Hotter Drought as a Disturbance at Upper Treeline in the Southern Rocky Mountains

References

• Alexander, J. M., L. Chalmandrier, J. Lenoir, T. I. Burgess, F. Essl, S. Haider, C. Kueffer, K. McDougall, A. Milbau, M. A. Nuñez, et al. 2018. Lags in the response of mountain plant communities to climate change. Global Change Biology 24 (2):563–79. doi: 10.1111/gcb.13976.
   PubMed Web of Science ®Google Scholar
• Allen, C. D., and D. D. Breshears. 1998. Drought-induced shift of a forest–woodland ecotone: Rapid landscape response to climate variation. Proceedings of the National Academy of Sciences 95 (25):14839–42. doi: 10.1073/pnas.95.25.14839.
   PubMed Web of Science ®Google Scholar
• Allen, C. D., D. D. Breshears, and N. G. McDowell. 2015. On underestimation of global vulnerability to tree mortality and forest die-off from hotter drought in the Anthropocene. Ecosphere 6 (8):art129. doi: 10.1890/ES15-00203.1.
   Web of Science ®Google Scholar
• Allen, C. D., A. K. Macalady, H. Chenchouni, D. Bachelet, N. McDowell, M. Vennetier, T. Kitzberger, A. Rigling, D. D. Breshears, E. H. Hogg, et al. 2010. A global overview of drought and heat-induced tree mortality reveals emerging climate change risks for forests. Forest Ecology and Management 259 (4):660–84. doi: 10.1016/j.foreco.2009.09.001.
   Web of Science ®Google Scholar
• Baker, W. L. 2009. Fire ecology in Rocky Mountain landscapes. Washington, DC: Island.
   Google Scholar
• Barnett, T. P., D. W. Pierce, H. G. Hidalgo, C. Bonfils, B. D. Santer, T. Das, G. Bala, A. W. Wood, T. Nozawa, A. A. Mirin, et al. 2008. Human-induced changes in the hydrology of the Western United States. Science 319 (5866):1080–83. doi: 10.1126/science.1152538.
   PubMed Web of Science ®Google Scholar
• Barry, R. G. 2008. Mountain weather and climate. 2nd ed. Cambridge, UK: Cambridge University Press.
   Google Scholar
• Bell, D. M., J. B. Bradford, and W. K. Lauenroth. 2014. Mountain landscapes offer few opportunities for high-elevation tree species migration. Global Change Biology 20 (5):1441–51. doi: 10.1111/gcb.12504.
   PubMed Web of Science ®Google Scholar
• Bourgeron, P. S., H. C. Humphries, D. Liptzin, and T. R. Seastedt. 2015. The forest–alpine ecotone: A multi-scale approach to spatial and temporal dynamics of treeline change at Niwot Ridge. Plant Ecology & Diversity 8 (5–6):763–79. doi: 10.1080/17550874.2015.1126368.
   Web of Science ®Google Scholar
• Breshears, D. D., N. S. Cobb, P. M. Rich, K. P. Price, C. D. Allen, R. G. Balice, W. H. Romme, J. H. Kastens, M. L. Floyd, J. Belnap, et al. 2005. Regional vegetation die-off in response to global-change-type drought. Proceedings of the National Academy of Sciences of the United States of America 102 (42):15144–48. doi: 10.1073/pnas.0505734102.
   PubMed Web of Science ®Google Scholar
• Bunn, A. G., M. W. Salzer, K. J. Anchukaitis, J. M. Bruening, and M. K. Hughes. 2018. Spatiotemporal variability in the climate growth response of high elevation bristlecone pine in the White Mountains of California. Geophysical Research Letters 45 (24):13312–21. doi: 10.1029/2018GL080981.
   Web of Science ®Google Scholar
• Butler, D. R. 1995. Zoogeomorphology: Animals as geomorphic agents. Cambridge, UK: Cambridge University Press.
