北京园林树木遭受倒春寒冻害的春季温度特征分析

目的]探讨北京市园林树木遭受倒春寒冻害的春季温度特征。方法]根据温带倒春寒天气特征,对北京市的春季温度进行分析,并根据建成区公园树种组成分析倒春寒冻害的潜在威胁。结果]倒春寒在40°N附近温带地区的发生规律是在4月份正常春季物候开始之前气温提前回暖并持续5 d以上后,最低气温立刻骤降至0℃以下所发生的冻害。2011—2016年北京市频繁发生倒春寒迹象,但是与2011—2013年相比,2013—2016年倒春寒天气迹象中的低温天数有所减少。结论]北京市的多数落叶乔木都曾有遭受倒春寒冻害的记录,而常绿树种的受害比例较低。建议在未来北京城市绿化中多采用常绿树种代替落叶树种,以降低树木遭受倒春寒冻害的风险。

Analysis on the Characteristic of Spring Temperature Fluctuation during Late Spring Frost on Ornamental Trees in Beijing

Objective] To study city garden trees suffered frost in spring late spring coldness temperature characteristics in Beijing.Method] Spring temperature in Beijing was analyzed according to the characteristics of late spring frost (LSF) in temperate area in 2011-2016.The potential threat of LSF was predicted on ornamental trees based on the component of their species in large parks of constructed areas of Beijing.Result] LSF usually resulted in significant effect on trees by a sudden decline to temperature to sub-zero following a warm spell for at least five days in temperate forests at around the north latitude of 40 ° before the start of spring phenology.Accordingly,LSF tended to occur frequently in 2011-2016.Compared to days with sub-zero temperature during possible LSF in 2011-2013,that in 2014-2016 tended to decline.Trees from the genera for many ornamental trees in Beijing had been recorded to suffer LSF,which had less impact on evergreen species than on deciduous species in past records.Conclusion] It is suggested to use more evergreen trees than deciduous trees for the construction of urban greening in Beijing to cope with more possible LSFs in future.