Expansion of high-latitude deciduous forests driven by interactions between climate warming and fire


High-latitude regions have experienced rapid warming in recent decades, and this trend is projected to continue over the twenty-first century1. Fire is also projected to increase with warming2,3. We show here, consistent with changes during the Holocene4, that changes in twenty-first century climate and fire are likely to alter the composition of Alaskan boreal forests. We hypothesize that competition for nutrients after fire in early succession and for light in late succession in a warmer climate will cause shifts in plant functional type. Consistent with observations, our ecosystem model predicts evergreen conifers to be the current dominant tree type in Alaska. However, under future climate and fire, our analysis suggests the relative dominance of deciduous broadleaf trees nearly doubles, accounting for 58% of the Alaska ecosystem’s net primary productivity by 2100, with commensurate declines in contributions from evergreen conifer trees and herbaceous plants. Post-fire deciduous broadleaf tree growth under a future climate is sustained from enhanced microbial nitrogen mineralization caused by warmer soils and deeper active layers, resulting in taller trees that compete more effectively for light. The expansion of deciduous broadleaf forests will affect the carbon cycle, surface energy fluxes and ecosystem function, thereby modifying important feedbacks with the climate system.

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Fig. 1: The model broadly reproduced the current tree composition of the Alaskan boreal forest.
Fig. 2: Modelled post-fire trajectories under the twentieth century climate differed from those under the twenty-first century climate.
Fig. 3: Deciduous broadleaf trees become dominant around 2058 because of interactions between increased soil temperatures, mineralization and fire.
Fig. 4: Deciduous broadleaf trees increase and evergreen conifer trees decrease in interior Alaska by 2100 because of warming and fire in the boreal forest.

Data availability

Data products in this study are archived at http://ngee-arctic.ornl.gov. Additional data that support the findings of this study can be found from the corresponding author upon request.


  1. 1.

    IPCC Climate Change 2013: The Physical Science Basis (eds Stocker, T. F. et al.) (Cambridge Univ. Press, 2013).

  2. 2.

    Flannigan, M., Stocks, B., Turetsky, M. & Wotton, M. Impacts of climate change on fire activity and fire management in the circumboreal forest. Glob. Change Biol. 15, 549–560 (2009).

  3. 3.

    Veraverbeke, S. et al. Lightning as a major driver of recent large fire years in North American boreal forests. Nat. Clim. Change 7, 529 (2017).

  4. 4.

    Lloyd, A. H. et al. in Alaska’s Changing Boreal Forest (eds Chapin, F. S. III et al.) 62–78 (Oxford Univ. Press, 2006).

  5. 5.

    Qian, H., Joseph, R. & Zeng, N. Enhanced terrestrial carbon uptake in the northern high latitudes in the 21st century from the coupled carbon cycle climate model intercomparison project model projections. Glob. Change Biol. 16, 641–656 (2010).

  6. 6.

    Euskirchen, E. S., McGuire, A. D., Chapin, F. S. III, Yi, S. & Thompson, C. C. Changes in vegetation in northern Alaska under scenarios of climate change, 2003–2100: implications for climate feedbacks. Ecol. Appl. 19, 1022–1043 (2009).

  7. 7.

    Johnstone, J. F., Hollingsworth, T. N., Chapin, F. S. & Mack, M. C. Changes in fire regime break the legacy lock on successional trajectories in Alaskan boreal forest. Glob. Change Biol. 16, 1281–1295 (2010).

  8. 8.

    Mann, D. H., Rupp, T. S., Olson, M. A. & Duffy, P. A. Is Alaska’s boreal forest now crossing a major ecological threshold? Arct. Antarct. Alp. Res. 44, 319–331 (2012).

  9. 9.

    Johnstone, J. F. et al. Fire, climate change, and forest resilience in interior Alaska. Can. J. For. Res. 40, 1302–1312 (2010).

  10. 10.

    Edwards, M. E., Brubaker, L. B., Lozhkin, A. V. & Anderson, P. M. Structurally novel biomes: a response to past warming in Beringia. Ecology 86, 1696–1703 (2005).

  11. 11.

    Van Cleve, K. et al. Taiga ecosystems in interior Alaska. Bioscience 33, 39–44 (1983).

  12. 12.

    Strömgren, M. & Linder, S. Effects of nutrition and soil warming on stemwood production in a boreal Norway spruce stand. Glob. Change Biol. 8, 1194–1204 (2002).

  13. 13.

    McPartland, M. Y. et al. The response of boreal peatland community composition and NDVI to hydrologic change, warming, and elevated carbon dioxide. Glob. Change Biol. 25, 93–107 (2019).

