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Title: Forest phenology and a warmer climate - Growing season extension in relation to climatic provenance

Abstract

Predicting forest responses to warming climates relies on assumptions about niche and temperature sensitivity that remain largely untested. Observational studies have related current and historical temperatures to phenological shifts, but experimental evidence is sparse, particularly for autumn responses. A five-year field experiment exposed four deciduous forest species from contrasting climates (Liquidambar styraciflua, Quercus rubra, Populus grandidentata, and Betula alleghaniensis) to air temperatures 2 and 4 C above ambient controls. Impacts of year-round warming on bud burst (BB), senescence and abscission were evaluated in relation to thermal provenance. Leaves emerged earlier in all species, by an average of 6-9 days at +2 and +4 C. Magnitude of advance varied with species and year, but was larger for the first 2 C increment than the second. The effect of warming increased with early BB, favoring Liquidambar, from the warmest climate, but even BB in northern species advanced, despite temperatures well beyond those of the realized niche. Treatment differences in BB were poorly explained by temperature sums, which increased with treatment. In autumn, chlorophyll was retained an average of 4 and 7 days longer in +2 and +4 C treatments, and abscission delayed by 8 and 13 days. Species differences in autumn responsesmore » were marginally significant. Growing seasons in the warmer atmospheres were 6 - 28 days longer, with the least impact in Quercus. Results are compared with a 16-year record of canopy onset and offset in a nearby upland deciduous forest, where BB showed similar responsiveness to spring temperatures (2 - 4 days C-1). Offset dates in the stand tracked August-September temperatures, except when late summer drought caused premature senescence. The common garden-like experimental approach provides evidence that warming alone extends the growing season, at both ends, even if stand-level impacts are complicated by other environmental factors.« less

Authors:
 [1];  [1];  [1];  [1];  [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Oak Ridge National Environmental Research Park
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1054994
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Global Change Biology
Additional Journal Information:
Journal Volume: 18; Journal Issue: 6; Journal ID: ISSN 1354-1013
Country of Publication:
United States
Language:
English
Subject:
Climate change; phenology; spring; autumn; trees; forest; warming; Betula alleghaniensis; Quercus rubra; Liquidambar styraciflua; Populus grandidentata; oak; birch; sweetgum; aspen

Citation Formats

Gunderson, Carla A, Edwards, Nelson T, Walker, Ashley V, O'Hara, Keiran H, Campion, Christina M, and Hanson, Paul J. Forest phenology and a warmer climate - Growing season extension in relation to climatic provenance. United States: N. p., 2012. Web. doi:10.1111/j.1365-2486.2011.02632.x.
Gunderson, Carla A, Edwards, Nelson T, Walker, Ashley V, O'Hara, Keiran H, Campion, Christina M, & Hanson, Paul J. Forest phenology and a warmer climate - Growing season extension in relation to climatic provenance. United States. doi:10.1111/j.1365-2486.2011.02632.x.
Gunderson, Carla A, Edwards, Nelson T, Walker, Ashley V, O'Hara, Keiran H, Campion, Christina M, and Hanson, Paul J. Sun . "Forest phenology and a warmer climate - Growing season extension in relation to climatic provenance". United States. doi:10.1111/j.1365-2486.2011.02632.x.
@article{osti_1054994,
title = {Forest phenology and a warmer climate - Growing season extension in relation to climatic provenance},
author = {Gunderson, Carla A and Edwards, Nelson T and Walker, Ashley V and O'Hara, Keiran H and Campion, Christina M and Hanson, Paul J},
abstractNote = {Predicting forest responses to warming climates relies on assumptions about niche and temperature sensitivity that remain largely untested. Observational studies have related current and historical temperatures to phenological shifts, but experimental evidence is sparse, particularly for autumn responses. A five-year field experiment exposed four deciduous forest species from contrasting climates (Liquidambar styraciflua, Quercus rubra, Populus grandidentata, and Betula alleghaniensis) to air temperatures 2 and 4 C above ambient controls. Impacts of year-round warming on bud burst (BB), senescence and abscission were evaluated in relation to thermal provenance. Leaves emerged earlier in all species, by an average of 6-9 days at +2 and +4 C. Magnitude of advance varied with species and year, but was larger for the first 2 C increment than the second. The effect of warming increased with early BB, favoring Liquidambar, from the warmest climate, but even BB in northern species advanced, despite temperatures well beyond those of the realized niche. Treatment differences in BB were poorly explained by temperature sums, which increased with treatment. In autumn, chlorophyll was retained an average of 4 and 7 days longer in +2 and +4 C treatments, and abscission delayed by 8 and 13 days. Species differences in autumn responses were marginally significant. Growing seasons in the warmer atmospheres were 6 - 28 days longer, with the least impact in Quercus. Results are compared with a 16-year record of canopy onset and offset in a nearby upland deciduous forest, where BB showed similar responsiveness to spring temperatures (2 - 4 days C-1). Offset dates in the stand tracked August-September temperatures, except when late summer drought caused premature senescence. The common garden-like experimental approach provides evidence that warming alone extends the growing season, at both ends, even if stand-level impacts are complicated by other environmental factors.},
doi = {10.1111/j.1365-2486.2011.02632.x},
journal = {Global Change Biology},
issn = {1354-1013},
number = 6,
volume = 18,
place = {United States},
year = {2012},
month = {1}
}