天然东北红豆杉(Taxus cuspidata)种内和种间竞争

竞争是植物种内和种间关系的主要形式之一。通过对黑龙江穆棱东北红豆杉自然保护区的95株东北红豆杉对象木及980株竞争木的调查,运用Hegyi的单木竞争指数计算分析了东北红豆杉的种内和种间竞争强度。东北红豆杉的种内竞争强度不大,占总竞争的4%。竞争压力更多的来自于种间竞争,占总竞争的96%。与东北红豆杉竞争激烈的树种主要是冷杉、紫椴、色木槭和红松等地带性植被的优势种。随着东北红豆杉胸径的增大,所受到的竞争压力逐渐减小,胸径在20cm以前所受到的竞争压力最大,竞争强度与对象木胸径符合幂函数（CI=AD^-B）关系。

Intraspecific and interspecific competition of Japanese yew (Taxus cuspidata)

Intraspecific and interspecific competitions are important relationships of plants. We analyzed competition intensity using field data for 95 Japanese yew (Taxus cuspidata) target trees and 980 individuals of competing species by using the competition index (CI) in Muling Nature Reserve of eastern Heilongjiang Province. The intraspecific competition of Japanese yew population was weak, accounting for 4 percent of total competition, and the main stress to the Japanese yew population came from interspecific competition, which accounted for 96 percent of the total. The main competitors were the dominant species of the zonal vegetation types,including Abies nephrolepis, Tilia amurensis, Acer mono and Pinus koraiensis. The competition intensity of Japanese yew declined with increasing DBH, and the stress was more intense for trees less than 20 cm in DBH. The relationship between competition intensity and DBH of target trees followed the equation CI=AD-B.