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我场位于大汶河中游冲积滩地,地势较平坦,水源较充足;细沙壤(混杂一些薄淤层),冬春风沙干旱,夏秋杂草丛生。前期采用加杨插条造的林,多形成小老树;后曾部分改为刺槐林,结果还是次生林。10—20年林令每亩蓄积量不过2立方米。 通过调查分析,我们认为形成次生林小老树的主要原因大体可分四个方面:①树种不适宜,造林密度大;②整地粗放,林地没改造;③抚育措施眼不上,管理水平差;④病虫危害,人畜毁害。
My field is located in the middle reaches of Dawen River alluvial beach, the terrain is relatively flat, water is more adequate; fine sandy soil (mixed with some thin silt), winter and spring sand arid summer weeds. Pre-use Yang plus insert made of forest, and more to form a small old tree; later part of the conversion to locust forest, the result is secondary forest. In 10-20 years, the volume of forest per mu is only 2 cubic meters. Through investigation and analysis, we think that the main reasons for the formation of small trees in the secondary forest can be roughly divided into four aspects: (1) unsuitable tree species and large afforestation density; (2) extensive land preparation without improvement of the forest land; (3) Pest damage, human and animal damage.