DOI: 10.5061/dryad.sqv9s4n9m
title: Potential alpine habitat in the western USA based on treeline elevation

description: Purpose: create a map of potential alpine habitat in the western USA as a
 basis for future studies in ecology and biogeography. Location: all
 mountains in the continental USA west of 104° longitude. Procedure:
 manually identify treeline elevations; interpolate a surface of these
 elevations; intersect the surface with a 90-m resolution DEM; record all
 areas above these elevations as projected alpine habitat; for display, map
 the area recorded as alpine at 90-m resolution. Products: a map for
 display; a dataset of elevations of treeline at 268 points on 66 mountain
 ranges in the western USA (61) and Canada (5); a dataset of points
 recorded as above treeline at 90-m resolution.
description: All mountain ranges in the western USA and southern Canada were
 examined. The relatively continuous Rocky Mountains were subdivided
 according to named ranges or previously identified regions. These totaled
 61 in the USA and 5 in Canada. The Canadian ranges were included to
 improve the interpolation at the northern end. At each
 range at least four treeline ecotone points were selected, one each on the
 north, east, south, and western edges of the range. Additional points were
 recorded on larger ranges such as the Sierra Nevada. The points were
 selected on Google Earth imagery by Malanson, who is experienced in
 treeline research (e.g., Alftine and Malanson 2004, Malanson and Butler
 1994, Malanson et al. 2001, 2007, 2009, 2012, 2019, 2023, Smith-McKenna et
 al. 2014, Grafius and Malanson 2015, Weiss et al. 2015). The uppermost
 continuous forest cover was identified for the point. If an extensive zone
 of krummholz was observed, its elevational midpoint was identified. The
 elevation, latitude, and longitude of each was recorded.
 The points were interpolated to create an elevational surface
 across the region. Both inverse distance weighting and kriging were
 applied. The kriging surface had more error at the original points and was
 rejected for further use. The IDW surface was intersected with the USGS
 90-meter DEM (https://www.sciencebase.gov/catalog/item/542aebf9e4b057766eed286a). All 90-m points above the IDW surface were recorded as potential alpine habitat. To create a map for outreach and display, projected alpine habitat was mapped at 90 m spatial resolution based on the above record. The potential alpine habitat cells were mapped as red against a gray-shaded relief map of 11 western states. <strong>References</strong> Alftine KJ, Malanson GP. 2004. Directional positive feedback and pattern at an alpine tree line. Journal of Vegetation Science 15:3-12. Grafius D, Malanson GP. 2015. Biomass distributions in dwarf tree, krummholz, and tundra vegetation in the alpine treeline ecotone. Physical Geography 36: 337-352. Malanson GP, Brown DG, Butler DR, Cairns DM, Fagre DB, Walsh SJ. 2009. Ecotone dynamics: invasibility of alpine tundra by tree species from the subalpine forest. In DR Butler, GP Malanson, SJ Walsh & DB Fagre, eds. The Changing Alpine Treeline: The Example of Glacier National Park, Montana, USA. Elsevier, Amsterdam, 35-61. Malanson GP, Butler DR, Fagre DB, Walsh SJ, Tomback DF, Daniels LD, Resler LM, Smith WK, Weiss DJ, Peterson DL, Bunn AG, Hiemstra CA, Liptzin D, Bourgeron PS, Shen Z, Millar CI. 2007b. Alpine treeline of western North America:  linking organism-to-landscape dynamics. Physical Geography 28: 378-396. Malanson GP, Butler DR, Fagre DB. 2007a. Alpine ecosystem dynamics and change: a view from the heights. In T Prato, DB Fagre (eds) Sustaining Rocky Mountain Landscapes: Science, Policy and Management of the Crown of the Continent Ecosystem. Resources for the Future, Washington DC, 85-101. Malanson GP, Butler DR. 1994. Tree - tundra competitive hierarchies, soil fertility gradients, and the elevation of treeline in Glacier National Park, Montana. <em>Physical Geography</em> 15: 166-180. Malanson GP, Butler DR. 1994. Tree - tundra competitive hierarchies, soil fertility gradients, and the elevation of treeline in Glacier National Park, Montana. Physical Geography 15: 166-180. Malanson GP, Resler LM, Bader MY, Holtmeier F-K, Weiss DJ, Butler DR, Fagre DB, Daniels LD. 2011. Mountain treelines: a roadmap for research orientation. Arctic, Antarctic, and Alpine Research 43: 167-177. Malanson GP, Resler LM, Butler DR, Fagre DB. 2019. Mountain plant communities: uncertain sentinels? Progress in Physical Geography 43:521-543. Malanson GP. 2023. Inclusions and exclusions in treeline definitions. Journal of Biogeography, in press. Smith-McKenna E, Malanson GP, Resler LM, Carstensen LW, Prisley SP, and Tomback DF. 2014. Cascading effects of feedbacks, disease, and climate change on alpine treeline dynamics. Environmental Modelling & Software 62: 85-96. Weiss D, Malanson GP, Walsh SJ. 2015. Multi-scale relationships between alpine treeline elevation and hypothesized environmental controls in the western United States. Annals of the Association of American Geographers 105: 437-453.
description: # Potential alpine habitat in the western USA based on treeline elevation
 An elevation surface was
 interpolated from points in the western USA and Canada identified as
 treelines on Google Earth imagery. The surface was intersected with a USGS
 90 m digital elevation model
 (, and all cells higher than the interpolated surface were recorded and mapped. Three products are included. ## Description of the data and file structure The first dataset, Final268Points, is a csv file of the 268 points identified as alpine treelines (Treeline Elevations). The data, in columns, include their latitude, longitude, and elevation as derived from Google Earth. The elevations of the points on the elevation surface generated by inverse distance weighting (IDW) and kriging (krig) are also listed. The second dataset, All90mPoints, is a compressed (zip) csv file of the c. 1.5 x 10^9 cells that were identified as having elevations greater than the surface generated by inverse distance weighting (All90mPoints); the longitude and latitude are listed as the x and y coordinates. The third product is the map of potential alpine habitat in the western USA (all the cells in the second dataset) that was created for outreach (Alpine Habitat Map); this is a jpeg. ## Sharing/Access information Data were derived from the following sources: * A USGS 90 m DEM was used: ## Code/Software na