In this work, we report a comprehensive study about the eco-environmental effects of the shelter forest along the Tarim Desert Highway, including the effects on aeolian environment, soil, micro-climate, biodiversity, ...In this work, we report a comprehensive study about the eco-environmental effects of the shelter forest along the Tarim Desert Highway, including the effects on aeolian environment, soil, micro-climate, biodiversity, and groundwater. The results show that: (1) The movement of windblown sand near the ground surface was affected by the shelter forest. The wind speed and sediment transport rate in the shelter forest decreased by 64%―80% and 87.45%―99.02%, respectively. In addition, there were also significant changes in the sand flux structure, the sand grain size, and the deflation and deposition on the ground surface. (2) Compared to the natural mobile sand, the soil bulk density in the forest area decreased while the total salt content, the total porosity, and the water content increased. In addition, the soil fertility was significantly improved in the forest area, and showed the "first rapid, then slow" variation pattern. (3) The shelter forest showed positive effects on the micro-climate. Within the 6 m height above the ground, the air temperature in the shelter forest at different heights was lower than that in the mobile sand, while the air humidity was higher, while, the soil temperature was also lower in the shelter forest than mobile sand. (4) The number of soil microbial species increased significantly with the improvement of habitat in the shelterbelt. However, the population of different species was not distributed evenly across the surveyed area. (5) Currently, no significant effects of groundwater-pumping and forest-irrigation water have been found on the groundwater level and its salinity. The variation amplitude of both groundwater level and salinity was at the level of centimeters and 1g/L, respectively. No obvious variation trend has been observed.展开更多
Site types of the afforestation region of the shelter-forest ecological project along the Tarim Desert Highway were classified based on the natural conditions and windblown sand damages. The extremely severe environme...Site types of the afforestation region of the shelter-forest ecological project along the Tarim Desert Highway were classified based on the natural conditions and windblown sand damages. The extremely severe environment, the irrigation with saline water, and large-scale linear project makes this classification of site types most unique and significant. It adopted a three-level classification system integrating the dominant factors and restrictive factors in regard to their impacts on plant survival and growth as well as on the protective property. Six site type districts were classified based on the medium-scale geomorphic unit, the windblown sand damages, and the major production facilities; 21 site type groups were obtained according to the small-scale geomorphic type, terrain, and wind regime; 36 site types were further classified based on the salt contents of the underground water and soil types. Especially, in this study, spatial distribution of the six site type districts along the desert highway is continuous, which is unique and different from that of most other classifications. In addition, the salt-stress tolerance threshold of the main afforestation plant species to underground water have been set to 8 g/L and 15 g/L according to selective breeding tests and the salinity spatial distribution of the underground water. Thus, the underground water with salinity lower than 8 g/L is defined as light saline water in this area.展开更多
Soil reinforcement of tree roots is the main mechanical effect of shelter-forest on soil stability and slope protection, and the traction effect of lateral roots plays an important role in this concern in mountainous ...Soil reinforcement of tree roots is the main mechanical effect of shelter-forest on soil stability and slope protection, and the traction effect of lateral roots plays an important role in this concern in mountainous areas. The magnetite of this role rises positively with the tensile strength of the roots in the soil. This study developed a mechanical model of relationship between the tensile strength of roots and the traction effect used in pine forests. The results showed that the tensile strength of the pines mostly lays in a range of 5～25MPa, and decreased with diameter of the roots. In the depth interval of 0～60cm, the density of lateral roots of the three pines is relatively high, and the roots are able to increase the tensile strength of the rooted soil by 6 85～9 50 kPa, through traction effect. Though the strength of the pine roots and its role in increasing strength of the rooted soil are significant, the strength of the pines is lower than those of some broad leaved trees. This means that the pines have certain limitation on their role of shallow slope stability.展开更多
