To illustrate this last point, the forester grow- 
ing 15-inch red pine on site index 60 will have 
available for final harvest either 112 trees at 
age 75, 128 at age 105, or 142 at age 165, 
depending upon whether he carries his stand 
at a low, medium, or high density. 
The number of trees per acre is also af- 
fected by site. On better sites there will be 
fewer trees at any given age and density level 
than on poorer sites. Basal area growth rates 
are higher on better sites, so a larger propor- 
tion of the trees must be cut each time the 
stand is thinned to the assigned basal area 
level. 
July 1963 
The examples given indicate that foresters 
can control the diameters and numbers of 
trees produced at a given age by varying the 
initial stocking and thinning intensity in red 
pine stands on different sites. A more detailed 
analysis now being completed will predict 
diameters and numbers of trees for any com- 
bination of initial stocking, stand basal area 
density, age, and site index over a wide range. 
With this information the forest manager will 
be in a better position to grow the number 
and kinds of red pine trees that will best 
satisfy his objectives. 
ALLEN" 1: ‘LUNDGREN, Research Forester 
(Forest Economics) 
ROBERT F. WAMBACH, Research Forester 
