UNITED STATES DEPARTMENT OF AGRICULTURE 
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of, e.5 + 
Washington, D. C. 7 July, 1929 
COVER TYPE AND FIRE CONTROL IN THE NATIONAL 
FORESTS OF NORTHERN CALIFORNIA’ 
By 8. B. Snow, District Forester, California District, and EK. I. Korox, Director, 
California Forest Experiment Station, Forest Service 
CONTENTS 
Page Page 
MTGLOUUC IONE ese ok cae le heen See 1 | Number and seasonal distribution of fires by 
Cover types of northern California___._______ 2 ViDOS shots spe See, Sa eee ee 14 
Definition and distribution_____________- 2 Seasonal distribution of fires____.......__- 14 
Differences between types______________- 4 Distribution of fires by types__...-.--___- 18 
Temperature, soil moisture, and pre- Number of lightning fires____.._....______ 19 
CLPIbA OMe ery eee ce ee CN 6 Number of man-caused fires______________ 20 
Fuels and behavior of fire_____________ 8 Relative ease of handling lightning fires 
‘Pheshresproblente “2teee) isis. ves ee. aa 10 and man-caused fires_____.-..._-______ 23 
Need of an index of fire danger___________ 10 Goncentration ofniskie= ae 23 
What constitutes successful protection?__ 11 | Control of fire as affected by types___________- 24 
What constitutes need for special protec- Results RprOleChiOn esas ee eee 25 
GRO TR ee ee ee ee ae 11 Concentration of hazard areas____________ 27 
NGeENOGIOER STIG yes eet Ets Sie Petre ess Te aS 12 Size of fires, rate of spread, speed of attack_ 28 
Material used and methods of handling__ 12 Measure of difficulty of control in fire 
Omission of special-risk fires.___.__._____ igs SUPPLESSION2 sa5. sass Sele ees hehe reer 30 
Coskorisuppressigne ss a eee 32 
C@oNRCHISIONS Sn. eee oa ee Oe eee 33 
INTRODUCTION 
In the complex forest-fire problem of the national forests of northern 
California, the group of factors dealing with man’s efforts to control 
fire has received most attention from all forest agencies, not only in 
the literature, but in everyday inspection and study by fire executives. 
The urgent need to learn what type of protection organization 
is most effective, how much a given scale of protection will reduce 
fire losses, and how the performance of the organization can be 
systematically checked and improved has dictated this concentration 
on means of attack. 
Important as such studies are, however, they must be supple- 
mented by analysis of a second group of factors, which include the 
physical nature of the forest itself, the character of vegetation or 
cover type, the behavior of fires as influenced by the kinds and 
volume of fuels peculiar to each type, and the climatic elements which 
affect alike the cover type and the occurrence and spread of fire. 
1 Northern California as defined includes the east and west slopes of the Sierra Nevada, the Coast Ranges 
north of San Francisco Bay, the plateaus of northeastern California, and the cross ranges of northwestern 
California. The national forests included in this area are for the purposes of this discussion divided into 
four groups, as follows: (1) Northern group, Klamath, Trinity, Shasta, and California; (2) east-side group, 
Modoe and Lassen; (3) northern Sierra group, Plumas, Tahoe, and Eldorado; (4) southern Sierra group, 
Stanislaus, Sierra, and Sequoia. These groups represent natural affiliations, geographically and otherwise. 
The division has been employed in earlier work, and having proved useful, isretained. The four protection 
forests of southern California represent a special problem and are not included, nor are the Inyo and Mono 
National Forests, because of the scarcity of fires on these forests, 
38207°—29——1 ih 
