6 



which did not require agricultural implements, the use of which 

 often results in serious erosion. In some cases wooden or brush har- 

 rows made on the ground were used. In other cases sheep driven in 

 a compact body over the lands after sowing served the purpose of 

 harrowing the seed into the ground. 



CHARACTER OF THE LANDS. 



The plots were located where the need for range improvement is 

 greatest. The areas seeded vary in altitude from 2,000 to 10,000 feet. 

 This range in elevation was accompanied by a corresponding diver- 

 sity in the growth conditions and in the character of the native vege- 

 tation. 



Among the more common and characteristic trees of the higher ele- 

 vations where studies were carried on may be mentioned : Whitebark 

 pine, foxtail pine, limber pine, subalpine fir, Engelmann spruce, and 

 mountain hemlock. The climatic conditions characteristic of regions 

 in which these trees predominate will be designated by the use of the 

 term " whitebark pine zone." Some of the characteristic trees of 

 the lower seeding stations are : Lodgepole pine, western yellow pine, 

 sugar pine, digger pine, western larch, and various species of willow 

 alder, dogwood, aspen, mountain mahogany, maple, and oak. These 

 species are found in successive zones which may be called the " lodge- 

 pole-pine zone," the "yellow-pine zone," and a still lower zone of 

 which no single tree is characteristic, usually known as "Upper 

 Sonoran." The great number of shrub species and herbs character- 

 istic of the places where the extensive studies were conducted will be 

 readily understood by anyone familiar with the great range of plant 

 life found where the various trees just mentioned grow. 



In this wide altitudinal and latitudinal range the more important 

 soil as well as climatic conditions were covered. The main soil 

 types were: Sandy loam, clay loam, decomposed pumice, volcanic 

 ash with varying amounts of organic matter, and soils of various 

 textures originating primarily from basaltic, granitic, sandstone, and 

 calcareous rocks. 



ESTABLISHMENT OF THE PLOTS. 



In all cases the seed was scattered broadcast, either with a machine 

 or by hand. The proportion of seed used in mixed sowings was 

 similar to that employed in the detailed reseeding work. The amount 

 of seed required to produce a full stand, when a single species was 

 sown, will be discussed elsewhere. In most situations the soil was 

 given no culture before the seed was scattered. In general, the areas 

 were closely grazed prior to seeding, and in the main inexpensive 

 methods of planting were emploj^ed, namely, harrowing in the seed 

 with a brush or wooden peg harrow, or trampling it in by sheep. 



