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Harvard Forest Symposium Abstract 2018

• Title: A framework for determining the vulnerability of tree populations to climatic change: a case study of Chamaecyparis thyoides from along its contiguous latitudinal distribution
• Primary Author: Neil Pederson (Harvard Forest)
• Additional Authors: Kevin Anchukaitis (University of Arizona); Daniel Bishop (Harvard Forest); H. Myvonwynn Hopton (Mayfield Junior High School); Caroline Leland (Columbia University in the City of New York); Dario Martin Benito (Columbia University in the City of New York); Jessie Pearl (University of Arizona)
• Abstract:

  Great uncertainty exists in determining the impact of global environmental change on forested ecosystems. Many factors play a role in this uncertainty including the climatological and ecological environment affecting tree growth, the broad range of conditions created by environmental heterogeneity through time and over space, and then genetic differences between trees at the individual level. We present a new framework using the climatic response of individual trees to determine the vulnerability of tree populations to climatic change. The framework for inferring vulnerability here is the interplay between the range of climatic sensitivity in a population at the tree level and potential changes in climate. For example, if a population of trees has a narrower range of climatic sensitivity (smaller variance or range of climatic sensitivity within the site), then growth and, potentially, survival of trees in that population will act in chorus in the response to the vagaries of climatic change. In the practical sense, if most trees in a population grow better with more water availability during the summer, but in different populations some trees grow positively, neutrally, or negatively with greater water variability, most of the trees in the former population will be more vulnerable during a severe, multiannual drought than those in the latter population. Here, we present how this framework is expressed in a network of 18 Chamaecyparis thyoides (Atlantic white cedar) populations along coastal eastern North America. Surprisingly, we find the central populations of our Chamaecyparis thyoides network to be more vulnerable to climate than southern or northern populations, particularly in regards to summer moisture availability. Upscaling how variability at spatial scales from tree to population to region could affect conservation in the context of climatic change and species vulnerability: If some trees survive climatic change, the population could persist. If some populations survive, the species could persist at regional level.

• Research Category: Regional Studies
  Historical and Retrospective Studies
  Conservation and Management


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