一、乡土树种结构及现状建国以来,我省黄土高原的植树造林工作取得了很大成绩。大力发展杨树、泡桐、刺槐、水杉等树种,促进了“四旁”和荒山荒坡的绿化,林木在水土保持、涵养水源、防风固沙、调节气候以及解决农村“四料”(肥料、燃料、饲料、木料)等方面取得了很好成绩,这是应当肯定的。但是值得注意的一个问题是各地在植树造林工作中,对发展乡土树种却重视不足,导致造林树种结构很不合理。目前山地造林中刺槐占相当大的比例,原区及“四旁”植树又以杨树占绝对优势。淳化县营造的12.9万亩防护林和用材林中,刺槐面积占11.1万亩,占造林总面 First, the native tree species structure and the status quo Since the founding of our country, the province’s afforestation work on the Loess Plateau has made great achievements. Vigorously develop poplar, paulownia, acacia, metasequoia and other tree species, and promote the “four sides” and barren hills and slopes of greening, forest in soil and water conservation, conservation of water sources, sand fixation, climate regulation and solve the rural “four materials” (fertilizer, fuel, Feed, wood) and other areas have achieved good results, it should be affirmed. However, one issue that deserves our attention is that in afforestation work around the country, insufficient attention has been paid to the development of native tree species, resulting in a very unreasonable afforestation tree structure. At present, the locust afforestation in mountainous area accounts for a considerable proportion of the original area and the “four sides” of trees and poplar absolute advantage. Chunhua County, 129,000 mu of shelterbelts and timber forests, acacia area of ​​11.1 hectares, accounting for the total afforestation