DOI: 10.5061/dryad.fbg79cns5
title: Data for: Landscape scale variation in the hydrologic niche of California coast redwood

description: Topoclimatic diversity within forest landscapes can underlie variation in
 water availability, which may correspond to patterns in habitat
 suitability of tree species with differing hydrologic niches. However, the
 trade-off between the collection of data at a fine grain size over large
 spatial extents has limited comprehensive analyses of landscape scale
 variation in habitat suitability. We present a fine scale analysis of the
 roles of topographic gradients in moisture availability, soil water
 storage, and fog frequency in the spatial pattern of habitat suitability
 for coast redwood (Sequoia sempervirens), at 10 m resolution across 34,800
 hectares and three landscapes spanning approximately one-third of
 redwood’s latitudinal range. A new 10 m resolution presence-absence map
 derived from airborne imaging spectroscopy was used to characterize
 current redwood distributions in three landscapes. Access to belowground
 moisture was assessed through four measures calculated from a
 high-resolution LiDAR digital elevation model, soil water storage was
 mapped from the USDA Soil Survey Geographic Database, and fog frequency
 was calculated from MODIS cloud cover data. Access to belowground moisture
 and fog predicted variation in suitability as redwood habitat from 22–75%
 and predicted redwood presence and absence at 10 m resolution with 63–74%
 accuracy. Across all three landscapes, redwood density consistently
 decreased with increasing interpolated height above a stream (IHAS), but
 the role of other predictors varied among the sites. Our results challenge
 previous assumptions that redwood habitat suitability within much coarser
 resolutions (800 m x 800 m) can be described by a single value. The
 elevated habitat suitability of sites close to streams suggests that these
 sites should be evaluated for their potential to become microrefugia
 within landscapes that may become climatically unsuitable for redwoods at
 a regional scale. 
description: This is the dataset corresponding to the manuscript: Francis,
 E.J., Asner, G.P., Mach, K.J., and Field, C.B. 2020. Landscape Scale
 Variation <br> in the Hydrologic Niche of California Coast Redwood.
 Ecography. doi: 10.1111/ecog.05080. This dataset
 contains maps of redwood presence and absence and six measures of access
 to moisture in three redwood forest landscapes <br> in California.
 All data are provided as GeoTiff files. Four of the six
 measures of access to moisture have been calculated from a high-resolution
 LiDAR-derived digital elevation model (DEM) collected by <br> the
 Global Airborne Observatory (GAO) from each site. 
 Measures calculated from the GAO DEM include: Interpolated height
 above a stream (IHAS), Topographic Wetness Index (TWI), Curvature, and
 Heat load index (HLI)<br> Fog frequency was calculated from NASA
 MODIS (Moderate Resolution Imaging Spectroradiometer) Data on Cloud
 Cover.<br> Soil available water storage was taken from the US
 Department of Agriculture Natural Resource Conservation (USDA NRCS) Soil
 Survey Geographic Database. Detailed methods describing
 how each measure of access to moisture was produced are provided in the
 corresponding publication and additional details are <br> provided
 in Appendix S1 Supplementary Text, Supplementary Methods for the
 corresponding manuscript. The maps of redwood presence
 and absence have been produced through a trained classification of
 airborne imaging spectroscopy data collected by the GAO. <br>
 Detailed methods on the collection of the data, the development of the
 presence absence maps, and specification of map performance (overall
 accuracy, true positive rate, false positive rate, and kappa statistic)
 are provided in the following publication:<br> Francis, E.J., and
 Asner, G.P. 2019. High-Resolution Mapping of Redwood (Sequoia
 sempervirens) Distributions in Three Californian Forests. <br>
 Remote Sensing. 11(3): 351, doi:10.3390/rs11030351.
description: Details are provided in the README.txt file; please read the file
 prior to use of the data.