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Elevation-dependent influence of snow accumulation on forest greening


Rising temperatures and declining water availability have influenced the ecological function of mountain forests over the past half-century. For instance, warming in spring and summer and shifts towards earlier snowmelt are associated with an increase in wildfire activity and tree mortality in mountain forests in the western United States1,2. Temperature increases are expected to continue during the twenty-first century in mountain ecosystems across the globe3,4, with uncertain consequences. Here, we examine the influence of interannual variations in snowpack accumulation on forest greenness in the Sierra Nevada Mountains, California, between 1982 and 2006. Using observational records of snow accumulation and satellite data on vegetation greenness we show that vegetation greenness increases with snow accumulation. Indeed, we show that variations in maximum snow accumulation explain over 50% of the interannual variability in peak forest greenness across the Sierra Nevada region. The extent to which snow accumulation can explain variations in greenness varies with elevation, reaching a maximum in the water-limited mid-elevations, between 2,000 and 2,600 m. In situ measurements of carbon uptake and snow accumulation along an elevational transect in the region confirm the elevation dependence of this relationship. We suggest that mid-elevation mountain forest ecosystems could prove particularly sensitive to future increases in temperature and concurrent changes in snow accumulation and melt.

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Figure 1: Study area and correspondence between SWE and NDVI across the Sierra Nevada Mountains.
Figure 2: Relationships between forest greenness and maximum snow accumulation on a regional basis.
Figure 3: Relationships between forest greenness and maximum snow accumulation across elevations.
Figure 4: In situ measurements of GEE and snow accumulation in the southern Sierra Nevada Mountains.


  1. Westerling, A. L., Hidalgo, H. G., Cayan, D. R. & Swetnam, T. W. Warming and earlier spring increase western US forest wildfire activity. Science 313, 940–943 (2006).

    Article  Google Scholar 

  2. Van Mantgem, P. J. et al. Widespread increase of tree mortality rates in the Western United States. Science 323, 521–524 (2009).

    Article  Google Scholar 

  3. Bradley, R. S., Keimig, F. T. & Diaz, H. F. Projected temperature changes along the American cordillera and the planned GCOS network. Geophys. Res. Lett. 31, L16210 (2004).

    Article  Google Scholar 

  4. Nogués-Bravo, D., Araújo, M. B., Errea, M. P. & Martı´nez-Rica, J. P. Exposure of global mountain systems to climate warming during the 21st Century. Glob. Environ. Change 17, 420–428 (2007).

    Article  Google Scholar 

  5. Buermann, W. et al. The changing carbon cycle at Mauna Loa observatory. Proc. Natl Acad. Sci. USA 104, 4249–4254 (2007).

    Article  Google Scholar 

  6. Angert, A. et al. Drier summers cancel out the CO2 uptake enhancement induced by warmer springs. Proc. Natl Acad. Sci. USA 102, 10823–10827 (2005).

    Article  Google Scholar 

  7. Monson, R. K. et al. Carbon sequestration in a high-elevation, subalpine forest. Glob. Change Biol. 8, 459–478 (2002).

    Article  Google Scholar 

  8. Sacks, W. J., Schimel, D. S. & Monson, R. K. Coupling between carbon cycling and climate in a high-elevation, subalpine forest: A model-data fusion analysis. Oecologia 151, 54–68 (2007).

    Article  Google Scholar 

  9. Hu, J., Moore, D. J. P., Burns, S. P. & Monson, R. K. Longer growing seasons lead to less carbon sequestration by a subalpine forest. Glob. Change Biol. 16, 771–783 (2010).

    Article  Google Scholar 

  10. Monson, R. K. et al. Climatic influences on net ecosystem CO2 exchange during the transition from wintertime carbon source to springtime carbon sink in a high-elevation, subalpine forest. Oecologia 146, 130–147 (2005).

    Article  Google Scholar 

  11. Christensen, L., Tague, C. L. & Baron, J. S. Spatial patterns of simulated transpiration response to climate variability in a snow dominated mountain ecosystem. Hydrol. Processes 22, 3576–3588 (2008).

    Article  Google Scholar 

  12. Tague, C., Heyn, K. & Christensen, L. Topographic controls on spatial patterns of conifer transpiration and net primary productivity under climate warming in mountain ecosystems. Ecohydrology 2, 541–554 (2009).

    Article  Google Scholar 

  13. Barnett, T. P. et al. Human-induced changes in the hydrology of the western United States. Science 319, 1080–1083 (2008).

    Article  Google Scholar 

  14. Mote, P. W., Hamlet, A. F., Clark, M. P. & Lettenmaier, D. P. Declining mountain snowpack in western north America. Bull. Am. Meteorol. Soc. 86, 39–49 (2005).

