22 BULLETIN 1495, U. 8S. DEPARTMENT OF AGRICULTURE 
The brush type represents reversions in all of the timber types, and 
it might be expected that its average number of man-caused fires 
should approximate that of the three timber-type groups. The 
average figure for the timber groups is 27.95, very close to the brush- 
field rate of 29.08. 
A separation of man-caused fires into camper and incendiary fires 
by types is made in Table 10. Here the highest camper-fire 8 rate is 
found in the mixed conifer, followed closely by western yellow pine, 
with the woodland type the lowest. The rate for the fir types is 
practically one half the average for the timber types dominated by 
the pines and is even less than the average for the nontimbered or 
poorly timbered types. 
TaBLe 10.—Average annual camper and incendiary fires by types, 1911-1920, 
12 tembered forests 
[Number of fires per 100,000 acres] 
- Ratio, 
ncen- incen- 
Type Career diary | diary to 
fir camper 
fires 
Number | Number | Per cent 
Wiesterm Vell we pines secs ere iain Se Mee NIE aie oe Ae Rea a) Sly Ree oon ee 18. 20 10. 10 55 
Maixed’coniferssshtacc 2s ates) lave Oe ea ug oe Se a Re Oe eee 19. 83 ek 72 69 
A YOY DRE BN ah Ce a a A OS ae a 7S oie Po Do care RO Sr Beedle 8. 21 22501 277 
SULpea eH freee PO Ae  Dahiel A FS  agae A AA 11. 79 4.42 37 
SENN WS SS AL NI eg AL a ON SS OA NO MN den been Gaal Ele hep 10. 71 1.58 15 
CGB Chg estat AN sre re ce Rea ee Mc aaa ame e eS cael GAR Ne 15. 50 5. 41 35 
Chaparral!) eis ee eas eh er en ee ore Ais ae ee Ee NE 17. 87 23. 57 132 
NUCL OG BIEN oY Lee are ail a SG a NS Nee inet Soh y Silber 6. 52 13525 203 
BVUSI Er fe UEP e ae ee BAe ee oe eee aU Cas Sea Oat 11.12 13. 71 123 
TaN) WG § ete ge i HAT EE AU A BORN a a ih Nhat Mot, 14. 87 11. 62 78 
SUMMARY BY TYPE GROUPS 
Western yellow pine, mixed conifer__.._..._.....-.....-_..-.-----------__ 18. 86 11. 57 61 
Sugarpine-firDouelas: fir, firs. eae ee ee 9. 99 9. 41 94 
iBrushvchaparral, woodland, prass228 sae e es) se ee a 11.31 13. 45 119 
Ye DWNT 10 0 01] 0 5) tea cae esa ite NON HOR CN th Rey rc Dao SR Ph AVN Te ABA a 16. 22 10. 93 67 
In a broad way these figures for camper fires indicate the relative 
recreational use of the different major type groups. The surprisingly 
high rate in the chaparral and brush is probably caused by the popu- 
larity of these types for deer and quail hunting. That there is a real 
difference in the amount of recreational use between the pine and fir 
types is indicated by the fact that the fir types, even in August, the 
peak of the fire season, have but 65 per cent as many camper fires 
per 100,000 acres as the pines. 
Incendiary fires in the chaparral type attain a still higher rate, in 
striking contrast to that for the western yellow pine and fir types. 
This indicates that the setting of incendiary fires is induced primarily 
by the presence of brush, which is burned on the theory that it will 
increase forage. Further, 47 per cent of the incendiary fires in the 
chaparral type occur in September and October, the months during 
which the severest burns may be obtained, a fact well appreciated by 
§ For this period camper fires include what are now segregated as smoker fires. 
