Effects of postfire climate and seed availability on postfire conifer regeneration.
Effects of postfire climate and seed availability on postfire conifer regeneration.
复制标题
火后气候和种子可用性对火后针叶树再生的影响。
DOI：
10.1002/eap.2280
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Thorne,JamesH
中科院分区：
文献类型：
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作者：
Stewart,JosephAE;vanMantgem,PhillipJ;Young,DerekJN;Shive,KristenL;Preisler,HaiganoushK;Das,AdrianJ;Stephenson,NathanL;Keeley,JonE;Safford,HughD;Wright,MicahC;Welch,KevinR;Thorne,JamesH
在美国西部的许多森林类型中，大规模、严重的火灾越来越频繁，导致数万公顷的树木死亡。这些地区的针叶树再生受到限制，因为种子必须经过很长的距离才能到达大片烧毁的土地的内部，而且越来越炎热和干燥的条件危及植被的建立。为了更好地为美国加州低海拔森林的灾后管理提供信息，我们从2004-2012年燃烧的19场野火中的1，234个研究地块收集了5年的灾后恢复数据，并从216个种子坠落陷阱中收集了18年的种子生产数据（1999-2017）。我们使用这些数据结合空间广泛的气候，地形，森林组成和烧伤严重程度表面构建分类特定的，空间明确的针叶树再生模型，将气候条件和种子可用性在火灾后恢复窗口。我们发现，在考虑其他预测因子后，火灾后和历史降水是再生的强预测因子，这表明火灾后的水分条件和历史气候的生物惯性的直接影响可能在再生中发挥作用。或者，火后再生可能只是由火后气候驱动，与历史气候的明显关系可能是虚假的。估计火灾后种子可用性的再生敏感性最强的冷杉和所有针叶树相结合，较弱的松树。种子生产表现出很高的时间变异性与种子生产变化超过两个数量级之间的年份。我们的模型表明，在干旱火灾后针叶树再生下降最显着在低到中等海拔的森林。这些发现增强了我们对预测和历史记录的树木分布变化的机械理解。
Large, severe fires are becoming more frequent in many forest types across the western United States and have resulted in tree mortality across tens of thousands of hectares. Conifer regeneration in these areas is limited because seeds must travel long distances to reach the interior of large burned patches and establishment is jeopardized by increasingly hot and dry conditions. To better inform postfire management in low elevation forests of California, USA, we collected 5‐yr postfire recovery data from 1,234 study plots in 19 wildfires that burned from 2004–2012 and 18 yrs of seed production data from 216 seed fall traps (1999–2017). We used these data in conjunction with spatially extensive climate, topography, forest composition, and burn severity surfaces to construct taxon‐specific, spatially explicit models of conifer regeneration that incorporate climate conditions and seed availability during postfire recovery windows. We found that after accounting for other predictors both postfire and historical precipitation were strong predictors of regeneration, suggesting that both direct effects of postfire moisture conditions and biological inertia from historical climate may play a role in regeneration. Alternatively, postfire regeneration may simply be driven by postfire climate and apparent relationships with historical climate could be spurious. The estimated sensitivity of regeneration to postfire seed availability was strongest in firs and all conifers combined and weaker in pines. Seed production exhibited high temporal variability with seed production varying by over two orders of magnitude among years. Our models indicate that during droughts postfire conifer regeneration declines most substantially in low‐to‐moderate elevation forests. These findings enhance our mechanistic understanding of forecasted and historically documented shifts in the distribution of trees.