I!IU>II l>ISIt)S.\l. IN WnS'lKUN VKI.I.OW I'lXK .U 



Though the above results apparently contradict previous ones, the 

 divergencies may be readily reconciled. The better survival along 

 logs and tops is due almost entirely to protection against sheep injury. 

 Germination is usually less in the brush owing to excessive litter 

 (under certain conditions it may be better than in the open) ; and 

 mortality is greater during the first two or three years due to the 

 rank growth of grass with which young seedlings are unable to com- 

 pete. In brush, particularly unlopped tops, the grass is scarcely grazed 

 at all and consequently makes a more luxuriant growth than where it 

 is subject to grazing. A few seedlings do survive in the brush, how- 

 ever, despite competition with the grass, while in the open practically 

 every seedling is destroyed by sheep. The bare spots such as burned 

 brush piles, roads, and stump areas, where seedlings are most numerous 

 to begin with, are just the places which are hardest hit by the sheep. 

 This is due to the fact that what forage grows on such spots is of the 

 succulent weed type ; hence sheep tend to concentrate there. The 

 growth of seedlings on such spots where protected against sheep is 

 astonishing. When brush is placed on such spots, or wherever the 

 grass has been exterminated, excellent seedling development results, 

 due to the fact that they have the benefit of the soil mulch without 

 being subjected to competition with the grass. This explains why 

 such excellent results were obtained on the 191-i experimental plot 

 where the ground icas plowed before scattering the brush, thus elimi- 

 nating the grasses. 



I have outlined only the most essential facts brought to light by this 

 season's study. There are a great many apparent exceptions to these 

 statements, all of which are traceable to special conditions, and may 

 be readily explained. The underlying fact is that western yellow pine 

 seedlings thrive best where the entire soil moisture supply is at their 

 disposal. Protection against wind and strong sunlight in dry periods 

 is beneficial, but in the end it is detrimental if it is secured at the 

 expense of the seedlings being robbed of soil moisture by a rank 

 growth of older and better established plants, such as bunch grasses 

 and other perenials. 



The practical application of the foregoing conclusions is that pulling 

 tops is not beneficial but is rather detrimental to reproduction, except- 

 ing that it serves as a temporary protection against sheep. Under 

 unrestricted sheep grazing, pulling tops is beneficial in a limited way 

 for a few years ; but as a means of promoting reproduction it is wholly 



