dmdiso: Density Management Iso Line Rendering

In mwritchie/standview: R Package for Density Management Diagrams

Density Management Iso Line Rendering

Description

This function draws iso-volume lines. It is intended to work with a call to dmd.view function in standview.

Usage

dmd.iso(ineq           = 3,
        v.at         = NULL,
        range.x      = NULL,
        max.sdi      = NULL,
        reineke.term = 1.60,
        vty          = 2,
        vcex         = 0.75,
        vcol         = "blue",
        show.vol     = TRUE,
        v.ann        = TRUE,
        use.metric   = FALSE)

Arguments

ineq	Selects volume and dominant height equations. This must be an integer value: 2, 3, 6, 7, or 9. Value 2 is for Long and Shaw (2005) ponderosa pine. Value 3 is for Jang et al. (2021) ponderosa pine. Value 6 is for Long and Shaw (2012) California mixed-conifer. Value 7 is for Drew and Flewelling (1979) Douglas-fir. Value 9 is for McCarter and Long (1986) lodgepole pine. Value 15 is for Williams (1994) loblolly pine. Default=3.
v.at	A vector of volume iso lines. Units are in cubic feet per acre if use.metric=FALSE, and units are cubic meters per hectare if use.metric=TRUE.
range.x	Range of tree density acre from range.x[1] to range.x[2] , must be a vector of length 2; e.g. range.x=c(50,500). Units are trees per acre if use.metric=FALSE, and units are trees per ha if use.metric=TRUE.
max.sdi	Maximum stand density index, must be expressed as trees per acre if use.metric=FALSE and trees per ha if use.metric=TRUE. This value only needed for ineq=6.
reineke.term	This is the inverse of the slope of sdi lines in sdi space. Default=1.605, the value derived by Reineke (1933).
vty	This is the line type for volume, default= 2.
vcex	This is the character size for volume annotations, default= 0.75.
vcol	This is the color for volume, default= "blue".
show.vol	Show volume iso-lines, default= TRUE.
v.ann	Turn on volume annotations, default= FALSE.
use.metric	Use metric units (logical), default= FALSE.

Value

Returns a data frame with tpa, qmd, ba, volume (cubic feet per acre), stand height (feet) and (if available) above-ground biomass (pounds per acre).

Note

This function returns a dataframe that could represent observations for a stand prescription over time. The observations could also be for sampled independent stands. The species for the observations should match the species identified by the value ineq. So if ineq=1 is chosen, then the volumes returned will be from Long and Shaw 2005. Vectors passed in must match in length. See Examples below.

Author(s)

Martin W. Ritchie, Research Forester, US Forest Service, Pacific Southwest Research Station. Email: [e-mail]

References

Drew, T.J. and J.W. Flewelling (1979). Stand density management: an alternative approach and its application to Douglas-fir plantations. For. Sci. 25(3):518-532.

Jang, W.S., M.W. Ritchie and J. Zhang (2021) Improved equations for the density management diagram isolines of ponderosa pine stands. For. Sci. 67(1):93-102

Long, J.N., J.B. McCarter, and S.B. Jack. (1988) A modified density management diagram for coastal Douglas-fir. West. J. Appl. For. 3(3):88-89.

Long, J.N. and J.D. Shaw (2005) A density management diagram for even-aged ponderosa pine stands. West. J. Appl. For. 20(4):205-215.

Long, J.N. and J.D. Shaw (2012) A density management diagram for even-aged Sierra Nevada mixed-conifer Stands. West. J. Appl. For. 27(4):187-195.

McCarter, J.D. and J.N. Long (1986) A logdepole pine density management diagram. West. J. Appl. For 1(1):6-11.

Reineke, L.H. (1933) Perfecting a stand density index for even-aged forests. J. Ag. Res. 46:627-638.

Williams, R.A. (1994) Stand density management diagram for loblolly pine plantations in north Louisiana. South. J. Appl. For. 18(1):40-45.

Examples

# 1. This example generate a prescription using equations from Ritchie and Zhang:

library(standview)
#pdf("Douglasfir.pdf", width=6, height=8) # recommended to extablish a 6x8 ratio for dmd.view
opar <- par(mar = c(2.0,2.0,2.0,2.0))

dmd.view(ineq=7, insdr=FALSE)
dmd.iso(ineq=7,
        range.x=c(50, 1000),
        v.at=c(200, 400, 600, 800, 1000, 2000, 3000, 4000, 6000, 8000))

par(opar)
# dev.off()  # close optional pdf device

# 2. A similar result may be obtained with the invol argument in dmd.view,
#    where invol=TRUE directs dmd.view to call the dmd.iso function:
#pdf("Douglasfir2.pdf", width=6, height=8) # recommended to extablish a 6x8 ratio for dmd.view
opar <- par(mar = c(2.0, 2.0, 2.0, 2.0))

dmd.view(ineq=7, insdr=FALSE, invol=TRUE)

par(opar)
#dev.off() # close optional pdf device

# 3. Converting to metric:
#pdf("Douglasfir2metric.pdf", width=6, height=8) # recommended to extablish a 6x8 ratio for dmd.view
opar <- par(mar = c(2.0,2.0,2.0,2.0))

dmd.view(ineq=7, insdr=FALSE, invol=TRUE, use.metric=TRUE)

par(opar)
#dev.off() # close optional pdf device

mwritchie/standview documentation built on May 10, 2024, 9:28 a.m.