    Article  Google Scholar 

  15. Loarie, S. R. et al. The velocity of climate change. Nature 462, 1052–U1111 (2009).

    Article  Google Scholar 

  16. Barbour, M. G., Berg, N. H., Kittel, T. G. F. & Kunz, M. E. Snowpack and the distribution of a major vegetation ecotone in the Sierra Nevada of California. J. Biogeogr. 18, 141–149 (1991).

    Article  Google Scholar 

  17. Serreze, M. C., Clark, M. P., Armstrong, R. L., McGinnis, D. A. & Pulwarty, R. S. Characteristics of the western United States snowpack from snowpack telemetry (SNOTEL) data. Water Resour. Res. 35, 2145–2160 (1999).

    Article  Google Scholar 

  18. Dunne, J. A., Harte, J. & Taylor, K. J. Subalpine meadow flowering phenology responses to climate change: Integrating experimental and gradient methods. Ecol. Monogr. 73, 69–86 (2003).

    Article  Google Scholar 

  19. Rahbek, C. The role of spatial scale and the perception of large-scale species-richness patterns. Ecol. Lett. 8, 224–239 (2005).

    Article  Google Scholar 

  20. McCain, C. M. Could temperature and water availability drive elevational species richness patterns? A global case study for bats. Glob. Ecol. Biogeogr. 16, 1–13 (2007).

    Article  Google Scholar 

  21. Grytnes, J-A. & McCain, C. in Encyclopedia of Biodiversity (ed. Levin, S.) 1–8 (Elsevier, 2007).

    Book  Google Scholar 

  22. Knowles, N., Dettinger, M. D. & Cayan, D. R. Trends in snowfall versus rainfall in the Western United States. J. Clim. 19, 4545–4559 (2006).

    Article  Google Scholar 

  23. Hansen, M. C., Defries, R. S., Townshend, J. R. G. & Sohlberg, R. Global land cover classification at 1km spatial resolution using a classification tree approach. Int. J. Rem. Sens. 21, 1331–1364 (2000).

    Article  Google Scholar 

  24. Hansen, M., DeFries, R., Townshend, J. R. G. & Sohlberg, R. UMD Global Land Cover Classification, 1 Kilometer, 1.0. (1998).

  25. Tucker, C. J. et al. An extended AVHRR 8-km NDVI dataset compatible with MODIS and SPOT vegetation NDVI data. Int. J. Rem. Sens. 26, 4485–4498 (2005).

    Article  Google Scholar 

  26. Tucker, C. J., Pinzon, J. E. & Brown, M. E. Global Inventory Modeling and Mapping Studies, NA94apr15b.n11-VIg, 2.0. (2004).

  27. Gallo, K., Ji, L., Reed, B., Dwyer, J. & Eidenshink, J. Comparison of MODIS and AVHRR 16-day normalized difference vegetation index composite data. Geophys. Res. Lett. 31, L07502 (2004).

    Article  Google Scholar 

  28. Gallo, K., Li, L., Reed, B., Eidenshink, J. & Dwyer, J. Multi-platform comparisons of MODIS and AVHRR normalized difference vegetation index data. Remote Sens. Environ. 99, 221–231 (2005).

    Article  Google Scholar 

  29. Brown, M. E., Pinzon, J. E., Didan, K., Morisette, J. T. & Tucker, C. J. Evaluation of the consistency of long-term NDVI time series derived from AVHRR, SPOT-Vegetation, SeaWiFS, MODIS, and Landsat ETM+ sensors. IEEE Trans. Geosci. Remote Sens. 44, 1787–1793 (2006).

    Article  Google Scholar 

  30. Goulden, M. L. et al. An eddy covariance mesonet to measure the effect of forest age on land–atmosphere exchange. Glob. Change Biol. 12, 2146–2162 (2006).

    Article  Google Scholar 

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This research was supported by NSF EAR-1032295, NSF EAR-1032308, NSF EAR-0619947, the Southern Sierra Critical Zone Observatory (NSF EAR-0725097), NASA-NNX08AH18G and the Jet Propulsion Laboratory Research and Technology Development Fund. Part of this work was performed at the Jet Propulsion Laboratory, California Institute of Technology under contract with NASA. We thank F. Gehrke for facilitating access to the California Department of Water Resources snow sensor data, M. Meadows and G. Winston for assistance in the field, and T. Veblen and M. Williams for comments on the manuscript and useful discussions.

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Authors and Affiliations



E.T. jointly conceived the study and designed the analyses with N.P.M. E.T. collected and performed the data analyses of NDVI and SWE. E.T. and N.P.M. carried out interpretation of results jointly, and E.T. prepared the initial manuscript. M.L.G., A.E.K. and R.C.B. provided the GEE data, and contributed with interpretations of the GEE and SWE measurements and the corresponding text. E.T. and N.P.M. edited the final version of the manuscript.

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Correspondence to Ernesto Trujillo.

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Trujillo, E., Molotch, N., Goulden, M. et al. Elevation-dependent influence of snow accumulation on forest greening. Nature Geosci 5, 705–709 (2012).

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