辽宁西部半干旱地区油松纯林改造的研究

喀左县位于辽宁西部地区，现存大面积油松人工纯林，不仅改善地力和水土保持效益差，而且火险性强、虫害蔓延成灾、生长早期衰退。为改善其林分生态条件，提高林木生长量和综合效益，在中三家镇对25年生油松人工纯林进行改造试验。结果表明，选择山杏、刺槐、沙棘等乔、灌木树种，利用林间空地、林缘隙地、侵蚀沟壑和疏林地造林，在大面积油松纯林连片地区进行窄带状或块状砍伐后造林，5年后效益显著，林分相对湿度提高了2．2％，土壤有机质含量提高5．4％，土壤含水量提高9．8％，减轻土壤容重３％,林分虫害明显下降，油松树高、胸径生长量分别提高22．6％、19．8％。

Study on Reforestation of Chinese Pine Pure Forest in Western Area of Liaoning

The large area of Kazuo's Chinese pine pure forest plantation not only has a low ability to improve the land capacity and the soil and water conservation,but also grow slowly and has high fire risk with insect pest spreading into calamity.In order to improve the ecological condition of its stands,promote the growth increment and comprehensive efficiency,a reforestation experiment was held in a 25-year-old Chinese pine pure forest plantation in Zhongsanjia town.The results indicated that shrubs such as Siberian Apricot(A.sibirica(L)Lam.),Locust(R.pseucloacacia L.),Sallow Thorn(H.rhamnoides L),Chinese pine(P.tabulaeformis Carr) were chosen to be planted on the empty land in the forest,forest edge,erosion gully and reforestation in open forest land,and afforest in large acreage Chinese pine pure forest after narrow strip cutting or group cutting.5years later,the efficiency is sufficient.The relative humidity,soil organic matter,soil moisture content were increased 2.2%,5.4%,9.8%,respectively.Whereas,the bulk density decreased 3% and the stand insect pest calamity declined obviously.The height and the breast diameter of the Chinese pine increased 22.6% and 19.8%,respectively.