E_VOL_AB_HmDm_HT.f: Estimate volume for stem and sections
In jonibio/TapeR: Flexible Tree Taper Curves Based on Semiparametric Mixed Models

Description Usage Arguments Details Value Author(s) References See Also Examples

Estimate volume for a complete stem from bottom to tip or for a section defined by lower and upper diameter or height. Variances for estimated volumes are calculated.

E_VOL_AB_HmDm_HT.f(
  Hm,
  Dm,
  mHt,
  sHt = 0,
  A = NULL,
  B = NULL,
  iDH = "D",
  par.lme,
  R0 = FALSE,
  IA = F,
  nGL = 51,
  ...
)

`Hm`	Numeric vector of stem heights (m) along which diameter measurements were taken for calibration. Can be of length 1. Must be of same length as `Dm`.
`Dm`	Numeric vector of diameter measurements (cm) taken for calibration. Can be of length 1. Must be of same length as `Hm`.
`mHt`	Scalar. Tree height (m).
`sHt`	Scalar. Standard deviation of stem height. Can be 0 if height was measured without error.
`A`	Numeric scalar defining the lower threshold of a stem section for volume estimation. Depends on `iDH`. If `iDH` = "D", a diameter (cm), if `iDH` = "H", a height (m). If NULL, section starts at lowest point.
`B`	Numeric scalar defining the upper threshold of a stem section for volume estimation. Depends on `iDH`. If `iDH` = "D", a diameter (cm), if `iDH` = "H", a height (m). If NULL, section ends at tip.
`iDH`	Character scalar. Either "D" or "H". Type of threshold for section volume estimation. See `A` or `B`.
`par.lme`	List of taper model parameters obtained by `TapeR_FIT_LME.f`.
`R0`	indicator whether taper curve should interpolate measurements
`IA`	Logic scalar. If TRUE, variance calculation of height estimate based on 2-point distribution. If FALSE, variance calculation of height estimate based on Normal approximation.
`nGL`	Numeric scalar. Number of support points for numerical integration.
`...`	not currently used

calculates the volume for a complete stem or sections defined by A and B, which might be defined as diameter or height. The parameter R0 determines whether the estimated taper curve is forced through the measured points (if R0=TRUE).

a list holding nine elements:

E_VOL: Estimated volume (m^3).
VAR_VOL: Variance of the volume estimate.
Hm: Height of diameter measurement (m).
Dm: Diameter measurement (cm).
Ht: Tree height (m).
Da: Diameter at lower section threshold (cm).
Db: Diameter at upper section threshold (cm).
Ha: Height at lower section threshold (m).
Hb: Height at upper section threshold (m).
R0: Taper curve forced through measurements (if TRUE) or not (if FALSE).

Edgar Kublin

Kublin, E., Breidenbach, J., Kaendler, G. (2013) A flexible stem taper and volume prediction method based on mixed-effects B-spline regression, Eur J For Res, 132:983-997.

TapeR_FIT_LME.f

#example data
data(DxHx.df)
taper curve parameters based on all measured trees
data(SK.par.lme)

#select data of first tree
Idi <- (DxHx.df[,"Id"] == unique(DxHx.df$Id)[1])
(tree1 <- DxHx.df[Idi,])

## Calculate the timber volume for the whole stem
VOL <- E_VOL_AB_HmDm_HT.f(Hm=tree1$Hx[3], 
                          Dm=tree1$Dx[3], 
                          mHt = tree1$Ht[1],
                          sHt = 0, # no height variance assumed
                          par.lme = SK.par.lme)
VOL$E_VOL #' expected value
VOL$VAR_VOL #' corresponding variance
VOL$R0

## Calculate the timber volume for the whole stem, using R0=TRUE
VOL <- E_VOL_AB_HmDm_HT.f(Hm=tree1$Hx[3], 
                          Dm=tree1$Dx[3], 
                          mHt = tree1$Ht[1],
                          sHt = 0, # no height variance assumed
                          par.lme = SK.par.lme,
                          R0 = TRUE)
VOL$E_VOL #' expected value
VOL$VAR_VOL #' corresponding variance
VOL$R0

