Skip to contents

Fuel stratification and fuel characteristics

Source: R/RcppExports.R
fuel_properties.Rd

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).

Usage

fuel_stratification(
  object,
  SpParams,
  gdd = NA_real_,
  heightProfileStep = 10,
  maxHeightProfile = 5000,
  bulkDensityThreshold = 0.05
)

fuel_FCCS(
  object,
  SpParams,
  cohortFMC = as.numeric(c()),
  loadingOffset = as.numeric(c(0, 0, 0, 0, 0)),
  gdd = NA_real_,
  heightProfileStep = 10,
  maxHeightProfile = 5000,
  bulkDensityThreshold = 0.05,
  depthMode = "crownaverage"
)

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.

loadingOffset

A vector of length five with fine fuel loading values (canopy, shrub, herb, woody and litter) to be added to loading estimations from forest.

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.

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).

References

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

Author

Miquel De Cáceres Ainsa, CREAF

Examples

#Load example plot plant data
data(exampleforest)

#Default species parameterization
data(SpParamsMED)

#Show stratification of fuels
fuel_stratification(exampleforest, SpParamsMED)
#> $surfaceLayerBaseHeight
#> [1] 0
#> 
#> $surfaceLayerTopHeight
#> [1] 10
#> 
#> $surfaceLayerAbsoluteBaseHeight
#> [1] 10
#> 
#> $surfaceLayerAbsoluteTopHeight
#> [1] 80
#> 
#> $understoryLAI
#> [1] 0
#> 
#> $canopyBaseHeight
#> [1] 280
#> 
#> $canopyTopHeight
#> [1] 760
#> 
#> $canopyAbsoluteBaseHeight
#> [1] 240
#> 
#> $canopyAbsoluteTopHeight
#> [1] 790
#> 
#> $canopyLAI
#> [1] 1.695727
#> 
  
#Calculate fuel properties according to FCCS
fccs <- fuel_FCCS(exampleforest, SpParamsMED)
fccs
#>                 w  cover hbc htc habc hatc       delta        rhob     rhop
#> canopy 0.62413684 100.00 2.8 7.6  2.4  7.9 4.960217784  0.12582851 570.3129
#> shrub  0.01561312   3.75 0.0 0.1  0.1  0.8 0.642625347  0.02429584 628.1644
#> herb   0.00000000   0.00 0.0  NA  0.0   NA 0.000000000  0.00000000 400.0000
#> woody  0.22731400     NA 0.0  NA  0.0   NA 0.008600605 26.43000000 730.0000
#> litter 0.23084538     NA 0.0  NA  0.0   NA 0.010374497 22.25123541 366.9009
#>                  PV         beta   betarel etabetarel     sigma        pDead
#> canopy 1.138507e-03 2.295276e-04 0.1593580  0.3693686  5531.511 0.0004377814
#> shrub  2.485515e-05 3.867752e-05 0.2788513  0.5735398  4141.000 0.0006800000
#> herb   0.000000e+00 0.000000e+00 1.6654521  0.8561108 11483.000 0.0000000000
#> woody  3.113890e-04 3.620548e-02 1.6654521  0.8561108  1601.050 1.0000000000
#> litter 6.291765e-04 6.064645e-02 8.7556347  0.1577217  7083.948 1.0000000000
#>              FAI        h           RV   MinFMC    MaxFMC ActFMC
#> canopy 6.4740133 21411.15 1.094376e-03 55.01978 118.81135     NA
#> shrub  0.1029252 20000.00 2.485515e-05 62.68714  98.39177     NA
#> herb   0.0000000 18608.00 0.000000e+00       NA        NA     NA
#> woody  0.4985494 18608.00 3.113890e-04       NA        NA     NA
#> litter 4.4570531 18608.00 6.291765e-04       NA        NA     NA