SOIL SURVEY

-25-The interaction of these soil-forming factors, as observed in Yoho Nationa lPark, has resulted in many different kinds of soils . For the purpose of the GeneralizedSoils Map (found in the pocket at the back of this report) the kinds of soil are dividedinto four broad groups : Montane, Montane-Subalpine, Subalpine and Upper Subalpin eand Alpine . The montane, subalpine and upper subalpine and alpine groups reflec tchanges in climate and the concomitant changes in vegetation . The soils of the montanesubalpinezone were established because the similarity of the parent materials and t osome extent the shortness of time prevent climate and vegetation from imparting thei rinfluence on the soil morphology . Thus soils in this group are found in both the montan eand subalpine vegetation zones .Soils of the Montane ZoneSoils of the montane zone are largely confined to the lower portions of th emajor valleys (elevations generally less than 1,550 m a .s .l .) . Brunisolic soil sdeveloped on till and sorted till are the most common . These soils typically havea thin leaf litter, 1 to 2 cm of Ae horizon and 45 to 50 cm of yellowish red tobrownish yellow Bm horizon with lime occurring at 50 to 75 cm (see description o f011) . There are also small areas within the montane zone where Brunisolic soil shave developed on shallow lacustrine deposits (see description DS 1) . Climate andvegetation are the dominant factors controlling the differential genetic developmen tof the soils in this zone from soils in adjacent zones .Soils of the Montane-Subalpine ZonesSoils of this group are placed . together for the purpose of the Generalized Soil sMap (back pocket of this report) because the influences of topography and time preven tthe profile morphology from reflecting the climatic and vegetational changes observe din the three other groups . These soils are developed on fluvial and glaciofluvia ldeposits located in the broader valley bottoms and on steep colluvial slopes in bot hthe montane and subalpine vegetation zones .Soils at or near the stream levels and in seepage positions fall within th e_Gleysolic order (see description BC 2) . Here the soil-forming factor of topographydominates,controlling profile development .