Long-term effects of catastrophic wind on southern US coastal forests: Lessons from a major hurricane.

Ajay Sharma,Luben D Dimov,Santosh K Ojha,Jarek Nowak,Jason G Vogel,Runguo Zang

doi:10.1371/journal.pone.0243362

Abstract

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.

Highlights

Forests of the southern United States (US) are among the most ecologically and economically important forests in the world
The trees removed in IDAH plots in 2009 following Hurricane Ivan represented salvage harvest on 22% of the plots while remaining plots were either clear cut or partially harvested
The high percent of dead saplings in NDBH plots (29.8%) in 2009 is likely because of the residual damage caused by the harvests (Fig 2B)

Summary

Introduction

Forests of the southern US are among the most ecologically and economically important forests in the world. Being among the most productive forests in the world, southern US forests yield about 18% of the world’s pulpwood and 7% of its industrial wood, while comprising just 2% of the world’s forest area [1]. Forestry and the forest products industry generated $251.1 billion, or over 2.7% of the regional economic output, and supported 2% of all jobs in the southern US in 2012 [1]. The southern US region includes the North American Coastal Plain (NACP), a global biodiversity hotspot [3]. These forests protect water quality, prevent erosion, help regulate climate, and provide opportunities for millions of people to hike, hunt, and experience natural beauty

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Conclusion