growth.indiv {CTFS} | R Documentation

## Annual Growth Rates for Individual Trees (3 methods of growth rate computation provided)

### Description

Computes annual growths rate for individual trees and returns a dataframe of these values for all trees. Two types of growth rates are computed: annual dbh increment (mm dbh per year), relative growth rate (% change in dbh per year). Growth rates can also be evaluated for unrealistically high and low values and removed from the summary values. The dataset must have at least 2 censuses to compute growth.

### Usage

    growth.indiv(census1, census2,
            rounddown = FALSE, mindbh = 10, 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`
`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.
`mindbh` | minimum DBH in `census1` for inclusion in computation.
`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 methods 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 results of `growth.indiv` are growth rates for individual trees, NOT MEAN GROWTH VALUES. A value is returned for each tree. If growth is invalid then NA is returned.

### Value

`growth.indiv` returns a dataframe with the following components:

`tag` | tree individual tag number
`sp` | species code
`gx` | "x" coordinate of tree within the plot
`gy` | "y" coordinate of tree within the plot
`dbh1` | DBH at the first census as defined by user
`dbh2` | DBH at the second census as defined by user
`years` | interval, in years, between censuses
`incgr` | annual growth; (dbh2 - dbh1) / time
`expgr` | relative growth; (log(dbh2)-log(dbh1))/time

### Author(s)

Rick Condit

### See Also

`CTFS.growth`

### Examples

    ## Not run:
    1. Default use of growth.indiv().  Warning messages may result from
    computation of exponential growth.  The values will be set to
    NA in the returned \strong{dataframe}

    growth.indiv.out <- growth.indiv(tst.bci90.full,tst.bci95.full)

    2.  Selecting a single species for growth.indiv()

    growth.alsebl.tree < -growth.indiv.out[growth.indiv.out$sp=="alsebl",]

    ## End(Not run)

[Package CTFS version 1.00 Index]