A 99-year chronology of blue pine (Pinus wallichiana) tree-rings concerning interannual climate variability in the central himalayas of Nepal

Abstract

We conducted a dendroclimatic study in the Mustang region of the Himalayas in Nepal with aims to develop the tree-ring chronology and to check response of blue pine (Pinus wallichiana) radial growth with climate variation in the area. We extracted 120 tree cores at an altitudinal range of 2350 to 2550 m and develop a 99-year long tree-ring width chronology of blue pine which spans from 1913 to 2011.Precipitation and temperature were the main climatic factors limiting the radial growth of P. wallichiana. Winter and spring time precipitation was positively correlated to blue pine growth, specifically: precipitation during the previous November (r =0.43, p < 0.01), December (r = 0.39, p < 0.05) and current March (r = 0.34, p < 0.05). Similarly, there was a positive correlation between growth and September temperature of the current year (r = 0.398, p < 0.05), while correlation with temperature in previous year October (r =-0.446, p < 0.05) and December (r =-0.424, p < 0.05) was negative. Site conditions played a significant role in modulating the effect of precipitation and temperature on radial growth. Longer term regional scale dendrochronological studies are needed to improve our understanding on long-term climate change and its impact on forest growth.