摘要
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Key message Qinghai spruce at different elevations showed inconsistent growth trends and responses to climate change. Under global warming, mountains in arid and semi-arid regions have become the main ecologically vulnerable areas...
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Key message Qinghai spruce at different elevations showed inconsistent growth trends and responses to climate change. Under global warming, mountains in arid and semi-arid regions have become the main ecologically vulnerable areas affected by climate change. Northwest China has experienced intermittent climate change in recent decades that can be divided into three periods: steady change (T1), a rapid temperature increase (T2) and a warming hiatus (T3). How this unsteady change in climate has affected the growth and response of trees at different elevations in the region remains unclear. Therefore, we established three standard chronologies of Qinghai spruce (Picea crassifolia) at high, middle and low elevations in the central Qilian Mountains to investigate its responses during different periods. We drew three primary conclusions. First, trees at high elevations are primarily impacted by higher temperatures, while trees at middle and low elevations are mainly impacted by water stress due to drought. Second, trees at the three elevations showed unstable responses to all temperature factors, while those at the middle and low elevations showed relatively stable responses to total precipitation in the late growing season of the previous year. Third, different interannual growth variations were observed at the three elevations, indicating a nonsignificant change at high elevations and significant declines at middle and low elevations. At the same time, growth patterns were different for the three climatic periods. Therefore, the dominant conifers at different elevations of the Qilian Mountains showed inconsistent responses during different periods. It is necessary to take effective measures to manage forest ecosystems according to spatial and temporal adaptation strategies for climate change.
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