   Google Scholar
• Butler, D. R., G. P. Malanson, L. M. Resler, S. J. Walsh, F. D. Wilkerson, G. L. Schmid, and C. F. Sawyer. 2009. Geomorphic patterns and processes at alpine treeline. In Developments in earth surface processes, ed. D. R. Butler, G. P. Malanson, S. J. Walsh, and D. B. Fagre, 63–84. Elsevier.
   Google Scholar
• Butler, D. R., G. P. Malanson, S. J. Walsh, and D. B. Fagre. 2007. Influences of geomorphology and geology on alpine treeline in the American West—More important than climatic influences? Physical Geography 28 (5):434–50. doi: 10.2747/0272-3646.28.5.434.
   Web of Science ®Google Scholar
• Caccianiga, M., S. Payette, and L. Filion. 2008. Biotic disturbance in expanding subarctic forests along the eastern coast of Hudson Bay. The New Phytologist 178 (4):823–34. doi: 10.1111/j.1469-8137.2008.02408.x.
   Web of Science ®Google Scholar
• Cairns, D. M., C. Lafon, J. Moen, and A. Young. 2007. Influences of animal activity on treeline position and pattern: Implications for treeline responses to climate change. Physical Geography 28 (5):419–33. doi: 10.2747/0272-3646.28.5.419.
   Web of Science ®Google Scholar
• Clark, J. S., L. Iverson, C. W. Woodall, C. D. Allen, D. M. Bell, D. C. Bragg, A. W. D'Amato, F. W. Davis, M. H. Hersh, I. Ibanez, et al. 2016. The impacts of increasing drought on forest dynamics, structure, and biodiversity in the United States. Global Change Biology 22 (7):2329–52. doi: 10.1111/gcb.13160.
   Web of Science ®Google Scholar
• Clow, D. W. 2010. Changes in the timing of snowmelt and streamflow in Colorado: A response to recent warming. Journal of Climate 23 (9):2293–2306. doi: 10.1175/2009JCLI2951.1.
   Web of Science ®Google Scholar
• Conlisk, E., C. Castanha, M. J. Germino, T. T. Veblen, J. M. Smith, and L. M. Kueppers. 2017. Declines in low-elevation subalpine tree populations outpace growth in high-elevation populations with warming. Journal of Ecology 105 (5):1347–57. doi: 10.1111/1365-2745.12750.
   Web of Science ®Google Scholar
• Corlett, R. T. 2015. The Anthropocene concept in ecology and conservation. Trends in Ecology & Evolution 30 (1):36–41. doi: 10.1016/j.tree.2014.10.007.
   PubMed Web of Science ®Google Scholar
• Cowell, C. M., and M. A. Urban. 2010. The changing geography of the U.S. water budget: Twentieth-century patterns and twenty-first-century projections. Annals of the Association of American Geographers 100 (4):740–54. doi: 10.1080/00045608.2010.497117.
   Web of Science ®Google Scholar
• Daly, C., M. Halbleib, J. I. Smith, W. P. Gibson, M. K. Doggett, G. H. Taylor, J. Curtis, and P. P. Pasteris. 2008. Physiographically sensitive mapping of climatological temperature and precipitation across the conterminous United States. International Journal of Climatology 28 (15):2031–64. doi: 10.1002/joc.1688.
   Web of Science ®Google Scholar
• Daniels, L. D., and T. T. Veblen. 2004. Spatiotemporal influences of climate on altitudinal treeline in northern Patagonia. Ecology 85 (5):1284–96. doi: 10.1890/03-0092.
   Web of Science ®Google Scholar
• Daubenmire, R. F. 1943. Vegetational zonation in the Rocky Mountains. The Botanical Review 9 (6):325–93. doi: 10.1007/BF02872481.
   Google Scholar
• DeRose, R. J., and J. N. Long. 2012. Drought-driven disturbance history characterizes a southern Rocky Mountain subalpine forest. Canadian Journal of Forest Research 42 (9):1649–60. doi: 10.1139/x2012-102.
