MARKING RUI.es FOR IDAHO AND MONTANA 675 



In Bj, B2, and B3 stands where reproduction on clear cutting with 

 seed trees is proposed and the only trees left upon the area are the seed 

 trees, mistletoe and rust infections are probably the only danger to 

 young growth to be guarded against. The marking rules should pro- 

 vide for the cutting of all mistletoe and rust-infected trees upon the sale 

 area, and in this manner eliminate the danger. The importance of the 

 cutting of trees infected with heart-destroying fungi on such areas is 

 not so great as upon the A^ and Ao stands, since it would take about 50 

 years for the reproduction (white pine) upon the area to reach the 

 earliest infection age.'^ The question of seed trees left upon the B 

 stands is an important one from a pathological point of view. Seed 

 trees attacked by wood-rotting fungi not only act as centers for the 

 spread of diseases which threaten reproduction and sound mature trees, 

 but also subject the trees to early wind-breakage through the weakening 

 of the trunks and to early windfall through the weakening of the roots. 

 If the seed trees suffer windfall or wind-breakage at an early date, be- 

 fore they have had time to properly reseed the area, then this loss is 

 sufficient to justify methods of prevention. In such stands as the B3 

 where there are no white pines evidently capable of living through a 

 second rotation (100-120 years), care should be exercised in the selec- 

 tion of seed trees. A'eteran trees having defects other than rot, rust, or 

 mistletoe, unless such defect greatly weakens the resistance to wind- 

 breakage or windthrow, may be selected as seed trees, if thrifty and 

 healthy seed trees cannot be had without such defects. Veteran white 

 pines showing indications of rot, but without visible sporophores, should 

 be the last choice for seed trees in case no sound trees can be found to 

 serve the purpose. In any event, trees with visible live sporophores 

 should not be selected for seed trees, and the tendency should always be 

 toward sound trees in the case of seed trees other than white pine. 

 Even though an infected veteran seed tree should not live over until the 

 reproduction reached the infection age, the damage done by allowing it 

 to remain, develop sporophores. and spread the disease to near-by 

 susceptible trees should be sufficient to condemn such a practice. The 

 recommendations for pathological marking on the western white pine 

 type resolve themselves into two main divisions : ( i ) those applicable to 

 the selective method of cutting or improvement cuttings, and (2) those 

 applicable to the clean-cutting method. The first method covers the A^ 

 and A, stands, while the second method covers the B^, Bo, and B, 

 stands. The recommendations are as follows : 



For the A^ and A2 stands : Designate to be cut all trees of whatever 



