抚育采伐后兴安落叶松的冠层结构参数

摘要

对大兴安岭的兴安落叶松天然用材林进行不同强度的人工抚育采伐后，分析林木冠层结构参数的相关性。结果表明：林木冠层结构参数中，林隙分数、开度、总定点因子、冠下总辐射通量，两两之间都有显著正相关关系（ P＜0．01），与叶面积指数均呈现显著负相关（ P＜0．01），与叶倾角没有明显相关性；林木冠层各结构参数的平均值为：林隙分数5．511％、开度6．417％、叶面积指数5．799、叶倾角15．175°、总定点因子0．109、冠下总辐射通量1．380 mol· m－2· d－1，冠层对太阳光的截获通量均值为20．73 mol· m－2· d－1；随采伐强度增加，林隙分数、开度、冠下总辐射通量、总定点因子，先减小后增加，而叶面积指数和冠层光截获通量先增大后减小，采伐强度对叶倾角的影响不明显；在采伐强度为20．86％的样地内，用材林冠层林隙分数、开度、冠下总辐射通量均小于对照样地，而其叶面积指数高于对照样地，抚育效果最好。%We studied the correlation of forest canopy structure parameters after different intensity felling for the natural timber forest of Larix gmelini in Daxing’ an Mountains.The natural timber forest canopy structure parameters of Larix gmelini are gap fraction, openness, total site factor, and total PPFD under canopy, there is a significant positive correlation ( P<0.01) between any two parameters, and they all have a significant negative correlation with the LAI (Leaf Area Index) (P<0.01), but have no apparent correlation with the mean of leaf angle.The mean of canopy structural parameters are gap fraction of 5.511%, openness of 6.417%, LAI of 5.799, mean leaf angle of 15.175°, total site factor of 0.109, total PPFD under canopy of 1.38 mol· m-2 · d-1 and the mean sunlight flux intercepted by canopy of 20.73 mol· m-2 · d-1 .With the increase of cutting intensity, the gap fraction, openness, total site factor, total PPFD under per day decreased and then in-creased, the LAI increased and then decreased, and the cutting intensity had no obvious effect on the mean leaf angle.In the plots with 20.86%of cutting intensity, the gap fraction, openness, and total PPFD under per day of timber canopy were less than the control plots, and LAI was higher than that of the control plots with the best tending effect.