天山北坡不同环境条件下雪岭云杉(Picea schrenkiana)林限土壤属性

为了研究干旱区天山北坡中山带长达1000余公里的单建群种山地针叶林的空间分布原因,选择精河、玛纳斯、阜康和巴里坤中山带作为四种不同的环境条件,通过对不同环境条件雪岭云杉(Picea schrenkiana)上、下限土壤的采样与分析,探讨土壤因素对天山北坡中山带雪岭云杉分布的控制作用.雪岭云杉在天山北坡的连续分布主要是水热组合条件和土壤因素相互作用的结果,上、下限土壤属性变化与环境条件变化间存在着紧密的联系,表现为降雨量丰富的玛纳斯林区土壤肥力较高,但CaCO3含量较低,而降雨量较小的巴里坤和精河林区土壤肥力较差,但CaCO3含量较高.虽然长达1000余公里的雪岭云杉中山带环境条件差异较大,但其土壤属性变化均在雪岭云杉发育所需土壤条件的允许范围之内,这主要是受土壤成土母质、不同海拔高度的降雨量、地形、局地环流等因素的共同影响.

Soil properties at the tree limits of Picea schrenkiana forests in response to varying environmental conditions on the northern slope of Tianshan mountains

Coniferous forests consisting predominantly of Picea schrenkiana occur continuously,forming an unbroken,1000 km forest zone extending from west to east on the northern slope of Tianshan mountains where conditions such as precipitation,temperature and terrain vary greatly.To gain insights into the role of pedological process in controlling the growth of P.schrenkiana,soil under the forests was studied along 4 transects located at Jinghe,Manasi,Fukang and Balikun where the natural conditions are typical and,therefore,representative for western,central and eastern Tianshan mountains.On the transects,soil samples were taken in the area near the upper and lower tree limits of the forest zone.The continuous distribution of P.schrenkiana on the northern slope of Tianshan mountains is a result of combined water-heat conditions and pedological factors.At the upper and lower tree limits where difference exists in soil parent material,precipitation,topography,combined water-heat conditions and local atmospheric pattern,the soil properties show a close relationship with the local conditions.Because of the presence of high precipitation over the Manasi transect,the soil is fertile and low in CaCO3 content.In contrast,low soil fertility with high CaCO3 is seen in the soil on the Jinghe and Balikun transects where low precipitation exists.Although soil properties vary spatially due to the presence of different environmental conditions across the 1000 km forest zone on the northern slope of Tianshan mountains,soil is suitable for P.schrenkiana to grow.This study indicates that soil plays an important role in controlling the continuous distribution of the P.schrenkiana forests on the northern slope of Tianshan mountains.