52 WESTERN YELLOW PINE IN ARIZONA AND NEW MEXICO, 
vary with local conditions. It is justified by Van Mantel’s method 
of regulating the yield, in which the growing stock, divided by half 
the number of years in the rotation, is the annual cut. This method 
tends to reduce automatically the excess growing stock to normal, 
and to increase the growing stock where it is dangerously low. The 
Austrian method of regulating the yield may also be followed. By 
this the annual cut is equal to the mean annual increment, plus the 
difference between the real growing stock and the normal growing 
stock, divided by the period during which the surplus is to be re- 
moved. The normal growing stock in turn is determined by multi- 
plying the mean annual increment by half the rotation. The chief 
difficulty in applying this method in the Southwest is the lack of 
exact information regarding annual growth after cutting. Steps 
have, however, been taken to secure accurate data, which should be 
available within 10 years. 
On some Forests empirical methods of limiting the cut may be 
adopted. For instance, where a certain area is to be cut on a 
200-year rotation, 1t may be assumed that the stand on one two- 
hundredths of the area could safely be cut each year, provided regen- 
eration follows. Whatever the method employed, the object is to 
limit the annual cut so that a sustained annual yield is possible. 
FIRE PROTECTION. 
During the year 1909 a total of 91,895 acres were burned over on 
the 19 National Forests in Arizona and New Mexico. It is remark- 
able that the total damage to timber on the entire area amounted to 
only $73,971. If the Gila National Forest were omitted, the total 
damage to timber on the 18 other Forests would amount to only 
$21,471. The damage on the Gila, amounting to $52,500, was the 
result of extraordinary conditions of drought and of the lack of 
settlement in the region, which made it exceedingly difficult to secure 
quick assistance in fighting the flames. 
The total number of fires which gained headway in Arizona and 
New Mexico in the calendar year of 1909 was 259. The causes of 
these, as far as it has been possible to ascertain, were: 
Cause: Number. 
MTU TV i a ir 108 
CAMA POLS: ks ee 69 
Tesh tare Ss ea i Se 30 
Railroad) 2282 2 sr ee Bele eee ee 12 
SUV DG ss ne es sg i eee 9 
Brush burning? 22 ot) oe ee ee ee eee 7 
Incendiary £02222. 2222.22 oe ee eee + 
Miscellancous) 32222 =a=—2 2 a a SAE ge LS Oz ei rein eG 


1 Wc) 7 eee een CU er rere a OP a 259 



1 



