abundance.quad {CTFS} | R Documentation |
Computes the number of trees for each species in user specified quadrates. The user can also specify any portion of the plot (or all of it) be considered. The default quadrate size is 1 hectare.
abundance.quad(census1, mindbh = 10, plotdim = c(1000, 500), gridsize = 100)
census1 |
name of census datafile for a single census |
mindbh |
Minimum DBH for computing population size in each census |
plotdim |
dimensions of the plot: east-west 1000m and north-south 500m |
gridsize |
side of the square quadrate, 100 x 100m (1 ha) by default |
This function produces the same results as running abundance
using
the split vars of species and quadrate.
See CTFS.abundance
for details on the computation methods
of abundance and associated functions. Values for only 1 census can be
computed at a time. A tree is included for the computation based on its
value for status
and dbh
for a single census.
abundance.quad
returns a list of arrays with the values
of species as the first dimension and the values of
gridsize as the second dimension of the array. The array
contains the following named components:
$N |
the abundance of each category, population size |
$dbhmean |
the mean dbh in mm for trees used to compute abundance |
$meandate |
mean date of census for trees used to compute abundance |
The first array of the returned list is a matrix
of the abundance of each species by gridsize.
Abundance values are returned for all levels of each vector and if
no value can be computed then 0 or NA is returned as appropriate.
Rick Condit, Suzanne Lao and Pamela Hall
## Not run: 1. Default use of abundance.quad abund.ha.out <- abundance.quad(tst.bci90.full) abund.ha.out[[1]] 2. Compute abundance for each quadrate. If some quadrates are missing from the input data file, then they will also be missing from the output. abund.quad.out <- abundance.quad(tst.bci90.full,gridsize=20) abund.quad.out[[1]][,1:10] ## End(Not run)