growth.dbh {CTFS}R Documentation

Annual Growth Rate for DBH Classes

Description

Computes annual growth rate for all trees for DBH classes. Two growth rates can be computed: simple change in dbh over time and relative growth rate. Unrealistically high and low values are removed from the summary values. Growth rate in mm dbh per year, relative growth rate in % change in dbh per year, standard deviation or 95% confidence limits, and sample size are provided. Two datasets must be used, one for each census.

Usage

growth.dbh(census1, census2, dbhclass = c(10, 100, 300), 
        rounddown = FALSE, method = "I", stdev = FALSE, 
        err.limit = 4, maxgrow = 75) 

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
dbhclass a vector of lower values for dbh categories
rounddown logical value in caps. When TRUE, if either of census is < 55, then the floor of the dbh value / 5 is provided. When FALSE, no change in the dbh is made.
method character indicating the type of growth rate to be calculated. When "I" the annual change in dbh is provided. When "E" the relative growth rate is provided. see CTFS.growth for more details on method.
stdev logical value in caps. When TRUE, the standard deviation of growth is provided. When FALSE, a 95% condfidence interval is provided. The confidence limits are not computed.
err.limit number of standard deviations: used for determining if an individual tree growth rate is too high or low for inclusion.
maxgrow maximum absolute growth rate, mm per year: used for determining if an individual tree growth rate is too high for inclusion.

Details

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

Any two censuses on a datafile must be used. They do not have to be sequential, only that census1 has to be before census2.

The vector for classbreak can be created outside of the function and reference by setting classbreak equal to that vector.

The results of growth.dbh can be organized into dataframes with the use of assemble.demography.

Value

growth.dbh returns a list of arrays with the following named components. Values are provided for each DBH class.

$N0 the number of trees used to compute growth rate
$rate the annual mean growth rate in mm per year or % per year, type determined by the argument method
$clim the 95% confidence limit based on a normal distribution
$dbhmean the mean dbh in mm for trees used to compute growth rate
$meanyrs mean number of years between census for trees used in growth rate computation.
$date0 mean date of first census
$date1 mean date of second census

Author(s)

Rick Condit

See Also

CTFS.growth

Examples

## Not run: 
1. Default use of growth.dbh()

growth.dbh.out <- growth.dbh(tst.bci90.full, tst.bci95.full)
growth.dbh.out$rate

2.  User defined DBH classes
dbh.vct = c(10,20,30,40,50,100,300)
growth.dbh.out <- growth.dbh(tst.bci90.full, tst.bci95.full, classbreak=dbh.vct)
growth.dbh.out$rate
## End(Not run)

[Package CTFS version 1.00 Index]