Climate constitutes the main limiting factor for tree-ring growth in high-elevation forests, and the relationship between tree-ring growth and climate is complex. Based on tree-ring chronology and meteorological data,...Climate constitutes the main limiting factor for tree-ring growth in high-elevation forests, and the relationship between tree-ring growth and climate is complex. Based on tree-ring chronology and meteorological data, the influence of precipitation, mean temperature and mean minimum temperature at yearly, seasonal and monthly scales on the tree-ring growth of Picea crossifolia was studied at treeline ecotones in the Qilian Mountains, northwestern China. The results show that growing season temperatures of previous and current years are important limiting factors on tree-ring growth, particularly June mean temperature and mean minimum temperature of current year. The precipitations in the previous winter and current spring have a positive correlation, and in the current fall has a negative correlation with tree-ring growth, but these correlations are not significant. Our results suggest that temperature controls tree-ring growth more strongly than precipitation at treeline ecotones in the Qilian Mountains.展开更多
On the basis of the relationship between tree ring width of Pinus tabulaeformis in the southern Taihang Mountains in Hebei Province and climate factors, such as mean temperature, mean maximum temperature, mean minimum...On the basis of the relationship between tree ring width of Pinus tabulaeformis in the southern Taihang Mountains in Hebei Province and climate factors, such as mean temperature, mean maximum temperature, mean minimum temperature and precipitation, we find that tree-ring width correlates positively and significantly with mean and maximum temperature in March and Spring, and with minimum temperature in March, April, Spring and Autumn. The sampling tree radial growth responds sensitively to spring temperature change.展开更多
The Atlas cedar (Cedrus atlantica) is one of the more valuable reforestation species in the Mediterranean areas. But this species suffers from rainfall limitation and climate changes, particularly in its originated ar...The Atlas cedar (Cedrus atlantica) is one of the more valuable reforestation species in the Mediterranean areas. But this species suffers from rainfall limitation and climate changes, particularly in its originated area, North Africa. Therefore, any knowledge about the plantation practices to improve the tree water availability and the reforestation success has great importance. The current study has been undertaken in this view, i.e. to compare the growth of cedar plots located in El M’Sid Mountains, Souk Ahras department (700 km east of Algiers), according to different planting methods. The radial growth and the productivity have been measured on a cedar plot with a total surface of 165 ha. 150 ha has been planted in 1970 on hillside ditches, and 15 ha of which the majority is planted in a simple hole and some bouquets on terraces, both are originated from a complementary reforestation achieved during 1980. The results show that most of the trees planted in 1970 reach a height ranging between 10 and 17 m and a diameter between 23 and 44 cm. Even some trees were 20 m high with diameter of 65 cm. The productivity fluctuates between 3 and 8 m3/ha/year, values close to the one of natural native plots. Trees planted in 1980 reach a height ranging between 5. 5 to 7 m, and diameter between 11.5 to 23 cm. The radial growth improves that the hillside ditches help the roots anchoring and trees growth during the first season after plantation. These results indicate that the cedar tree can be used with success in areas outside the natural cedar forest presence, and that appropriate planting techniques can compensate in part the lower rainfall occurring in these chosen regeneration areas.展开更多
[Objective] The aim was to study change tendency of the precipitation resource during growth period of the conventional crops in plain area before Taihang Mountains. [ Method] Based on daily precipitation data at Shij...[Objective] The aim was to study change tendency of the precipitation resource during growth period of the conventional crops in plain area before Taihang Mountains. [ Method] Based on daily precipitation data at Shijiazhuang meteorological station in recent 51 years, average rainfall dudng growth periods of the 9 kinds of conventional crops was obtained. Precipitation tendency dudng growth periods of the 9 kinds of conventional crops in plain area before Taihang Mountains was analyzed by Mann-Kendall nonparametric test. [ Result] Seen from rainfall during growth pedods of the different crops, rainfall was the least during the growth period of winter wheat, followed by summer corn. Rainfall during growth peri- ods of the cotton, oil plant, vegetable, fruit tree, potato, rice and legumes was more. Under different guaranteed rates, precipitation change also had difference. Rainfall change during growth periods of the wheat and corn was bigger, and rainfall change during growth period of the rice was smaller. Change degree of the precipitation during growth periods of the cotton, oil plant, vegetable, fruit tree and legumes was equivalent, while precipitation change during growth period of the potato was the biggest. Seen from change tendency of the precipitation during growth periods of the different crops, precipitation in the growth period of winter wheat was increasing at a speed of 0.62 mm/a. However, precipitation in growth periods of the other crops had a decreasing tendency. Precipitation in the growth periods of summer corn and legumes decreased at the same speed which was 2.11 mm/a, while precipitation in growth periods of the cotton, oil plant, vegetable, fruit tree, potato and rice decreased insignificantly. [ Con dusion] The study laid foundation for determination of the agricultural irrigation water and provided theoretical reference for regional agricultural water-saving.展开更多
基金supported by the Major Research Plan of National Natural Science Foundation of China (No. 91025014),the National Natural Science Foundation of China (No. 30800147)
文摘Climate constitutes the main limiting factor for tree-ring growth in high-elevation forests, and the relationship between tree-ring growth and climate is complex. Based on tree-ring chronology and meteorological data, the influence of precipitation, mean temperature and mean minimum temperature at yearly, seasonal and monthly scales on the tree-ring growth of Picea crossifolia was studied at treeline ecotones in the Qilian Mountains, northwestern China. The results show that growing season temperatures of previous and current years are important limiting factors on tree-ring growth, particularly June mean temperature and mean minimum temperature of current year. The precipitations in the previous winter and current spring have a positive correlation, and in the current fall has a negative correlation with tree-ring growth, but these correlations are not significant. Our results suggest that temperature controls tree-ring growth more strongly than precipitation at treeline ecotones in the Qilian Mountains.
