338 



Forestry Quarterly. 



This table shows that the density for all diameter classes is 

 less than .5 and that it decreases as the diameter increases. This 

 compensates for the greater intolerance of old trees as compared 

 with young trees, and for the greater shade cast by tall trees as 

 compared with short trees. 



The volume which an even aged stand of Yellow pine may 

 be expected to produce in a certain time, having a normal num- 

 ber of dominant trees per acre as permitted by the crown space 

 requirements of the trees, is' also shown. 



In order to compare the results of this table with conditions 

 as they actually exist in the wild state, ten sample plots com- 

 prising altogether 60 acres and composed of pure Yellow pine 

 were chosen. A summary of these plots is given in Table V 

 which follows: 



TABLE V. 



Showing summary of 10 sample plote taken in pure stands of Yellow- 

 pine in Oregon. 



Average Average 



Total No. D. B. H. 



Size No. of Trees of Trees 



Locality of Trees per Acre above 



of Plot on above 12" 



Plot Acres. Plot. 12" D. B. H. Inches 



170 

 190 



119 

 176 

 159 

 669 

 301 

 124 

 30 

 Z2, 



34 

 38 

 30 

 44 

 26 



30 

 31 

 30 

 33 



21 



23 

 19 

 19 

 21 



21 

 22 

 22 



21 

 24 



These sample plots were taken in stands where no large open- 

 ings occurred, the endeavor being to find as even a crown cover 

 as possible. They do not by any means represent maximum 

 yields, however. It is noticed in these plots that the average 

 number of trees per acre falls below the figures given in Table 

 IV. The average diameter for the diflferent plots varies between 

 19 and 24 inches. According to Table IV the number of trees 

 per acre of 19" trees should be about 68, and for 24" trees, 45. 

 On the sample plots respectively but 44 and 33 trees were grow- 

 ing on an average acre. It was very evident that these plots were 



