Abstract:

Precise quantification of climate-growth relationships can make a major contribution to scientific forest management. However, whether differences in the response of growth to climate at different altitudes remains unclear. To answer this, 264 trees of Larix kaempferi from 88 plots, representing different altitudinal ranges (1000–2100 m) and tree classes were sampled and used to develop tree-ring chronologies. Tree-ring growth (TRG) was either positively (dominant) or negatively (intermediate and suppressed) correlated with climate in different tree classes at different altitudes. TRG was strongly correlated with growing season at low altitudes, but was less sensitive to climate at middle altitudes. It was mainly limited by precipitation and was highly sensitive to climate at low altitudes. Climate-growth relationships at high altitudes were opposite compared to those at low altitudes. TRG of dominant trees was more sensitive to climate change compared to intermediate and suppressed trees. Climate factors (annual temperatures; moisture, the number of frost-free days) had different effects on tree-ring growth of different tree classes along altitudinal gradients. It was concluded that the increase in summer temperatures decreased water availability, resulting in a significant decline in growth rates after 2005 at lower altitudes. L. kaempferi is suitable for planting in middle altitudes and dominant trees were the best sampling choice for accurately assessing climate-growth relationships.

Key words: Tree-ring width index, Chronology, Correlation coefficient, Additive mixed models, Tree classes