THE FOOTHILL VEGETATION 105 



indicate something of the severity of the conditions involved. 

 Three situations were chosen on the grassy slope of a mountain 

 facing the west and southwest. One of these by reason of a 

 slight depression and less direct exposure to the sun was con- 

 sidered more favorable than the others; the other two areas, 

 lying on a steep and rocky slope directly facing the southwest, 

 were regarded as exceptionally severe. Upon these areas plant- 

 ings were made in three successive seasons (1910-1912) with 

 considerable numbers of yellow pines, both seedlings and trans- 

 plants one or two years old. Unusual conditions in the form of 

 drouth and fire at first beset the efforts, but in the end, owing 

 to circumstances attending the planting and a season more than 

 usually favorable, the plantations weathered the first summer 

 with about 25% of the trees surviving. 



It was thought that the main difficulty besetting either 

 natural or artificial afforestation was the establishment of the 

 seedling, and that if the first season could be survived they 

 might maintain themselves indefinitely. Such, however, seems 

 not to be the case, for in these experiments the number surviv- 

 ing waned rapidly from year to year until none were left. The 

 stems and leaves eventually turned dry and crisp, and, inasmuch 

 as the planted seedlings could be clearly identified, any conclu- 

 sion that they had been destroyed by other agencies was obviated. 



Growth, as usual under such circumstances, was slow. Even 

 the plants that survived two years or more grew a scant inch 

 or more of stem and a few dwarfed leaves while those of the 

 same stock remaining in the nursery increased by several vig- 

 orous inches and a full brush of healthy leaves. 



Seeding operations were even less successful, as was expect- 

 ed. Several variations of method gave uniformly negative re- 

 sults. The difficulties that beset natural seeding are largely 

 present in artificial methods and that forest extension over grass- 

 lands by natural means is exceedingly slow is generally true and 

 a matter of common knowledge. Along the tension line of yellow 

 pine forest and bunch-grass prairie of western Montana the 

 direction and rate of transition is evident in the scattered pines 

 successively younger and more sparse from the forest outward. 



It would hardly be safe to say that successful forestation 

 of such areas with Piniis ponderosa is impossible, but the fail- 



