16 BULLETIN 1402, U. S. DEPARTMENT OF AGRICULTUEE 
stumps or in slash before the slash is burned. So far as insects or 
fungous attacks are concerned, slash may be left on the ground. 
Bark beetles as a rule avoid limbs and small tops which may dry 
out before the brood matures. The danger to living trees from fungi 
which destroy slash is slight. 
Studies under way will at some future time make it possible to 
define the effect on subsequent reproduction of leaving slash. Even 
now it is fairly certain that no pronounced trouble is due to leaving 
slash ; and in some cases, especially in yellow pine, there is evidence 
that the slash is an actual aid in establishing reproduction. Some 
advance reproduction is, of course, bent over Iby undisposed-of slash, 
but at the worst this is only a small percentage of the total left after 
logging, and it is safe to say that loss from this source is no greater 
than that from piling and burning. 
The question of leaving slash then resolves itself into a study 
of the fire hazard, the possibility of controlling fires, the rapidity 
with which slash disappears naturally, the possibility of preventing 
fires starting, and the suppression while small of those fires that do 
start. 
In a field study of many cut-over areas of ages varying up to 47 
years, the examiners noted in all cases the degree of decomposition 
of the slash in relation to the length of time since cutting.- The 
period required for slash to disappear entirely is rather long, prob- 
ably 20 to 25 years, but it was found that after the needles and 
twigs were gone, the remainder, consisting of the larger limbs, 
pieces of the main stem, etc., did not seriously increase the difficulty 
of control or the damage caused by fires. Because of the heavy 
snowfall in the California pine region, piles or windrows of slash 
are mashed dowm rapidly ; after the needles drop, usually the second 
year after logging, the whole mass is flat on the ground and de- 
composition fairly rapid. Where slash is flattened fires are not so 
intense or difficult to control as in fresh slash, since the whole mass 
can not catch simultaneously as it does when propped up in the air. 
In the majority of cases it v/as found that, in a period of 8 to 12 
years after cutting, the slash had ceased to be a special hazard. Ex- 
ceptional areas varied from 5 to 15 years, and even on cuttings of 
30 years or more some of the larger limbs and sections of the trunk 
remained. As a general working rule, however, within 10 years after 
cutting decay and compacting so reduce slash that special protection 
is unnecessary on this account alone. 
The argument for slash disposal rests on the well-proved fact that 
fires in fresh slash are very difficult to control and are extremely dam- 
aging to the remaining stand of timber. The argument for leaving 
slash in whole or in part is based on the facts that it ceases to be a 
menace in fire protection in the course of a comparatively few years, 
that any form of disposal unless carefully done causes material dam- 
age to the remaining stand, and that the money necessary to dis- 
pose of slash properly would provide for intensive protection of the 
cut-over areas. Such protection will be necessary even if slash is 
burned. 
Final decision as to the best method of slash disposal must wait 
upon an examination of fire-protection possibilities on cut-over 
lands. Leaving most of the slash and maintaining an intensive 
patrol is a possibility. 
