论文部分内容阅读
基于大兴安岭新林林业局落叶松林、白桦林和混交林3种主要林分类型16块样地的调查数据,依照幼苗幼树的株高划分为3个等级:Ⅰ级,株高≤60 cm;Ⅱ级,60 cm<株高≤200 cm;Ⅲ级,株高>200 cm且胸径<5 cm.在4种取样尺度下,采用负二项指数等7种聚集度指数,判定幼苗幼树的分布格局及格局强度,分析格局变化和格局规模.结果表明:除落叶松林的落叶松幼苗幼树Ⅱ级最多,且随等级升高幼苗幼树密度先升高后降低外,白桦林和混交林的落叶松以及3种林分的白桦幼苗幼树Ⅲ级最多,而Ⅰ级最少,随等级升高,幼苗幼树密度均升高.落叶松幼苗幼树在3种林分4种取样尺度下均呈聚集分布.白桦幼苗幼树在白桦林中除在10 m×20 m尺度为随机分布外,均呈聚集分布.除落叶松幼苗幼树在混交林中5 m×10m尺度时聚集强度最大外,落叶松在其他林分以及白桦在3种林分均在5 m×5 m尺度下聚集强度最大.在落叶松林,落叶松和白桦幼苗幼树的聚集强度随等级增大而减小,其中白桦由聚集分布变为随机或均匀分布;在白桦林和混交林中,落叶松和白桦幼苗幼树的聚集强度随等级升高不断增大,由均匀分布变为聚集分布.在3种林分类型中,不同更新等级落叶松和白桦幼苗幼树种群的格局规模均为25 m2.落叶松和白桦幼苗幼树种群格局强度在不同林分类型、不同更新等级中差异明显.
Based on the survey data of 16 plots of three main forest types of larch forest, birch forest and mixed forest in Xinlin Forestry Bureau of Daxing’anling, the data were divided into three grades according to the plant height of seedling saplings: grade Ⅰ, plant height ≤ 60 cm, Ⅱ grade, 60 cm 200 cm and diameter at breast height <5 cm. Under the four sampling scales, seven kinds of aggregative indexes such as negative binomial index Distribution pattern and intensity of pattern, analysis of pattern change and pattern scale.The results showed that the seedlings of Larix gmelinii and Larix gmelinii were the most, and the seedling density of Larix gmelinii first increased and then decreased with the increase of grade, Larix gmelinii and Larix principis-rupprechtii had the highest level of Grade Ⅲ and the lowest grade Ⅰ, while the density of seedlings was increased with the increase of grade.The seedlings of Larix gmelini were planted under 4 sampling scales All showed aggregated distribution.The young birch seedlings were aggregated in the birch forest except the 10 m × 20 m scale.While the seedlings of Larix seedlings had the largest aggregation intensity at the scale of 5 m × 10 m in the mixed forest In addition, Larix principis-rupprechtii and Betula platyphylla had the highest aggregation intensity at the scale of 5 m × 5 m In the larch, larch and birch seedling young tree aggregation intensity decreases with the grade increases, in which the distribution of birch from aggregation to a random or uniform distribution; in the birch and mixed forest, larch and birch seedlings saplings The intensity of aggregation increased from uniform distribution to aggregative distribution.The seedling size of all tree species with different renewal grades and birch seedlings was 25 m2 in all of the three types of forest types.The larch and birch Seedling saplings pattern intensity in different forest types, different grades significantly different.