MANAGEMENT PLANS THE NATIONAL EORESTS 47 



DISCUSSION OF CEUISE 



The Government land on this area was cruised in 1910. The trees were 

 tallied by 2-inch diameter classes, the number of logs per tree not being tallied. 

 Volumes were computed from especially prepared volume tables. Trees from 

 12 to 20 inches d. b. h. were not tallied. 



Checking the estimate for 1,300 acres of cut-over land against the cut and 

 the amount left for the same area gives the following result : 



Board feet 



Cut 34, 541, 000 



Left 6, 425, 900 



Total 40, 966, 900 



Estimate 35. 928. 100 



Difiference 5. 038. 800 



Underestimate per cent — 12. 3 



A comparison of the Forest Service cruise on 4,160 acres on the south side 

 of the area with the cruise made by the University of California Forest School 

 on the same area results as follows : 



Board feet 



University of California Forest School estimate 151, 767, 000 



Forest Service estimate 130, 720, 000 



Difference « 21, 047, 000 



A part of the underestimate of the Forest Service cruise was probably due 

 to the fact that trees from 12 to 20 inches d. b. h. were not included. 



FIRE HAZABD 



This unit would be classed as an area of low fire hazard for the following 

 reasons : 



1. A heavy snowfall, with cool nights during most of the year, prevents a 

 rapid drying out of the area. 



2. The entire area is directly under the eye of the Spanish Peak lookout, so 

 fires should be detected when small. 



3. All parts of the area are readily accessible by roads and trails. 



4. There is a good supply of labor close at hand. 



5. The area is comparatively free from the two chief causes of fires — 

 lightning and campers. 



Summary of -fire record for last 11 years 



Year 



Number 

 of fixes 



Acreage 

 burned 



. 



Year 





1 



i Number 



: of fires 



1 



Acreage 

 burned 



1911 



1912 



1913... . 





2 



4 

 8 

 8 

 1 

 

 1 

 1 



0.5 

 12 

 16 

 160 

 

 

 .5 

 



1919. 

 1920. 

 1921_ 







3 

 2 



1 



2 

 340 



Q 



1914 





Total 



.\verage per 



year ... 







1915 



31 



531 



1916 







1917 





48 



1918.... 













On the basis of the fire record for the last 11 years the loss from fire during 

 the first cutting cycle would not be heavy. A total of 2,400 acres would be 

 burned over, but only part of this would fall on virgin timberland, and the loss 

 on this should not be high. The main loss would come through the destruc- 

 tion of poles and advance reproduction. With the steady improvement in 

 the fire-protection system, normal loss from fire should not seriously interfere 

 with the plan for the institution of sustained yield. 



GROWTH AND YIELD 



Growth and yield data for mixed stands are very meager. The problem of 

 predicting yield for the second cutting cycle and for the rotation period is 



" 16.1 p*r cent of Forest Service estimate. 



