All in all, we are a long way from eliminating 
the fire menace on private and State forests—on 
the whole the most accessible and potentially the 
most productive of our forest holdings. Fire pro- 
tection alone will not assure good forestry, but 
obviously it is a first order of business on these 
lands. 
Forest Insects and Diseases 
Take a Heavy Toll” 
Insect and disease depredations are far less spec- 
tacular than forest fires and seldom attract much 
public attention. The destruction is of two main 
kinds: (1) The “endemic” losses resulting from 
normal activities of established insect and disease 
pests; and (2) the more evident “epidemic” losses 
from outbreaks that rapidly and markedly affect 
forests.34 » 
A great variety of pests that cause endemic losses 
are constantly at work in the forest. Examples are 
the heart rots, blister rusts, and most of the insects 
and diseases that attack tree leaves and stems. 
These seldom kill trees outright, but gradually 
reduce growth and timber quality. Endemic losses 
may be of minor importance in young, fully 
stocked forests. But in mature stands they often 
accumulate to destroy timber faster than it is re- 
placed by current growth. They flourish especially 
in unmanaged forests. 
There is no satisfactory measure of endemic 
losses. ‘They are, however, very large and offset a 
sizable portion of gross annual timber growth.*> 
Except in parts of the West, the losses from disease 
are generally greater than from insects. <A princi- 
pal source is the heart rots, which occur in practi- 
cally every timber stand. ‘These cause annual cull 
losses of many million dollars in standing timber. 
* This subject is more fully treated in Reappraisal Report 
5, Protection Against Forest Insects and Diseases in the 
United States. U. S. Dept. Agr., Forest Service. 1947. 
* The distinction is not always sharp. The difference is 
often one of severity rather than of the pest or its mode of 
attack. Thus, a low level of pest incidence, which usually 
characterizes the endemic state, may build up, where con- 
ditions are favorable, to epidemic proportions. On the other 
hand, pests which commonly figure in destructive epidemics 
May remain in an endemic status for many years, causing 
little damage. Examples of endemic losses and lists of 
major epidemics, both by regions, are given in Reappraisal 
Report 5. 
% Epidemic losses are usually included as an item of forest 
drain, whereas allowance is made for endemic losses in growth 
calculations. 
806034°—49—8 
Forests and National Prosperity 
Epidemic losses are usually unpredictable. Little 
allowance can be made for them in the long-range 
management plans. Frequently so destructive as 
to jeopardize lumbering investments and opera- 
tions, epidemic losses have always attracted most of 
the public attention and remedial action. 
This country has many examples of damage from 
epidemics. The larch sawfly destroyed practically 
all mature stands of larch in the Lake States about 
35 years ago. Chestnut was wiped out by an intro- 
duced parasite, the chestnut blight. Numerous 
bark-beetle outbreaks in the pine forests of the 
West and South have destroyed many billions of 
board feet of timber. Blister rust is a threat to 
valuable white pines wherever they occur. 
Government agencies have mostly centered 
efforts on control of epidemics after they have 
become full-blown outbreaks; on quarantine and 
inspection to exclude foreign pests; and on research 
to develop the basic techniques of control. 
Only a small beginning has been made in adjust- 
ing forest-management practices to reduce insect 
and disease losses. Yet, generally speaking, good 
forestry is the best preventive for these losses. It 
helps keep insects and diseases from reaching the 
epidemic stage where control may be very expen- 
sive, if not impossible. Moreover, well-managed 
forests are usually. accessible and closely utilized. 
This permits better clean-up of dead and dying 
timber and greatly facilitates control operations. 
Conversion of natural stands to fast-growing, man- 
aged forests will remove the trees most susceptible 
to attack. A vigorous growing forest—a prime aim 
in forestry—suffers comparatively little injury from 
most insects and certain diseases. For others, 
against which mere vigor does not protect, much 
can be done through adjusting species mixture or 
stand density and avoiding unnecessary wounding. 
During the decade 1936-45, 54 million dollars 
of Federal, State, and private funds was spent on 
control: 
Expenditures for forest insect-disease 
control, 1936-45 (million dollars) 
State and 
Federal private Total 
Item: 
White pine blister rust ........ 26.2 2.5 28.7 
Gypsy moth ooo. 12.9 11.0 23.9 
Other imsects .000ooo.....ceeceeeeeeee 1.4 al 1.5 
Total 40.5 13.6 54.1 
More than half was spent on white pine blister 
rust, about 44 percent on gypsy moth. Much of 
the latter, however, was spent for protection of 
85 