   Web of Science ®Google Scholar
• Dettinger, M. D., D. R. Cayan, H. F. Diaz, and D. M. Meko. 1998. North–south precipitation patterns in western North America on interannual-to-decadal timescales. Journal of Climate 11 (12):3095–111. doi: 10.1175/1520-0442(1998)011<3095:NSPPIW>2.0.CO;2.
   Web of Science ®Google Scholar
• Dolanc, C. R., H. D. Safford, J. H. Thorne, and S. Z. Dobrowski. 2014. Changing forest structure across the landscape of the Sierra Nevada, CA, USA, since the 1930s. Ecosphere 5 (8):art101. doi: 10.1890/ES14-00103.1.
   Web of Science ®Google Scholar
• Elliott, G. P. 2003. Quaking aspen (Populus tremuloides Michx.) and conifers at treeline: A century of change in the San Juan Mountains, Colorado, USA. Master’s thesis, University of Wyoming.
   Google Scholar
• Elliott, G. P. 2011. Influences of 20th-century warming at the upper tree line contingent on local-scale interactions: Evidence from a latitudinal gradient in the Rocky Mountains, USA. Global Ecology and Biogeography 20 (1):46–57. doi: 10.1111/j.1466-8238.2010.00588.x.
   Web of Science ®Google Scholar
• Elliott, G. P. 2012. Extrinsic regime shifts drive abrupt changes in regeneration dynamics at upper treeline in the Rocky Mountains, USA. Ecology 93 (7):1614–25. doi: 10.1890/11-1220.1.
   PubMed Web of Science ®Google Scholar
• Elliott, G. P. 2017. Treeline ecotones. In International encyclopedia of geography, ed. N. Castree, M. F. Goodchild, A. Kobayashi, W. Liu, and R. A. Marston, 1–10. Chichester, U.K.: Wiley. https://onlinelibrary.wiley.com/doi/abs/10.1002/9781118786352.wbieg0539.
   Google Scholar
• Elliott, G. P., and C. M. Cowell. 2015. Slope aspect mediates fine-scale tree establishment patterns at upper treeline during wet and dry periods of the 20th century. Arctic, Antarctic, and Alpine Research 47 (4):681–92. doi: 10.1657/AAAR0014-025.
   Web of Science ®Google Scholar
• Elliott, G. P., and K. F. Kipfmueller. 2010. Multi-scale influences of slope aspect and spatial pattern on ecotonal dynamics at upper treeline in the southern Rocky Mountains. U.S.A. Arctic, Antarctic, and Alpine Research 42 (1):45–56. doi: 10.1657/1938-4246-42.1.45.
   Web of Science ®Google Scholar
• Elliott, G. P., and K. F. Kipfmueller. 2011. Multiscale influences of climate on upper treeline dynamics in the southern Rocky Mountains, USA: Evidence of intraregional variability and bioclimatic thresholds in response to twentieth-century warming. Annals of the Association of American Geographers 101 (6):1181–1203. doi: 10.1080/00045608.2011.584288.
   Web of Science ®Google Scholar
• Elliott, G. P., and C. A. Petruccelli. 2018. Tree recruitment at the treeline across the Continental Divide in the northern Rocky Mountains, USA: The role of spring snow and autumn climate. Plant Ecology & Diversity 11 (3):319–33. doi: 10.1080/17550874.2018.1487475.
   Web of Science ®Google Scholar
• Ellis, E. C., K. Klein Goldewijk, S. Siebert, D. Lightman, and N. Ramankutty. 2010. Anthropogenic transformation of the biomes, 1700 to 2000. Global Ecology and Biogeography 19 (5):589–606. doi: 10.1111/j.1466-8238.2010.00540.x.
   Web of Science ®Google Scholar
• Fajardo, A., and E. J. B. McIntire. 2012. Reversal of multicentury tree growth improvements and loss of synchrony at mountain tree lines point to changes in key drivers. Journal of Ecology 100 (3):782–94. doi: 10.1111/j.1365-2745.2012.01955.x.