## Calculate the timber volume for the whole stem
VOL <- E_VOL_AB_HmDm_HT.f(Hm=tree1$Hx[3], 
                          Dm=tree1$Dx[3], 
                          mHt = tree1$Ht[1],
                          sHt = 1, # no height variance assumed
                          par.lme = SK.par.lme)
VOL$E_VOL #' expected value
VOL$VAR_VOL #' corresponding variance
VOL$R0

## Calculate the timber volume for the whole stem, using R0=TRUE
VOL <- E_VOL_AB_HmDm_HT.f(Hm=tree1$Hx[3], 
                          Dm=tree1$Dx[3], 
                          mHt = tree1$Ht[1],
                          sHt = 1, #  height variance assumed
                          par.lme = SK.par.lme,
                          R0 = TRUE)
VOL$E_VOL #' expected value
VOL$VAR_VOL #' corresponding variance
VOL$R0

## Calculate the timber volume for a selected section given a height (0.3 - 5 m)
VOL <- E_VOL_AB_HmDm_HT.f(Hm=tree1$Hx[3], 
                          Dm=tree1$Dx[3], 
                          mHt = tree1$Ht[1], 
                          sHt = 1, 
                          par.lme = SK.par.lme, 
                          A=0.3, 
                          B=5, 
                          iDH = "H")
VOL$E_VOL #' expected value
VOL$VAR_VOL #' corresponding variance
VOL$R0

## Calculate the timber volume for a selected section given a height (0.3 - 5 m)
VOL <- E_VOL_AB_HmDm_HT.f(Hm=tree1$Hx[3], 
                          Dm=tree1$Dx[3], 
                          mHt = tree1$Ht[1], 
                          sHt = 1, 
                          par.lme = SK.par.lme, 
                          A=0.3, 
                          B=5, 
                          iDH = "H", 
                          R0=TRUE)
VOL$E_VOL #' expected value
VOL$VAR_VOL #' corresponding variance
VOL$R0

## Calculate the timber volume for a selected section given a diameter
## threshold (30cm - 15cm) (negative value if A<B)
VOL <- E_VOL_AB_HmDm_HT.f(Hm=tree1$Hx[3],
                          Dm=tree1$Dx[3], 
                          mHt = tree1$Ht[1], 
                          sHt = 1, 
                          par.lme = SK.par.lme, 
                          A=30, 
                          B=15, 
                          iDH = "D")
VOL$E_VOL #' expected value
VOL$VAR_VOL #' corresponding variance

## Not run: 
## The variance estimate resulting from the tree height uncertainty using
## a Normal approximation takes much longer...
ptm <- proc.time()
E_VOL_AB_HmDm_HT.f(Hm=tree1$Hx[3], Dm=tree1$Dx[3], mHt = tree1$Ht[1], 
                   sHt = 1, par.lme = SK.par.lme, IA=FALSE)
proc.time() - ptm


##... than the calculation using a 2-point distribution...
ptm <- proc.time()
E_VOL_AB_HmDm_HT.f(Hm=tree1$Hx[3], Dm=tree1$Dx[3], mHt = tree1$Ht[1],
                   sHt = 1, par.lme = SK.par.lme, IA=TRUE)
proc.time() - ptm

##...fastest if no height variance is assumed
ptm <- proc.time()
E_VOL_AB_HmDm_HT.f(Hm=tree1$Hx[3], Dm=tree1$Dx[3], mHt = tree1$Ht[1],
                   sHt = 0, par.lme = SK.par.lme, IA=FALSE)
proc.time() - ptm

## Also the number of supportive points for the numerical integration
## influences the calculation time
ptm <- proc.time()
E_VOL_AB_HmDm_HT.f(Hm=tree1$Hx[3], Dm=tree1$Dx[3], mHt = tree1$Ht[1],
                   sHt = 0, par.lme = SK.par.lme, IA=FALSE, nGL=10)
proc.time() - ptm
##' End(Not run)