赤峰城郊杨树经营活动的分析

本文根据赤峰地区降水少,沙丘起伏,土壤干旱瘠薄的自然条件,划分了冲积沙地,沙丘背风坡、沙丘迎风坡、平缓沙地、以及风蚀坑等五个主要的沙地杨树立地类型。提出杨树幼龄后期,对风蚀坑与平缓沙地的部分地段的“小老树”,采取施硫铵、中耕和灌水等综合措施;对于郁闭后的成林,主伐前分两次间伐、初次在林龄14年,间伐强度为25％,第二次间伐在16～18年,其强度为30％,每亩保留不低于50株。对成熟林应及时采伐更新;主伐年龄定为22～24年,采伐方式为3～5最大不超过10亩的小面积皆伐.水肥条件好的类型,人工更新以杨树为主,条件较差者,则更新油松、樟子松,最终形成块状(?)阔混交林,可取得良好的生态和经济效益。

An Analysis of Chifeng Suburban Poplar Forest Management Activities

Chifeng is located in lnner Mongolia, where sand dunes prevail, and where the climate is severe and dry, and the soil poor. Based on such natural conditions, different forest management strategies are recommended to meet different situations: For those "small old trees" planted in wind--eroded pits and on gentle slopes of sand land, the desirable measures include timely irragation and cultivation and the application of ammonium sulfate fertilizer. For close stands, thinning twice before main harvest is recommended, with the first thinning taking place at the age of 14 years, to remove 25% of the trees, and the second thinning at the age of 16--18 years, to remove 30% of the remaining trees. The number of trees finally left over should be no less than 50 trees per mu. For mature forests, cutting and regenaration should be executed in time. The main harvest could be done at the age of 22--24 years in small patches, usually 3--4 mu each, never exceeding 10. Artificial regeneration is to follow immediately, with poplar species in case that the soil conditions are good, and with Chinese pine and Mongolian Scotch pine for poor soil, in order to form patched mixed forests of coniferous and broad--leaved trees.