drawTreePop {ssExtra} | R Documentation |
This routine will generate a simulated northern hardwoods population to the user's specifications where diameters are drawn from a three-parameter Weibull distribution. The heights and spatial process are as described below.
drawTreePop(tract, solidTypes = c(1.5, 3), topDiams = c(0, 0), B = 80, hgt.sd = 6, a = 4, b = 8, c = 2, inhibitDist = 3, showPlot = TRUE, startSeed = 144, runQuiet = FALSE, ...)
tract |
A |
solidTypes |
See the argument of the same name in
|
topDiams |
See the argument of the same name in
|
B |
The basal area per acre, always in ‘English’. |
hgt.sd |
Standard deviation for height for |
a |
Weibull location parameter always in ‘English’. |
b |
Weibull scale parameter always in ‘English’. |
c |
Weibull shape parameter always in ‘English’. |
inhibitDist |
This is the inhibition distance and it is in the
same units as |
showPlot |
|
startSeed |
A scalar specifying a random number seed
for the Weibull draws, spatial locations, &c. See
|
runQuiet |
|
... |
Further arguments passed on to
|
This routine will set up a reasonable simulated population of trees for northern hardwoods based on the Weibull diameter distribution parameters and height equation from Fast and Ducey (2011).
The spatial coordinates are drawn within the tract using an inhibition process; the spatial package code is used here because it is faster than the corresponding routine in the spatstats package.
The input units are always ‘English’ for everything but the tract, which can be either; the output units are the same as that of the tract. Therefore, if the tract is metric, then the returned tree list is also.
A data frame with the synthetic trees that can be cast to standingTrees
.
Note especially the the basal area, height perturbations, and Weibull parameters are always entered in ‘English’ units, regardless of whether the “Tract” object (and thus, the output tree data frame) is in metric. This is for people (like the author) that still have English as their primary units-of-measure.
Jeffrey H. Gove
Fast, A. J. and M. J. Ducey. 2011. Height-diameter equations for select New Hampshire tree species. Northern Journal of Applied Forestry, 28(3):157–160.
# # a simple example... # ## Not run: tr = Tract(c(x=100, y=100), cellSize=1) btr = bufferedTract(10, tr) s.trees = drawTreePop(btr, B=120) #BA = 27.5/ha head(s.trees) ## End(Not run)