Climate sensitivity and drought legacy of tree growth in plantation forests in northeast China are species and age-dependent

The occurrence,frequency,and severity of drought is accelerating under global warming.Understanding the vulnerability of plantation forests to climate change,particularly to drought events is critical to reveal the underlying mechanisms of tree resilience,recovery and acclimation which are important for plantation management.How stand age affects climate sensitivity of tree growth,as well as the direction,magnitude and duration of drought legacy in plantation forests in northeast China is still unclear.In this study we used MODIS derived NDVI time series with gridded climate data from 2000 to 2020 to fill this knowledge gap.The selected plantation forests were dominated by four coniferous species including Kore an pine(Pinus koraiensis),Scots pine(Pinus sylvestris),Japanese larch(Larix kaempferi),and Dahurian larch(Larix gmelinii).Results showed that the climate sensitivity of tree growth differed among species and age groups.Growth of Korean pine and Scots pine were mostly dependent upon precipitation,while growth of Japanese larch and Dahurian larch were determined primarily by temperature.Relatively old Japanese larch(21-40 years)and Dahurian larch trees(31-60 years)were more climate-sensitive than young conspecifics(10-20 years and 10-30 years respectively),while old Korean pine(41-60 years)and Scots pine trees(31-60 years)were less climate-sensitive than young conspecifics(10-40 years and 10-30 years respectively).Furthermore,the legacy of drought lasted one year for Korean pine and Japanese larch,two years for Dahurian larch and over three years for Scots pine.Old trees were more severely affected by drought,particularly Scots pine and Dahurian larch.The findings of the study can help improve plantation forest management for better adaptation to future climate change.