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We have had to search for differenl and inexpensive methods, :m<! as Our kn^u I- 
edge of the life history and habits of the principal depredators <>n foresl treesand 
forest products increases, as the results of recenl investigations, it becomes plain thai 
a vast amount of loss from this source can be prevented without cost. 
It is in the adjustment of business methods in harvesting and caring for foresl 
products that we have a simple and inexpensive means of dealing with the principal 
forest insect problems. We have found that certain methods of lumbering and caring 
for the manufactured products contribute to the multiplication of the destructive 
insects and consequent losses from their work. We have also determined that a 
change in these methods, which involves no hardship or additional expense, will have 
the opposite effect. This has been demonstrated in the .Maine woods, where, upon 
recommendation, the principal cutting is concent rated in the areas of dying and beetle- 
infested spruce. We have another example, in the tan-bark industry, where it has 
been shown that, if the bark is utilized for tanning before it is three years old, the 
heretofore great loss of bark from insect work is entirely prevented. It lias been 
shown that the pine forests of the Black Hills forest reserve may be saved from pos- 
sible destruction by the pine-destroying beetle, by cutting a Large per cent of the 
infested trees during seven months, from the 1st of October to the 1st of May, and 
converting the same into merchantable products, and that this can be done without 
cost to the Government. We have experiments under way the results of which are 
already making it clear that very extensive losses in the cypress lumber business 
of the South, from insect work, can be avoided without additional cost. It will only 
be necessary to ad just the operation of girdling trees so that the principal work will be 
done at a time of year which will result in unfavorable conditions for insect attack. 
The methods of determining the facts on which to base recommendations for this 
class of preventive measures involves some expensive experiments, but with the 
cooperation of the Bureau of Forestry and the practical lumbermen, which is being 
so liberally extended, we feel that much will be accomplished along this line in the 
future. 
There is another method involving the destruction of infested trees which has 
yielded encouraging results. In cases where the felled timber can not be utilized and 
must be burned, it is an expensive process, and is only available where the promised 
results will justify it, while in other cases where the felled timber can be converted 
into merchantable products, there is little or no loss. The practicability of this 
method seems to he demonstrated this year at Belle Isle Park, Detroit, where a 
large number of hickory trees, thickly infested with the hickory bark-beetle, were 
felled and burned during "Slay, the work having been done just in time to effectually 
destroy the broods before the adults commenced to emerge. The result of this w< »rk 
by the park commission was specially satisfactory, as no evidence of the work of the 
insect has since been observed, while the previous summer it seemed that all of the 
hickories in the park (one of its most important features) would be completely 
exterminated. 
The methods of obtaining facts on which to base recommendations for the cutting 
and destruction of infested trees involves the determination of the life histories of 
the destructive insect and its principal natural enemies, in order to designate the 
beginning and ending of the period within which the infested timber must be felled. 
It is important to determine whether or not the entire tree or only the bark of the 
trunk should be burned, or if the simple operation of removing the bark would be 
sufficient to kill the young broods. The life history and habits of the natural 
enemies must be studied to determine whether or not they emerge some days or 
weeks in advance of the tree-destroying insects, in order that they may be allowed 
to escape before the trees or bark is burned. 
We have also the trap-tree method of combating forest insects, which consists in 
the providing of girdled and felled trees at the proper time of year to attract certain 
destructive bark-infesting insects. By this method swarms of the beetles are con- 
centrated on a few trees, and after they have entered the bark and the broods are 
partially developed, they are all destroyed by the simple removal of the bark from 
the infested parts of the stumps, trunks, and larger branches, leaving the wood 
available for lumber or fuel. 
The determination of the particular species of insects which can or can not be 
trapped and destroyed in this manner, and the proper time and method of doing the 
work to meet the requirements of each species, involves extensive experiments and 
the use of a large number of different kinds of trees in differenl sections of the 
country. As an example, over 200 large trees were utilized in one experiment 
last year in the Black Hills Forest Reserve. The results from this and other similar 
experiments have so far been very gratifying in showing that some species arc read- 
ily attracted to felled and girdled trees, while others, like the pine-destroying beetle 
