20th Century hurricanes leave long lasting legacies on tropical forest structure and composition
Abstract
Projected increases in cyclonic storm intensity under a warming climate will have profound effects on many coastal forests, with the potential to increase the dominance of tree species resistant to storms and perpetuate shorter forest structures with lower biomass. Nevertheless, evidence of any selective, long-term effects of hurricane disturbance on forest composition and structure remains scant. Here we employ a novel machine learning framework and high-resolution aerial photos collected over the 115 Km2 of El Yunque National Forest in Puerto Rico to map two hurricane-dependent woody species: a highly wind-resistant palm and a pioneer tree species that depends on canopy damage for persisting in the landscape. We use these maps together with LiDAR coverage of the forest to examine the effects of topographic exposure to two 20th century hurricanes, Hugo (1989) and Georges (1998), on current forest structure and species composition. We find that forests in areas with greater historical hurricane exposure had shorter canopies and higher densities of both species. Our results demonstrate that cyclonic storms select for windstorm resistance and influence forest structure. A change in storm disturbance regimes under a warming climate may therefore expand the distribution of shorter forests dominated by a few pioneers and wind-resistant species.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMB059...01U
- Keywords:
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- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCES;
- 0426 Biosphere/atmosphere interactions;
- BIOGEOSCIENCES;
- 0429 Climate dynamics;
- BIOGEOSCIENCES;
- 0439 Ecosystems;
- structure and dynamics;
- BIOGEOSCIENCES