| E_VOL_AB_HmDm_HT.f {TapeR} | R Documentation |
Estimate volume for stem and sections
Description
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.
Usage
E_VOL_AB_HmDm_HT.f(
Hm,
Dm,
mHt,
sHt = 0,
A = NULL,
B = NULL,
iDH = "D",
par.lme,
Rfn = list(fn = "sig2"),
IA = F,
nGL = 51,
...
)
Arguments
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 |
Numeric vector of diameter measurements (cm) taken for calibration.
Can be of length 1. Must be of same length as |
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 |
B |
Numeric scalar defining the upper threshold of a stem section for
volume estimation. Depends on |
iDH |
Character scalar. Either "D" or "H". Type of threshold for section
volume estimation. See |
par.lme |
List of taper model parameters obtained by
|
Rfn |
list with function name to provide estimated or assumed residual variances for the given measurements, optionally parameters for such functions |
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 |
Details
calculates the volume for a complete stem or sections defined by
A and B, which might be defined as diameter or height. The
parameter Rfn can be used to force the taper curve through the
measured points (e.g. by Rfn=list(fn="zero"), cf. resVar).
Value
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).
Rfn: Function applied for estimated or assumed residual variance.
Author(s)
Edgar Kublin
References
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.
See Also
Examples
# 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$Rfn
## Calculate the timber volume for the whole stem, using Rfn="zero"
VOL <- E_VOL_AB_HmDm_HT.f(Hm=tree1$Hx[3],
Dm=tree1$Dx[3],
mHt = tree1$Ht[1],
sHt = 0, # no height variance assumed
par.lme = SK.par.lme,
Rfn = list(fn="zero"))
VOL$E_VOL #' expected value
VOL$VAR_VOL #' corresponding variance
VOL$Rfn
## Calculate the timber volume for the whole stem
VOL <- E_VOL_AB_HmDm_HT.f(Hm=tree1$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$Rfn
## Calculate the timber volume for the whole stem, using Rfn="zero"
VOL <- E_VOL_AB_HmDm_HT.f(Hm=tree1$Hx[3],
Dm=tree1$Dx[3],
mHt = tree1$Ht[1],
sHt = 1, # height variance assumed
par.lme = SK.par.lme,
Rfn = list(fn="zero"))
VOL$E_VOL #' expected value
VOL$VAR_VOL #' corresponding variance
VOL$Rfn
## Calculate the timber volume for a selected section given a height (0.3 - 5 m)
VOL <- E_VOL_AB_HmDm_HT.f(Hm=tree1$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$Rfn
## Calculate the timber volume for a selected section given a height (0.3 - 5 m)
VOL <- E_VOL_AB_HmDm_HT.f(Hm=tree1$Hx[3],
Dm=tree1$Dx[3],
mHt = tree1$Ht[1],
sHt = 1,
par.lme = SK.par.lme,
A=0.3,
B=5,
iDH = "H",
Rfn=list(fn="zero"))
VOL$E_VOL #' expected value
VOL$VAR_VOL #' corresponding variance
VOL$Rfn
## Calculate the timber volume for a selected section given a diameter
## threshold (30cm - 15cm) (negative value if A<B)
VOL <- E_VOL_AB_HmDm_HT.f(Hm=tree1$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)