Leitold V; Morton D; Martinuzzi S; Paynter I; Uriarte M; Keller M; Ferraz A; Cook B; Corp L; González G
El Verde Ridge; El Verde Valley
March 5, 2017
March 15, 2020
Hurricane Maria (Category 4) snapped and uprooted canopy trees, removed large branches, and defoliated vegetation across Puerto Rico. The magnitude of forest damages and the rates and mechanisms of forest recovery following Maria provide important benchmarks for understanding the ecology of extreme events. We used airborne lidar data acquired before (2017) and after Maria (2018, 2020) to quantify landscape-scale changes in forest structure along a 439-ha elevational gradient (100 to 800 m) in the Luquillo Experimental Forest. Damages from Maria were widespread, with 73% of the study area losing ≥1 m in canopy height (mean = -7.1 m). Taller forests at lower elevations suffered more damage than shorter forests above 600 m. Yet only 13% of the study area had canopy heights ≤2 m in 2018, a typical threshold for forest gaps, highlighting the importance of damaged trees and advanced regeneration on post-storm forest structure. Heterogeneous patterns of regrowth and recruitment yielded shorter and more open forests by 2020. Nearly 45% of forests experienced initial height loss (<-1 m, 2017-2018) followed by rapid height gain (>1 m, 2018-2020), whereas 21.6% of forests with initial height losses showed little or no height gain, and 17.8% of forests exhibited no structural changes >|1| m in either period. Canopy layers <10 m accounted for most increases in canopy height and fractional cover between 2018-2020, with gains split evenly between height growth and lateral crown expansion by surviving individuals. These findings benchmark rates of gap formation, crown expansion, and canopy closure following hurricane damage. Included in the attached zip file are four TIF and four KML files.
Airborne lidar data over the Luquillo Experimental Forest were collected using the G-LiHT Airborne Imager (Cook and others, 2013) in three separate campaigns. Data were acquired in March 2017 (pre-hurricane), April 2018 (7 months post-hurricane), and March 2020 (2.5 years post-hurricane), with time intervals between lidar data collections of 13 months (2017-2018) and 23 months (2018-2020). All three airborne surveys used the same G-LiHT v2 instrumentation, including two VQ-480i scanning lidars (Riegl Laser Measurement Systems, Horn Austria). Data were acquired from a nominal flying altitude of 335 m AGL and 130 knots, which produced approximately 10 cm laser footprints (1550 nm) and an average sampling density of 12 laser pulses m-2. Pre- and post-flight boresight alignment of the lidar sensors ensured vertical accuracies of <10 cm (1 sigma) for all three campaigns. G-LiHT terrain and canopy height products are openly available online from the G-LiHT data portal (https://gliht.gsfc.nasa.gov).
NASA Goddard Space Flight Center
US Department of Energy, USDA Forest Service, US Department of Interior, NASA
Morton, Doug - NASA ([email protected])
Leitold V; Morton D; Martinuzzi S; Paynter I; Uriarte M; Keller M; Ferraz A; Cook B; Corp L; González G (2021): Canopy damage and recovery following Hurricane Maria using multitemporal lidar data, Mar/2017 - Mar/2020, Puerto Rico. 1.0. NGEE Tropics Data Collection. (dataset). http://dx.doi.org/10.15486/ngt/1797399
Funding for this study was provided by the US Department of Energy (Terrestrial Ecosystem Science Program, Interagency Agreements with the US Forest Service # 89243018SSC000012 and with NASA # 89243018SSC000013, and support to VL, DCM, and MK from the Next Generation Ecosystem Experiment-Tropics, Office of Biological and Environmental Research). Additional funding was provided by the USDA Forest Service, US Department of Interior (National Institute of Food and Agriculture # 2018-67030-28124), and NASA. The USDA Forest Service International Institute of Tropical Forestry, Luquillo LTER, and NASA’s Airborne Science Program provided logistical support.
Data Link: Download Dataset
Leitold, V., Morton, D.C., Martinuzzi, S. et al. Tracking the Rates and Mechanisms of Canopy Damage and Recovery Following Hurricane Maria Using Multitemporal Lidar Data. Ecosystems 25, 892–910 (2022). https://doi.org/10.1007/s10021-021-00688-8