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生态学杂志

• 方法与技术 • 上一篇    下一篇

不通过髓心的树木圆盘年轮直径测定方法

张宁,刘琪璟*,孟盛旺,周华,刘文慧   

  1. (北京林业大学林学院省部共建森林经理重点实验室, 北京 100083)
  • 出版日期:2017-01-10 发布日期:2017-01-10

A nonthroughpith method for tree stem analysis.

ZHANG Ning, LIU Qi-jing*, MENG Sheng-wang, ZHOU Hua, LIU Wen-hui   

  1. (Key Laboratory of Forest Management, College of Forestry, Beijing Forestry University, Beijing 100083, China).
  • Online:2017-01-10 Published:2017-01-10

摘要: 树干解析是测树学的基础技术,在森林生物量和生产力的测算上起着不可替代的作用。传统树干解析树木直径的测定方法是测量每个圆盘东西、南北两条直径线上每年(或龄阶)的直径,取两个方向同一年(或龄阶)直径的平均数作为测定结果。由于横断面为绝对圆形的树干很少,且髓心常常偏倚,使用传统方法测量的年轮直径往往小于真实直径,造成树木材积与生物量的低估。本研究对传统树干解析圆盘年轮的测定方法进行了改进,提出了不通过髓心的树木圆盘几何直径测定法,并制定了测定规则,以期减少个体测定差异,使测量值最大限度地接近真实值。使用不同方法对圆盘的年轮直径进行了测定,通过比较圆形度、逼近度指数,证明了本方法较传统方法更为准确。本方法原理简明,易于操作,具有较强的实用性,对于提高森林蓄积量和生物量的估算精度具有重要意义。

关键词: 除趋势典范对应分析法, 环境解释, 双向指示种法, 植物群落

Abstract: Stem analysis is the most fundamental technique in forest mensuration. The traditional method for measuring diameters of tree rings is to average two geomagnetic directions (southnorth and eastwest) passing through the pith, which are perpendicular to each other. Since disks are usually eccentric, biomass or section area estimated by diameters passing through the pith can be significantly underestimated in general, which has been ignored in the past. This oldstyle method has never been challenged in dealing with accuracy. A new method, tested by digital photo technology, for getting individual ring diameters more close to the real diameters, was proposed in this paper. The line representing diameter of a ring was not necessarily set through the pith, rather on a subtense close to the real diameter. The ring diameters of the disks were measured by using different methods for accuracy comparison. It is proved that this method is more accurate than the traditional one tested by circularity index and closeness index. The method is easier for operation compared with the traditional one, which is expected to reduce the uncertainty in the measurement of tree growth as well as forest productivity.

Key words: DCCA, environmental interpretation., TWINSPAN, plant community