Drought timing and local climate determine the sensitivity of eastern temperate forests to drought

Loïc D'Orangeville, Justin Maxwell, Daniel Kneeshaw, Neil Pederson, Louis Duchesne, Travis Logan, Daniel Houle, Dominique Arseneault, Colin M. Beier, Daniel A. Bishop, Daniel Druckenbrod, Shawn Fraver, François Girard, Joshua Halman, Chris Hansen, Justin L. Hart, Henrik Hartmann, Margot Kaye, David Leblanc, Stefano ManzoniRock Ouimet, Shelly Rayback, Christine R. Rollinson, Richard P. Phillips

Research output: Contribution to journalArticlepeer-review

46 Scopus citations

Abstract

Projected changes in temperature and drought regime are likely to reduce carbon (C) storage in forests, thereby amplifying rates of climate change. While such reductions are often presumed to be greatest in semi-arid forests that experience widespread tree mortality, the consequences of drought may also be important in temperate mesic forests of Eastern North America (ENA) if tree growth is significantly curtailed by drought. Investigations of the environmental conditions that determine drought sensitivity are critically needed to accurately predict ecosystem feedbacks to climate change. We matched site factors with the growth responses to drought of 10,753 trees across mesic forests of ENA, representing 24 species and 346 stands, to determine the broad-scale drivers of drought sensitivity for the dominant trees in ENA. Here we show that two factors—the timing of drought, and the atmospheric demand for water (i.e., local potential evapotranspiration; PET)—are stronger drivers of drought sensitivity than soil and stand characteristics. Drought-induced reductions in tree growth were greatest when the droughts occurred during early-season peaks in radial growth, especially for trees growing in the warmest, driest regions (i.e., highest PET). Further, mean species trait values (rooting depth and ψ50) were poor predictors of drought sensitivity, as intraspecific variation in sensitivity was equal to or greater than interspecific variation in 17 of 24 species. From a general circulation model ensemble, we find that future increases in early-season PET may exacerbate these effects, and potentially offset gains in C uptake and storage in ENA owing to other global change factors.

Original languageEnglish (US)
Pages (from-to)2339-2351
Number of pages13
JournalGlobal Change Biology
Volume24
Issue number6
DOIs
StatePublished - Jun 2018

All Science Journal Classification (ASJC) codes

  • Global and Planetary Change
  • Environmental Chemistry
  • Ecology
  • Environmental Science(all)

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