珍稀濒危植物梓叶槭种群径级结构与种内种间竞争关系

该研究对四川省珍稀濒危植物梓叶槭(Acer catalpifolium)种群的主要分布区进行调查,分析梓叶槭种群径级结构与种内和种间的竞争关系,探讨竞争强度与径级和距离之间的关系。结果表明:(1)梓叶槭胸径与树高之间存在显著的幂函数关系;种群径级结构呈正态分布,中小径级树木较多,高径级树木较少。(2)梓叶槭种内和种间竞争强度分别占总竞争强度(222.87)的15.16%和84.84%,说明竞争主要来自种间。(3)梓叶槭与主要伴生种之间的竞争强度大小依次为柳杉桢楠白栎刺楸灯台树桦木杉木厚朴光皮桦;对象木和竞争木距离与竞争指数之间较好地服从指数函数关系,当对象木与竞争木距离小于1m时,竞争指数可达到5.5,随着距离逐渐增加,其竞争指数相应降低,并最终趋于平缓。(4)竞争强度随对象木胸径的增大而减小,当对象木胸径小于20cm时,受到的竞争压力最大,竞争指数最大的分别是梓叶槭与整个林分(234.98)以及梓叶槭与种间(184.01);当对象木胸径小于10cm时,竞争指数均可以达到18;当对象木胸径大于20cm时,竞争强度变化很小且竞争指数较低;竞争强度与对象木胸径服从幂函数关系(CI=AD-B)。(5)模型预测结果表明,随着梓叶槭胸径的增加,竞争指数均越来越小,竞争强度呈降低趋势;当梓叶槭胸径为0~5cm时,梓叶槭与整个林分受到的竞争强度最大,竞争指数为7.14,占总竞争强度的50%;当胸径大于20cm时,竞争指数变化不大;该模型能很好的预测梓叶槭种内和种间竞争强度。

Relationship between Diameter Class Structure and Intraspecific and Interspecific Competitions of Precious and Endangering Plant Acer catalpifolium

The research investigated the main distribution areas of the population of Acer catalpifolium, a precious and endangering plant in Sichuan Province, and analyzed the relationship between the diameter structure and the intraspecific and interspecific competition of the population, and explored the relationship about competition intensity, diameter and distance. The results show: (1) there is a significant power function relationship between A. catalpifolium diameter and height. The diameter class structure of the population is normally distributed. There are many trees at middle and small diameters and fewer trees at higher and higher diameters. (2) The intraspecific and interspecific competition intensity of the A. catalpifolium accounting for 15.16% and 84.84% of the total competition intensity (222.87), respectively, indicating that the competition mainly comes from the interspecies. (3) The competition intensity between A. catalpifolium and its main associated species was in order of Cryptomeria fortunei > Phoebe zhennan > Quercus fabri > Kalopanax septemlobus > Bothrocaryum controversum > Betula platyphylla > Cunninghamia lanceolata > Magnolia officinalis > Betula luminifera. The target trees and competitors distance and competition index are well subject to the exponential function relationship; When the distance between the target trees and competitors is less than 1 m, the competition index can reach 5.5; with the gradual increase of the distance, its competition index decrease accordingly and eventually tends to be flat. (4) The competition intensity decreased with the increase of the diameter of the target. When the diameter of the target is less than 20 cm, the competition pressure is the greatest, and the competition index is the largest among the A. catalpifolium and the entire forest (234.98) and the A. catalpifolium and interspecific (184.01); When the target diameter is less than 10 cm, the competition index can reach 18; when the target diameter is larger than 20 cm, the competition intensity changes little and the competition index is lower; the competition intensity and the target trees diameter obey the power function relationship (CI=AD^-B). (5) The model prediction results show that with the increase of the A. catalpifolium diameter, the competition index is getting smaller and smaller, and the competition intensity is decreasing. When the A. catalpifolium diameter is 0 to 5 cm, the competition intensity between A. catalpifolium and the entire forest is the highest, and the competition index was 7.14, accounting for 50% of the total competition intensity. When the diameter is greater than 20 cm, the competition index has changed little. This model can predict perfectly the intraspecific and interspecific competition intensity of A. catalpifolium.