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
To understand the effects of leaf physiological and morphological characteristics on δ13C of alpine trees, we examined leaf δ13C value, LA, SD, LNC, LPC, LKC, Chla+b, LDMC, LMA and Narea in one-year-old needles of P...To understand the effects of leaf physiological and morphological characteristics on δ13C of alpine trees, we examined leaf δ13C value, LA, SD, LNC, LPC, LKC, Chla+b, LDMC, LMA and Narea in one-year-old needles of Picea schrenkiana var. tianschanica at ten points along an altitudinal gradient from 1420 m to 2300 m a.s.l. on the northern slopes of the Tianshan Mountains in northwest China. Our results indicated that all the leaf traits differed significantly among sampling sites along the altitudinal gradient(P<0.001). LA, SD, LPC, LKC increased linearly with increasing elevation, whereas leaf δ13C, LNC, Chla+b, LDMC, LMA and Narea varied non-linearly with changes in altitude. Stepwise multiple regression analyses showed that four controlled physiological and morphological characteristics influenced the variation of δ13C. Among these four controlled factors, LKC was the most profound physiological factor that affected δ13C values, LA was the secondary morphological factor, SD was the third morphological factor, LNC was the last physiological factor. This suggested that leaf δ13C was directly controlled by physiological and morphological adjustments with changing environmental conditions due to the elevation.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 Major Research Plan of the National Natural Science Foundation of China (Grant No. Y411381001)the National Natural Science Foundation of China (Grant No. 91125025)the Postdoctoral Science Foundation of China (Grant No. 2013M532096)
文摘To understand the effects of leaf physiological and morphological characteristics on δ13C of alpine trees, we examined leaf δ13C value, LA, SD, LNC, LPC, LKC, Chla+b, LDMC, LMA and Narea in one-year-old needles of Picea schrenkiana var. tianschanica at ten points along an altitudinal gradient from 1420 m to 2300 m a.s.l. on the northern slopes of the Tianshan Mountains in northwest China. Our results indicated that all the leaf traits differed significantly among sampling sites along the altitudinal gradient(P<0.001). LA, SD, LPC, LKC increased linearly with increasing elevation, whereas leaf δ13C, LNC, Chla+b, LDMC, LMA and Narea varied non-linearly with changes in altitude. Stepwise multiple regression analyses showed that four controlled physiological and morphological characteristics influenced the variation of δ13C. Among these four controlled factors, LKC was the most profound physiological factor that affected δ13C values, LA was the secondary morphological factor, SD was the third morphological factor, LNC was the last physiological factor. This suggested that leaf δ13C was directly controlled by physiological and morphological adjustments with changing environmental conditions due to the elevation.
