28 FOREST commissioner's REPORT. 



eraljle numbers of trees, thrifty and unthrifty together, the 

 run of what stands on cut-over land. Used in that way, the 

 table ought to give good practical results, 

 totlnded'^ This method of obtaining the per cent of growth, 



"^^- and, given the volume of the tree, its actual amount 



has been used on many hundred trees during the summer's 

 exploration. Being so many in number, and scattered 

 through a large section of our timberlands, arranged too, 

 with relation to the soil, drainage and other biological con- 

 ditions of the trees involved, the results obtained, checked 

 as was lately described, are thought to be a safe basis for 

 sweeping and important deductions. I propose to use them 

 for no less a purpose than to estimate the growth of spruce 

 upon all the country covered by this study, 



Jtowui on 1^6* ^^ ^^^'» *'o^' ^^^ '^'^ke of practice, engage in a 



Pratt tract, jj^^j^ percentage calculation on the subject of the 



Pratt tract. Men who have explored it set its stand of spruce 

 and pine at sixteen million feet, which amount, let us say, 

 stands on 4,000 acres. Now all things considered — the stand 

 and the estimate — it is probable that board feet of merchant- 

 able timber cannot, in this case, be converted into cubic feet 

 of wood in the total stand, at a larger ratio than two to one. 

 That makes an average stand — hard wood species left out of 

 account — of 2,000 cubic feet per acre over the 4,000. Atone 

 and one-half per cent a year, which probal)ly is quite enough, 

 in a thick and not particularly thrifty stand like this, to allow, 

 the yearly growth is therefore thirty cubic feet. This is the 

 gross amount, in trees of all sizes and qualities. If we could 

 assume that all the trees in this stand will some time reach 

 full size and be harvested, we could convert this figure into 

 board feet at the ratio of four to one, and the yearly gain in 

 lumber would be set at 120 board feet per acre. As a matter 

 of fact, that supposition is not a fair one. In cutting a stand 

 like this, many small trees will l)c destroyed and not taken, 

 while as it stands much of this growth must be offset l)y 

 death and decay. The calculation, however, is worth mak- 



