skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Reevaluating growing season length controls on net ecosystem production in evergreen conifer forests

Abstract

Growing season length (GSL) is a key unifying concept in ecology that can be estimated from eddy covariance-derived estimates of net ecosystem production (NEP). Previous studies disagree on how increasing GSLs may affect NEP in evergreen coniferous forests, potentially due to the variety of methods used to quantify GSL from NEP. We calculated GSL and GSL-NEP regressions at eleven evergreen conifer sites across a broad climatic gradient in western North America using three common approaches: (1) variable length (3–7 days) regressions of day of year versus NEP, (2) a smoothed threshold approach, and (3) the carbon uptake period, followed by a new approach of a method-averaged ensemble. The GSL and the GSL-NEP relationship differed among methods, resulting in linear relationships with variable sign, slope, and statistical significance. For all combinations of sites and methods, the GSL explained between 6% and 82% of NEP with p-values ranging from 0.45 to < 0.01. These results demonstrate the variability among GSL methods and the importance of selecting an appropriate method to accurately project the ecosystem carbon cycling response to longer growing seasons in the future. To encourage this approach in future studies, we outline a series of best practices for GSL method selectionmore » depending on research goals and the annual NEP dynamics of the study site(s). These results contribute to understanding growing season dynamics at ecosystem and continental scales and underscore the potential for methodological variability to influence forecasts of the evergreen conifer forest response to climate variability.« less

Authors:
ORCiD logo [1]; ORCiD logo [2];  [1];  [3];  [4];  [5];  [1]
  1. U.S. Geological Survey, Boulder, CO (United States); Univ. of Colorado Boulder, Boulder, CO (United States). Inst. of Arctic and Alpine Research
  2. Univ. of Colorado Boulder, Boulder, CO (United States). Inst. of Arctic and Alpine Research; Univ. of Arizona, Tucson, AZ (United States)
  3. Univ. of California, Irvine, CA (United States)
  4. Univ. of Arizona, Tucson, AZ (United States)
  5. Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Biology
Publication Date:
Research Org.:
Univ. of Colorado, Boulder, CO (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1610912
Grant/Contract Number:  
SC0006968
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 8; Journal Issue: 1; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; Science & Technology

Citation Formats

Barnard, David M., Knowles, John F., Barnard, Holly R., Goulden, Michael L., Hu, Jia, Litvak, Marcy E., and Molotch, Noah P. Reevaluating growing season length controls on net ecosystem production in evergreen conifer forests. United States: N. p., 2018. Web. doi:10.1038/s41598-018-36065-0.
Barnard, David M., Knowles, John F., Barnard, Holly R., Goulden, Michael L., Hu, Jia, Litvak, Marcy E., & Molotch, Noah P. Reevaluating growing season length controls on net ecosystem production in evergreen conifer forests. United States. doi:10.1038/s41598-018-36065-0.
Barnard, David M., Knowles, John F., Barnard, Holly R., Goulden, Michael L., Hu, Jia, Litvak, Marcy E., and Molotch, Noah P. Wed . "Reevaluating growing season length controls on net ecosystem production in evergreen conifer forests". United States. doi:10.1038/s41598-018-36065-0. https://www.osti.gov/servlets/purl/1610912.
@article{osti_1610912,
title = {Reevaluating growing season length controls on net ecosystem production in evergreen conifer forests},
author = {Barnard, David M. and Knowles, John F. and Barnard, Holly R. and Goulden, Michael L. and Hu, Jia and Litvak, Marcy E. and Molotch, Noah P.},
abstractNote = {Growing season length (GSL) is a key unifying concept in ecology that can be estimated from eddy covariance-derived estimates of net ecosystem production (NEP). Previous studies disagree on how increasing GSLs may affect NEP in evergreen coniferous forests, potentially due to the variety of methods used to quantify GSL from NEP. We calculated GSL and GSL-NEP regressions at eleven evergreen conifer sites across a broad climatic gradient in western North America using three common approaches: (1) variable length (3–7 days) regressions of day of year versus NEP, (2) a smoothed threshold approach, and (3) the carbon uptake period, followed by a new approach of a method-averaged ensemble. The GSL and the GSL-NEP relationship differed among methods, resulting in linear relationships with variable sign, slope, and statistical significance. For all combinations of sites and methods, the GSL explained between 6% and 82% of NEP with p-values ranging from 0.45 to < 0.01. These results demonstrate the variability among GSL methods and the importance of selecting an appropriate method to accurately project the ecosystem carbon cycling response to longer growing seasons in the future. To encourage this approach in future studies, we outline a series of best practices for GSL method selection depending on research goals and the annual NEP dynamics of the study site(s). These results contribute to understanding growing season dynamics at ecosystem and continental scales and underscore the potential for methodological variability to influence forecasts of the evergreen conifer forest response to climate variability.},
doi = {10.1038/s41598-018-36065-0},
journal = {Scientific Reports},
issn = {2045-2322},
number = 1,
volume = 8,
place = {United States},
year = {2018},
month = {12}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 3 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

