Radial growth response of Pinus yunnanensis to rising temperature and drought stress on the Yunnan Plateau, southwestern China

摘要

The relative influence of energy and water availability on tree growth at specific sites under warming conditions remains insufficiently understood on the Yunnan Plateau, which obstructs the rational selection and development of forest management measures in the context of climate change. In this study, a dendroecological investigation was conducted in four sites on the Yunnan Plateau to evaluate growth trends and climate responses of Pinus yunnanensis under warming and drought stress across cold-dry (CD), warm-humid (WH), warm (WR), and hot-dry (HD) zones. The effects of energy and water availability on the radial growth of P. yunnanensis varied in different sites and showed site-specific characteristics. The radial growth of P. yunnanensis in the CD zone benefited from rising temperatures, especially in the pre-growing season and core growing season. However the radial growth of P. yunnanensis in the WH zone was restricted by excess water in the core growing season. The radial growth of P. yunnanensis in the WR and HD zones became increasingly limited by temperature and drought stress, and the growth switched from responding to energy stress to moisture stress. The sensitivity of P. yunnanensis to climate factors in the warm-humid zone and humid seasons was relatively stable; in contrast, this species was vulnerable to warming and drought stress under harsh growth conditions and showed considerable instability. Intense warming in the future may cause a significant variation of tree growth response to climate. It would trigger a noticeable redistribution effect of energy and water availability on forest growth, which motivates assessments of climate-growth relationships, not only at large spatial scales, but also in specific sites. This research provides a basis for the adoption of effective forest management measures for specific sites according to their response characteristics associated with the distribution of climate drivers.