DETAILS OF THE METHOD 47 



The seed trees must be old enough to produce abundant 

 fertile seed. The age at which seed bearing begins in closed 

 stands is the point which should be considered. Besides 

 being old enough to bear seed the seed trees should be pref- 

 erably of the dominant or at least of the co-dominant classes. 

 Trees of the dominant class show the best crown development 

 and may be expected to produce the largest amount of the 

 best seed of any trees in the stand. The dominant trees are 

 also among the stockiest and most strongly rooted trees. 



Under "Definition" it was stated that the seed trees might 

 either be removed after their function of establishing repro- 

 duction was performed or else left during the rotation in most 

 cases to die before being harvested with the second crop. The 

 selection of the seed trees will vary depending upon which of 

 these two plans is to be followed. 



If a second cutting can be made within a few years and the 

 seed trees saved, then fine healthy dominant trees presum- 

 ably the best seed producers and containing valuable timber 

 may be selected. Where the seed trees are going to be left 

 and must be considered as a total loss, then trees of a lower 

 commercial value may have to be chosen. These may be 

 the deformed or limby trees or trees attacked by fungi. 

 As a general proposition it is unsafe and unwise to leave fun- 

 gus infected trees if it can be avoided, because of the probable 

 quality of the seed and seedlings produced, and the low vigor 

 in resisting disease which trees from such stock may possibly 

 inherit. Definite information as to the effect on future tree 

 generations of different types of fungi is still fragmentary. 



Investigations ^ carried on at the Wind River Experiment 

 Station, Carson, Washington, with Douglas fir indicate that 

 conkiness caused mainly by Tratnetes pini reduces the yield 

 of good seed per bushel of cones to 62 per cent of the normal 

 and decreases the height growth of young seedlings in the 



