沱江流域两种人工针叶林群落结构比较

Comparison of community structure between two artificial coniferous forests in the Tuojiang River Valley

关键词:  湿地松  马尾松  群落结构  物种多样性  种群更新

Key words:  Pinus elliottii  Pinus massoniana  community structure  species diversity  regeneration of population

摘要:

采用样方调查法比较了沱江流域两种人工针叶林群落的结构。结果表明,湿地松林中湿地松幼苗幼树很少; 马尾松林中有较多的马尾松幼苗幼树。马尾松种群多度比湿地松种群大38%,而湿地松种群的平均高度、平均冠幅比马尾松种群分别大32.7%和22.2%。从高度结构及径级结构来看,马尾松种群在各个级别上都有分布; 而在湿地松种群中,没有Ⅰ级和Ⅱ级的幼苗和小树,种群中以大树为主,呈现出更新不良。马尾松在各个树高级别上都形成一定的盖度,但湿地松在1 m以下不形成盖度,反映出湿地松缺乏幼苗幼树,这与树高及径级研究中得出的结果是一致的。乔木层地上生物产量是湿地松林大于马尾松林; 而灌木层地上生物产量却是马尾松林大于湿地松林; 草本层地上生物产量则在两种林分中则无明显差异。湿地松林灌木层和草本层的物种多样性都比马尾松林低一些,这与湿地松林乔木层盖度较大,对林下灌草层的阴蔽作用有关。从快速绿化及用材的角度来看,湿地松更适合于当地大面积的推广种植。

Abstract:

By using plot sample method,community structure of two artificial forests were studied in a low mountain area of the Tuojiang River Valley. The results showed that there were less Pinus elliottii seedlings and saplings in P.elliottii community compared with P.massoniana community. Individuals of P.massoniana were 38% more than those of P.elliottii. However,average hight and average diameter of tree crown of P.elliottii were 32.7% and 22.2% bigger than that of P.massoniana,respectively. Judged from height and DBH(diameter at breast height)structure,individuals of P.massoniana distributed through all classes. On the contrary,P.elliottii population had no individuals of class Ⅰ and Ⅱ,and was dominated by the biggest trees,suggesting that it was difficult for the population to regenerate in the future. P.massoniana at each height class could form certain coverage,but P.elliottii individuals under 1 m could not form any coverage,indicating that P.elliottii population was short of seedlings and saplings,which was consistent with the conclusion drawn from height and DBH study. Aboveground biomass yield of tree layer in P.elliottii stand was bigger than that in P.massoniana stand,while biomass of shrub layer in P.elliottii stand was smaller than that in P.massoniana stand. As to biomass of herb layer,the two stands had no significant difference. Species diversity in both shrub layer and herb layer in P.massoniana community was higher than that in P.elliottii community,which was closely related to big coverage of tree layer in P.elliottii community,because big coverage of tree layer could exert an strong negative influence on plants under tree layer. Considering fast afforestation and production of wood,it is more suitable for P.elliottii to be grown widely.