MARKING RULES FOR IDAHO AND MONTANA 671 



This entails a working knowledge of the principal disease-producing 

 organisms found attacking the timber trees of this region. The pres- 

 ence of "punks" or "conks," the fruiting bodies of fungi, the presence 

 of punk knots, pitch flows and swellings at the branch whorls, and stag 

 heads on older trees killed by fungi or mistletoe are all included as 

 diagnostic characters indicating the diseased condition of the tree. 



2. A fairly accurate judgment of the extent of rot in each 

 tree found attacked by wood-rotting fungi and a knowledge of 

 the amount of damage done and to be expected from other im- 

 portant tree diseases, such as rusts and mistletoes. 



Tapping the trunk of the tree with any blunt instrument in order to 

 determine whether the tree is sound or rotted, and the extent to which 

 it is decayed, is one of the most reliable methods when no fruiting 

 bodies or other symptoms are present. Good practice can be secured 

 by applying the test to doubtful trees and later checking the conclu- 

 sions by examining the identical trees after they have been cut. The 

 extent of rot up the trunk, the difference between sound and slightly 

 infected trees, as well as the identification of the various kinds of rots, 

 can be determined by the above practice. 



3. A knowledge of the age of first infection of the various 

 species of trees found in the stand. (The use of data collected 

 by the Office of Forest Pathology on separate tree species*, ''.) 



Knowing the age of earliest infection for a single tree species oc- 

 curring upon a given site, the marking officer knows how early in the 

 age of the stand to expect decay. From this age on infection in the 

 stand is to be guarded against, and as the stand becomes older this 

 danger increase. By knowing the age classes of the trees to be 

 marked in the stand and applying the knowledge secured from rot 

 studies made of similar species and age classes-, *, ', a good idea of the 

 pathological condition of the stand may be had. This knowledge can 

 be applied to the marking practice. For Echiiiodontimn tinctorium 

 attacking western hemlock, the average age of first infection for the 

 river-bottom type is approximately 44 years, and for the slope type 57 

 years;* this for the Priest River region. 



In the case of western white pine, for all the principal rots found 

 in the stand, an age of earliest infection of 50 years was determined 

 for the tree in general. These data are from the Coeur d'Alene Na- 

 tional Forest. The principal fungi attacking this tree in order of their 



