REPRODUCTION OF WESTERN YELLOW PINE 393 



sonably be expected to do is to throw the weight of man's endeavor 

 on the right side of the balance. The extent to which management can 

 be depended upon to expedite reproduction is a matter requiring 

 further investigation. 



Next to unfavorable climatic conditions, the factors most inimical 

 to reproduction of western yellow pine are fire, unregulated grazing, 

 and insects. 



On extensive areas fire has vitiated the efforts of the forest to per- 

 petuate itself With the present fire-protection system in effect, dam- 

 age from this source will in the future be greatly reduced. Notwith- 

 standing this fact, when it is considered that the recurrence of fire on 

 a given area once in 20 years may nullify all progress in reproduction, 

 the importance of this factor can scarcely be overestimated. 



Grazing animals, especially sheep, are responsible for much dam- 

 age. On the other hand, grazing is beneficial, in that it facilitates the 

 control of fires, aids germination by covering tree seeds, and decreases 

 competition between tree seedlings and herbaceous vegetation. The 

 solution of the grazing problem lies in regulation rather than exclusion 

 of stock. Since this is one of the few large factors capable of control, 

 it demands serious attention. 



Insect damage ranks with fire and grazing damage. Unfortunately, 

 no practical means for controlling the insect enemies of forest repro- 

 duction in this region are at present available. 



