Method 2 



Assuming existence of the following data: 



1. Mean plot d.b.h. in inches = 10, 



2. Mean plot age in years = 100, 



3. Number of serotinous-cone type of trees per acre = 150. 



Then using the proper formula (see page 2) we would have: 



1.925(10)2 - 1.371(100) + 3.411(150) - 0.00615(150)2 + 45 2 = 474.9 



The square of 474.9 or 225,530 is the estimate of number of cones per acre, 



or approximately 226,000. 



B. Number of Seed Per Acre 



Either make a direct seed count per cone or obtain length measurements and use 

 Thompson's formula. Then, assume a sample cone estimate of 10 seed per cone. Using 

 Method 1 we would estimate: 



220,000 X 10 = 2,200,000 seed/acre. 



Using Method 2 we would estimate: 



226,000 X 10 = 2,260,000 seed/acre. 



C. Number of Viable Seed Per Acre 



Assume that either cutting or germination tests on seed from sample cones resulted 

 in viability estimates of 80 percent. Then we would estimate viable seed per acre as 

 being : 



2,200,000(0.8) = 1,760,000, using Method 1 



or, 2,260,000(0.8) = 1,808,000, using Method 2. 



LIMITATIONS OF EQUATIONS (1) AND (2) 



Equations (1) and (2) are interim and are most applicable to the largely mature 

 and overmature stands sampled in this study near West Yellowstone, Montana, and Island 

 Park, Idaho (Lotan 1967, 1968). The characteristics of these stands are shown in table 

 4. It is believed that these two equations will also be representative for the vast 

 acreages of these types of stands in the northern Rocky Mountain and Intermountain Re- 

 gions (Idaho, Montana, Wyoming, and Utah) not sampled here. 



A positive coefficient might be expected for age in equations (1) and (2) for 



stands up to about 60 years old. However, in older stands such as those studied here, 



the trees gradually, with increased age, lose their capacity for cone production. Thus, 

 we have a negative coefficient for age. 



8 