   Web of Science ®Google Scholar
• Fattorini, S., L. D. Biase, and A. Chiarucci. 2019. Recognizing and interpreting vegetational belts: New wine in the old bottles of a von Humboldt’s legacy. Journal of Biogeography 46 (8):1643–51. doi: 10.1111/jbi.13601.
   Web of Science ®Google Scholar
• Germino, M. J., W. K. Smith, and A. C. Resor. 2002. Conifer seedling distribution and survival in an alpine-treeline ecotone. Plant Ecology 162 (2):157–68. doi: 10.1023/A:1020385320738.
   Web of Science ®Google Scholar
• Gill, R. A., C. S. Campbell, and S. M. Karlinsey. 2015. Soil moisture controls Engelmann spruce (Picea engelmannii) seedling carbon balance and survivorship at timberline in Utah, USA. Canadian Journal of Forest Research 45 (12):1845–52. doi: 10.1139/cjfr-2015-0239.
   Google Scholar
• Harsch, M. A., P. E. Hulme, M. S. McGlone, and R. P. Duncan. 2009. Are treelines advancing? A global meta-analysis of treeline response to climate warming. Ecology Letters 12 (10):1040–49. doi: 10.1111/j.1461-0248.2009.01355.x.
   PubMed Web of Science ®Google Scholar
• Hart, S. J., T. T. Veblen, K. S. Eisenhart, D. Jarvis, and D. Kulakowski. 2014. Drought induces spruce beetle (Dendroctonus rufipennis) outbreaks across northwestern Colorado. Ecology 95 (4):930–39. doi: 10.1890/13-0230.1.
   Web of Science ®Google Scholar
• Hinckley, E.-L. S., B. A. Ebel, R. T. Barnes, R. S. Anderson, M. W. Williams, and S. P. Anderson. 2014. Aspect control of water movement on hillslopes near the rain–snow transition of the Colorado Front Range. Hydrological Processes 28 (1):74–85. doi: 10.1002/hyp.9549.
   Web of Science ®Google Scholar
• Holtmeier, F.-K., and G. Broll. 2005. Sensitivity and response of northern hemisphere altitudinal and polar treelines to environmental change at landscape and local scales. Global Ecology and Biogeography 14 (5):395–410. doi: 10.1111/j.1466-822X.2005.00168.x.
   Web of Science ®Google Scholar
• Holtmeier, F.-K., and G. Broll. 2019. Treeline research—From the roots of the past to present time: A review. Forests 11 (1):1–38. doi: 10.3390/f11010038.
   Web of Science ®Google Scholar
• Jiang, X., S. A. Rauscher, T. D. Ringler, D. M. Lawrence, A. P. Williams, C. D. Allen, A. L. Steiner, D. M. Cai, and N. G. McDowell. 2013. Projected future changes in vegetation in western North America in the twenty-first century. Journal of Climate 26 (11):3671–87. doi: 10.1175/JCLI-D-12-00430.1.
   Web of Science ®Google Scholar
• Körner, C. 2012. Alpine treelines: Functional ecology of the global high elevation tree limits. Basel, Switzerland: Springer.
   Google Scholar
• Kueppers, L. M., E. Conlisk, C. Castanha, A. B. Moyes, M. J. Germino, P. de Valpine, M. S. Torn, and J. B. Mitton. 2017. Warming and provenance limit tree recruitment across and beyond the elevation range of subalpine forest. Global Change Biology 23 (6):2383–95. doi: 10.1111/gcb.13561.
   PubMed Web of Science ®Google Scholar
• Lazarus, B. E., C. Castanha, M. J. Germino, L. M. Kueppers, and A. B. Moyes. 2018. Growth strategies and threshold responses to water deficit modulate effects of warming on tree seedlings from forest to alpine. Journal of Ecology 106 (2):571–85. doi: 10.1111/1365-2745.12837.
   Web of Science ®Google Scholar
• League, K., and T. Veblen. 2006. Climatic variability and episodic Pinus ponderosa establishment along the forest-grassland ecotones of Colorado. Forest Ecology and Management 228 (1–3):98–107. doi: 10.1016/j.foreco.2006.02.030.
