To elucidate the development of heartwood,bark,sapwood,pith and specific gravity of wood in fastgrowing teak(Tectona grandis)plantations in Costa Rica,we sampled three trees in each of 55 plantations and modelled each...To elucidate the development of heartwood,bark,sapwood,pith and specific gravity of wood in fastgrowing teak(Tectona grandis)plantations in Costa Rica,we sampled three trees in each of 55 plantations and modelled each variable with age,site and different tree heights.Age and stand density of plantations were significant correlated with stem diameter at breast height and total height of the tree.Formation of heartwood was initiated at the age of 4-year-old and increased in direct proportion with age.The age of plantation had a significant relationship with stem diameter at breast height,heartwood percentage,sapwood thickness,sapwood percentage,percentage of bark,pith diameter and percentage,and specify gravity.The model for these tree parameters was model with these parameters as dependent variable and in relation to age as independent variable.展开更多
Tree shrews(also named banxrings),the small mammals native to Southeast Asia,are featured by moderate size,easy breeding,high reproductivity and close genetic background to primates(Xu et al.,2012;Xiao et al.,2017...Tree shrews(also named banxrings),the small mammals native to Southeast Asia,are featured by moderate size,easy breeding,high reproductivity and close genetic background to primates(Xu et al.,2012;Xiao et al.,2017).Tiee shrews possess both conserved and unique features compared to primates,and thus will become a suitable animal model with modest cost-effciency(Yao,2017).展开更多
文摘To elucidate the development of heartwood,bark,sapwood,pith and specific gravity of wood in fastgrowing teak(Tectona grandis)plantations in Costa Rica,we sampled three trees in each of 55 plantations and modelled each variable with age,site and different tree heights.Age and stand density of plantations were significant correlated with stem diameter at breast height and total height of the tree.Formation of heartwood was initiated at the age of 4-year-old and increased in direct proportion with age.The age of plantation had a significant relationship with stem diameter at breast height,heartwood percentage,sapwood thickness,sapwood percentage,percentage of bark,pith diameter and percentage,and specify gravity.The model for these tree parameters was model with these parameters as dependent variable and in relation to age as independent variable.
基金supported by the National Natural Science Foundation of China(No.31600841)the Shanghai brain-intelligence project from STCSM(16JC1420500)the Beijing brain project (Z161100002616004)
文摘Tree shrews(also named banxrings),the small mammals native to Southeast Asia,are featured by moderate size,easy breeding,high reproductivity and close genetic background to primates(Xu et al.,2012;Xiao et al.,2017).Tiee shrews possess both conserved and unique features compared to primates,and thus will become a suitable animal model with modest cost-effciency(Yao,2017).