Dendroecological Methods for Reconstructing High-Severity Fire in Pine-Oak Forests

Christopher H. Guiterman, Ellis Q. Margolis, Thomas Swetnam

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Recent high-severity fires in pine-oak forests of the southwestern United States are creating shrubfields that may persist for decades to centuries. Shrubfields embedded in conifer forests that pre-date documentary records are potential evidence of older high-severity fire patches, and may therefore provide insights into the occurrence and extent of past high-severity fires and vegetation type conversion dynamics. In this paper we test whether dendroecological evidence can be used to reconstruct a high-severity, type-changing fire of known date in a ponderosa pine-dominated (Pinus ponderosa var scopulorum Engelm.) forest. Dendroecological evidence included (1) Gambel oak (Quercus gambelii, Nutt.) regeneration dates, (2) fire scars, (3) death dates, and (4) tree-ring growth changes. We reconstructed the historical fire regime and fire-climate relationship to evaluate whether the recent high-severity fire was driven by climate or fuel build-up related to a fire regime disruption. The dendroecological evidence correctly dated the year (1993) and season (spring) of the documented fire, and synchronous oak re-sprouts provided a means to estimate the minimum high-severity patch size. The historical fire regime at the site (1625-1871) consisted of frequent, low-severity fires occurring in dry years preceded by wet years. Fires stopped in 1871, coincident with increased regional livestock grazing. The 1993 fire occurred under relatively cool and wet conditions, but followed a 122-year fire-free interval (four times the maximum historical interval). Multiple lines of evidence suggest that increased fuel loads from fire exclusion, combined with high winds, were primary drivers of the high-severity fire. The dendroecological approach we outline can be applied to reconstruct high-severity fire across a range of conifer-shrubland ecosystems.

Original languageEnglish (US)
Pages (from-to)67-77
Number of pages11
JournalTree-Ring Research
Volume71
Issue number2
DOIs
StatePublished - Jul 1 2015

Fingerprint

fire severity
Quercus
Pinus
fire regime
Quercus gambelii
fuels (fire ecology)
Pinus ponderosa
methodology
fire scars
climate
wet environmental conditions
Southwestern United States
growth rings
method
oak
shrublands
vegetation types
coniferous forests
conifers
livestock

Keywords

  • fire scar
  • Gambel oak
  • high-severity fire
  • pineoak
  • ponderosa pine
  • Quercus gambelii
  • shrubland
  • tree rings

ASJC Scopus subject areas

  • Forestry
  • Atmospheric Science
  • Geology
  • Palaeontology

Cite this

Dendroecological Methods for Reconstructing High-Severity Fire in Pine-Oak Forests. / Guiterman, Christopher H.; Margolis, Ellis Q.; Swetnam, Thomas.

In: Tree-Ring Research, Vol. 71, No. 2, 01.07.2015, p. 67-77.

Research output: Contribution to journalArticle

Guiterman, Christopher H. ; Margolis, Ellis Q. ; Swetnam, Thomas. / Dendroecological Methods for Reconstructing High-Severity Fire in Pine-Oak Forests. In: Tree-Ring Research. 2015 ; Vol. 71, No. 2. pp. 67-77.
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