基金Supported by Major Orientation Foundation of the CAS Innovation Program (Grant No. KZCX3-SW-342)CAS Action-Plan for West Development (Grant No. KZCX2- XB2-13)+2 种基金Major Scientific and Technological Special of Xinjiang Uygur Autono-mous Region (Grant No. 200733144-3)National Natural Science Foundation of China (Grant No.40701019)the research projects of the Tarim Branch of PetroChina Company Limited (Grant Nos. 971008090016 and 971008090017), and the Western
文摘In this work, we report a comprehensive study about the eco-environmental effects of the shelter forest along the Tarim Desert Highway, including the effects on aeolian environment, soil, micro-climate, biodiversity, and groundwater. The results show that: (1) The movement of windblown sand near the ground surface was affected by the shelter forest. The wind speed and sediment transport rate in the shelter forest decreased by 64%―80% and 87.45%―99.02%, respectively. In addition, there were also significant changes in the sand flux structure, the sand grain size, and the deflation and deposition on the ground surface. (2) Compared to the natural mobile sand, the soil bulk density in the forest area decreased while the total salt content, the total porosity, and the water content increased. In addition, the soil fertility was significantly improved in the forest area, and showed the "first rapid, then slow" variation pattern. (3) The shelter forest showed positive effects on the micro-climate. Within the 6 m height above the ground, the air temperature in the shelter forest at different heights was lower than that in the mobile sand, while the air humidity was higher, while, the soil temperature was also lower in the shelter forest than mobile sand. (4) The number of soil microbial species increased significantly with the improvement of habitat in the shelterbelt. However, the population of different species was not distributed evenly across the surveyed area. (5) Currently, no significant effects of groundwater-pumping and forest-irrigation water have been found on the groundwater level and its salinity. The variation amplitude of both groundwater level and salinity was at the level of centimeters and 1g/L, respectively. No obvious variation trend has been observed.
基金Supported by Major Orientation Foundation of the CAS Innovation Program (Grant No. KZCX3-SW-342)CAS Action-Plan for West Development (Grant No. KZCX2-XB2- 13)+3 种基金Major Scientific and Technological Special of Xinjiang Uygur Autonomous Region (Grant No. 200733144-3)National Natural Science Foundation of China (Grant No. 40701019)the research projects of the Tarim Branch of PetroChina Company Limited (Grant Nos. 971008090016 and 971008090017)the Western Light of the Chinese Academy of Sciences (Grant No. 20052118)
文摘Site types of the afforestation region of the shelter-forest ecological project along the Tarim Desert Highway were classified based on the natural conditions and windblown sand damages. The extremely severe environment, the irrigation with saline water, and large-scale linear project makes this classification of site types most unique and significant. It adopted a three-level classification system integrating the dominant factors and restrictive factors in regard to their impacts on plant survival and growth as well as on the protective property. Six site type districts were classified based on the medium-scale geomorphic unit, the windblown sand damages, and the major production facilities; 21 site type groups were obtained according to the small-scale geomorphic type, terrain, and wind regime; 36 site types were further classified based on the salt contents of the underground water and soil types. Especially, in this study, spatial distribution of the six site type districts along the desert highway is continuous, which is unique and different from that of most other classifications. In addition, the salt-stress tolerance threshold of the main afforestation plant species to underground water have been set to 8 g/L and 15 g/L according to selective breeding tests and the salinity spatial distribution of the underground water. Thus, the underground water with salinity lower than 8 g/L is defined as light saline water in this area.
文摘Soil reinforcement of tree roots is the main mechanical effect of shelter-forest on soil stability and slope protection, and the traction effect of lateral roots plays an important role in this concern in mountainous areas. The magnetite of this role rises positively with the tensile strength of the roots in the soil. This study developed a mechanical model of relationship between the tensile strength of roots and the traction effect used in pine forests. The results showed that the tensile strength of the pines mostly lays in a range of 5～25MPa, and decreased with diameter of the roots. In the depth interval of 0～60cm, the density of lateral roots of the three pines is relatively high, and the roots are able to increase the tensile strength of the rooted soil by 6 85～9 50 kPa, through traction effect. Though the strength of the pine roots and its role in increasing strength of the rooted soil are significant, the strength of the pines is lower than those of some broad leaved trees. This means that the pines have certain limitation on their role of shallow slope stability.
