Abstract:
Growth basal area (GBA) is that basal area at which
dominant trees grow at 1.0 inch in diameter per decade at
age 100. Diameter growth rate of 1.0 inch per decade is a
constant used to compare sites; basal area is a variable
used to express stockability. GBA is a field method for estimating
site potential for stockability using current stand
growth. Parameters measured are basal area per acre
and rate of diameter growth. Current basal area is adjusted
by use of a GBA curve to that basal area which will
result in 1.0 inch diameter growth per decade of dominant
trees, the GBA of the site. Two GBA curves are provided.
The GBA concepts employed, development of GBA, determination
of GBA, use of GBA, and GBA in relation to stand
growth are discussed. GBA is combined with site index to
index different productivity levels within a site index class
and to help identify those productivity levels in the field.
Appendixes provide description of a GBA slide rule, additional
data, and forms for determining GBA.
