杉木不同造林方式效益分析

从福建省洋口国有林场引进杉木2代苗木，通过炼山和不炼山2种方式在福建省沙县设立造林对比试验。结果显示：杉木不炼山方式造林比炼山方式造林投资高12.6%；杉木炼山方式造林前期生长比不炼山方式造林快，5a后渐渐持平，8a后不炼山方式造林显著优于炼山造林；炼山造林还导致土壤容重增大，土壤孔隙度降低，土壤变得紧实。

Study on Different Forestation Effect of China fir

The second generation of Chinese fir seedlings introduction,from the Yangkou Forest Farm,Fuji-an province in 2006.The forestation effect without soil preparation in the Sha county of Fujian province were studied.The main results were as follows：forestation investment without soil preparation was 39.2%more than controlled burning;on the early days,increment of forestation without soil preparation was slow-er than the other,they are the same after 5 years,but 8 years later,increment of forestation without soil preparation was faster than controlled burning markedly. The soil fertility of forestation without soil prepara-tion was better as well. Soil bulk density was enlarged,soil porosity was reduced arised from the controlled burning,and the soil becomed tight.