次生林不同植被类型下各个径阶竞争强度探析

Analysis on the Competitive Intensity of Different Diameter Classunder Different Vegetation Types in the Secondary Forest

影响植株生长的必然因素是林木之间的相互竞争,结合之前的研究发现,在林分中林木竞争通常采用胸径比来研究,可以有效地得出林分中林木的竞争情况,故本研究采用了竞争指数CI1来作为量化竞争关系的指标进行研究比较。研究得出:热带雨林、热带季雨林及落叶阔叶林的竞争强度出现断崖式的变弱,热带雨林及落叶阔叶林对象木的胸径超过20cm时,竞争强度趋势变得平缓,各径阶的竞争强度波动较小,且随着胸径的变大,各径阶的竞争强度趋于平稳不变;热带季雨林则是16cm时开始趋于平缓;季风常绿阔叶林、热性竹林及山地雨林的竞争强度变化表现比较平缓,不存在比较大幅度的变化。如是对以上6种植被类型开展空间结构调整,减少林分间的竞争,则在调整时对6种植被类型应该分3种情况开展:热带雨林及落叶阔叶林以胸径20cm作为分界;热带季雨林以胸径16cm作为分界;季风常绿阔叶林、热性竹林及山地雨林则依据林分培养目标而具体作出相应调整。

The inevitable factor affecting plant growth is the competition among trees.Combined with previous studies,it is found that the competition among trees in stands is usually studied by DBH ratio,which can effectively obtain the competition situation of trees in stands.Therefore,the competition index CI1 is used as an index to quantify the competition relationship for research and comparison.The study concluded:The competition intensity of tropical rain forest,tropical seasonal rain forest and deciduous broad-leaved forest showed a cliff-like weakening.When the DBH of tropical rain forest and deciduous broad-leaved forest was more than 20cm,the trend of competition intensity became gentle,and the fluctuation of competition intensity of each diameter class was small.With the increase of DBH,the competition intensity of each diameter class tended to be stable.The tropical monsoon starts to flatten out at 16cm;The variation of competition intensity in monsoon evergreen broad-leaved forest,thermogenic bamboo forest and mountain rainforest was relatively gentle,and there was no significant change.In order to adjust the spatial structure of the above six vegetation types and reduce the competition among stands,the six vegetation types should be adjusted in three situations.The 20cm DBH of tropical rainforest and deciduous broad-leaved forest should be used as the boundary.The tropical monsoon rainforest is bounded by a diameter of 16cm at breast height.Monsoon evergreen broad-leaved forest,thermogenic bamboo forest and montane rainforest were adjusted according to the target of stand culture.