抚育间伐对冀北山地华北落叶松生态景观林林内美景度的影响

Effects of thinning on in-stand scenic beauty of Larix principis-rupprechtii Mayr.ecological landscape forest in the mountainous area of northern Hebei province

为了科学经营冀北山地不同季相的华北落叶松生态景观林,运用美景度评价法探究抚育间伐对夏、秋、冬3个季节的华北落叶松林景观质量的影响。结果表明：夏、秋季林分密度在350~500株/hm2之间时,美景度均值最大;冬季林分密度在650~800株/hm2之间时,美景度均值最大;3个季节林分密度都是在950~1 100株/hm2之间时,美景度均值最小。通过多元数量化模型Ⅰ建立各季节景观要素与美景度值之间的关系模型,可知,夏季对林分美景度值贡献较大的景观要素有林分密度、林下层高度、枝下高;秋季对林分美景度值贡献较大的景观要素有林分密度、树干形态、树冠形态、草本盖度;冬季对林分美景度值贡献较大的景观要素有林内透视距离、枝下高、树高。综合夏、秋、冬3个季节景观要素对美景度值的影响可知,林分密度较小、树干通直、树冠圆满、林下草本盖度大于90%、林下层高度大于25cm、枝下高在6m左右时,森林景观效果较好。

In order to manage the different seasonal ecological landscape of Larix principis-rupprechtii Mayr.forest in the mountainous area of northern Hebei province,the effects of thinning on scenic beauty quality of Larix principis-rupprechtii Mayr.landscape in different seasons were analyzed by using scenic beauty estimation method.The results showed that the mean value of scenic beauty reached the maximum when stand density was between350 and 500individual/hm2 in summer and autumn,and in winter the stand density was between 650 and 800individual/hm2.The mean value of scenic beauty was the minimum when the stand density was between 950-1 100individual/hm2 in those 3seasons.The analytical method of multivariate quantified model I was applied to build the relation model betweenlandscape elements and the values of scenic beauty.The model showed that the main factors influencing the values of scenic beauty were stand density,height of undergrowth and height of under branch in summer,stand density,trunk form,crown form and the coverage of herb in autumn,and visibility of forest,height of under branch and tree height in winter.In a word,preference was shown on forest with smaller density,straight trunk form,symmetry crown form,herb coverage90%,height of undergrowth25cm and height of under branch about 6m.