基金Supported by the Science and Technology Plan Projects of Hebei Province(15454201D)
文摘On the basis of the relationship between tree ring width of Pinus tabulaeformis in the southern Taihang Mountains in Hebei Province and climate factors, such as mean temperature, mean maximum temperature, mean minimum temperature and precipitation, we find that tree-ring width correlates positively and significantly with mean and maximum temperature in March and Spring, and with minimum temperature in March, April, Spring and Autumn. The sampling tree radial growth responds sensitively to spring temperature change.
文摘The Atlas cedar (Cedrus atlantica) is one of the more valuable reforestation species in the Mediterranean areas. But this species suffers from rainfall limitation and climate changes, particularly in its originated area, North Africa. Therefore, any knowledge about the plantation practices to improve the tree water availability and the reforestation success has great importance. The current study has been undertaken in this view, i.e. to compare the growth of cedar plots located in El M’Sid Mountains, Souk Ahras department (700 km east of Algiers), according to different planting methods. The radial growth and the productivity have been measured on a cedar plot with a total surface of 165 ha. 150 ha has been planted in 1970 on hillside ditches, and 15 ha of which the majority is planted in a simple hole and some bouquets on terraces, both are originated from a complementary reforestation achieved during 1980. The results show that most of the trees planted in 1970 reach a height ranging between 10 and 17 m and a diameter between 23 and 44 cm. Even some trees were 20 m high with diameter of 65 cm. The productivity fluctuates between 3 and 8 m3/ha/year, values close to the one of natural native plots. Trees planted in 1980 reach a height ranging between 5. 5 to 7 m, and diameter between 11.5 to 23 cm. The radial growth improves that the hillside ditches help the roots anchoring and trees growth during the first season after plantation. These results indicate that the cedar tree can be used with success in areas outside the natural cedar forest presence, and that appropriate planting techniques can compensate in part the lower rainfall occurring in these chosen regeneration areas.
基金Supported by National Science and Technology Support Plan Item, China ( 2007BAD69B09)Soft Science Research Plan Project in Hebei Province,China (10457204D-30,114572124)
文摘[Objective] The aim was to study change tendency of the precipitation resource during growth period of the conventional crops in plain area before Taihang Mountains. [ Method] Based on daily precipitation data at Shijiazhuang meteorological station in recent 51 years, average rainfall dudng growth periods of the 9 kinds of conventional crops was obtained. Precipitation tendency dudng growth periods of the 9 kinds of conventional crops in plain area before Taihang Mountains was analyzed by Mann-Kendall nonparametric test. [ Result] Seen from rainfall during growth pedods of the different crops, rainfall was the least during the growth period of winter wheat, followed by summer corn. Rainfall during growth peri- ods of the cotton, oil plant, vegetable, fruit tree, potato, rice and legumes was more. Under different guaranteed rates, precipitation change also had difference. Rainfall change during growth periods of the wheat and corn was bigger, and rainfall change during growth period of the rice was smaller. Change degree of the precipitation during growth periods of the cotton, oil plant, vegetable, fruit tree and legumes was equivalent, while precipitation change during growth period of the potato was the biggest. Seen from change tendency of the precipitation during growth periods of the different crops, precipitation in the growth period of winter wheat was increasing at a speed of 0.62 mm/a. However, precipitation in growth periods of the other crops had a decreasing tendency. Precipitation in the growth periods of summer corn and legumes decreased at the same speed which was 2.11 mm/a, while precipitation in growth periods of the cotton, oil plant, vegetable, fruit tree, potato and rice decreased insignificantly. [ Con dusion] The study laid foundation for determination of the agricultural irrigation water and provided theoretical reference for regional agricultural water-saving.
