不同类型防护林中樟子松的构型特征分析

 影响植物枝系构型的因素有各级分枝长度、各级分枝角度、枝径比、逐步分枝率和总体分枝率等。采用枝系构型的理论和方法,对甘肃民勤不同类型防护林中樟子松的分枝构型特征进行研究。结果表明：①不同类型防护林中的樟子松分枝格局有较大的差异,主要表现在分枝长度、分枝率等变化明显;②不同类型防护林中樟子松在不同部位处的分枝格局也存在一定的差异性,劣势类型Ⅰ的中下部枝条占优势,优势类型Ⅱ、中间类型Ⅲ以中上部枝条占优势,而劣势类型Ⅰ的基部分枝角度大于其他两种类型的;③优势类型防护林中樟子松在距地面不同高度处的分枝长度、分枝角度随高度呈规律性变化,在不同高度处的枝系构型指标以中上部占优势,基部较弱;④通过分枝构型特征研究认为在干旱区营造樟子松防护林以杨树和樟子松株间混交效果较好,杨树与樟子松行间混交效果较差,樟子松纯林居中。

Analysis on Branching Architectures Characteristics of Pinus sylvestris var. mongolica in Different Shelterbelts

The factors that influence the branching architectures of plants comprise branch length, branching angle at different branching levels, branch-stem ratio, stepwise bifurcation ratio(SBR) and overall bifurcation ratio(OBR), etc. The branching architecture characters of Pinus sylvestris var. mongolica in three different shelterbelt types were researched by using the theory of Branching Architecture. The results indicate that: ①There was very significant variation in branching architectures of Pinus sylvestris var. mongolica among the three shelterbelt types, especially remarkable in branch length and stepwise bifurcation ratio, etc.; ②There was relatively significant variation in branching architectures at different branching levels of Pinus sylvestris var. mongolica among the three shelterbelt types, that is the branches of middle-lower part in typeⅠare dominant, the branches of top-middle part are dominant in typeⅡand type Ⅲ, in addition the branching angle of typeⅠat basal level is larger than the other two types; ③The branch length, branching angle of typeⅡ changed regularly from base to top, all branching architecture parameters of middle and top part are significant than that of the lower part; ④The research results showed that the effect of typeⅡis better, type Ⅲ is middle, and typeⅠis relatively inferior.