Y 



(0.0807 d.b.h.2 + 60.3 cr - 58.7 cr^ - 0.0754 age + 

 0.1585 count - 3.45)2 



(1) 



where 



Y 



D.b.h 



Cr 



Age 



Count 



Total serotinous cones per tree, 

 Diameter at breast height in inches. 

 Live crown ratio. 



Age of tree at stump height in years , 



Total number of serotinous cones on the 25-branch segments. 



The coefficient of multiple determination, or R^, was 0.834; i.e., these variables ac- 

 count for 83 percent of the variance in Y. The standard error of the estimate is 40 

 cones per tree, with an average of 965. The half-confidence interval is approximately 

 120 cones. 



HoU) to collect data:-- \ss\xm\ng the application of conventional sampling techniques, 

 plot size should be large enough to include at least 4 to 6 trees of cone-producing 

 size. The required data include: 



1. D.b.h. in inches, 



2. Total height in feet, 



3. Crown length in feet, 



4. Tree age at stump height in years, 



5. The 25- limb sample count of serotinous cones. 



For the 25- limb sample, all trees of cone-producing size must be felled prior to 

 sampling. Count the serotinous cones on 25 outer-one- foot segments of main branches 

 only. Start sampling at the top and work downward around the tree until 25 samples are 

 collected. Record the total number of cones on the 25-limb samples. Use equation (1) 

 and compute the estimated number of serotinous cones per tree. The cones-per-tree 

 values can then be summed for each plot, expanded to per-acre values, and these 

 averaged over plots. 



A preliminary sample of plots can be used to determine the coefficient of variation 

 of plot values. These in turn can be used to determine sample size, as is done for 

 other sampling problems. Our samples had means from about 60,000 to 200,000 cones per 

 acre and coefficients of variation that varied from 148 percent for the lower means to 

 77 percent for the higher means. The standard deviation will usually be about one- 

 quarter to one-third of the range of data. 



This second method has a potential for rough estimates only, but all required 

 measurements are relatively easy to make and it seems to be the most reasonable alter- 

 native available for obtaining stored-cone information. 



The equation is: 



Method 2 



Y 



= (1.925 d.b.h. 2 



1.371 age + 3.411 tpa - 0.00615 tpa^ + 46.2)2 



(2) 



where 



Y = Serotinous cones per acre, 



D.b.h. = Mean plot d.b.h. in inches. 



Age = Mean plot age in years, 



Tpa = The number of serotinous-cone-type trees per acre. 



2 



