass of P. edulis but significantly affected the relative growth rate of branch-total biomass and leaf-total biomass, which changed from allometric growth to isokinetic growth.【Conclusion】 The results showed that strip cutting balanced resource allocation among the components through physiological integration, the allometric growth relationship was changed, and the morphological plasticity of new bamboo was induced.