West Florida Research and Education Center, University of Florida, Milton, Florida, United States of America.
Department of Biological and Environmental Sciences, Alabama A&M University, Normal, Alabama, United States of America.
PLoS One. 2021 Jan 6;16(1):e0243362. doi: 10.1371/journal.pone.0243362. eCollection 2021.
Threats posed by windstorms are an increasing concern to forest managers in the southern United States (US). Studies suggest that the southern US will experience an increase in the occurrence as well as the intensity of windstorms, such as hurricanes, in the future. However, forest managers may have difficulty preparing for this future because there is limited understanding of how windstorms affect the structure and composition of forests over the long term. In this study, we evaluated the impacts of Hurricane Ivan, which made landfall in September 2004 near Gulf Shore, Alabama, impacting forests in the western Florida Panhandle and southwestern Alabama. We acquired the United States Department of Agriculture Forest Inventory and Analysis (FIA) plot data available for the period from 2002 to 2018 for the Ivan-affected area and classified the plots into 4 categories: (1). ND (No Disturbance), (2). NDBH (No Disturbance but Harvested), (3). ID (Disturbance caused by Hurricane Ivan), and (4). IDAH (Disturbance caused by Hurricane Ivan and Harvested). The plots that were damaged by Hurricane Ivan (ID and IDAH plots) had significantly (α = 0.05) (1) higher basal area, (2) higher quadratic mean diameter and height, (3) more diverse tree species composition (species richness and Shannon diversity index), (4) denser stocking of seedling and saplings, (5) lower proportion of dead trees or saplings, and (6) higher live aboveground biomass than the plots that were not damaged by the hurricane (ND and NDBH plots). Diverse stands were not necessarily more windstorm resistant. Species diversity in the overstory may not improve forest resistance to hurricane damage but may improve its resilience following the hurricane. The study suggests that managing stand structure through density management and stand improvement could be critical to windstorm resilience and resistance in the southern US forests.
美国南部的森林管理者越来越关注风灾带来的威胁。研究表明，未来美国南部地区发生飓风等强风灾害的频率和强度都将增加。然而，由于对风灾如何长期影响森林结构和组成的了解有限，森林管理者可能难以为此做好准备。在这项研究中，我们评估了 2004 年 9 月飓风伊凡（Ivan）登陆美国阿拉巴马州格尔夫海岸（Gulf Shore）时对佛罗里达州狭长地带西部和阿拉巴马州西南部森林的影响。我们获得了美国农业部林务局森林清查和分析（FIA）在伊凡影响地区 2002 年至 2018 年期间可用的测树数据，并将这些样地分为 4 类：（1）ND（无干扰），（2）NDBH（无干扰但已收获），（3）ID（飓风伊凡造成的干扰），和（4）IDAH（飓风伊凡造成的干扰和已收获）。受飓风伊凡破坏的样地（ID 和 IDAH 样地）的基底面积显著更高（α = 0.05），（1）平均胸径和树高更高，（2）树种组成（物种丰富度和香农多样性指数）更多样化，（3）幼苗和幼树密度更大，（4）枯树或幼树比例更低，（5）活体地上生物量更高。未受飓风破坏的样地（ND 和 NDBH 样地）的基底面积、（2）平均胸径和树高、（3）树种组成、（4）幼苗和幼树密度、（5）枯树或幼树比例和（6）活体地上生物量都低于受飓风破坏的样地。多样的林分不一定更能抵御风灾。上层林分的物种多样性可能不会提高森林抵御飓风破坏的能力，但可能会提高其在飓风后的恢复能力。研究表明，通过密度管理和林分改良来管理林分结构可能对美国南部森林的风灾抵御和恢复能力至关重要。
