abundance.change.dbh {CTFS}R Documentation

Annual Change in Population Size by DBH

Description

Computes annual change in population size by DBH classes. DBH class is determined independently for each census. Any two census datasets can be provided in order of date of census. The rate of change is computed, but no probability is provided. For categories that do not include DBH use abundance.change.

Usage

abundance.change.dbh(census1, census2, alivecode = c("A"), 
   dbhclass = c(10, 100, 300), split = 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
alivecode character, codes of the variable status that indicate the tree is alive. The most general valid categories are: "A" and "AB" and "AS".
dbhclass a vector of dbh class levels - also sets minimum dbh
split a vector of categorical values of the same length as census which groups trees into classes of interest for which abundance values are computed. This vector can be composed of characters or numbers.

Details

See CTFS.abundance for details on the computation of abundance and associated functions.

Two censuses must be used. They do not have to be sequential, only that census1 has to be before census2.

The vector split must be of the same length as census1 and census2 but can contain NA. The vector dbhclass only has to contain the minimum dbh for each class of interest. A maximum dbh does not have to be specified. The smallest value of dbhclass is used as mindbh.

The inclusion of a tree is determined independently for each census. The user can only define status and dbhclass once. These values are used for assessing a tree for inclusion for each census.

Value

abundance.change.dbh 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:

$N0 abundance in first census
$N1 abundance in second census
$rate annual rate of change in abundance
$meanyrs mean number of years between census for trees used in mortality rate computation
$date0 mean date of first census
$date1 mean date of second census

Author(s)

Rick Condit, Suzanne Lao, Pamela Hall

See Also

CTFS.abundance

Examples

## Not run: 
# 1. Default use of abundance.change.dbh
abund.ch.dbh.out <- abundance.change.dbh(tst.bci90.full,tst.bci95.full)

# 2. Set different dbhclasses and also by species
abund.ch.dbh.sp.out <- 
abundance.change.dbh(tst.bci90.full,tst.bci95.full, +
  dbhclass=c(10,20,30,100,300),split=tst.bci90.full$sp)
## End(Not run)

[Package CTFS version 1.00 Index]