ba.change {CTFS}R Documentation

Annual Change in Basal Area by Categories (User Defined Group)

Description

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.

Usage

ba.change(census1, census2, mult1 = NULL, mult2 = NULL, 
        alivecode = c("A"), mindbh = 10, 
        split1 = NULL, split2 = NULL)

Arguments

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.

Details

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.

Value

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

Author(s)

Rick Condit, Suzanne Lao, Pamela Hall

See Also

CTFS.basalarea

Examples

## 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)

[Package CTFS version 1.00 Index]