摘要
近年来全球干旱事件频发,树木的生长受到严重影响.本研究选取塞罕坝机械林场不同密度(1950、2355和2595株·hm-2)的华北落叶松人工林,采集树芯,计算单木胸高断面积增量(BAI),研究华北落叶松的径向生长对干旱事件的生态弹性(抵抗力、恢复力和恢复弹力).结果表明:干旱事件发生在2006-2010年、2015年和2018年.3次干旱期间,除第2次干旱时密度为2355株·hm-2的林分(抵抗力为0.69)外,其余林分的抵抗力为0.76～2.01,均表现出较高的抵抗力.密度为2595株·hm-2的华北落叶松的抵抗力随3次干旱事件显著降低,密度为1950和2355株·hm-2的华北落叶松的抵抗力随着3次干旱事件无显著变化.不同密度华北落叶松对同一次干旱事件的恢复力无显著差异,且均随干旱事件的发生呈显著上升趋势.不同密度华北落叶松对第1次干旱事件的恢复弹力无显著差异,密度为2595株·hm-2的华北落叶松对第二、三次干旱事件的恢复弹力分别显著低于密度为1950和2355株·hm-2的华北落叶松.密度为2595株·hm-2的华北落叶松在第2次干旱事件(2015年)时出现明显的生长衰退(生长变化率为-26.5％),而密度为1950和2355株·hm-2的华北落叶松无显著生长衰退.总的来说,密度为2595株·hm-2的华北落叶松对干旱事件的恢复弹力最差.
Abstract
In recent years,a surge in drought occurrences has dramatically impacted tree growth worldwide.We examined the ecological resilience of Larix principis-rupprechtii plantations with varying densities(1950,2355,and 2595 trees·hm-2)at the Saihanba Mechanical Forest Farm,by extracting the increment cores using the standard dendrochronological method to measure individual-tree basal area increments(BAI)as part of our assessment of ecological resilience,including resistance(R,),recovery(Rc),and resilience(Rs).The results showed that drought events occurred in 2006-2010,2015,and 2018.The R,for L.principis-rupprechtii plantations varied from 0.76 to 2.01 across three drought events,indicating generally high resistance,except for the plantation with 2355 trees·hm-2 during the second dry year(Rt=0.69).The Rt for the plantation with 2595 trees·hm-2 significantly decreased across all drought events,while no significant change was observed in the plantations with 1950 and 2355 trees·hm-2.The Rc showed no differences in response to a single drought event across plantation densities,with a significant upward trend for all the densities with each occurrence of drought event.There was no significant differ-ence in the resilience of different densities of L.principis-rupprechtii to the first drought event,whereas the planta-tion with 2595 trees·hm-2 exhibited significantly lower Rs during the second and third drought events compared with 1950 and 2355 trees·hm-2,respectively.During the 2015 drought event,plantation with 2595 trees·hm-2 experienced a significant growth decline(radial growth change rate was-26.5％),while no such decline was observed in the plantations with 1950 and 2355 trees·hm-2.Overall,the plantation with 2595 trees·hm-2 demon-strated the lowest resilience to drought events.
基金项目
河北农业大学引进人才专项(YJ201943)
河北省省属高等学校基本科研业务费研究项目(KY2022047)
亚太森林组织项目(2021SP2CHN)
维普
万方数据