Forests in a warmer and drier climate

   Charlotte Grossiord

Charlotte Grossiord

Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA

le lundi 21 novembre 2016 - 11h Grande Salle CEFE (1919 Rte de Mende, 1e étage, aille C)

Moisture loss through temperature-driven increases in evapotranspiration and sparse precipitation are expected to affect the functioning of forest ecosystems. Understanding the consequences of these climatic changes and subsequently suggesting climate-smart management options are emerging as grand challenges for global change scientists. To persist and thrive under projected climate, plants will need to undergo rapid adjustments in their physiology and morphology. However, although the capacity of woody species to tune their traits to changing environmental conditions is widely recognized, climate–vegetation models rarely consider changes in individual species traits. In addition to natural tree-level acclimation processes, stand-level human interventions promoting sustainability, resilience and species conservation can help forests tackle the climate challenge. Among other approaches, promoting species diversity has been suggested to improve ecosystem resistance to climate change. However, it remains unclear whether higher tree diversity also leads to improved resistance of forest ecosystems to the more extreme conditions expected in the future. I will first present recent results showing how trees can acclimate both physiologically and structurally to atmospheric warming and precipitation reduction. Then I will present results on the relationship between tree species diversity and forest drought resistance across a large gradient of climatic conditions.

Selected publications:

Grossiord C, Sevanto S, Adams HD, Collins AD, Dickman LT, McBranch N, Michaletz ST, Stockton EA, Vigil M and McDowell NG, 2016. Precipitation, not air temperature, drives functional responses of trees in semi‐arid ecosystems. Journal of Ecology. DOI: 10.1111/1365-2745.12662

Grossiord C, Granier A, Ratcliffe S, Bouriaud O, Bruelheide H, Chećko E, Forrester DI, Dawud SM, Finér L, Pollastrini M and Scherer-Lorenzen M, 2014. Tree diversity does not always improve resistance of forest ecosystems to drought. PNAS, 111(41), pp.14812-14815.