DOI: 10.5061/dryad.7pvmcvf39
title: Data from: Aridity and forest age mediate landscape scale patterns of tropical forest resistance to cyclonic storms

description: Cyclonic storms, or hurricanes, are expected to intensify as ocean heat
 energy rises due to climate change. Ecological theory suggests that
 tropical forest resistance to hurricanes should increase with forest age
 and wood density. However, most data on hurricane effects on tropical
 forests come from a limited number of well-studied long-term monitoring
 sites, restricting our capacity to evaluate the resistance of tropical
 forests to hurricanes across broad environmental gradients. In this study,
 we assessed whether forest age and aridity mediate the effects of
 hurricanes Irma and Maria in Puerto Rico, Vieques and Culebra islands. We
 leveraged functional trait data for 410 tree species, remotely sensed
 measurements of canopy height and cover, along with data on forest stand
 characteristics of 180 out of 339 forest monitoring plots, each covering
 an area of 0.067 ha. The plots represent a broad mean annual precipitation
 (MAP) gradient from 701 to 4598 mm and a complex mosaic of forest age from
 5 to around 85 years since deforestation. Hurricanes resulted in a 25%
 increase in basal area mortality rates, a 45% decrease in canopy height,
 and a 21% reduction in canopy cover. These effects intensified with forest
 age, even after considering proximity to the hurricane path. The links
 between forest age and hurricane disturbances were likely due the
 prevalence of tall canopies. Tall forest canopies were strongly linked
 with low community-weighted wood density (WD). These characteristics were
 on average more common in moist and wet forests (MAP &gt; 1250 mm).
 Conversely, dry forests were dominated by short species with high wood
 density (WD &gt; 0.6 g cm-3) and did not show significant increases in
 basal area mortality rates after the hurricanes. Synthesis: Our findings
 show that in dry forests selection towards drought tolerant traits, such
 as short stature and dense wood, enhances resistance to hurricanes.
 However, forest age modulated responses to hurricanes, with older forests
 being less resistant across the islands. This evidence highlights the
 importance of considering the intricate links between ecological
 succession and plant function when forecasting tropical forests responses
 to increasingly strong hurricanes.
description: # Data from: Aridity and forest age mediate landscape scale patterns of
 tropical forest resistance to cyclonic storms
 [https://doi.org/10.5061/dryad.7pvmcvf39](https://doi.org/10.5061/dryad.7pvmcvf39) ## Description of the data and file structure #### Readme file for: Vargas G., G., Marcano-Vega H, Ruzycki T, Wood T.E., Anderegg W\.R.L., Powers J.S. & E.H. Helmer. Aridity and forest age mediate landscape scale patterns of tropical forest resistance to cyclonic storms. Journal of Ecology: accepted 2023 August 22. **Data description:** The following datasets contains functional composition metrics: community weighted means and community weighted standard deviation, as well as rate of change of community weighted means (*i.e.*, trait velocities). This data was used to characterize the effects of hurricanes on changes in basal area forest mortality rates derived from the Forest Inventory Analysis data for Puerto Rico, and changes in canopy structure. **Disclaimer:** Due to the sensitive nature of some portions of the data used in the study and concerns regarding landowner privacy rights, I believe that certain portions of the dataset should be exempt from public availability under the United States Food Security Act of 1985 (P.L. 99-198, also known as the 1985 U.S. Farm Bill). Specifically, any data that can be associated with the FIA plot geolocation should be considered confidential and protected from public disclosure. This includes any data derived from geospatial information that could potentially be used to identify the plot location. This includes: Aridity, minimum standardized precipitation evapotranspiration index, canopy cover, canopy height, topographic slope, forest stand age, and distance to the hurricane track. **Data available:** Three datasets that encompass the community weighted mean trait values, the the trait velocities, and the hydraulic traits collected for this study. ### Files and variables #### File: cwm\_PR.csv **Description:** FIA plot community weighted mean trait values. Each column is described below. Empty values are set as "NA". ##### Variables * plot_code_unique: unique plot identifier created in this study using FIA data columns STATECD-COUNTYCD-PLOT. * MEASYEAR: Year the plot was measured. * MEASMON: Month the plot was measured. * MEASDAY: Day the plot was measured. * date: Date in the format YYYY-MM-DD. * STATECD: Code in the FIA database associated with a state (72 = Puerto Rico). * COUNTYCD: Code in the FIA database associated with a county. * PLOT: Plot number. * lifezone: Climatic lifezone obtained from Helmer et al. (2023). * geology_3class: Soil geologic class obtained from Helmer et al. (2023). * richness: species richness. * shannon: shannon diversity index. * hurricane_disturbance: whether the community weighted mean was calculated for before or after the hurricanes. * DE_perc: percentage of deciduous species. * EV_perc: percentage of evergreeen species. * FD_perc: percentage of facultative deciduous species. * INT_perc: percentage of introduced species. * NAT_perc: percentage of native species. * Wood_Density.rep: proportion of plot's total basal area represented in the community-weighted trait moments calculations for wood density. * Wood_Density.cwm: community weighted wood density in gcm^-3. * Wood_Density.cwsd: community weighted standard deviation for wood density. * SLA_m2kg.rep: proportion of plot's total basal area represented in the community-weighted trait moments calculations for specific leaf area. * SLA_m2kg.cwm: community