   Web of Science ®Google Scholar
• Lloyd, A. H. 2005. Ecological histories from Alaskan tree lines provide insight into future change. Ecology 86 (7):1687–95. doi: 10.1890/03-0786.
   Web of Science ®Google Scholar
• Lloyd, A. H., and L. J. Graumlich. 1997. Holocene dynamics of treeline forests in the Sierra Nevada. Ecology 78 (4):1199–210. doi: 10.1890/0012-9658(1997)078[1199:HDOTFI]2.0.CO;2.
   Web of Science ®Google Scholar
• Lu, X., E. Liang, Y. Wang, F. Babst, S. W. Leavitt, and J. J. Camarero. 2019. Past the climate optimum: Recruitment is declining at the world’s highest juniper shrublines on the Tibetan Plateau. Ecology 100 (2):e02557. doi: 10.1002/ecy.2557.
   Web of Science ®Google Scholar
• Malanson, G. P., D. G. Brown, D. R. Butler, D. M. Cairns, D. B. Fagre, and S. J. Walsh. 2009. Ecotone dynamics: Invasibility of alpine tundra by tree species from the subalpine forest. In Developments in earth surface processes, ed. D. R. Butler, G. P. Malanson, S. J. Walsh, and D. B. Fagre, 35–61. Elsevier.
   Google Scholar
• Malanson, G. P., D. R. Butler, D. B. Fagre, S. J. Walsh, D. F. Tomback, L. D. Daniels, L. M. Resler, W. K. Smith, D. J. Weiss, D. L. Peterson, et al. 2007. Alpine treeline of western North America: Linking organism-to-landscape dynamics. Physical Geography 28 (5):378–96. doi: 10.2747/0272-3646.28.5.378.
   Web of Science ®Google Scholar
• Malanson, G. P., L. M. Resler, D. R. Butler, and D. B. Fagre. 2019. Mountain plant communities: Uncertain sentinels? Progress in Physical Geography: Earth and Environment 43 (4):521–43. doi: 10.1177/0309133319843873.
   Google Scholar
• Marsicek, J., B. N. Shuman, P. J. Bartlein, S. L. Shafer, and S. Brewer. 2018. Reconciling divergent trends and millennial variations in Holocene temperatures. Nature 554 (7690):92–96. doi: 10.1038/nature25464.
   PubMed Web of Science ®Google Scholar
• Martínez-Vilalta, J., and F. Lloret. 2016. Drought-induced vegetation shifts in terrestrial ecosystems: The key role of regeneration dynamics. Global and Planetary Change 144:94–108. doi: 10.1016/j.gloplacha.2016.07.009.
   Web of Science ®Google Scholar
• Mensing, S., J. Korfmacher, T. Minckley, and R. Musselman. 2012. A 15,000 year record of vegetation and climate change from a treeline lake in the Rocky Mountains, Wyoming, USA. The Holocene 22 (7):739–48. doi: 10.1177/0959683611430339.
   Web of Science ®Google Scholar
• Millar, C. I., and N. L. Stephenson. 2015. Temperate forest health in an era of emerging megadisturbance. Science 349 (6250):823–26. doi: 10.1126/science.aaa9933.
   PubMed Web of Science ®Google Scholar
• Millar, C. I., R. D. Westfall, D. L. Delany, A. L. Flint, and L. E. Flint. 2015. Recruitment patterns and growth of high-elevation pines in response to climatic variability (1883–2013), in the western Great Basin, USA. Canadian Journal of Forest Research 45 (10):1299–1312. doi: 10.1139/cjfr-2015-0025.
   Google Scholar
• Minckley, T. A., R. K. Shriver, and B. Shuman. 2012. Resilience and regime change in a southern Rocky Mountain ecosystem during the past 17 000 years. Ecological Monographs 82 (1):49–68. doi: 10.1890/11-0283.1.