  14. 14.

    Rogers, B. M., Soja, A. J., Goulden, M. L. & Randerson, J. T. Influence of tree species on continental differences in boreal fires and climate feedbacks. Nat. Geosci. 8, 228–234 (2015).

  15. 15.

    Liu, H., Randerson, J. T., Lindfors, J. & Chapin, F. S. III Changes in the surface energy budget after fire in boreal ecosystems of interior Alaska: An annual perspective. J. Geophys. Res. Atmos. 110, D13 (2005).

  16. 16.

    Mack, M. C. et al. Carbon loss from an unprecedented Arctic tundra wildfire. Nature 475, 489–492 (2011).

  17. 17.

    Neff, J., Harden, J. & Gleixner, G. Fire effects on soil organic matter content, composition, and nutrients in boreal interior Alaska. Can. J. For. Res. 35, 2178–2187 (2005).

  18. 18.

    Genet, H. et al. Modeling the effects of fire severity and climate warming on active layer thickness and soil carbon storage of black spruce forests across the landscape in interior Alaska. Environ. Res. Lett. 8, 045016 (2013).

  19. 19.

    Driscoll, K., Arocena, J. & Massicotte, H. Post-fire soil nitrogen content and vegetation composition in sub-boreal spruce forests of British Columbia’s central interior, Canada. For. Ecol. Manag. 121, 227–237 (1999).

  20. 20.

    Kimmins, J. P. Forest Ecology: A Foundation for Sustainable Forest Management and Environmental Ethics in Forestry (Prentice Hall, 2004).

  21. 21.

    Grant, R. F. et al. Interannual variation in net ecosystem productivity of Canadian forests as affected by regional weather patterns—A Fluxnet-Canada synthesis. Agric. For. Meteorol. 149, 2022–2039 (2009).

  22. 22.

    Johnstone, J. F., Rupp, T. S., Olson, M. & Verbyla, D. Modeling impacts of fire severity on successional trajectories and future fire behavior in Alaskan boreal forests. Landsc. Ecol. 26, 487–500 (2011).

  23. 23.

    Chaste, E., Girardin, M. P., Kaplan, J. O., Bergeron, Y. & Hély, C. Increases in heat-induced tree mortality could drive reductions of biomass resources in Canada’s managed boreal forest. Landsc. Ecol. 34, 403–426 (2019).

  24. 24.

    Lloyd, A. H., Rupp, T. S., Fastie, C. L. & Starfield, A. M. Patterns and dynamics of treeline advance on the Seward Peninsula, Alaska. J. Geophys. Res. Atmos. 107, 8161 (2002).

  25. 25.

    Wei, Y. et al. The North American carbon program multi-scale synthesis and terrestrial model intercomparison project–part 2: Environmental driver data. Geosci. Model Dev. 7, 2875–2893 (2014).

  26. 26.

    Wang, T., Hamann, A., Spittlehouse, D. & Carroll, C. Locally downscaled and spatially customizable climate data for historical and future periods for North America. PLoS ONE 11, e0156720 (2016).

  27. 27.

    Rollins, M. G. LANDFIRE: a nationally consistent vegetation, wildland fire, and fuel assessment. Int. J. Wildland Fire 18, 235–249 (2009).

  28. 28.

    Rogers, B., Randerson, J. & Bonan, G. High-latitude cooling associated with landscape changes from North American boreal forest fires. Biogeosciences 10, 699–718 (2013).

  29. 29.

    Wright, I. J. et al. The worldwide leaf economics spectrum. Nature 428, 821–827 (2004).

  30. 30.

    Aerts, R. Nutrient use efficiency in evergreen and deciduous species from heathlands. Oecologia 84, 391–397 (1990).

  31. 31.

    Poorter, H., Niinemets, Ü., Poorter, L., Wright, I. J. & Villar, R. Causes and consequences of variation in leaf mass per area (LMA): a meta‐analysis. New Phytol. 182, 565–588 (2009).

  32. 32.

    Euskirchen, E., McGuire, A. D., Chapin, F. & Rupp, T. The changing effects of Alaska’s boreal forests on the climate system. Can. J. For. Res. 40, 1336–1346 (2010).

  33. 33.

    Nelson, J. L., Zavaleta, E. S. & Chapin, F. S. Boreal fire effects on subsistence resources in Alaska and adjacent Canada. Ecosystems 11, 156–171 (2008).

  34. 34.

    Rupp, T. S., Starfield, A. M., Chapin, F. S. & Duffy, P. Modeling the impact of black spruce on the fire regime of Alaskan boreal forest. Clim. Change 55, 213–233 (2002).

