Table 2.

Variables included and retained during regression model selection for the reburn and salvage-plant questions

VariablesReburnSalvage-plantDefinition
Disturbance history
    Silver severity Differenced NBR from the Silver Fire, calculated from pre- and postfire Landsat TM
    Managed site Salvage-logged in 1988, 1989, or 1990, planted with conifers, then later certified as a ″successful″ plantation
Topography
    Elevation In meters from a 10-m DEM
    AspectAspect folded around south facing slopes (folded aspect = |180 − |aspect − 180‖), from 10-m DEM
    Slope In percent, from 10-m DEM
    Topographic position (fine) Difference between sample elevation and mean elevation of an annulus spanning 150–300 m from the sample
    Topographic position (intermediate)Difference between sample elevation and mean elevation of an annulus spanning 850–1,000 m from the sample
    Topographic position (coarse)Difference between sample elevation and mean elevation of an annulus spanning 1,850–2,000 m from the sample
Biophysical
    PAG Potential vegetation in the absence of disturbance, based on climatic, biogeographical and physiographic factors; obtained from RSNF
    1986 brightnessBrightness axis from tasseled cap transformation of 1986 Landsat data (15)
    1986 wetnessWetness axis from tasseled cap transformation of 1986 Landsat data (15)
    1986 greenness Greenness axis from tasseled cap transformation of 1986 Landsat TM data (15)
    SoilSoil data from Curry and Josephine counties (four soil types)
Weather and other temporal change
    Burn indexDaily fire behavior index measured using current and past weather data, heavily influenced by wind speed, Calculated by the ODF using data from the Quail Prairie, Oregon RAWS
    Energy release componentDaily fuel moisture index that reflects the contribution of live and dead fuels to potential fire intensity, Calculated by the ODF using data from the Quail Prairie, Oregon RAWS
    Day The day on which the Biscuit Fire flaming front passed (a count from the first to the last day); obtained from RSNF
  • retained in full covariate regression model after AIC model selection;

  • the variable being tested after fitting the best covariate regression model.

  • NBR, normalized burn ratio; DEM, digital elevation model; ODF, Oregon Department of Forestry; RAWS, remote automated weather station.