MARKING OF WESTKRX WHITE PINE 873 



necessary at that time to provide for reproduction, in addition to the 

 advance growth already on the ground, by reserving from cutting a 

 large quantity (approximately 25 per cent of the volume) of the valu- 

 able species. The most practical method of applying the principles was 

 to clean cut between strips or blocks laid out with mechanical preci- 

 sion — that is, perpendicular to the contours and along ridge summits. 



Further study brought out new principles, chief among which was a 

 more definite knowledge of the possibilities of reproduction from seed 

 stored in the duff. The advance is shown clearly in the silvicultural 

 plan drafted for the Lolo Creek chance on the Clearwater Forest. 



The principal lines of development in the Lolo marking rules are : 



1. Recognition of the fact that seed stored in the duff will usually 

 be sufficient for satisfactory restocking. 



2. The comparative wind firmness of white pine. 



3. The meeting of practical requirements by reserving less mer- 

 chantable material. 



4. More specific classification of the various stands in the white-pine 



type- 

 Extracts from the marking rules for Lolo Creek follow. For mark- 

 ing purposes the stand is classified as : 



1. Mature white-pine stands. 



2. Overmature white-pine stands. 



3. Selection stands. 



Mature White-pine Stands 



These are areas containing upward of 30 per cent of white pine of 

 from approximately 100 to approximately 180 years in age. 



The object of marking is to harvest the mature timber by clean cut- 

 ting, which furnishes the best conditions for white-pine reproduction, 

 and to insure restocking both with white pine and with the tolerant 

 species — cedar, spruce, and white fir — which form a desirable mixture 

 and understory. It is expected that satisfactory white-pine reproduc- 

 tion will be secured from advance growth and seed stored in the duff. 

 Sufficient timber will be reserved, however, to seed areas burned in 

 brush disposal and to insure restocking in case the first reproduction 

 is destroyed by fire. 



Approximately 10 per cent of the merchantable volume of the stand 

 should be retained in compact groups, the remainder being cut clean 

 excepting for a few individual white pine, cedar, and larch trees, as 

 noted below. The groups reserved should contain, as a rule, from 12 

 to 15 trees of merchantable size. The groups should be spaced from 

 three to six chains apart in each direction, reserving on the average one 



