Extreme late-summer drought causes neutral annual carbon balance in southwestern ponderosa pine forests and grasslands

Thomas E Kolb, Sabina Dore, Mario Montes-Helu

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

We assessed the impacts of extreme late-summer drought on carbon balance in a semi-arid forest region in Arizona. To understand drought impacts over extremes of forest cover, we measured net ecosystem production (NEP), gross primary production (GPP), and total ecosystem respiration (TER) with eddy covariance over five years (2006-10) at an undisturbed ponderosa pine (Pinus ponderosa) forest and at a former forest converted to grassland by intense burning. Drought shifted annual NEP from a weak source of carbon to the atmosphere to a neutral carbon balance at the burned site and from a carbon sink to neutral at the undisturbed site. Carbon fluxes were particularly sensitive to drought in August. Drought shifted August NEP at the undisturbed site from sink to source because the reduction of GPP (70%) exceeded the reduction of TER (35%). At the burned site drought shifted August NEP from weak source to neutral because the reduction of TER (40%) exceeded the reduction of GPP (20%). These results show that the lack of forest recovery after burning and the exposure of undisturbed forests to late-summer drought reduce carbon sink strength and illustrate the high vulnerability of forest carbon sink strength in the southwest US to predicted increases in intense burning and precipitation variability.

Original languageEnglish (US)
Article number015015
JournalEnvironmental Research Letters
Volume8
Issue number1
DOIs
StatePublished - 2013

Fingerprint

Pinus ponderosa
Drought
Droughts
carbon balance
Ecosystems
Ecosystem
Carbon
net ecosystem production
grassland
drought
Carbon Sequestration
summer
carbon sink
primary production
Respiration
respiration
ecosystem
Southwestern United States
Carbon Cycle
eddy covariance

Keywords

  • Arizona
  • carbon balance
  • drought
  • eddy covariance

ASJC Scopus subject areas

  • Environmental Science(all)
  • Renewable Energy, Sustainability and the Environment
  • Public Health, Environmental and Occupational Health

Cite this

Extreme late-summer drought causes neutral annual carbon balance in southwestern ponderosa pine forests and grasslands. / Kolb, Thomas E; Dore, Sabina; Montes-Helu, Mario.

In: Environmental Research Letters, Vol. 8, No. 1, 015015, 2013.

Research output: Contribution to journalArticle

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