   Web of Science ®Google Scholar
• Mitchell, V. L. 1976. The regionalization of climate in the western United States. Journal of Applied Meteorology 15 (9):920–27. doi: 10.1175/1520-0450(1976)015<0920:TROCIT>2.0.CO;2.
   Google Scholar
• Morgan, C., A. Losey, and L. Trout. 2014. Late-Holocene paleoclimate and treeline fluctuation in Wyoming’s Wind River Range, USA. The Holocene 24 (2):209–19. doi: 10.1177/0959683613516817.
   Web of Science ®Google Scholar
• Mote, P. W., S. Li, D. P. Lettenmaier, M. Xiao, and R. Engel. 2018. Dramatic declines in snowpack in the western U.S. NPJ Climate and Atmospheric Science 1 (1):1–6. doi: 10.1038/s41612-018-0012-1.
   Google Scholar
• Moyes, A. B., C. Castanha, M. J. Germino, and L. M. Kueppers. 2013. Warming and the dependence of limber pine (Pinus flexilis) establishment on summer soil moisture within and above its current elevation range. Oecologia 171 (1):271–82. doi: 10.1007/s00442-012-2410-0.
   Web of Science ®Google Scholar
• Moyes, A. B., M. J. Germino, and L. M. Kueppers. 2015. Moisture rivals temperature in limiting photosynthesis by trees establishing beyond their cold-edge range limit under ambient and warmed conditions. New Phytologist 207 (4):1005–14. doi: 10.1111/nph.13422.
   Web of Science ®Google Scholar
• Munier, A., L. Hermanutz, J. D. Jacobs, and K. Lewis. 2010. The interacting effects of temperature, ground disturbance, and herbivory on seedling establishment: Implications for treeline advance with climate warming. Plant Ecology 210 (1):19–30. doi: 10.1007/s11258-010-9724-y.
   Web of Science ®Google Scholar
• Noble, I. R. 1993. A model of the responses of ecotones to climate change. Ecological Applications: A Publication of the Ecological Society of America 3 (3):396–403. doi: 10.2307/1941908.
   PubMed Web of Science ®Google Scholar
• Nogués-Bravo, D., M. B. Araújo, M. P. Errea, and J. P. Martínez-Rica. 2007. Exposure of global mountain systems to climate warming during the 21st century. Global Environmental Change 17 (3–4):420–28. doi: 10.1016/j.gloenvcha.2006.11.007.
   Web of Science ®Google Scholar
• Paulsen, J., U. M. Weber, and C. Körner. 2000. Tree growth near treeline: Abrupt or gradual reduction with altitude? Arctic, Antarctic, and Alpine Research 32 (1):14–20. doi: 10.2307/1552405.
   Web of Science ®Google Scholar
• Peet, R. K. 1978. Latitudinal variation in southern Rocky Mountain forests. Journal of Biogeography 5 (3):275–89. doi: 10.2307/3038041.
   Web of Science ®Google Scholar
• Peet, R. K. 2000. Forests and meadows of the Rocky Mountains. In North American terrestrial vegetation, ed. M. G. Barbour and W. D. Billings, 79–121. Cambridge, UK: Cambridge University Press.
   Google Scholar
• Pepin, N., R. S. Bradley, H. F. Diaz, M. Baraer, E. B. Caceres, N. Forsythe, H. Fowler, G. Greenwood, M. Z. Hashmi, X. D. Liu, et al. 2015. Elevation-dependent warming in mountain regions of the world. Nature Climate Change 5 (5):424–30.
   Web of Science ®Google Scholar
• PRISM Climate Group. 2019. PRISM Climate Data. Accessed 10 November 2019. https://prism.oregonstate.edu/.
   Google Scholar
• Resler, L. M., and D. F. Tomback. 2008. Blister rust prevalence in Krummholz whitebark pine: Implications for treeline dynamics, northern Rocky Mountains, Montana, U.S.A. Arctic, Antarctic, and Alpine Research 40 (1):161–70. doi: 10.1657/1523-0430(06-116)[RESLER]2.0.CO;2.
