Tsuga lorgibracteata\% is one of the rare gymnosperms and endemic to China. With the changes in environment and ecosystems, the total number of individuals has decreased rapidly and it is considered an endangered plan...Tsuga lorgibracteata\% is one of the rare gymnosperms and endemic to China. With the changes in environment and ecosystems, the total number of individuals has decreased rapidly and it is considered an endangered plant on the brink of extinction. This paper dealt with the growth dynamics of dominance of rare and endangered \%Tsuga lorgibracteata\% population based on the growth models, which were four limited space growth models for population. Compared with the fitting results of four models, the best growth model was selected to express the growth dynamics of dominance for \%Tsuga lorgibracteata\% population, which was \%s\%=exp (-0 046 804 ln\+2(1+108.386 5 e\+\{-0.594 42\%t\%\})-0.873 71 ln(1+108.386 5 e\+\{-0.594 42\%t\%\})+3.655 44). Then the environmental capacity of dominance of \%Tsuga lorgibracteata\% population was calculated. It was 38.684 7 m\+2\5hm\+\{-2\}. And the simulated result of dominance showed that when the diameter at breast height was about 40 cm, the population growth of dominance would be highest, which would provide a theoretical basis for the protection and management of \%Tsuga lorgibracteata.展开更多
Based on the measurement of monthly litterfall and their gross calor ic values, the seasonal dynamics of energy return through litterfall were determ ined in a pure and a mixed T. odorum (Tsoongiodendron odorum Chun) ...Based on the measurement of monthly litterfall and their gross calor ic values, the seasonal dynamics of energy return through litterfall were determ ined in a pure and a mixed T. odorum (Tsoongiodendron odorum Chun) forests with Ch inese fir (Cunninghamia lanceolata (Lamb.) Hook.) in Sanming, Fujian Provinc e. Annual ene rgy return through litterfall was estimated as 12.648×10 6J·m -2 for the mixed fo rest, being 4 2% higher than that of the pure forest, and a large proportion of the energy return comprised leaf litter. The conversion efficiency of solar rad i ation energy into litterfall was 0 56% for mixed forest and 0 54% for pure for es t, respectively. The monthly energy flux in litterfall of Chinese fir showed a t hree-apex curve, peaked in March, August and December, respectively, which was s imilar to that in various fractions of leaf, twig, flower and fruit litter. The consistency in monthly patterns among different litter fractions of Chinese fir was attributed to their solid connections all the while. The monthly energy flux in litterfall of T. odorum culminated in January, May and August, the same was true for its leaf and twig litter. However, energy flux in flower litter only oc curred during March to May and that in fruit litter appeared in January and Marc h. The monthly dynamics of energy flux through litterfall of the two forests wer e both determined by their respective litterfall pattern of Chinese fir. Seasona l energy flux in litterfall for both mixed and pure forests followed the sequenc e of spring>winter>summer>autumn, but fluctuations in the former were less disti nct than those in the latter.展开更多
文摘Tsuga lorgibracteata\% is one of the rare gymnosperms and endemic to China. With the changes in environment and ecosystems, the total number of individuals has decreased rapidly and it is considered an endangered plant on the brink of extinction. This paper dealt with the growth dynamics of dominance of rare and endangered \%Tsuga lorgibracteata\% population based on the growth models, which were four limited space growth models for population. Compared with the fitting results of four models, the best growth model was selected to express the growth dynamics of dominance for \%Tsuga lorgibracteata\% population, which was \%s\%=exp (-0 046 804 ln\+2(1+108.386 5 e\+\{-0.594 42\%t\%\})-0.873 71 ln(1+108.386 5 e\+\{-0.594 42\%t\%\})+3.655 44). Then the environmental capacity of dominance of \%Tsuga lorgibracteata\% population was calculated. It was 38.684 7 m\+2\5hm\+\{-2\}. And the simulated result of dominance showed that when the diameter at breast height was about 40 cm, the population growth of dominance would be highest, which would provide a theoretical basis for the protection and management of \%Tsuga lorgibracteata.
基金SupportedbytheFoundationofPost doctoralResearchof China (2 0 0 0F0 0 4 )
文摘Based on the measurement of monthly litterfall and their gross calor ic values, the seasonal dynamics of energy return through litterfall were determ ined in a pure and a mixed T. odorum (Tsoongiodendron odorum Chun) forests with Ch inese fir (Cunninghamia lanceolata (Lamb.) Hook.) in Sanming, Fujian Provinc e. Annual ene rgy return through litterfall was estimated as 12.648×10 6J·m -2 for the mixed fo rest, being 4 2% higher than that of the pure forest, and a large proportion of the energy return comprised leaf litter. The conversion efficiency of solar rad i ation energy into litterfall was 0 56% for mixed forest and 0 54% for pure for es t, respectively. The monthly energy flux in litterfall of Chinese fir showed a t hree-apex curve, peaked in March, August and December, respectively, which was s imilar to that in various fractions of leaf, twig, flower and fruit litter. The consistency in monthly patterns among different litter fractions of Chinese fir was attributed to their solid connections all the while. The monthly energy flux in litterfall of T. odorum culminated in January, May and August, the same was true for its leaf and twig litter. However, energy flux in flower litter only oc curred during March to May and that in fruit litter appeared in January and Marc h. The monthly dynamics of energy flux through litterfall of the two forests wer e both determined by their respective litterfall pattern of Chinese fir. Seasona l energy flux in litterfall for both mixed and pure forests followed the sequenc e of spring>winter>summer>autumn, but fluctuations in the former were less disti nct than those in the latter.
