蒙古栎林种内和种间竞争研究

蒙古栎(Quercus mongolica Fischer ex Ledebour)林是东北地区常见的典型森林类型之一。以黑龙江中央站黑嘴松鸡国家级自然保护区面积为1 hm 2的蒙古栎林固定样地为研究对象,采用固定样圆法确定了竞争范围,并利用Hegyi竞争指数分析了蒙古栎林的种内和种间竞争状态。研究结果表明:蒙古栎的种内和种间竞争强度分别占总竞争强度的28.08%和71.92%,说明了蒙古栎的种内竞争强度小,竞争压力主要来自于种间。白桦(Betula platyphylla Suk.)、黑桦(Betula dahurica Pall.)、兴安落叶松(Larix gmelinii(Ruprecht)Kuzeneva)数量较多,个体高大,对蒙古栎的竞争压力较大。蒙古栎种内和种间竞争强度的顺序为:白桦>蒙古栎>黑桦>兴安落叶松>山杨(Populus davidiana Dode)>紫椴(Tilia amurensis Rupr.)>大黄柳(Salix raddeana Laksch.)。蒙古栎的胸径与整个林分、伴生树种以及蒙古栎种内的竞争强度成幂函数关系,随着对象木胸径增大,3种竞争强度均减小。当蒙古栎胸径小于20 cm时,竞争强度较大;当胸径大于20 cm时,蒙古栎所受的竞争压力较小,并趋于稳定,通过所得的模型可以很好地预测出蒙古栎种内和种间的竞争强度。

Intraspecific and Interspecific Competition of Quercus mongolica Forest

Quercus mongolica forest is one of the typical forest types in Northeast China. The Hegyi competition index was used to analyze the intraspecific and interspecific competition status of Q.mongolica using fixed sample circle method in a 1 hm² permanent plot of Q.mongolica forest in Heilongjiang Zhongyangzhan Black-Billed Capercaillie National Nature Reserve. The intraspecific and interspecific competition intensity of Q.mongolica accounted for 28.08% and 71.92% of the total competition intensity, respectively. Some species, includingBetula platyphylla,B.dahurica and Larix gmelinii,with big size and large quantity, gave a high competition pressure to Q.mongolica. The order of the intraspecific and interspecific competition intensity of Q.mongolica was:Betula platyphylla > Quercus mongolica > Betula dahurica > Larix gmelini > Populus davidiana > Tilia amurensis > Salix raddeana. The DBH of Q.mongolica has a power function relationship with the competition intensity of the whole stand, intraspecific and interspecific competition intensity. With the increase of the DBH of the objective trees, the three types of competition decreased. When the DBH Q.mongolica is less than 20 cm, the competition intensity is greater. When the DBH is greater than 20 cm, the competitive pressure on Q.mongolica is less and tends to stabilize. The obtained model can well predict the intraspecific and interspecific competition intensity of Q.mongolica.