RESUMO
Changbai Mountain is one of the hotspots for tree ring research in Northeast China, with a large number of related research results having been published. To clarify the advance of tree ring research in Changbai Mountain and understand the responses of tree radial growth to climate factors, we reviewed the related literature and analyzed the differences among them based on tree species identity, elevation, and detrended methods. The radial growth of trees in Changbai Mountain was generally affected by temperature and precipitation, with greater influence of temperature. The relationship between tree radial growth and climate variables varied across both species and altitudes. Most studies reported that the radial growth of conifers were mainly affected by temperature in early growing season (April-May) and growing season precipitation (June-August). The radial growth of broadleaved trees were mainly affected by the temperature in previous and current growing season, the precipitation in dormancy season (November-March), and the precipitation in the current growing season. The previous September precipitation had significant effects on the radial growth of conifers and broadleaved trees. However, many studies had reported different or even opposite results. Most of the differences in the results of the studies appeared at low and medium altitudes, indicating that the altitudinal location of sampling points had impacts on the results. In addition, the detrended method was also the main cause for the variation of results across different studies. Comparatively, the linear or negative exponential detrended method might increase the effective significance of precipitation, especially the effect of precipitation on tree growth during dormancy period, and also strengthen the effective significance of the temperature at the end of the growing season. This study showed the habitat and the detrended method used in chronology were the main reasons for the difference of results among the studies. Therefore, for tree ring research in Changbai Mountain, the number of sampling sites should be increased and the detrended method should be carefully selected.
Assuntos
Clima , Árvores/crescimento & desenvolvimento , Altitude , China , Estações do AnoRESUMO
Non-structural carbohydrates (NSC, including soluble sugars and starch) are key meta-bolites in tree, the storage characteristics of which in tree organs have received extensive attention. It is still unclear how NSC are allocated in the tissues (phloem and xylem) that have different function. In this study, we analyzed the concentration and allocation of NSC in the roots, and in phloem and xylem of the trunk in three dominant species of broadleaved Korean pine forest in the Changbai Mountain, Pinus koraiensis, Fraxinus mandschurica, and Tilia amurensis. The results showed that there was a significant difference in the concentration of NSC between the phloem and xylem. The soluble sugar dominated in the phloem, while starch dominated in the xylem. The concentration of NSC in trunk outside (divided by annual rings, 0-20 years), intermediate (20-40 years) and inner (>40 years) of different tree species was significantly different, but with no difference in the roots. The total soluble sugar concentration in the phloem of P. koraiensis and F. mandschurica was significantly higher than that of T. amurensis, while the difference in xylem was not significant. The results indicated that NSC allocation in the phloem and xylem of the tree had clear tissue differentiation, which might be related to the succession stage of the tree species or the functional evolution of the tissue. These findings would improve our understanding of the carbon storage characteristics and allocation mechanism in temperate trees.
