biomass {CTFS}R Documentation

Compute Above Ground Biomass for Trees for 2 Censuses using Wood Specific Gravity for Species

Description

Computes the above ground biomass for individual trees for 2 censuses including biomass of main stem, any and all multiple stems and total for tree. Growth rate used for the computation is also provided. The biomass is computed using the models in Chave, J. et.al. (2005).

Usage

biomass(census1, census2, mult1 = NULL, mult2 = NULL, wsgfile = NULL, 
        forest = NULL, badgrowth = "meangrowth", dbhuse = "second", 
        trim = c(-5, 75), recsize = 110, rounddown = FALSE)

Arguments

census1 name dataframe of first census, must be of same length as census2
census2 name dataframe of second census, must be of same length as census1
mult1 name of dataframe with dbh measurements of secondary stems of census1. Tree tag numbers can appear multiple times in this file if there is more than two stems for a tree.
mult2 name of dataframe with dbh measurements of secondary stems of census2. Tree tag numbers can appear multiple times in this file if there is more than two stems for a tree.
wsgfile name of the dataframe that contains wood density values for selected species. See tst.ctfs.wsg
forest parameter indicating forest type which affects the coeficients used to compute above ground biomass. Valid values are “wet”, “moist”, “dry” and NULL. The last results in a computation based on coefficients based on all forest types, a “mean” value.
badgrowth parameter indicating how to handle trees with “bad” growth. “bad” growth is defined by trim. Valid values are: “keep” for retaining all bad growth rates without alteration, “nogrowth” for setting bad growths to 0, “meangrowth” for setting bad growth to the mean value of the dbh size class of the tree, “trim” for using the values of trim to set growth to maximum and minium as appropriate.
dbhuse indicate which dbh to use for computing growth after implementing value of badgrowth. Valid values are: “first” for the dbh in the first census, “second” for dbh in the second census.
trim minimum and maximum value of growth that is considered acceptable when badgrowth = “trim”
recsize the maximum DBH (mmm) a recruit to the second census that is considered appropriate, a very site and species specific value that should be carefully determined by the user.
rounddown how to round down values of growth for trees enumerated at Pasoh in 1990 due to a measurement standard. See CTFS.datafiles

Details

This function computes above ground biomass relying upon coefficients and models presented in Chave, J. et.al. (2005) (see references below). The function can be used to explore the impact of different choices for handling mismeasured dbh which affect growth rates. See CTFS.biomass for further details.

This function makes NO selection of records. The returned object is of the same length and structure as the input file. Use this object for further analysis of biomass for instance with biomass.change.

Value

Returns a dataframe with row of tag numbers and the following columns:

tag tree tag number, same as in CTFS main dataset
errtype indication of whether a DBH was estimated for AGB, values are:
AGBm1 above ground biomass of main stems in census1
AGBm2 above ground biomass of main stems in census2
AGBs1 summed above ground biomass of all secondary stems in census1
AGBs2 summed above ground biomass of all secondary stems in census2
AGBt1 summed above ground biomass of main and secondary stems in census1
AGBt2 summed above ground biomass of main and secondary stems in census1

Note

This function calls the following functions which are specific for biomass: pick.dbh, getwsg.vct, agb.ind, agb.mult, gr.raw, growth.dbh, trim.growth and badgrowth.tree

Author(s)

Pamela Hall

References

Chave, J. et.al.(2005). Tree allometry and improved estimation of carbon stocks and balance in tropical forests. Oecologia. 145. pg 87

See Also

CTFS.biomass

Examples

## Not run: 
1.  AGB in 1990 and 1995 for BCI which is a moist forest, use mean growth
for dbh class as replacement for bad growth rates and rely upon the dbh in
1995 (second).

bci9095.biomass <- biomass(bci90.full,bci95.full,mult1=tst.bci90.mult,mult2=tst.bci95.mult,wsgfile=wsg.ctfs,
        forest="moist",badgrowth="meangrowth",dbhuse="second",trim=c(-5,75),recsize=110,rounddown=FALSE)
  ## End(Not run)

[Package CTFS version 1.00 Index]