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]