Browsing by Author "Guzman Q., J. Antonio"

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    Data and Code for Mechanistic links between physiology and spectral reflectance enable pre-visual detection of oak wilt and drought stress
    (2024-01-04) Sapes, Gerard; Schroeder, Lucy; Scott, Allison; Clark, Isaiah; Juzwik, Jennifer; Montgomery, Rebecca; Guzman Q., J. Antonio; Cavender-Bares, Jeannine; gsapes@ufl.edu; Sapes, Gerard; University of Minnesota; University of Florida; Northern Research Station, USDA Forest Service
    Tree mortality due to global change-including range expansion of invasive pests and pathogens- is a paramount threat to forest ecosystems. Oak forests are among the most prevalent and valuable ecosystems both ecologically and economically in the United States. There is increasing interest in monitoring oak decline and death due to both drought and the oak wilt pathogen (Bretziella fagacearum). We combined anatomical and ecophysiological measurements with spectroscopy at leaf, canopy, and airborne levels to enable differentiation of oak wilt and drought, and detection prior to visible symptom appearance. We performed an outdoor potted experiment with Quercus rubra saplings subjected to drought stress and/or artificially inoculated with the pathogen to detect and distinguish both types of stressors. We also performed a field experiment where we validated the capacity of spectral reflectance models to predict physiological status and distinguish oak wilt from healthy trees. The data and code provided here address these goals.
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    Data and code for spectral canopy transmittance in diverse tree communities
    (2024-12-02) Williams, Laura J.; Kovach, Kyle R.; Guzman Q., J. Antonio; Stefanski, Artur; Bermudez, Raimundo; Butler, Ethan E.; Glenn-Stone, Catherine; Hajek, Peter; Klama, Johanna; Moradi, Aboubakr; Park, Maria H.; Scherer-Lorenzen, Michael; Townsend, Philip A.; Reich, Peter B.; Cavender-Bares, Jeannine; Schuman, Meredith C.; laura.williams@westernsydney.edu.au; Williams, Laura
    Light may shape forest function not only as a source of energy or a cause of stress but also as a context cue: plant photoreceptors can detect specific wavelengths of light, and plants use this information to assess their neighborhoods and adjust their patterns of growth and allocation. Here, we examined how the spectral profile of light (350-2200 nm) transmitted through tree canopies differs among communities within three tree diversity experiments on two continents (200 plots each planted with one to 12 tree species). This dataset includes data and metadata on canopy transmittance and leaf area index (LAI) measured on these plots as well as leaf-level transmittance measured for each species in monoculture plots. Data processing code and example analysis code are also provided.