fit_clutter: Fit the Clutter model for growth and yield

In forestmangr: Forest Mensuration and Management

Fit the Clutter model for growth and yield

Description

Fit the Clutter model for growth and yield using the two stage least squares method (2SLS).

Usage

fit_clutter(
  df,
  age,
  dh,
  basal_area,
  volume,
  site,
  plot,
  .groups = NA,
  model = "full",
  keep_model = FALSE
)

Arguments

df	A data frame.
age	Quoted name for the age variable.
dh	Quoted name for the dominant height variable.
basal_area	Quoted name for the basal area variable.
volume	Quoted name for the volume area variable.
site	Quoted name for the site variable.
plot	Quoted name for the plot variable.
.groups	Optional argument. Quoted name(s) of grouping variables used to fit multiple regressions, one for each level of the provided variable(s). Default NA.
model	Character variable for the type of the model fitted. If "full", the full model will be used. if "mod", a modified model will be fitted, where the X3 variable is excluded from the regression. Default: full.
keep_model	If TRUE a variable with the regression model will be kept in the data frame. Default: FALSE.

Value

A data frame with the regression coefficients.

Author(s)

Sollano Rabelo Braga [e-mail]

References

Clutter, J. L. (1963) Compatible Growth For Loblolly by the Southeastern, Forest Science, 9(3), pp. 354–371. Sullivan, A. D. and Clutter, J. L. (1972) A Simultaneous Growth and Yield for Loblolly Pine, Forest Science, 18(1), pp. 76–86. Campos, J. C. C. and Leite, H. G. (2017) Mensuracao Florestal: Perguntas e Respostas. 5a. Vicosa: UFV.

See Also

other sampling functions: est_clutter for estimating the Clutter growth and yield model variables, and classify_site for classifying data according to site.

Examples

library(forestmangr)
data("exfm17")
head(exfm17)

# To fit the Clutter model we just need to define the data, and age, dominant height,
# basal area, volume, site and plot variables:
fit_clutter(exfm17, "age", "DH", "B", "V", "S", "plot")

# To fit the alternate model (without a1) just use model="mod":
fit_clutter(exfm17, "age", "DH", "B", "V", "S", "plot",model="mod")

# To keep the regression model, use keep_model=TRUE:
fit_clutter(exfm17, "age", "DH", "B", "V", "S", "plot", keep_model=TRUE) 
             

forestmangr documentation built on Nov. 24, 2023, 1:07 a.m.