Average stand age from forest inventory plots does not describe historical fire regimes in ponderosa pine and mixed-conifer forests of western North America

Jens T. Stevens, Hugh D. Safford, Malcolm P. North, Jeremy S. Fried, Andrew N. Gray, Peter M. Brown, Christopher R. Dolanc, Solomon Z. Dobrowski, Donald A. Falk, Calvin A. Farris, Jerry F. Franklin, Peter Z Fule, R. Keala Hagmann, Eric E. Knapp, Jay D. Miller, Douglas F. Smith, Thomas W. Swetnam, Alan H. Taylor

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

Quantifying historical fire regimes provides important information for managing contemporary forests. Historical fire frequency and severity can be estimated using several methods; each method has strengths and weaknesses and presents challenges for interpretation and verification. Recent efforts to quantify the timing of historical high-severity fire events in forests of western North America have assumed that the "stand age" variable from the US Forest Service Forest Inventory and Analysis (FIA) program reflects the timing of historical high-severity (i.e. stand-replacing) fire in ponderosa pine and mixed-conifer forests. To test this assumption, we re-analyze the dataset used in a previous analysis, and compare information from fire history records with information from co-located FIA plots. We demonstrate that 1) the FIA stand age variable does not reflect the large range of individual tree ages in the FIA plots: older trees comprised more than 10% of pre-stand age basal area in 58% of plots analyzed and more than 30% of pre-stand age basal area in 32% of plots, and 2) recruitment events are not necessarily related to high-severity fire occurrence. Because the FIA stand age variable is estimated from a sample of tree ages within the tree size class containing a plurality of canopy trees in the plot, it does not necessarily include the oldest trees, especially in uneven-aged stands. Thus, the FIA stand age variable does not indicate whether the trees in the predominant size class established in response to severe fire, or established during the absence of fire. FIA stand age was not designed to measure the time since a stand-replacing disturbance. Quantification of historical "mixed-severity" fire regimes must be explicit about the spatial scale of high-severity fire effects, which is not possible using FIA stand age data.

Original languageEnglish (US)
Article numbere0147688
JournalPLoS One
Volume11
Issue number5
DOIs
StatePublished - May 1 2016

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Pinus ponderosa
Coniferophyta
fire regime
forest inventory
mixed forests
North America
coniferous forests
Fires
Equipment and Supplies
fire severity
tree classes
tree age
basal area
uneven-aged stands
USDA Forest Service
Forests
canopy

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Average stand age from forest inventory plots does not describe historical fire regimes in ponderosa pine and mixed-conifer forests of western North America. / Stevens, Jens T.; Safford, Hugh D.; North, Malcolm P.; Fried, Jeremy S.; Gray, Andrew N.; Brown, Peter M.; Dolanc, Christopher R.; Dobrowski, Solomon Z.; Falk, Donald A.; Farris, Calvin A.; Franklin, Jerry F.; Fule, Peter Z; Keala Hagmann, R.; Knapp, Eric E.; Miller, Jay D.; Smith, Douglas F.; Swetnam, Thomas W.; Taylor, Alan H.

In: PLoS One, Vol. 11, No. 5, e0147688, 01.05.2016.

Research output: Contribution to journalArticle

Stevens, JT, Safford, HD, North, MP, Fried, JS, Gray, AN, Brown, PM, Dolanc, CR, Dobrowski, SZ, Falk, DA, Farris, CA, Franklin, JF, Fule, PZ, Keala Hagmann, R, Knapp, EE, Miller, JD, Smith, DF, Swetnam, TW & Taylor, AH 2016, 'Average stand age from forest inventory plots does not describe historical fire regimes in ponderosa pine and mixed-conifer forests of western North America', PLoS One, vol. 11, no. 5, e0147688. https://doi.org/10.1371/journal.pone.0147688
Stevens, Jens T. ; Safford, Hugh D. ; North, Malcolm P. ; Fried, Jeremy S. ; Gray, Andrew N. ; Brown, Peter M. ; Dolanc, Christopher R. ; Dobrowski, Solomon Z. ; Falk, Donald A. ; Farris, Calvin A. ; Franklin, Jerry F. ; Fule, Peter Z ; Keala Hagmann, R. ; Knapp, Eric E. ; Miller, Jay D. ; Smith, Douglas F. ; Swetnam, Thomas W. ; Taylor, Alan H. / Average stand age from forest inventory plots does not describe historical fire regimes in ponderosa pine and mixed-conifer forests of western North America. In: PLoS One. 2016 ; Vol. 11, No. 5.
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