avg_tree_curve function

Generate the curve of a forest's average tree using the Kozak taper model

Generate a ggplot curve of a forest's average tree using the Kozak taper model (Kozak, Munro and Smith, 1969).

avg_tree_curve(
  df,
  d,
  dbh,
  h,
  th,
  facet = NA,
  color = NA,
  eq = TRUE,
  mirror = TRUE
)

Arguments

• df: A data frame.
• d: Quoted name of the section diameter variable, in cm.
• dbh: Quoted name of the diameter at breast height variable, in cm.
• h: Quoted name of the section height variable, in meters.
• th: Quoted name of the total height variable, in meters.
• facet: Optional argument. If supplied with the Quoted name of a factor variable(s), this variable is used to divide the plot into facets. Default: NA.
• color: Quoted name of a variable. If supplied, this variable will be used to classify the data by color. Default: NA.
• eq: if TRUE, Kozak's taper model is adjusted and the equation is shown on the plot. Default TRUE
• mirror: if TRUE, the plot will be mirrored, to resemble the shape of a tree. Default: TRUE

Returns

A ggplot object.

Examples

library(forestmangr)
data("exfm7")
head(exfm7)

# Get the data's average tree curve inserting the section diameter and height,
# total height and dbh variables: 
avg_tree_curve(df=exfm7,d="di_wb",dbh="DBH",h="hi",th="TH",eq=FALSE)

# It's possible to get the average tree curve of each strata with the facet arg.,
# and divide the data by color with the color argument:
avg_tree_curve(exfm7,"di_wb","DBH","hi","TH","STRATA","GENCODE",FALSE)

References

Kozak, A., Munro, D. D. and Smith, J. H. G. (1969) Taper Functions and their Application in Forest Inventory, The Forestry Chronicle, 45, pp. 278–283.

Author(s)

Sollano Rabelo Braga sollanorb@gmail.com