aed 
~ 
APPENDIX. 195 
Tape 64.—Birch, Paper—Yield Per Acre—Pure (100 Per Cent) 
Birch Stands. 
PENOBSCOT, PISCATAQUIS, SOMERSET, AND FRANKLIN 
COUNTIES, ME. 
[Data gathered by R. L. Marston for Paper Birch Study, 1903-1907.] 
| | Quality I. | Quality II. 
= n .' tH [ ny 
i ae = mite 
) Sa eer ® Cay (bp 
E geS| ag. feu 
oot ri = OO eam - oD oO 
Age. | 320 = 28h | mak | a Bee 
Bet ee lone LS pee . | gas 
_ on) ~ @ ~~ 
= od aes a |Se8\ na | Ss) a pees 
Se hos es ese | Peel ee: | ota lees 
= 3 3 =ah| 2 5 3 =e% 
> S = 23a > > So 23a 
< <q - > <q < a > 
| 
| Years. | Inches. | Feet. | Cu.ft. | Per ct. | Inches.| Feet.| Cu.ft. | Per ct 
15 23 24 710 0 
20 3.4 231 1,026 4 
25 4.5 41 | 1,340 27 
30 5.6 48; 1,700 46 
35 6.4 54| 2,090 63 
40 12 58 | 2,520 75 
45 7.8 62 | 2,950 85 
50| 8.4 65 | 3,340 91 
55} 8.8 68 | 3,660 96 
60 9.2 70 | 3,940 98 
65} 9.6 72 | 4,190 100 
Oro: 40:0 74| 4,450 100 
NotTe.—These sample plots were taken in unmanaged stands. All plots witha 
density less than 50 per cent were discarded. All plots containing less than 40 per 
cent birch were discarded and the remainder reduced to 100 per cent birch by 
dividing the actual birch yield by the percentages of the total basal area formed by 
the birch. Hence the table applies only to pure birch stands of average density 
(quality I, 83 per cent and quality II1,75 percent). For the yield of a mixed stand, 
containing, for example, 60 per cent of birch, a corresponding reduction would be 
made in the yield. The number of trees per acre was exceedingly irregular and 
was therefore excluded from the table. 
The volume given is total stem volume, though the lowest measurement taken 
in the sample trees was at 4.5 feet, and this disregard for butt swelling makes the 
yield conservative. 
Based on 20 quality I and 26 quality II, sample plots. 
