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
According to the relationship between Toona sinensis Roem stand volume,productivity and forest age,site conditions,stand density and other factors,through selecting 8 representative cities or counties,using standard i...According to the relationship between Toona sinensis Roem stand volume,productivity and forest age,site conditions,stand density and other factors,through selecting 8 representative cities or counties,using standard investigation and stem analysis method,this paper makes relatively systematic research about the Toona sinensis Roem plantation accumulation,productivity,and the relationship between them and site conditions.Through comparative analysis indicators of multiple site conditions,this paper expects to give a more comprehensive picture about the source of accumulation and productivity difference.展开更多
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.
文摘According to the relationship between Toona sinensis Roem stand volume,productivity and forest age,site conditions,stand density and other factors,through selecting 8 representative cities or counties,using standard investigation and stem analysis method,this paper makes relatively systematic research about the Toona sinensis Roem plantation accumulation,productivity,and the relationship between them and site conditions.Through comparative analysis indicators of multiple site conditions,this paper expects to give a more comprehensive picture about the source of accumulation and productivity difference.
