Epaminondas S.B. Ferraz has developed a regression
equation relating biomass increment in
Eucalyptus to precipitation at three sites in the
State of SaÄo Paulo [7]. The increments were
determined by gamma-ray attenuation dendrometry
applied to tree rings in wood samples covering
the 1964±1991 period. The samples were
from a mixture of species: Eucalyptus grandis, E.
propinqua, E. saligna and E. alba. Over a range
of precipitation from 40% below the mean to
50% above the mean, the percent increase in the
annual biomass increment above the mean is
given by the following equation (n= 39,
r 2= 0.49):
B ÿ0:017 0:348 P
1