Growth Analysis on the Competition-Density Effect in Populus deltoids Stands
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摘要: 用竞争密度效果的倒数式分析了I-69杨(Populusdeltoids)的生长过程.随着时间的推移,C-D曲线在双对数图上向上移动.生物时间τ(τ被定义为逻辑斯蒂生长曲线中生长系数λ(t)的积分)与物理时间t的关系可以用双曲线方程表示.C-D效果倒数式(即1/w=Aρ+B,式中w和ρ分别代表平均单株材积和密度)中的系数A和B被求出.随着生物的时间τ的增加,系数A急剧增加到最大值后逐渐下降,而系数B呈指数下降,倾向于接近零.随着林分的生长,生长系数λ(t)倾向于下降.Abstract: The competition density (C-D) effect for Populus deltoides stands was analyzed using the reciprocal equation of the C-D effect, i.e. 1/w=Aρ+B, where w and ρ respectively represent mean stem volume and density. The C-D curve, which is given by the reciprocal equation on logarithmic coordinates, shifted upward with the progress of time. The relationship between biological time τ and physical time t followed a hyperbolic curve. The coefficients Aand Bincluded in the reciprocal equation were calculated at each growth stage. With increasing τ, the coefficient Aincreased abruptly up to a maximum value, whereas the coefficient Bdecreased exponentially and tended to close to zero. The λ(t) decreased with increasing stand age.
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Keywords:
- C-D effect /
- Reciprocal equation /
- Populus deltoides
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