黄土高原半干旱区几种人工林的土壤水分、光照变化及其对林分的影响  

Change of Soil Water Content and Light of Several Plantations at Loess Plateau Semi-arid Area and Its Effect on Forest Stand

作　　者：刘晨峰[1] 王正宁[1] 贺康宁[1] 尹婧[1] 张卫强[1] 田晶会[1] 

机构地区：[1]北京林业大学水土保持学院,北京100083

出　　处：《西部林业科学》2004年第3期34-41,共8页Journal of West China Forestry Science

摘　　要：对黄土高原半干旱的山西黄土丘陵沟壑区17年生4种造林密度(1 5m×2m、1 5m×4m、1 5m×6m、1 5m×8m)的人工刺槐林、2种造林密度(1 5m×3m、1 5m×5m)的白榆林及2种造林密度(1 5m×3m、1 5m×5m)的油松林地土壤水分、林下光照强度进行了观测;并对各林分林木的生长状况和林下植物的种类、数量、生长及发育状况进行了研究。结果表明,在相同林分类型中,密度小、营养空间大的林分林内土壤水分、光照强度有显著随林分密度增大而减小的趋势。在刺槐林内随着林分密度的增大,渐渐出现干旱、半干旱地区成龄人工林所具有的土壤干化现象,林下植被的种类和数量相应减少,物种丰富度和物种多样性指数也降低,且逐步由以田旋花、小菅草为典型的中生植物,向以铁杆蒿、达乌里胡枝子、铁丝草为典型的旱生植物过渡;白榆林密度1 5m×5m的林分中已有30%的林木出现枯梢,密度为1 5m×3m的林分中65%的林木严重枯梢,林下植被以耐旱性强的达呼里胡枝子为主要植物;油松林两个密度的林分林地平均土壤水分含量均比其他林分低。反映出林分内的小环境条件、林木生长状况和林下植被发育水平随林分种类、林分密度变化而变化的特点。因此,在半干旱区的营林中,树种选择要以其生物生态特性和实际生长状况为依据,且密度不可过大。The soil water content and light under forest of seventeen years old Robinia pseudoacacia plantation of four planting density (1.5 m×2 m, 1.5 m×4 m, 1.5 m×6 m, 1.5 m×8 m), ulmus pumila plantation of two planting density (1.5 m 3 m, 1.5 m 5 m) and Pinus tabulaeformis plantation of two planting density (1.5 m×3 m, 1.5 m×5 m) at Loess Plateau Semi-arid Area of Shanxi province were observed and determined. Studies were conducted on the growth of trees in different forest stand, the species and their number of undergrowth, and the growth and development of undergrowth. The results showed that within the forest with low planting density and big nutrition space the soil water content and light decreased with the increasing of planting density. Within the stand of Robinia pseudoacacia, as the planting density increase, the phenomenon of dry soil emerges as that occurred in mature plantation in arid and semi-arid areas. The abundance ratio and species diversity also decreased. The species gradually change from mesophyte such as Convolvulus arvensis and Themeda minor to typical xerophyte such as Artemisia sacrorum, Lespedeza dahurica and Adiantam capiuarisveneris. The average soil water content of two planting density Pinus tabulaeformis plantation were lower than other stands, which interpreted that the micro-environment, forest tree growth and development of undergrowth varied with the type of stand and planting density. In constructing plantation in semi-arid areas, the species should be selected based on bio-ecological characteristics and growth conditions. The planting should not be too dense so as to increase the productivity and stability of stand, and to prevent the occurrence of soil drought.

关 键 词：黄土高原半干旱区 人工林 土壤水分 光照变化 林分 

分 类 号：S714[农业科学—林学]