沼泽交错带白桦个体生长动态及径级结构与种内种间竞争

Diameter class structure,growth dynamic,intraspecific and interspecific competitions of Betula platyphylla on swamp ecotone

根据野外调查数据,对长白山沼泽交错带白桦个体生长动态、径级结构以及种内和种间竞争强度进行研究,并探讨竞争强度与径级之间的关系。结果表明:白桦植株胸高断面积与树高之间存在显著的Sigmoid函数关系,胸径和树高分别为18.3 cm和19.4 m,是白桦由高生长向径生长过渡阶段;白桦种群更新幼苗稀少,径级结构呈纺锤形,径级-株数密度分布规律可以用Lognormal函数很好地表征;白桦种内和种间竞争强度分别为48.80%和51.20%;白桦种内和种间竞争强度的顺序为:白桦种内>长白落叶松>辽东桤木>山杨>蒙古栎>稠李>水曲柳>色木槭>茶条槭>春榆;竞争强度随对象木胸径的增加而降低,当对象木胸径在20 cm以内时,竞争强度较大,当胸径达20 cm以上时,竞争强度变化很小,竞争强度与对象木胸径较好地服从幂函数关系(CI=AD^(-B)),该模型能够较好地预测沼泽交错带白桦种内和种间竞争强度。

In this study, the diameter class, growth dynamic, and intraspecific and interspecific competitions of Betula platyphylla were investigated on swamp ecotone. Furthermore, the relation- ship between competition intensity and diameter class was analyzed. The results showed that there was an obvious sigmoid functional relationship between basal area at breast height and tree height, and the B. platyphylla trees began to shift from height growth to DBH growth when DBH and tree height were 18.3 cm and 19.4 m, respectively. The regeneration seedlings of the B, platyphylla population were rare, and the diameter class of the B. platyphylla population followed a spindle shape. Lognormal function well represented the relationship between diameter and density. The intraspecific and interspecific competition intensity of B. platyphylla accounted for 48.80% and 51.20% of the total competition intensity, respectively. The intensity of intraspecific and interspecific competition with B. platyphylla followed the order of B. platyphylla （ intraspecific） 〉 Larix olgensis 〉 Alnus hirsuta 〉 Populus davidiana 〉 Quercus mongolica 〉 Padus raceraosa 〉 Fraxinus mandsehurica 〉 Aeer mono 〉 Acer ginnala 〉 Ulmus davidiana. The eompetition intensity of B. platyphylla declined with increasing DBH. However, the competition intensity exhibited little variation when DBH was larger than 20 cm. The relationshio between the eomoetition intensity and DBH of target trees followed the power function （CI=AD^-B）. This model could effectively predict the intraspecific and interspecific competition intensity of B. platyphylla.