ROLE OF FIRE IN CALIFORNIA PINE FORESTS TF 
of the total tree volume, it includes that part from which the clear 
erates of lumber, the highest quality of material in the tree, are ob- 
ained. 
A study made in 1911, covering 155 sample trees in the yellow pine 
region of eastern Oregon, an extension of the California pine region, 
disclosed the fact that 42 per cent of the merchantable trees were fire 
scarred. On1,184 representative trees in Grant-County, Oreg., 23 per 
cent of the butt logs were fire scarred, not counting stumps from which 
the trees had been cut high enough to avoid the scars (19). Of these 
logs 18.6 per cent were so badly scarred that an average of 46 board 
feet, or 14 per cent of the full scale, had to be deducted from the 
total log scale. A typical scar of this sort is shown in Plate III. 
A study of cause of cull for a typical mill in the Sierra region 
showed that more than 50 per cent of the total cull was due directly 
to fire and that this loss amounted to 9 per cent of the total scale of 
defective logs. Table 2, covering this study, shows, beside the direct 
loss of wood from fire, the total loss due not directly to fire but to 
decay, entrance of which is generally through fire scars.° 
No detailed figures are available showing the reduction in lumber 
grade on account of the increased amount of pitch surrounding fire 
scars. That there is such a reduction is a wall dccanthid fact. This 
reduction is of particular importance because it affects those species 
which furnish the most valuable pine lumber. 
TABLE 2.—Comparison of cull due to fire and other causes in western yellow pine 
logs? 
| 
A verage | Reduction 
: diame- Gross Net 
Kind of defect ter of seale scale | 
Total 
log In class 
Inches |Board feet| Board feet| Per cent | Per cent 
24 4 732 1523 
Ware SCAR sass eee Coe ee she 11, 490 9, 732 4.72 
@atfacen Sa es ee ae oe eee 20 660 400 39. 4 0. 70 
Burned butt_..--.----------------------------------- 25 460 428 7.0 0. 09 
Hire scananG: piichseee se eee eee eee ees tS 23 1, 880 1, 204 36. 0 1. 82 
Bire'scan and: centernrote-s" 25-4. 782s ce Se 28 580 517 10.9 0.17 
Hire scar andistumipirOb nc 2 oo ee os oe ee 29 3, 040 2, 485 18.3 1.49 
TOE AIG UIC tA be ee ees ee ek ee ae pos Sey See 18, 110 14, 766 18.5 8. 98 
@ull’not duotto: nrewss 2s: 22 et Sse a esc [PS uae 19, 110 16, 043 16.0 8. 24 
Totals allesusese.= 55528 a s.-8 Pha irae Ss ey Meg Sect ae 37, 220 30, 809 175.2 17. 22 
1 Basis, 106 defective logs, on Plumas National Forest; Delleker Mill scale. 
DIRECT HEAT KILLING 
An always obvious form of damage to merchantable timber 1s 
direct heat killing. This occurs when fire has swept through the 
crowns of the trees, burning up the foliage completely, or when fire 
on the forest floor has developed such heat that the foliage and buds 
are killed without being consumed. Occasionally the mner, living 
bark on the trunks or on the roots near the surface of the ground is 
killed by long-continued intense heat from burning logs or deep layers 
of litter and duff. 
5 The influence of fire on decay is treated more in detail later. It is sufficient here to note that decay is 
one of the invariable secondary causes of loss of timber directly chargeable to fire. 
