Three gaps with different sizes were selected in Qingyuan Experimental Station of Forest Ecology,Institute of Applied Ecology,Chinese Academy of Sciences,which located in eastern montane regions of Liaoning Province,C...Three gaps with different sizes were selected in Qingyuan Experimental Station of Forest Ecology,Institute of Applied Ecology,Chinese Academy of Sciences,which located in eastern montane regions of Liaoning Province,China for observations of air temperature and soil temperature. The observations were conducted in the gaps in June 2006,2 years after the formation of the gaps. The results indicated that both air and soil temperatures at the gap center points exhibited bell-shaped curves. The maximum temperatures occurred at different time in the gaps. The appearance of the highest temperature was earlier in large gap than that in small gaps. In the night,the larger the gap was,the lower the air temperature became. However,it was just opposite in the daytime. The highest temperature was at northern points nearby the center points for gap 1 and gap 2,and their appearance time was 10: 00 and 11: 00 respectively. But the highest temperature was at the center point for gap 3,and the appearance time was 13: 00. The soil temperatures at gap center points ranked as middle gap,large gap,and small gap. The soil temperature in gap 2 was higher than that in gap 1 and gap 2. The air temperature and soil temperature were significantly positive correlation for gap 1 and gap 3 (r=0.814,P<0.01和r=0.581,P<0.05).展开更多
Mongolian pine (Pinus sylvestiris Linnaeus var. mongolica Litvinov) as a valuable conifer tree species has been broadly introduced to the sandy land areas in 揟hree North?regions (North, northwest and northeast of Chi...Mongolian pine (Pinus sylvestiris Linnaeus var. mongolica Litvinov) as a valuable conifer tree species has been broadly introduced to the sandy land areas in 揟hree North?regions (North, northwest and northeast of China), but many problems occurred in the earliest Mongolian pine plantations in Zhanggutai, Zhangwu County, Liaoning Province (ZZL). In order to clarify the reason, comprehensive investigations were carried out on differences in structure characteristics, growth processes and ecological factors between artificial stands (the first plantation established in ZZL in 1950s) and natural stands (the origin forests of the tree species in Honghuaerji, Inner Mongolia) on sandy land. The results showed that variation of diameter-class distributions in artificial stands and natural stands could be described by Weibull and Normal distribution models, respectively. Chapman-Richards growth model was employed to reconstruct the growth process of Mongolian pine based on the data from field investigation and stem analysis. The ages of maximum of relative growth rate and average growth rate of DBH, height, and volume of planted trees were 11, 22 years, 8, 15 years and 35, 59 years earlier than those of natural stand trees, respectively. In respect of the incremental acceleration of volume, the artificial and natural stands reached their maximum values at 14 years and 33 years respectively. The quantitative maturity ages of artificial stands and natural stands were 43 years and 102 years respectively. It was concluded that the life span of the Mongolian pine trees in natural stands was about 60 years longer than those in artificial stands. The differences mentioned above between artificial and natural Mongolian pine forests on sandy land were partially attributed to the drastic variations of ecological conditions such as latitude, temperature, precipitation, evaporation and height above sea level. Human beings' disturbances and higher density in plantation forest may be ascribed as additional reasons. Those results may be potentially useful for the management and afforestation of Mongolian pine plantations on sandy land in arid and semi-arid areas.展开更多
文摘Three gaps with different sizes were selected in Qingyuan Experimental Station of Forest Ecology,Institute of Applied Ecology,Chinese Academy of Sciences,which located in eastern montane regions of Liaoning Province,China for observations of air temperature and soil temperature. The observations were conducted in the gaps in June 2006,2 years after the formation of the gaps. The results indicated that both air and soil temperatures at the gap center points exhibited bell-shaped curves. The maximum temperatures occurred at different time in the gaps. The appearance of the highest temperature was earlier in large gap than that in small gaps. In the night,the larger the gap was,the lower the air temperature became. However,it was just opposite in the daytime. The highest temperature was at northern points nearby the center points for gap 1 and gap 2,and their appearance time was 10: 00 and 11: 00 respectively. But the highest temperature was at the center point for gap 3,and the appearance time was 13: 00. The soil temperatures at gap center points ranked as middle gap,large gap,and small gap. The soil temperature in gap 2 was higher than that in gap 1 and gap 2. The air temperature and soil temperature were significantly positive correlation for gap 1 and gap 3 (r=0.814,P<0.01和r=0.581,P<0.05).
基金The research was supported by innovation research project of Chinese Academy of Sciences (KZCX3-SW-418) and by Nature Science Foundation of Liaoning Province (20021006).
文摘Mongolian pine (Pinus sylvestiris Linnaeus var. mongolica Litvinov) as a valuable conifer tree species has been broadly introduced to the sandy land areas in 揟hree North?regions (North, northwest and northeast of China), but many problems occurred in the earliest Mongolian pine plantations in Zhanggutai, Zhangwu County, Liaoning Province (ZZL). In order to clarify the reason, comprehensive investigations were carried out on differences in structure characteristics, growth processes and ecological factors between artificial stands (the first plantation established in ZZL in 1950s) and natural stands (the origin forests of the tree species in Honghuaerji, Inner Mongolia) on sandy land. The results showed that variation of diameter-class distributions in artificial stands and natural stands could be described by Weibull and Normal distribution models, respectively. Chapman-Richards growth model was employed to reconstruct the growth process of Mongolian pine based on the data from field investigation and stem analysis. The ages of maximum of relative growth rate and average growth rate of DBH, height, and volume of planted trees were 11, 22 years, 8, 15 years and 35, 59 years earlier than those of natural stand trees, respectively. In respect of the incremental acceleration of volume, the artificial and natural stands reached their maximum values at 14 years and 33 years respectively. The quantitative maturity ages of artificial stands and natural stands were 43 years and 102 years respectively. It was concluded that the life span of the Mongolian pine trees in natural stands was about 60 years longer than those in artificial stands. The differences mentioned above between artificial and natural Mongolian pine forests on sandy land were partially attributed to the drastic variations of ecological conditions such as latitude, temperature, precipitation, evaporation and height above sea level. Human beings' disturbances and higher density in plantation forest may be ascribed as additional reasons. Those results may be potentially useful for the management and afforestation of Mongolian pine plantations on sandy land in arid and semi-arid areas.
