biomass.change: Finds biomass in two censuses and change between them.
In forestgeo/ctfs: Tools for the Analysis of Forest Dynamics

Description Usage Arguments Details Value Examples

Finds biomass in two censuses and change between them. The submitted dataframes are exactly the standard CTFS R Analytical tables, with a column for biomass (agb) already calculated. Each dataframe has a record for every tree in a single census (or a stem table can be passed, with one record for each stem). Biomass for all living trees is summed over whatever grouping variables are submitted (split1 and split2) in both censuses, along with the annual rate of change in each category.

1 2	biomass.change(census1, census2, alivecode = c("A"), mindbh = NULL, split1 = NULL, split2 = NULL)

`census1`	The R Analytical Table for a single census, either tree or stem.
`census2`	The matching R Analytical Table for a later census.
`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
`mindbh`	The minimum diameter above which the counts are done. Trees smaller than `mindbh` are excluded. If `NULL`, all living trees are included.
`split1`	a vector of categories, one per individual
`split2`	another vector of categories, one per individual
`dbhunit`	'cm' or 'mm', only used for basal area

Based closely on the function pop.change() in abundance.r, and differs only in taking sum of agb instead of counting individuals.

If no split variables are submitted (split1 = split2 = NULL), each component of the returned list is a single number, for the entire plot. If split1 is submitted but not split2, each component is a vector, one value for each category of split. If both splits are submitted, each component of the list is a matrix.

A list with 6 components:

N.1: Total biomass in first census submitted
N.2: Total biomass in second census submitted
date1: Mean date in first census
date2: Mean date in second census
interval: The mean census interval in years
little.r: The rate of biomass change, or (log(N.2) - log(N.1))/interval

## Not run: 

CTFSplot("bci", "full", census = c(3, 7))

deltaAGB = biomass.change(bciex::bci12t3mini, bciex::bci12t7mini)

deltaAGB.spp = biomass.change(
  bciex::bci12t3mini, bciex::bci12t7mini, split1 = bciex::bci12t3mini$sp
)

deltaAGB.table = assemble.demography(deltaAGB.spp, type = "a") 

rate = deltaAGB.table$little.r

hist(rate, breaks = 50)

summary(rate[is.finite(rate)])

subset(deltaAGB.table, is.infinite(rate))

## End(Not run)