中亚热带格氏栲天然林幼苗竞争强度研究

Study on the Seedlings Competition Intensity in a Mid-subtropical Castanopsis kawakamii Nature Forest

摘要:

采用Hegyi单木竞争指数模型对格氏栲幼苗种内和种间竞争强度进行定量分析。结果表明, 格氏栲幼苗种内竞争强度随幼苗高度的增加而逐渐减少。种间竞争强度的顺序为：桂北木姜子＞梨茶＞黄润楠＞毛鳞省藤＞矩圆叶鼠刺＞木荷＞酸味子＞狗骨柴＞少叶黄杞＞山黄皮＞光叶山矾＞沿海紫金牛＞小叶赤楠＞尖叶水丝梨＞赤楠＞草珊瑚＞格氏栲＞丝栗栲＞杜茎山。阳生性树种竞争强度强，高度优势明显；阴生性树种或幼苗初期需耐荫的树种竞争强度低，高度低且生长缓慢。竞争木对对象木的竞争强度与对象木高度服从幂函数分布，竞争强度与对象木的高度呈显著负相关。对格氏栲幼苗种内与种间竞争强度进行了模拟和预测，格氏栲幼苗初期的种内竞争强度处于中等水平，随着高度的增加，种内竞争强度逐渐减弱，种间竞争强度越来越明显，种群呈衰退趋势。格氏栲幼苗高度低于125 cm时应加强对其保护，采取人工抚育措施促进生长，提高格氏栲幼苗存活率；格氏栲幼苗高度达到125 cm后，竞争强度趋于稳定。

Abstract:

The intraspecific and interspecific competitions intensity of C. kawakamii seedlings in C. kawakamii Nature Reserve were quantitatively analyzed by using Hegyi’s competition index model. The results showed that the intraspecific competition intensity of C. kawakamii seedlings decreased gradually with increment of seedlings height. The interspecific competition intensity in C. kawakamii community was in order as Litsea subcoriacea＞Camellia octopetala＞Machilus grijsii＞Calamus thysanolepis＞Itea oblonga＞Schima superba＞Antidesma japonicum＞Diplospora dubia＞Engelhardtia fenzelii＞Clausena dentata＞Syplocos lancifolia＞Ardisia punctata＞Syzygium buxifolium＞Distyliopsis dunnii＞Syzygii buxifolii＞Chloranthus glabra＞Castanopsis kawakamii＞Castanopsis fargesii＞Maesa japonica. The competition intensities of heliophytes species were strong with obvious height advantage, while those of skiophytes species or seedlings with shade-tolerance at early growth stage were weak and grown slowly. The competition intensities between the competitive trees and the objective trees with the objective trees’ height conformed to power function distribution which showed significantly negative correlation. At the same time, the intraspecific and interspecific competition intensities of C. kawakamii seedlings were also simulated and forecasted. The results showed that the intraspecific competition intensities of C. kawakamii seedlings at the early growth stage were at medium level. With the height of seedlings increasing, the intraspecific competition of C. kawakamii seedlings was weak gradually, while the interspecific competition of C. kawakamii seedlings obviously increased, and the C. kawakamii population had the tendency of deterioration. In order to improve the survival of C. kawakamii seedlings, the C. kawakamii seedlings should be protected strengthen and promoted growth by artificial cultivations when the seedling height were under 125 cm. The competition intensity of C. kawakamii seedlings tended to be stable when the height reached up to 125 cm.