Abstract
Betula platyphylla and Betula costata are impor-tant species in mixed broadleaved-Korean pine(Pinus koraiensis)forests.However,the specific ways in which their growth is affected by warm temperatures and drought remain unclear.To address this issue,60 and 62 tree-ring cores of B.platyphylla and B.costata were collected in Yichun,China.Using dendrochronological methods,the response and adap-tation of these species to climate change were examined.A"hysteresis effect"was found in the rings of both species,linked to May-September moisture conditions of the previ-ous year.Radial growth of B.costata was positively corre-lated with the standardized precipitation-evapotranspiration index(SPEI),the precipitation from September to October of the previous year,and the relative humidity in October of the previous year.Growth of B.costata is primarily restricted by moisture conditions from September to Octo-ber.In contrast,B.platyphylla growth is mainly limited by minimum temperatures in May-June of both the previ-ous and current years.After droughts,B.platyphylla had a faster recovery rate compared to B.costata.In the context of rising temperatures since 1980,the correlation between B.platyphylla growth and monthly SPEI became positive and strengthened over time,while the growth of B.costata showed no conspicuous change.Our findings suggest that the growth of B.platyphylla is already affected by warm-ing temperatures,whereas B.costata may become limited if warming continues or intensifies.Climate change could disrupt the succession of these species,possibly accelerat-ing the succession of pioneer species.The results of this research are of great significance for understanding how the growth changes of birch species under warming and dry-ing conditions,and contribute to understanding the struc-tural adaptation of mixed broadleaved-Korean pine(Pinus koraiensis)forests under climate change.
基金项目
Key Project of the China National Key Research and Development Program(2021YFD2200401)
National Natural Science Foundation of China(42177421)
National Natural Science Foundation of China(41877426)
维普
万方数据