R/crown_base_height.r

In nrcan-cfs-fire/cffdrs: Canadian Forest Fire Danger Rating System

crown_base_height <- function(FUELTYPE, CBH, SD, SH) {
  # logic originally in fbp() pulled into its own function
  CBHs <- c(
    2, 3, 8, 4, 18, 7, 10,
    0, 6, 6, 6, 6, 0, 0, 0, 0, 0
  )
  names(CBHs) <- c(
    "C1", "C2", "C3", "C4", "C5", "C6", "C7",
    "D1", "M1", "M2", "M3", "M4", "S1", "S2", "S3", "O1A", "O1B"
  )
  CBH <- ifelse(
    CBH <= 0 | CBH > 50 | is.na(CBH),
    ifelse(
      FUELTYPE %in% c("C6") & SD > 0 & SH > 0,
      -11.2 + 1.06 * SH + 0.0017 * SD,
      CBHs[FUELTYPE]
    ),
    CBH
  )
  CBH <- ifelse(CBH < 0, 1e-07, CBH)
  return(CBH)
}