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Litter cover is especially high (84 percent average) as many of the deciduous shrubs and the aspen were dropping • their leaves at the time of sampling. Exposed soil is low, averaging only two percent cover. Rock was not encountered on any stand and moss and lichens were uncommon. 2.2 Oak Community The oak community occurs on all slope exposures. However, on the steep south and southeast exposures, the most xeric (dry) sites, the oak occur infrequently in small isolated clumps. Tree heights and diameters in these sites are small compared to other, more favorable sites. On the north, east and west exposures, oak com- munities occur either in small clumps surrounded by smaller shrubs or in extensive stands. Even in the extensive stands (up to 30 acres), which appear to be characteristic . of the moist north exposures, there is a tendency toward clumping. This is perhaps due to the method of propagation. Although oaks reproduce by seed, the most common means is by suckers (sprouts growing from surface roots) and stool shoots (sprouts growing from the base of the trunk near the root cellar). Reproduction from suckers and shoots would result in the gradual expansion of a stand as well as an increase in density. • The density of.oak stands is variable, ranging from 46 to 106 per 125m2 or an average of 2,235 per acre, approximately twice as dense as the aspen community. Thirty-one percent of all standing trees are dead. Studies of the ecology of oaks on the western slope, indicate that the density of oaks are affected by the age of the stand, characteristics of the site and past history. Tree core analysis of oak at the site indicates that the sampled communities are variable in age. Site characteristics and past histories of the oak may also be different. Eowever, analysis of the data does not indicate a correlation of density with soil depth, slope or exposure or site char- acteristics. Charred oak in one area indicates a past fire; the date or extent of the fire could not be deter- mined. Thus all, or a portion of the area, may have been burned in the recent past, which may have increased oak density through stimulation of root suckering. Height of the oaks are variable, ranging from 2.5 to 5 meters. Tree height is often influenced by surface soil depth. Those stands on the deep loam soils (Routt Series) of the northern exposures are generally taller than the oaks growing on the shallow gravelly loam (Delphill Series Complex) soils. The diameter-at-breast . height of the largest oaks ranges from 10 to 20 centimeters. Age of stands range from 71 to 156 years. The 156-year old tree may be a relic from a previous community. -9-