ba.change {CTFS} | R Documentation |
Computes annual change in basal area (m^2 per year) for any user defined groups. If a tree has more than one stem, the other stems recorded in the multi-stem file are included in its basal area, if the files exist. Two datasets are used: one with the primary stem and one with all multiple stems for that cenus. The two datasets contain completely non-overlapping sets of DBH. Adding the two together produces the total basal area for each tagged tree. Two censuses are required to compute annual change.
ba.change(census1, census2, mult1 = NULL, mult2 = NULL, alivecode = c("A"), mindbh = 10, split1 = NULL, split2 = NULL)
census1 |
name of census datafile for first census, must be a
dataframe, must be of same length as census2 |
census2 |
name of census datafile for second census, must be a
dataframe, must be of same length as census1 |
mult1 |
name of file (not in quotes) must be a dataframe with trees as rows and column as DBH. Tree tag numbers can appear multiple times in this file if there is more than two stems for a tree. |
mult2 |
name of file (not in quotes) must be a dataframe with trees as rows and column as DBH. Tree tag numbers can appear multiple times in this file if there is more than two stems for a tree. |
alivecode |
character, codes of the variable status
that indicate the tree is alive. The most general valid categories are: "A" and
"AB" and "AS". |
mindbh |
Minimum DBH for computing population size in each census |
split1 |
a vector of categorical values of the same
length as census which groups trees into classes of
interest for which basal area values are computed. This vector can be
composed of characters or numbers. |
split2 |
a second vector of categorical values of the same
length as census which groups trees into classes of
interest for which basal area values are computed. This vector can be
composed of characters or numbers. |
See CTFS.basalarea
for details on the computation methods
of basal area and associated functions.
The inclusion of a tree is determined independently for each census. The
user can only define status
and mindbh
once. These values
are used for assessing a tree for inclusion for each census.
ba.change
returns a list of arrays with the values
of split1
as the first dimension and the values of
split2
as the second dimension of the array. The array
contains the following named components:
$B0 |
abundance of species in census 1 |
$B1 |
abundance of species in census 2 |
$rate |
annual rate of change in abundance |
$time |
mean number of years between census for trees used in change in basal area computation. |
$date1 |
mean date of first census |
$date2 |
mean date of second census |
Rick Condit, Suzanne Lao, Pamela Hall
## Not run: 1. Default use of ba.change ba.change.out <- ba.change(tst.bci90.full, tst.bci95.full, tst.bci90.mult, tst.bci95.mult) 2. Change in basal area for species spp.vct <- tst.bci90.full$sp ba.change.out <- ba.change(tst.bci90.full, tst.bci95.full, tst.bci90.mult, tst.bci95.mult, split1=spp.vct) 3. Basal area dynamics for larger trees ba.change.large.trees.out <- ba.change(tst.bci90.full, tst.bci95.full, tst.bci90.mult, tst.bci95.mult, mindbh=100) ## End(Not run)