DIFFERENCES IN RESPONSES OF TREE-RING WIDTH AND DENSITY OF LARIX MASTERSIANA TO CLIMATIC FATORS IN THE WEST SICHUAN PLATEAU
Clarifying the response differences of different tree-ring parameters to climatic factors are critical for understanding the relationship between tree growth and climate changes.In this study,we investigated the response characteristics of tree-ring width and density of Larix mastersiana to climatic factors(i.e.,monthly air temperature and precipitation)as well as the temporal stability.The tree-ring samples,including 21 tree-ring cores from 14 trees,were collected at one site(33.27°N,103.77°E,2668 m a.s.l.)in the West Sichuan Plateau in China,which were used for obtaining tree-ring indicators such as tree-ring width,earlywood width,latewood width,average earlywood density,minimum density,average latewood density and maximum density.The chronologies of these tree-ring indicators cover a common period of 1806～2013.The data of climate variables,including precipitation,mean temperature,minimum temperature and maximum temperature,were obtained from Songpan Meteorological Station close to our sampling site.Our results showed that there were significantly(P＜0.01)positive correlations among the ring width index,earlywood width index,and latewood width index of this species,indicating a high degree of synchronicity in the interannual changes of the three ring-width indices.The minimum density was significantly(P＜0.01)and positively correlated with average earlywood density,which implied a high degree of synchronicity in the interannual changes of the two-tree ring-density parameters.Furthermore,a strong association occurred between maximum density and average latewood density,both of which were also significantly(P＜0.01)and positively correlated with minimum density and average earlywood density.Response analysis of the different tree-ring parameters to climatic factors showed that tree ring-width parameters(i.e.,ring width,earlywood width and latewood width)correlated with precipitation positively in May and June and negatively in January and February.Different to the ring-width parameters,tree ring-density parameters(i.e.,average earlywood density,minimum density,average latewood density and maximum density)were mainly influenced by temperature.The average earlywood density and minimum density showed highly positive correlations with mean temperature in early growing season(March,April,and May),while the average latewood density and maximum density were significantly and positively correlated with mean temperature in late growing season(September and October)and in May.The relationships of tree ring-density parameters with minimum temperature and maximum temperature were generally weaker than those with mean temperature.Moving correlation analysis showed that the correlations of two tree ring-density parameters related to earlywood(i.e.,average earlywood density and minimum density)with temperatures have presented a strengthening trend recently.Latewood width exhibited a decreasing correlation with mean temperature in March but a relatively stable relationship with June mean temperature.The correlations of average latewood density and maximum density with temperatures in early growing season(May)were unstable in time,while the in the late growing season(September and October)were relatively stable.This study reveals the different responses of different tree ring-parameters of Larix mastersiana to climatic factors and their temporal stability.The results can provide scientific understanding for the response relationship of coniferous tree growth with climate in the West Sichuan Plateau.
Larix mastersianatree growthtree-ring widthtree-ring densityclimate changethe West Sichuan Plateau
NETL
NSTL
万方数据
