basal.area {CTFS} | R Documentation |
Computes basal area (m^2) for all trees or any user defined categorization of trees. 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 file exists. 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.
basal.area(census1, mult1, alivecode = c("A"), mindbh = 10, split1 = NULL, split2 = NULL)
census1 |
name of census datafile for first census, must be a dataframe |
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. |
alivecode |
character, codes of the variable status
that indicate the tree is alive and has a valid DBH. The default is:
"A" for trees >= 10 mm DBH |
mindbh |
minimum DBH to determine which trees will be included in computation |
split1 |
a vector of categorical values of the same
length as datafile which groups trees into classes of
interest for which growth values are computed. This vector can be
composed of charcters or numbers. |
split2 |
a second vector of categorical values of the same
length as datafile which groups trees into classes of
interest for which growth values are computed. This vector can be
composed of charcters or numbers. |
See CTFS.basalarea
for details on the computation methods
of basal area and associated functions.
A tree is included for the computation based on its value for
status
and dbh
for a single census.
basal.area
returns a list of arrays with the
following named components. Values for each category of the split
vectors are provided.
$basalarea |
sum of basal area m^2 |
$meandate |
mean date of enumeration |
If the vector(s) split1
and split2
are provided by the
user, then basal area and associated statistics are computed for each
value of the vectors. The vectors are nested so that basal area is
computed for each category of split2
within each category of
split1
Rick Condit, Suzanne Lao, Pamela Hall
## Not run: 1. Default use of basal.area basal.out <- basal.area(tst.bci90.full, tst.bci90.mult) 2. Basal area for trees >= 100 mm (10 cm) basal100.out <- basal.area(tst.bci90.full, tst.bci90.mult, mindbh=100) 3. Basal area for each species spp.vct <- tst.bci90.full$sp basal.spp.out <- basal.area(tst.bci90.full, tst.bci90.mult, split1=spp.vct) ## End(Not run)