  35. 35.

    Mekonnen, Z. A., Riley, W. J. & Grant, R. F. Accelerated nutrient cycling and increased light competition will lead to 21st century shrub expansion in North American Arctic tundra. J. Geophys. Res. Biogeosci. 123, 1683–1701 (2018).

  36. 36.

    Grant, R. F. Modelling changes in nitrogen cycling to sustain increases in forest productivity under elevated atmospheric CO2 and contrasting site conditions. Biogeosciences 10, 7703–7721 (2013).

  37. 37.

    Aerts, R. The advantages of being evergreen. Trends Ecol. Evol. 10, 402–407 (1995).

  38. 38.

    Liu, S. et al. The Unified North American Soil Map and its implication on the soil organic carbon stock in North America. Biogeosciences 10, 2915–2930 (2013).

  39. 39.

    Hugelius, G. et al. A new data set for estimating organic carbon storage to 3 m depth in soils of the northern circumpolar permafrost region. Earth Syst. Sci. Data 5, 393–402 (2013).

  40. 40.

    Dentener, F. Global Maps of Atmospheric Nitrogen Deposition, 1860, 1993, and 2050 (Oak Ridge National Laboratory Distributed Active Archive Center, 2006); https://doi.org/10.3334/ORNLDAAC/830

  41. 41.

    Mekonnen, Z. A., Grant, R. F. & Schwalm, C. Sensitivity of modeled NEP to climate forcing and soil at site and regional scales: Implications for upscaling ecosystem models. Ecol. Modell. 320, 241–257 (2016).

  42. 42.

    Rogers, B. et al. Quantifying fire‐wide carbon emissions in interior Alaska using field measurements and Landsat imagery. J. Geophys. Res. Biogeosci. 119, 1608–1629 (2014).

  43. 43.

    Turetsky, M. R. et al. Recent acceleration of biomass burning and carbon losses in Alaskan forests and peatlands. Nat. Geosci. 4, 27–31 (2011).

  44. 44.

    Boby, L. A., Schuur, E. A., Mack, M. C., Verbyla, D. & Johnstone, J. F. Quantifying fire severity, carbon, and nitrogen emissions in Alaska’s boreal forest. Ecol. Appl. 20, 1633–1647 (2010).

  45. 45.

    Kasischke, E. S. et al. Alaska’s changing fire regime—implications for the vulnerability of its boreal forests. Can. J. For. Res. 40, 1313–1324 (2010).

  46. 46.

    Balshi, M. S. et al. Assessing the response of area burned to changing climate in western boreal North America using a multivariate adaptive regression splines (MARS) approach. Glob. Change Biol. 15, 578–600 (2009).

  47. 47.

    Euskirchen, E., McGuire, A. D., Rupp, T., Chapin, F. & Walsh, J. Projected changes in atmospheric heating due to changes in fire disturbance and the snow season in the western Arctic, 2003–2100. J. Geophys. Res. Biogeosci. 114, G04022 (2009).

  48. 48.

    Bachelet, D., Lenihan, J., Neilson, R., Drapek, R. & Kittel, T. Simulating the response of natural ecosystems and their fire regimes to climatic variability in Alaska. Can. J. For. Res. 35, 2244–2257 (2005).

  49. 49.

    Tape, K., Sturm, M. & Racine, C. The evidence for shrub expansion in northern Alaska and the pan‐Arctic. Glob. Change Biol. 12, 686–702 (2006).

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This research was supported by the Director, Office of Science, Office of Biological and Environmental Research of the US Department of Energy under contract no. DE-AC02-05CH11231 to Lawrence Berkeley National Laboratory as part of the Next-Generation Ecosystem Experiments in the Arctic (NGEE-Arctic) project and the RUBISCO Scientific Focus Area. B.M.R. was funded by NASA’s Arctic-Boreal Vulnerability Experiment (ABoVE) and Carbon Cycle Science programmes (NNX17AE13G).

Author information

All authors contributed to this work. Z.A.M., W.J.R. and J.T.R. designed the model experiments and implementation of regional fire regime. Z.A.M performed the simulations and analysed the results. Z.A.M., W.J.R., J.T.R., R.F.G. and B.M.R. contributed extensively to the contents of the manuscript.

Correspondence to Zelalem A. Mekonnen.

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Supplementary Information

Supplementary Information I (Supplementary Figs. 1–14, Supplementary Tables 1–4 and Supplementary References) and Supplementary Information II (model development and definition of variables, and Supplementary References).

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