32 BULLETIN 1112, U. S. DEPARTMENT OF AGRICULTURE. 
and the amount of infection should also be recorded. Weir has 
suggested that this could easily be done by timber-survey parties in |} 
connection with their regular mapping and cruising work. Such | 
tangible records of mistletoe infections would be invaluable to forest 
officers in showing just where diseased stands are located, in order }» 
that an attempt.be made to exploit stands of seriously diseased tim- }' 
ber as rapidly as possible. 
The advent of a large commercial timber-sale operation should not 
be awaited before undertaking mistletoe-control work. Small ranger 
sales and even the issuance of free-use permits would materially assist 
in the reduction of severe infections. Although in many instances 
the large lumbering operation is more economical than the small one, 
the latter can render a definite service in improving the hygienic con- 
dition of the forest through removing more or less isolated infections 
which are too small to be exploited in a large operation. The prod- 
ucts of the small operation are not marketed in such highly finished 
or specialized form as are many of the products of the large operation. 
In the case of a small lumbering operation mistletoe-infected trees | 
will, in almost every case, be as well adapted to the desired uses as the 
products of healthy trees. 
The problem of the control of mistletoe assumes two quite different 
aspects, depending upon the degree of infection on a given area. 
Silvicultural systems of regeneration should provide for the eradica- 
tion of the mistletoe from the stand as one of the most necessary re- 
sults to be accomplished. On areas adequately stocked with advance 
reproduction all infected trees should be cut. On the other hand, on 
areas of light to moderate infection special emphasis should be laid 
upon the need of leaving all healthy trees possible, even if they belong 
to the ‘ yellow-pine” class, in order to insure as good a condition of 
the forest cover and seed production as possible. Where the injury 
is not very serious the marking rules should call for the removal of all 
mistletoe-infected trees possible without breaking up the continuity 
of the stand or materially interfermg with the silvicultural system 
of management adopted for the area. Lightly infected areas should 
be marked in such a manner that, with supplemental pruning at the 
time of marking, the stand would be practically free of infection. 
Lightly infected black jacks and transition trees on areas bearing no 
advance reproduction should not be cut when otherwise thrifty and 
sound, except where thinnings are desirable to obtain increased growth 
or where reproduction is established. Such thinnings, however, may 
be somewhat heavier than in uninfected stands; but in lightly 1 in- 
fected black-jack stands where reproduction is not established vigor- 
ously growing and thrifty trees should not be radically sacrificed. 
13 Weir, James R. Somé Suggestions on the Control of Mistletoein the National Forests of the North- 
west. Forestry Quarterly, 14: 567-577, 1916. 