Modeling CO2 and water vapor exchange of a temperate broadleaved forest across hourly to decadal time scales
journal, August 2001


Tracking the rhythm of the seasons in the face of global change: phenological research in the 21st century
journal, June 2009

  • Morisette, Jeffrey T.; Richardson, Andrew D.; Knapp, Alan K.
  • Frontiers in Ecology and the Environment, Vol. 7, Issue 5
  • DOI: 10.1890/070217

Interannual variability and timing of growing-season CO 2 exchange in a boreal forest : INTERANNUAL VARIABILITY OF CO
journal, May 2003

  • Suni, Tanja; Berninger, Frank; Markkanen, Tiina
  • Journal of Geophysical Research: Atmospheres, Vol. 108, Issue D9
  • DOI: 10.1029/2002JD002381

A remotely sensed pigment index reveals photosynthetic phenology in evergreen conifers
journal, November 2016

  • Gamon, John A.; Huemmrich, K. Fred; Wong, Christopher Y. S.
  • Proceedings of the National Academy of Sciences, Vol. 113, Issue 46
  • DOI: 10.1073/pnas.1606162113

Topoclimate effects on growing season length and montane conifer growth in complex terrain
journal, May 2017

  • Barnard, D. M.; Barnard, H. R.; Molotch, N. P.
  • Environmental Research Letters, Vol. 12, Issue 6
  • DOI: 10.1088/1748-9326/aa6da8

Climate controls over the net carbon uptake period and amplitude of net ecosystem production in temperate and boreal ecosystems
journal, September 2017


The Global Carbon Cycle: A Test of Our Knowledge of Earth as a System
journal, October 2000


Effects of climate variability on the carbon dioxide, water, and sensible heat fluxes above a ponderosa pine plantation in the Sierra Nevada (CA)
journal, March 2000

  • Goldstein, A. H.; Hultman, N. E.; Fracheboud, J. M.
  • Agricultural and Forest Meteorology, Vol. 101, Issue 2-3
  • DOI: 10.1016/S0168-1923(99)00168-9

Evidence of threshold temperatures for xylogenesis in conifers at high altitudes
journal, December 2006


Large-scale variations in the vegetation growing season and annual cycle of atmospheric CO 2 at high northern latitudes from 1950 to 2011
journal, August 2013

  • Barichivich, Jonathan; Briffa, Keith R.; Myneni, Ranga B.
  • Global Change Biology, Vol. 19, Issue 10
  • DOI: 10.1111/gcb.12283

Growing season length as an indicator of climatic variations?
journal, January 1979


Canopy duration has little influence on annual carbon storage in the deciduous broad leaf forest
journal, July 2003


Fluxes of energy, water, and carbon dioxide from mountain ecosystems at Niwot Ridge, Colorado
journal, April 2014


Xylem phenology and wood production: resolving the chicken-or-egg dilemma: Xylem phenology and wood production
journal, September 2010


Evapotranspiration along an elevation gradient in California's Sierra Nevada: SIERRA NEVADA EVAPOTRANSPIRATION
journal, September 2012

  • Goulden, M. L.; Anderson, R. G.; Bales, R. C.
  • Journal of Geophysical Research: Biogeosciences, Vol. 117, Issue G3
  • DOI: 10.1029/2012JG002027

Observed Impact of Snow Cover on the Heat Balance and the Rise of Continental Spring Temperatures
journal, January 1994


A long-term record of carbon exchange in a boreal black spruce forest: means, responses to interannual variability, and decadal trends
journal, March 2007


Seasonal pattern of regional carbon balance in the central Rocky Mountains from surface and airborne measurements
journal, January 2011

