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medfate (version 0.2.2)

fuel.properties: Fuel stratification and fuel characteristics

Description

Function fuel.Stratification provides a stratification of the stand into understory and canopy strata. Function fuel.FCCS calculates fuel characteristics from a forest object following an adaptation of the protocols described for the Fuel Characteristics Classification System (Prichard et al. 2013). Function fuel.WindAdjustmentFactor determines the adjustment factor of wind for surface fires, according to Andrews (2012).

Usage

fuel.Stratification(object, SpParams, gdd = NA, 
                      heightProfileStep = 10.0, maxHeightProfile = 5000.0,
                      bulkDensityThreshold = 0.05)
fuel.FCCS(object, ShrubCover, CanopyCover, SpParams, 
          gdd = NA, heightProfileStep = 10, maxHeightProfile = 5000, 
          bulkDensityThreshold = 0.05)
fuel.WindAdjustmentFactor(topShrubHeight, bottomCanopyHeight, topCanopyHeight,
                          canopyCover)

Arguments

object

An object of class link{forest}

ShrubCover

Total shrub cover (in percent) of the stand.

CanopyCover

Total canopy cover (in percent) of the stand.

SpParams

A data frame with species parameters (see SpParamsMED).

gdd

Growth degree-days.

heightProfileStep

Precision for the fuel bulk density profile.

maxHeightProfile

Maximum height for the fuel bulk density profile.

bulkDensityThreshold

Minimum fuel bulk density to delimit fuel strata.

topShrubHeight

Shrub stratum top height (in m).

bottomCanopyHeight

Canopy base height (in m).

topCanopyHeight

Canopy top height (in m).

canopyCover

Canopy percent cover.

Value

Function fuel.FCCS returns a data frame with five rows corresponding to fuel layers: canopy, shrub, herb, woody and litter. Columns correspond fuel properties:

  • w: Fine fuel loading (in kg/m2).

  • cover: Percent cover.

  • hbc: Height to base of crowns (in m).

  • htc: Height to top of crowns (in m).

  • delta: Fuel depth (in m).

  • rhob: Fuel bulk density (in kg/m3).

  • rhop: Fuel particle density (in kg/m3).

  • PV: Particle volume (in m3/m2).

  • beta: Packing ratio (unitless).

  • betarel: Relative packing ratio (unitless).

  • etabetarel: Reaction efficiency (unitless).

  • sigma: Surface area-to-volume ratio (m2/m3).

  • pDead: Proportion of dead fuels.

  • FAI: Fuel area index (unitless).

  • h: High heat content (in kJ/kg).

  • etaF: Flammability modifier (between 1 and 2).

  • RV: Reactive volume (in m3/m2).

  • MinFMC: Minimum fuel moisture content (as percent over dry weight).

  • MaxFMC: Maximum fuel moisture content (as percent over dry weight).

Function fuel.Stratification returns a list with the following items:

  • surfaceLayerBaseHeight: Base height of crowns of shrubs in the surface layer (in cm).

  • surfaceLayerTopHeight: Top height of crowns of shrubs in the surface layer (in cm).

  • understoryLAI: Cumulated LAI of the understory layer (i.e. leaf area comprised between surface layer base and top heights).

  • canopyBaseHeight: Base height of tree crowns in the canopy (in cm).

  • canopyTopHeight: Top height of tree crowns in the canopy (in cm).

  • canopyLAI: Cumulated LAI of the canopy (i.e. leaf area comprised between canopy base and top heights).

Function fuel.WindAdjustmentFactor returns a value between 0 and 1.

Details

Details are described in a vignette.

References

Andrews, P. L. 2012. Modeling wind adjustment factor and midflame wind speed for Rothermel<U+2019>s surface fire spread model. USDA Forest Service - General Technical Report RMRS-GTR:1<U+2013>39.

Prichard, S. J., D. V Sandberg, R. D. Ottmar, E. Eberhardt, A. Andreu, P. Eagle, and K. Swedin. 2013. Classification System Version 3.0: Technical Documentation.

Reinhardt, E., D. Lutes, and J. Scott. 2006. FuelCalc: A method for estimating fuel characteristics. Pages 273<U+2013>282.

See Also

fire.FCCS

Examples

Run this code
# NOT RUN {
#Load example plot plant data
data(exampleforest)

#Default species parameterization
data(SpParamsMED)

#Show stratification of fuels
fuel.Stratification(exampleforest, SpParamsMED)

#Calculate fuel properties according to FCCS
fccs = fuel.FCCS(exampleforest, 50,100, SpParamsMED)
fccs

fuel.WindAdjustmentFactor(fccs$htc[2], fccs$hbc[1], fccs$htc[1], fccs$cover[1])
# }

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