pop.change.dbh: Change between two censuses in abundance or basal area.
In forestgeo/ctfs: Tools for the Analysis of Forest Dynamics

Description Usage Arguments Details Value See Also Examples

Finds abundance or basal area in two censuses and the rate of change between them, in several dbh categories.

1 2	pop.change.dbh(census1, census2, type = "abund", dbhunit = "mm", alivecode = c("A"), classbreak = c(10, 100, 300), split = NULL)

`census1`	The R Analytical Table for a single census, either tree or stem.
`census2`	The matching R Analytical Table for a later census.
`type`	Either 'abund' (default) for abundance, 'ba' for basal area, or 'agb'.
`dbhunit`	'cm' or 'mm', only used for basal area
`alivecode`	character, codes of the variable `status` that indicate the tree is alive. The default 'A' is the standard CTFS designation for living trees or stems
`classbreak`	xxxdocparam
`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.

Accepts two dataframes, each an R Analytical Table for one census, the earlier census first. Only one additional splitting variable (other than dbh category) is allowed. Typically, this is species, but genus or quadrat are other examples.

The return value is a list of two elements, one name abund (or ba) and the other meandate, just as other abundance results. Each is a table having one pair of columns for every dbh category: the first for census 1, the second for census 2. So if there are 3 dbh categories, the table has 6 columns. The rows of the table are the splitting variable (eg, species).

abundance()

## Not run: 
Nchange = pop.change.dbh(bciex::bci12t5mini, bciex::bci12t6mini, classbreak = c(10, 100, 300))
Nchange$abund

BAchangePerSpp <- pop.change.dbh(
  bciex::bci12t5mini,
  bciex::bci12t6mini,
  classbreak = c(10, 100),
  split = bciex::bci12t5mini$sp
)
head(BAchangePerSpp$ba)
## End(Not run)