32 BULLETIN 1112, U, S. DEPARTMENT OE 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 

 ojfficers 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 Imnbering operation is more economical than the small one, 

 the latter can render a definite service in improving the hygienic con- 

 dition of the forest tlirough 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 interfering 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 

 tune 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 in- 

 fected black-jack stands where reproduction is not established vigor- 

 ously growing and thrifty trees should not be radically sacrificed. 



1 5 Weir, James R . Some Suggestions on the Control of Mistletoe in the National Forests of the North- 

 west. Forestry Quarterly, 14 : 567-577, 1916. 



