66 NATURAL RESEEDING AND MAINTENANCE 



The experiments here cited show clearly how utterly dependent 

 is the plant on a reasonable leaf surface for the manufacture of 

 food. Not only is the development of foUage determined largely 

 by the amount of food stored in the plant for future use, but the 

 development of the root system, upon which the plant is de- 

 pendent for an ample supply of water and soil salts, is also de- 

 termined by the elaborated food supply. 



Seed Production. — The revegetation of native pastures in 

 general and of bunchgrass lands in particular is dependent upon 

 the production of a fertile seed crop. Natural reseeding, there- 

 fore, presupposes the maintenance of the seed plants at all times 

 in a high state of vigor. Without vigorous growth few flower 

 stalks are sent up, and these appear so late in the season that Httle 

 fertile seed is developed. 



In the Blue Mountains of northeastern Oregon an area which 

 for several years had been severely overgrazed was fenced 

 against stock, and for five years note was made of the recovery 

 in vigor of the vegetation. During the first year of protection 

 no flower stalks appeared until July 25, although flower stalks 

 of vigorous vegetation of the same species growing under similar 

 conditions started about June 20. The second season, however, 

 flower stalks on the fenced plot began to appear as early as July 

 10, although the growing season was no earlier than in the 

 previous year. As the seasons of protection proceeded, the 

 flower stalks appeared earlier in the spring, the seed crop was 

 larger, and the viability of the seed was very much higher. In 

 mountain ranges where the growing season is short, the great 

 struggle of the vegetation is to mature its seed crop. If this is 

 to be accomplished, the vegetation, as shown, must be in a high 

 state of vigor. 



Generalizing, it may be stated that vigorous plants, which 

 have not been weakened by overgrazing, produce a large forage 

 yield and a viable seed crop which matures fairly early; that 

 those of average vigor develop a moderate amount of herbage 

 and a small seed crop which matures late; and that seriously 

 weakened plants produce but little forage and usually fail to 

 develop any seed. 



