| 基于相邻木关系的林木密集程度表达方式研究 |
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| 引用本文： | 胡艳波,惠刚盈.基于相邻木关系的林木密集程度表达方式研究[J].北京林业大学学报,2015,37(9):1-8. |
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| 作者姓名： | 胡艳波 惠刚盈 |
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| 作者单位： | 中国林业科学研究院林业研究所,国家林业局林木重点培育实验室;中国林业科学研究院林业研究所,国家林业局林木重点培育实验室 |
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| 基金项目： | "十二五"国家科技支撑计划项目 |
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| 摘 要： | 林木密集程度是林分空间结构的重要属性,反映林木的疏密程度,包含一定的竞争信息,同时直观表达了林冠层对林地是否连续覆盖。如何通过构建空间结构参数准确量化单株林木周围和林分整体的密集程度是本研究的主要目的。以相邻木空间关系为基础,采用模拟林分数据和实际林分调查数据相结合的方法,提出了一种新的与林木距离有关的林分空间结构参数——密集度,它以林分空间结构单元为基础,通过判断林分空间结构单元中树冠的连接程度分析林木的密集程度。密集度有5种取值,以中度级为岭脊,明确地定义了参照树所在的结构单元的林木密集程度,密集度的值越大说明参照树所处小环境林木密集程度越高,参照树可能面临的竞争越激烈,林冠层越连续覆盖;密集度值越小说明林木密集程度越低,参照树面临的竞争压力越小,参数生物学意义十分明显。在计算林分密集度时,综合考虑分布格局对于林木占据空间方位的影响,增加了参数的准确性。在模拟林分和吉林蛟河红松阔叶林、江西分宜大岗山杉木人工纯林等不同格局、不同密度、不同类型的林分密集程度研究中,密集度均取得了满意的结果,密集度在实际应用中与其他结构参数相似,也可通过抽样调查直接获得,不需要测量距离,并为分析林分空间结构与林木竞争的关系提供了一种可行的途径。如何突破技术上的限制,将密集度与混交度、大小比数和角尺度联合分析,实现空间结构参数的多元联立是下一步研究的重点。
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| 关 键 词： | 林分结构参数 林木密集度 结构单元 |
| 收稿时间： | 2015-04-20 |
How to describe the crowding degree of trees based on the relationship of neighboring trees |
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| Institution: | Research Institute of Forestry, Chinese Academy of Forestry, Key Laboratory of Tree Breeding and Cultivation,State Forestry Administration,Beijing,100091,P. R. China. |
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| Abstract: | Whether the forest is dense or not is an important attribute of spatial forest structure. It reflects not only the crowding degree of trees and their neighbors with competition information, but also the condition of whether or not the forest canopy layer covers the woodland continuously. This study proposes the crowding index, a new neighborhood-based parameter, by which we may analyze the crowding degree of a neighborhood unit according to the overlapping of the crown in spatial micro-environment. Crowding can have five possible values ranging from 0 to 1 , which clearly define the crowding degree for a reference tree and its four nearest neighbors, and to some degree the competition pressure on it as well. Greater values generally indicate more intense competition around the reference tree. For a stand, the greater the cumulative value of crowding, the higher the stand density, and the more continuous the coverage of the canopy is. Based on observations in field plots with mapped trees, values of crowding were sensitive to various simulated spatial tree patterns with similar stand density, to field data of planted forests with different tree densities, and to mixed and uneven aged natural forests as well. Thus, the type of tree distribution pattern should be considered while calculating the crowding of a forest stand. |
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| Keywords: | stand structure parameter crowding spatial structural unit |
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