This function calculates the competition index BAL (Basal Area in Large trees)
and adds it to the table of individual tree measurements that include basal
area and the upscale factors. All trees should also be described with plotID
and year variables
Usage
calculate_BAL(df)
Value
a data frame with calculated basal area in large trees (BAL)
Arguments
df
a data frame with individual tree measurements that include basal
area and the upscale factors. All trees should also be described with plotID
and year variables