   Web of Science ®Google Scholar
• Rodionov, S. N. 2004. A sequential algorithm for testing climate regime shifts. Geophysical Research Letters 31 (9):L09204. doi: 10.1029/2004GL019448.
   Web of Science ®Google Scholar
• Salzer, M. W., E. R. Larson, A. G. Bunn, and M. K. Hughes. 2014. Changing climate response in near-treeline bristlecone pine with elevation and aspect. Environmental Research Letters 9 (11):114007. doi: 10.1088/1748-9326/9/11/114007.
   Web of Science ®Google Scholar
• Schickoff, U. 2005. The upper timberline in the Himalayas, Hindu Kush and Karakorum: A review of geographical and ecological aspects. In Mountain ecosystems: Studies in treeline ecology, ed. G. Broll and B. Keplin, 275–354. Berlin: Springer.
   Google Scholar
• Schoennagel, T., T. T. Veblen, D. Kulakowski, and A. Holz. 2007. Multidecadal climate variability and climate interactions affect subalpine fire occurrence, western Colorado (USA). Ecology 88 (11):2891–902. doi: 10.1890/06-1860.1.
   Web of Science ®Google Scholar
• Shankman, D., and C. Daly. 1988. Forest regeneration above tree limit depressed by fire in the Colorado Front Range. Bulletin of the Torrey Botanical Club 115 (4):272–79. doi: 10.2307/2996159.
   Google Scholar
• Shuman, B. 2012. Recent Wyoming temperature trends, their drivers, and impacts in a 14,000-year context. Climatic Change 112 (2):429–47. doi: 10.1007/s10584-011-0223-5.
   Web of Science ®Google Scholar
• Sigdel, S. R., Y. Wang, J. J. Camarero, H. Zhu, E. Liang, and J. Peñuelas. 2018. Moisture-mediated responsiveness of treeline shifts to global warming in the Himalayas. Global Change Biology 24 (11):5549–59. doi: 10.1111/gcb.14428.
   Web of Science ®Google Scholar
• Smith, J. M., J. Paritsis, T. T. Veblen, and T. B. Chapman. 2015. Permanent forest plots show accelerating tree mortality in subalpine forests of the Colorado Front Range from 1982 to 2013. Forest Ecology and Management 341:8–17. doi: 10.1016/j.foreco.2014.12.031.
   Web of Science ®Google Scholar
• Smithers, B. V., M. P. North, C. I. Millar, and A. M. Latimer. 2018. Leap frog in slow motion: Divergent responses of tree species and life stages to climatic warming in Great Basin subalpine forests. Global Change Biology 24 (2):e442. doi: 10.1111/gcb.13881.
   Web of Science ®Google Scholar
• Solomon, S., G.-K. Plattner, R. Knutti, and P. Friedlingstein. 2009. Irreversible climate change due to carbon dioxide emissions. Proceedings of the National Academy of Sciences of the United States of America 106 (6):1704–9. doi: 10.1073/pnas.0812721106.
   PubMed Web of Science ®Google Scholar
• Steffen, W., J. Grinevald, P. Crutzen, and J. McNeill. 2011. The Anthropocene: Conceptual and historical perspectives. Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences 369 (1938):842–67. doi: 10.1098/rsta.2010.0327.
   PubMed Web of Science ®Google Scholar
• Stine, M. B., and D. R. Butler. 2015. Effects of fire on geomorphic factors and seedling site conditions within the alpine treeline ecotone, Glacier National Park, MT. Catena 132:37–44. doi: 10.1016/j.catena.2015.04.006.
   Web of Science ®Google Scholar
• Stueve, K. M., D. L. Cerney, R. M. Rochefort, and L. L. Kurth. 2009. Post-fire tree establishment patterns at the alpine treeline ecotone: Mount Rainier National Park, Washington, USA. Journal of Vegetation Science 20 (1):107–20. doi: 10.1111/j.1654-1103.2009.05437.x.
