论文部分内容阅读
毛白杨(Populus tomentosa carr.)是我国特有的树种,已有两千多年的栽培历史。它生长迅速,高大通直,寿命长,材质好,用途广,是北方平原地区营造用材林、防护林和“四旁”绿化的重要树种之一,深受广大群众的喜爱。在沙地造林的实践中证明毛白杨与刺槐(Robinia pseuboacia L.)混交是一种较好的乔木混交林。这种混交林可以充分发挥刺槐的有利特性,对于改良土壤,提高肥力,消灭杂草,加速林木生长具有重要的作用。刺槐的这种作用到底有多大,采取什么样的混交方式才能够更充分地发挥这种作用呢?这是一个值得研究的问题。我场于1965年营造的毛白杨与刺槐带状混交林,带宽22米,株行距2×2米。由于地处黄河故道,系黄河冲积所形成的内陆沙地,土壤
Populus tomentosa carr. Is a peculiar tree species in our country, which has been cultivated for more than two thousand years. Its rapid growth, tall and straight, long life, good material, wide use, is the northern plains to create timber forests, shelterbelts and “all around” one of the important tree species, by the masses favorite. In the practice of afforestation in sandy land, it was proved that the combination of Populus tomentosa and Robinia pseuboacia L. was a better mixed tree. This mixed forest can give full play to the favorable characteristics of black locusts, for improving the soil, increase fertility, eliminate weeds, accelerate the growth of trees play an important role. This role of acacia in the end how big, what kind of hybrid approach can we take full advantage of this role? This is a problem worth studying. I field in 1965 to create a mixture of white poplar and locust bandwith a bandwidth of 22 meters, spacing of 2 × 2 meters. Because it is located in the old course of the Yellow River, the Yellow River alluvial formed by the inland sand, soil