weighted specific leaf area in m2kg^-1. * SLA_m2kg.cwsd: community weighted standard deviation for specific leaf area. * tlp_mpa.rep: proportion of plot's total basal area represented in the community-weighted trait moments calculations for the water potential at turgor loss point. * tlp_mpa.cwm: community weighted water potential at turgor loss point in MPa. * tlp_mpa.cwsd: community weighted standard deviation for the water potential at turgor loss point. * p50_mpa.rep:  proportion of plot's total basal area represented in the community-weighted trait moments calculations for the water potential at 50% accumulation of embolisms or loss in xylem hydraulic conductivity. * p50_mpa.cwm: community-weighted mean for the water potential at 50% accumulation of embolisms or loss in xylem hydraulic conductivity. * p50_mpa.cwsd: community-weighted standard deviation for the water potential at 50% accumulation of embolisms or loss in xylem hydraulic conductivity. #### File: delta\_CWtraits.csv **Description:** trait velocities and proyected community weighted mean trait values before and after the impact of the hurricanes. Empty values are set as "NA". ##### Variables * plot_code_unique: unique plot identifier created in this study using FIA data columns STATECD-COUNTYCD-PLOT. Links to the community weighted mean trait database. * lifezone: Climatic lifezone obtained from Helmer et al. (2023). * geology_3class: Soil geologic class obtained from Helmer et al. (2023). * delta_wom.Wood_Density.cwm: community weighted wood density trait velocity before the impact of the hurricane. * delta_wm.Wood_Density.cwm: community weighted wood density trait velocity after the impact of the hurricane. * t_wom.Wood_Density.cwm: projected community weighted wood density in gcm^-3 before the impacted of the hurricane. * t_wm.Wood_Density.cwm: projected community weighted wood density in gcm^-3 after the impacted of the hurricane. * delta_wom.SLA_m2kg.cwm: community weighted specific leaf area trait velocity before the impact of the hurricane. * delta_wm.SLA_m2kg.cwm: community weighted specific leaf area trait velocity after the impact of the hurricane. * t_wom.SLA_m2kg.cwm: projected community weighted specific leaf area in m2kg^-1 before the impacte of the hurricane. * t_wm.SLA_m2kg.cwm: projected community weighted specific leaf area in m2kg^-1 after the impacte of the hurricane. * delta_wom.tlp_mpa.cwm: community weighted turgor loss point trait velocity before the impact of the hurricane. * delta_wm.tlp_mpa.cwm: community weighted turgor loss point trait velocity after the impact of the hurricane. * t_wom.tlp_mpa.cwm: projected community weighted water potential at turgor loss point in MPa before the impact of the hurricane. * t_wm.tlp_mpa.cwm: projected community weighted water potential at turgor loss point in MPa after the impact of the hurricane. * delta_wom.p50_mpa.cwm: community weighted water potential at 50% accumulation of embolisms trait velocity before the impact of the hurricane. * delta_wm.p50_mpa.cwm: community weighted water potential at 50% accumulation of embolisms trait velocity after the impact of the hurricane. * t_wom.p50_mpa.cwm: projected community-weighted mean for the water potential at 50% accumulation of embolisms or loss in xylem hydraulic conductivity before the impact of the hurricane. * t_wm.p50_mpa.cwm: projected community-weighted mean for the water potential at 50% accumulation of embolisms or loss in xylem hydraulic conductivity after the impact of the hurricane. #### File: PR\_hydraulic\_traits.csv **Description:** Hydraulic traits collected in this study. Empty cells, coded as "NA", mean that for a given trait data are not available and were not collected for a species ##### Variables * species_name: Species binomial name according to USDA plant species classification database ([https://plants.usda.gov/home](https://plants.usda.gov/home)). * SPCD: Species numerical code in line with the FIA database. * Symbol: Species four letter symbol where the first two letters are from the genus and the last two from the specific epithet. For example, Alchornea latifolia will be ALLA. * Origin: Whether the species is introduced or native. * Height_m: Average height of the trees sampled for the plant hydraulic traits. * Height_max: Maximum height obtained from measurements in the FIA database. * Deciduous: Whether the species is drought deciduous, evergreen or facultative deciduous as described in Helmer et al. 2023. * Family: Taxonomic family identity according to USDA plant species classification database ([https://plants.usda.gov/home](https://plants.usda.gov/home)). * Nfixer: Whether the is species is a nitrogen fixer or not as described in Helmer et al. 2023. * tlp_mpa: Mean water potential at turgor loss point in MPa. * method_tlp: method for collection TLP, where PVC indicates pressure volume curve. * p50_mpa: the water potential at 50% accumulation of embolisms in leaf veins in MPa. * method_p50: method for collecting P50, where OV indicates optical vulnerability curves. ## Access information Data was derived from the following sources: * This study. * Helmer, E. H., Kay, S. L., Marcano-Vega, H., Powers, J. S., Wood, T. E., Zhu, X., Gwenzi, D., & Ruzycki, T. S. (2023). Forest age map, tree species traits and Landsat phenology metrics for Puerto Rico and the U.S. Virgin Islands. Forest Service Research Data Archive. [https://doi.org/10.2737/RDS-2023-0004](https://doi.org/10.2737/RDS-2023-0004) * Vargas G., German et al. (2023). Leaf habit affects the distribution of drought sensitivity but not water transport efficiency in the tropics [Dataset]. Dryad. [https://doi.org/10.5061/dryad.1ns1rn8x4](https://doi.org/10.5061/dryad.1ns1rn8x4) * Smith-Martin, Chris et al. (2022). Hydraulic traits are not robust predictors of tree species stem growth during a drought in a wet tropical forest [Dataset]. Dryad. [https://doi.org/10.5061/dryad.fn2z34tzd](https://doi.org/10.5061/dryad.fn2z34tzd)