Hurricane Maria in the U.S. Caribbean: Disturbance Forces, Variation of Effects, and Implications for Future Storms

Abstract

The impact of Hurricane Maria on the U.S. Caribbean was used to study the causes of remotely-sensed spatial variation in the effects of (1) vegetation index loss and (2) landslide occurrence. The vegetation index is a measure of canopy ‘greenness’, a combination of leaf chlorophyll, leaf area, canopy cover and structure. A generalized linear model was made for each kind of effect, using idealized maps of the hurricane forces, along with three landscape characteristics that were significantly associated. In each model, one of these characteristics was forest fragmentation, and another was a measure of disturbance-propensity. For the greenness loss model, the hurricane force was wind, the disturbance-propensity measure was initial greenness, and the third landscape characteristic was fraction forest cover. For the landslide occurrence model, the hurricane force was rain, the disturbance-propensity measure was amount of land slope, and the third landscape characteristic was soil clay content. The model of greenness loss had a pseudo R2 of 0.73 and showed the U.S. Caribbean lost 31% of its initial greenness from the hurricane, with 51% lost from the initial in the Luquillo Experimental Forest (LEF) from Hurricane Maria along with Hurricane Irma. More greenness disturbance was seen in areas with less wind sheltering, higher elevation and topographic sides. The model of landslide occurrence had a pseudo R2 of 0.53 and showed the U.S. Caribbean had 34% of its area and 52% of the LEF area with a landslide density of at least one in 1 km2 from Hurricane Maria. Four experiments with parameters from previous storms of wind speed, storm duration, rainfall, and forest structure over the same storm path and topographic landscape were run as examples of possible future scenarios. While intensity of the storm makes by far the largest scenario difference, forest fragmentation makes a sizable difference especially in vulnerable areas of high clay content or high wind susceptibility. This study showed the utility of simple hurricane force calculations connected with landscape characteristics and remote-sensing data to determine forest susceptibility to hurricane effects.

Attitudes toward Residential Trees and Awareness of Tree Services and Disservices in a Tropical City

“…For example, residents seldom mentioned natural hazard moderation as a service and property damage due to natural hazards as a disservice. The surveys presented here, however, were performed before Puerto Rico suffered a devastating hurricane season in 2017, causing severe damage to urban green and grey infrastructure and a significant vegetation loss that has been estimated to be up to 31% in Puerto Rico and the U.S. Virgin Islands combined [119]. Experiences after the hurricanes, including the complexities of managing accumulated vegetation debris, the damage to power lines as a contributing factor to the complete collapse of the electric system, the damage of fallen trees and branches to private and public infrastructure, potentially influenced perceptions of tree disservices that could play a role in attitudes or management decisions [61].…”

Changes in mangrove tree mortality, forest canopy, and aboveground biomass accumulation rates following the 2017 hurricane season in Puerto Rico and the role of urbanization

“…Distance or wind energy also were not significant predictors of tree death, canopy loss, or recovery. This is surprising given the differences in wind power between Ponce and the northern coast sites (Van Beusekom et al 2018), which is consistent with a lower mortality at Ponce. This may reflect an inadequate tree sampling size and/or inaccuracy in the wind power model.…”

Understanding Tropical Forest Abiotic Response to Hurricanes using Experimental Manipulations, Field Observations, and Satellite Data

“…However, they appear to exhibit spatial smoothing horizontally and vertically across the landscape. The Luquillo Experimental Forest lost 51% of the initial greenness in hurricane María, but the U.S. Caribbean overall lost 31% of its initial greenness (Van Beusekom et al, 2018), so for the hurricane disturbance, including area outside the forest would be expected to smooth the hurricane signal. The solar radiation data were based on leaf area index (LAI) measured by the MODIS satellite at 500 m resolution.…”