Heterogeneity in fire severity within early season and late season prescribed burns in a mixed-conifer forest
Document Type: Journal Article
Author(s): Eric E. Knapp; Jon E. Keeley
Publication Year: 2006

Cataloging Information

  • FFS - Fire and Fire Surrogate Study
  • fire severity
  • landscape heterogeneity
  • season of burn
  • seasonal effects
  • Sequoia National Park
  • Sierra Nevada mixed-conifer
JFSP Project Number(s):
Record Maintained By:
Record Last Modified: July 31, 2019
FRAMES Record Number: 235


Structural heterogeneity in forests of the Sierra Nevada was historically produced through variation in fire regimes and local environmental factors. The amount of heterogeneity that prescription burning can achieve might now be more limited owing to high fuel loads and increased fuel continuity. Topography, woody fuel loading, and vegetative composition were quantified in plots within replicated early and late season burn units. Two indices of fire severity were evaluated in the same plots after the burns. Scorch height ranged from 2.8 to 25.4 m in early season plots and 3.1 to 38.5 m in late season plots, whereas percentage of ground surface burned ranged from 24 to 96% in early season plots and from 47 to 100% in late season plots. Scorch height was greatest in areas with steeper slopes, higher basal area of live trees, high percentage of basal area composed of pine, and more small woody fuel. Percentage of area burned was greatest in areas with less bare ground and rock cover (more fuel continuity), steeper slopes, and units burned in the fall (lower fuel moisture). Thus topographic and biotic factors still contribute to the abundant heterogeneity in fire severity with prescribed burning, even under the current high fuel loading conditions. Burning areas with high fuel loads in early season when fuels are moister may lead to patterns of heterogeneity in fire effects that more closely approximate the expected patchiness of historical fires.

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Link to this document (154 KB; full text; pdf)
Knapp, Eric E.; Keeley Jon E. 2006. Heterogeneity in fire severity within early season and late season prescribed burns in a mixed-conifer forest. International Journal of Wildland Fire 15(1):37-45.