  • Desai, Ankur R.; Moore, David J. P.; Ahue, William K. M.
  • Journal of Geophysical Research, Vol. 116, Issue G4
  • DOI: 10.1029/2011JG001655

Influence of spring and autumn phenological transitions on forest ecosystem productivity
journal, October 2010

  • Richardson, Andrew D.; Andy Black, T.; Ciais, Philippe
  • Philosophical Transactions of the Royal Society B: Biological Sciences, Vol. 365, Issue 1555
  • DOI: 10.1098/rstb.2010.0102

Growing season extension and its impact on terrestrial carbon cycle in the Northern Hemisphere over the past 2 decades: PHENOLOGY AND CARBON CYCLE IN NH
journal, September 2007

  • Piao, Shilong; Friedlingstein, Pierre; Ciais, Philippe
  • Global Biogeochemical Cycles, Vol. 21, Issue 3
  • DOI: 10.1029/2006GB002888

Longer growing seasons lead to less carbon sequestration by a subalpine forest
journal, February 2010


The influence of warm-season precipitation on the diel cycle of the surface energy balance and carbon dioxide at a Colorado subalpine forest site
journal, January 2015


Carbon sequestration studied in western U.S. mountains
journal, January 2002

  • Schimel, David; Kittel, Timothy G. F.; Running, Steven
  • Eos, Transactions American Geophysical Union, Vol. 83, Issue 40
  • DOI: 10.1029/2002EO000314

On the separation of net ecosystem exchange into assimilation and ecosystem respiration: review and improved algorithm
journal, September 2005


Satellite chlorophyll fluorescence measurements reveal large-scale decoupling of photosynthesis and greenness dynamics in boreal evergreen forests
journal, June 2016

  • Walther, Sophia; Voigt, Maximilian; Thum, Tea
  • Global Change Biology, Vol. 22, Issue 9
  • DOI: 10.1111/gcb.13200

Growing season extended in Europe
journal, February 1999

  • Menzel, Annette; Fabian, Peter
  • Nature, Vol. 397, Issue 6721
  • DOI: 10.1038/17709

A montane Mediterranean climate supports year-round photosynthesis and high forest biomass
journal, January 2016


Characteristics of evapotranspiration from a permafrost black spruce forest in interior Alaska
journal, June 2013


Climate change in mountains: a review of elevation-dependent warming and its possible causes
journal, March 2012


Identifying anomalously early spring onsets in the CESM large ensemble project
journal, August 2016


Net carbon uptake has increased through warming-induced changes in temperate forest phenology
journal, June 2014

  • Keenan, Trevor F.; Gray, Josh; Friedl, Mark A.
  • Nature Climate Change, Vol. 4, Issue 7
  • DOI: 10.1038/nclimate2253

Inter-annual variability of net and gross ecosystem carbon fluxes: A review
journal, February 2018


Joint control of terrestrial gross primary productivity by plant phenology and physiology
journal, February 2015

  • Xia, Jianyang; Niu, Shuli; Ciais, Philippe
  • Proceedings of the National Academy of Sciences, Vol. 112, Issue 9
  • DOI: 10.1073/pnas.1413090112

Phenology Feedbacks on Climate Change
journal, May 2009


Terrestrial biosphere models need better representation of vegetation phenology: results from the North American Carbon Program Site Synthesis
journal, November 2011


Effects of biotic disturbances on forest carbon cycling in the United States and Canada
journal, October 2011


Increased activity of northern vegetation inferred from atmospheric CO2 measurements
journal, July 1996

  • Keeling, C. D.; Chin, J. F. S.; Whorf, T. P.
  • Nature, Vol. 382, Issue 6587
  • DOI: 10.1038/382146a0

Persistent wind-induced enhancement of diffusive CO 2 transport in a mountain forest snowpack
journal, January 2011

  • Bowling, D. R.; Massman, W. J.
  • Journal of Geophysical Research, Vol. 116, Issue G4
  • DOI: 10.1029/2011JG001722

Spatial analysis of growing season length control over net ecosystem exchange
journal, October 2005


The AmeriFlux network: A coalition of the willing
journal, February 2018


A longer vernal window: the role of winter coldness and snowpack in driving spring transitions and lags
journal, September 2016

  • Contosta, Alexandra R.; Adolph, Alden; Burchsted, Denise
  • Global Change Biology, Vol. 23, Issue 4
  • DOI: 10.1111/gcb.13517