Spatial variability of tree growth along a latitudinal transect in the Qilian Mountains, northeastern Tibetan Plateau

Abstract

Abstract:Little is known about the spatial variability in tree growth and its responses to climate on the Tibetan Plateau; however, such information is essential for improving predictions of forest ecosystem response to climatic change. A network of 16 ring width chronologies was developed along a latitudinal transect in the Qilian Mountains, northeastern Tibetan Plateau. A principal components analysis revealed that the residual chronologies had a positive loading on the first unrotated principal component (PC1). After rotation, PC1 yielded the highest loadings on the driest sites in the northwest and decreased to the south and to the east. PC2 was negatively correlated with altitude. Moisture availability was a dominant limiting factor for tree growth, and this dominance increased northwards and westwards along the precipitation gradient. Loadings of the first two rotated principal components separated the 16 forest sites into three major groups corresponding to the three regions affected by the East Asian Monsoon, Westerlies, and their interaction. Thus, spatial variability in tree growth is an excellent bioindicator of regional climate.Résumé : On connaît peu de choses sur la variation spatiale de la croissance des arbres et de sa réaction au climat sur le plateau tibétain. Toutefois, cette information est nécessaire pour améliorer les prédictions de la réaction des écosystèmes forestiers aux changements climatiques. Un réseau de 16 séries dendrochronologiques a été mis en place le long d'un transect latitudinal dans les monts Qilian, au nord-est du plateau tibétain. Une analyse en composantes principales a révélé que les chronologies résiduelles avaient des valeurs positives le long de la première composante principale sans rotation (CP1). Après rotation, les plus grandes valeurs de la CP1 étaient associées aux stations les plus sèches dans le nord-ouest et les valeurs diminuaient vers le sud et vers l'est. La CP2 était négativement corrélée à l'altitude. La disponibilité en eau était un facteur limitatif dominant pour la croissance des arbres et cette dominance augmentait vers le nord et vers l'ouest le long d'un gradient de précipitations. Après rotation, les deux premières composantes principales ont divisé les 16 stations forestières en trois groupes principaux qui correspondaient aux trois régions influencées par la mousson est-asiatique, les vents d'ouest et leur interaction. Par conséquent, la variation spatiale de la croissance des arbres est un excellent bioindicateur du climat régional.[Traduit par la Rédaction]

Early summer temperature reconstruction in the eastern Tibetan plateau since ad 1440 using tree-ring width of Sabina tibetica

“…This is in agreement with earlier studies (Bräuning 2001;Shi et al 2010;Wang et al 2008) on the same species from the eastern, central, and southwestern TP. Negative influences of early summer warmth on tree growth were reported for S. przewalskii on the northeastern TP (Gou et al 2008;Liang et al 2010;Liu et al 2006;Shao et al 2010;Sheppard et al 2004;Zhang et al 2003). In the western Himalayas, warm summers also limit the growth of Juniperus polycarpos (Yadav et al 2010), Cedrus deodara (Yadav et al 1997(Yadav et al , 1999Yadav et al 2004) and Abies pindrow (Hughes 1992).…”

Relationships between Tree Age and Climate Sensitivity of Radial Growth in Different Drought Conditions of Qilian Mountains, Northwestern China

“…Franco significantly correlated with summer temperatures in the warm and arid region and with winter temperatures in the cool region [4]. Precipitation exerted an increasingly positive influence on tree growth in the Qilian Mountains, northwest China, along the east-west drought gradient there [5]. The study area lies in a transition zone between the East Asian Monsoon and the Westerlies.…”

“…The five areas were named TLG (i.e., Tulugou), HX (i.e., Haxi), SDL (i.e., Sidalong), HYG (i.e., Heiyagou) and QKD (i.e., Qingkedi) along the southeast-northwest mountain range. Soil characteristics were similar among them [5]. One to three sampling sites with a slope from 25 to 35 degrees were set in each area (Table 1).…”

Radial Growth Response of Larix gmelinii to Climate along a Latitudinal Gradient in the Greater Khingan Mountains, Northeastern China

“…The stem radial growth of trees in any year integrates the effects of the climate during the previous and current year [1][2][3][4]. Tree radial growth is influenced by environmental factors (e.g., temperature, precipitation, and competition) and conditions within the individual tree [1,2].…”