MARKING OF WESTERN WHITE PINE 881 



Further provision for seed production should be made by leaving seed trees of 

 mixed species, giving preference to larch, cedar, spruce, and Douglas fir, in the 

 order named. The ground should be cleared as much as possible of all other 

 trees. 



If it proves necessary to plant such areas to secure a good proportion of white 

 pine in the reproduction, broadcast burning will be employed to dispose of the 

 brush and only larch seed trees need be left. Broadcast burning and planting 

 will not be employed, however, without the specific apprqval of the district 

 forester. 



Scientific Facts Concerning the Life History of Western White Pine Which 

 Have a Bearing upon Marking 



Reproduction After Cutting 



(i) Reproduction of white pine may be expected from seed stored in the 

 duff, if the seed is not destroyed by fire. The intensity of a fire which is suffi- 

 cient to kill the seed stored in the duff has not been determined. 



(2) The number of seedlings per acre resulting from stored seed depends 

 upon : 



a. The quantity of seed stored (largely dependent upon the number and 

 distribution of seed-bearing white-pine trees in the original stand. In- 

 vestigations indicate that from 300 to S,ooo seedlings per acre may be 

 expected)-. 



b. The amount of light the seedlings receive after germination. (White- 

 pine seedlings require full light for the most profitable growth, but the 

 proper size of opening in crown cover has not been determined.) 



Germination of Seed 



The bulk of white-pine germination from seed stored in the duff appears to 

 take place the second season after the stand is cut, although some germination 

 occurs the first, third, and fourth seasons. White-pine seedlings germinate well 

 on all surfaces — mineral, duff, rotten wood, and humus. Mineral soil, if moist, 

 otherwise mineral soil covered with one-half to one inch of duff, provides the 

 most favorable seed-bed. 



Development After Germination 



White-pine seed will germinate under dense shade, but evidence has been 

 secured to indicate that seedlings which do germinate under dense shade will 

 usually die. Satisfactory growth will take place only when the seedlings are 

 given plenty of light. Investigations indicate that 50 to 100 per cent of unob- 

 structed overhead light is necessary. 



Seed Production 



White pine is comparatively a light seed-producer. Fair to good crops of 

 white-pine seed occur at intervals of two, three, or four years. Fully stocked 

 stands usually contain enough seed to completely stock the ground with seed- 

 lings within ordinary migrating distance of parent trees. 



