20 BULLETIN 1294, U. S. DEPARTMENT OF AGRICULTURE 
TABLE 9.—Losses due to insects following fire © 
[Snake Lake experimental area] 
BURNED ARB#A: FIRST FIRE (1919), 105 ACRES; SECOND FIRE (1920), 126 ACRES 
| Loss in 1919 Loss in 1920 Loss in 1921 Loss in 1922 
Species SRE PL i we Bey Ee a SSE. sa 
Trees | Volume} Trees | Volume} Trees | Volume} Trees} Volume 
Board feet Board feet Boardfeet | Board feet 
Western yellow pine________-__._-._- 5 4, 240 11 6, 680 17 | 10, 200 2 2, 660 
SUPaESDING- sen as ae ee eee See 38 | 70, 600 17 | 32,520 2 2, 900 2 2, 920 
DGH Sas Hirt ee tee 5 at 3 3, 440 2 1, 930 1 750 2 5, 600 
Wihitexfir= 2.5.2 eee petite tay oe 2 3, 800 6 8, 450 3 2, 420 3 920 
WIYCOMSC COGAY = see oe ho oS es eh 5p ee | eee ee | bie oe [--------- 
Potakloss “sss so! ease Safi s 48 | 82,080 36 | 49,580 | 23 | 16,270 9 12, 100 
BOSS, per. acre: cE 0. 46 782 | 0.29 393 | 0. 18 129 | 0.07 
UNBURNED CONTROL AREA, 200 ACRES 
Western yellow pine____-=__________- 4 3, 200 3 2, 090 2 | 1, 200 6 5, 690 
Sugars pIMes:- cio oy ae ee Eh tee 4 3, 600 1 80 2 LS 606; |= ats Shee Eee 
DOU EAS iT epee ya Ree poe ok oe 1 ADO 222 oo ee eS | aon Bee ee 1 2,610 
White fir re Spices yaaa YS Ue an. (Sree ee ene 4 2, 870 3 1, 700 2 940 
Ineense: ced ara. -+ ant ob ead, cele a pete Sele Se eee [eros 2 oe eee se ea tee eee 
Rotalslossiss2 seis eres 22 Seen 9 7, 250 8 5, 040 7 4, 500 9 9, 240 
OSS! POriaCkKe:. 2-22 22 eae 2 0. 04 36 | 0.04 25}; 0.04 22 0.04 46 
Comparative losses on burned and unburned areas.—Considering 
first the contro! plot for the Snake Lake burn, it will be observed 
that the loss for each acre is comparatively small and has shown no 
conspicuous tendency to mcrease since the experiment was begun. 
On the burned area the contrast is striking. In the first year follow- 
ing the initial burn, 48 trees were killed by insects on 105 acres, 
which is at the rate of 293 trees to the section (640 acres), compared 
to the rate on the control plot for the same year of 29 trees to the 
section. In the second year, following the second burn, which 
covered 126 acres, the loss was at the rate of 183 trees to the section. 
in the third year the rate of loss was 117 trees to the section. 
Averaging the results of the three years, it is found that the rate for 
the control plot is 26 trees a section each year and the equivalent 
board-foot loss is 17,900; whereas, on the burned area, the correspond- 
ing values on a section basis are, in round numbers, 200 trees and 
275,000 board feet. Definite proof that the insects entered the trees 
on the burned area after the fire, was found in the fact that the pitch 
tubes overlaid the scorched and blackened bark. 
These results from two independent observations are strikingly 
similar, although the two areas are far apart and in different timber 
types, and the time and intensity of fires were dissimilar. 
The Crane Valley fire in the Sierra National Forest is also of interest 
in studying relation of burning to insect infestation. The fire oc- 
curred in October, 1916, and spread rapidly uphill through an excellent 
stand of thrifty western yellow pine, killing many trees outright and 
scorching the bark and Seis part of the crown of nearly every 
individual in the stand. In the spring of 1917, six months after the 
fire, an insect-control crew employed by the owner of the land worked 
the area covered by the fire, as well as the surrounding unburned 
2 
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