   Web of Science ®Google Scholar
• Tomback, F. D., M. L. Resler, E. R. Keane, R. E. Pansing, J. A. Andrade, and C. A. Wagner. 2016. Community structure, biodiversity, and ecosystem services in treeline whitebark pine communities: Potential impacts from a non-native pathogen. Forests 7 (12):1–21. doi: 10.3390/f7010021.
   Google Scholar
• van Mantgem, P. J., N. L. Stephenson, J. C. Byrne, L. D. Daniels, J. F. Franklin, P. Z. Fulé, M. E. Harmon, A. J. Larson, J. M. Smith, A. H. Taylor, et al. 2009. Widespread increase of tree mortality rates in the Western United States. Science (New York, N.Y.) 323 (5913):521–24. doi: 10.1126/science.1165000.
   PubMed Web of Science ®Google Scholar
• von Humboldt, A., and A. Bonpland. 1805. Essai sur la géographie des plantes (Essay on the Geography of Plants). Paris Levrault, Schoell et Compagnie.
   Google Scholar
• Walsh, S. J., D. R. Butler, T. R. Allen, and G. P. Malanson. 1994. Influence of snow patterns and snow avalanches on the alpine treeline ecotone. Journal of Vegetation Science 5 (5):657–72. doi: 10.2307/3235881.
   Web of Science ®Google Scholar
• Wang, Y., B. Case, X. Lu, A. M. Ellison, J. Peñuelas, H. Zhu, E. Liang, and J. J. Camarero. 2019. Fire facilitates warming-induced upward shifts of alpine treelines by altering interspecific interactions. Trees 33 (4):1051–61. doi: 10.1007/s00468-019-01841-6.
   Web of Science ®Google Scholar
• Weisberg, P. J., and W. L. Baker. 1995. Spatial variation in tree regeneration in the forest–tundra ecotone, Rocky Mountain National Park, Colorado. Canadian Journal of Forest Research 25 (8):1326–39. doi: 10.1139/x95-145.
   Web of Science ®Google Scholar
• Williams, A. P., C. D. Allen, A. K. Macalady, D. Griffin, C. A. Woodhouse, D. M. Meko, T. W. Swetnam, S. A. Rauscher, R. Seager, H. D. Grissino-Mayer, et al. 2013. Temperature as a potent driver of regional forest drought stress and tree mortality. Nature Climate Change 3 (3):292–97. doi: 10.1038/nclimate1693.
   Web of Science ®Google Scholar
• Williams, J. W., J. L. Blois, and B. N. Shuman. 2011. Extrinsic and intrinsic forcing of abrupt ecological change: Case studies from the late Quaternary. Journal of Ecology 99 (3):664–77. doi: 10.1111/j.1365-2745.2011.01810.x.
   Web of Science ®Google Scholar
• Wolkovich, E. M., B. I. Cook, K. K. McLauchlan, and T. J. Davies. 2014. Temporal ecology in the Anthropocene. Ecology Letters 17 (11):1365–79. doi: 10.1111/ele.12353.
   PubMed Web of Science ®Google Scholar
• Young, K. R. 2014. Biogeography of the Anthropocene: Novel species assemblages. Progress in Physical Geography: Earth and Environment 38 (5):664–73. doi: 10.1177/0309133314540930.
   Google Scholar
• Zapata-Rios, X., P. D. Brooks, P. A. Troch, J. McIntosh, and Q. Guo. 2016. Influence of terrain aspect on water partitioning, vegetation structure and vegetation greening in high-elevation catchments in northern New Mexico. Ecohydrology 9 (5):782–95. doi: 10.1002/eco.1674.
   Web of Science ®Google Scholar
• Zier, J. L., and W. L. Baker. 2006. A century of vegetation change in the San Juan Mountains, Colorado: An analysis using repeat photography. Forest Ecology and Management 228 (1–3):251–62. doi: 10.1016/j.foreco.2006.02.049.
   Web of Science ®Google Scholar