fuel_properties: Fuel stratification and fuel characteristics

In medfate: Mediterranean Forest Simulation

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_real_,
  heightProfileStep = 10,
  maxHeightProfile = 5000,
  bulkDensityThreshold = 0.05
)

fuel_FCCS(
  object,
  SpParams,
  cohortFMC = as.numeric(c()),
  gdd = NA_real_,
  heightProfileStep = 10,
  maxHeightProfile = 5000,
  bulkDensityThreshold = 0.05,
  depthMode = "crownaverage"
)

fuel_windAdjustmentFactor(
  topShrubHeight,
  bottomCanopyHeight,
  topCanopyHeight,
  canopyCover
)

Arguments

object	An object of class forest
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.
cohortFMC	A numeric vector of (actual) fuel moisture content by cohort.
depthMode	Specifies how fuel depth (and therefore canopy and understory bulk density) should be estimated: "crownaverage": As weighed average of crown lengths using loadings as weights. "profile": As the difference of base and top heights in bulk density profiles. "absoluteprofile": As the difference of absolute base and absolute top heights in bulk density profiles.
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).

• 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).

• ActFMC: Actual fuel moisture content (as percent over dry weight). These are set to NA if parameter cohortFMC is empty.

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_cohortFineFMC returns a list with three matrices (for leaves, twigs and fine fuels). Each of them contains live moisture content values for each day (in rows) and plant cohort (in columns).

Function fuel_windAdjustmentFactor returns a value between 0 and 1.

Author(s)

Miquel De Cáceres Ainsa, CREAF

References

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

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 273–282.

See Also

fire_FCCS, spwb

Examples

#Load example plot plant data
data(exampleforestMED)

#Default species parameterization
data(SpParamsMED)

#Show stratification of fuels
fuel_stratification(exampleforestMED, SpParamsMED)
  
#Calculate fuel properties according to FCCS
fccs = fuel_FCCS(exampleforestMED, SpParamsMED)
fccs

fuel_windAdjustmentFactor(fccs$htc[2], fccs$hbc[1], fccs$htc[1], fccs$cover[1])

medfate documentation built on Aug. 29, 2023, 5:07 p.m.