A great portion of south-western Colorado and the other western states of the U.S.A. is covered with gambel oak (Quercus gambelii). Gambel oak was determined by Brown (1958) to be an important component of the mountain brush type in Colorado. It occurs in pure stands as well as in association with pinyon pine, juniper, ponderosa pine, aspen, and spruce on several million hectares. Ranges covered with gambel oak have relatively low grazing capacity and low availability of the understory vegetation for grazing animals. Jeffries (1965), studying the effect of gambel oak on range forage production, indicated that herbage yield under the oak canopy was less than that of grasses growing in the open. The restriction in forage growth under the oak is attributed to the shading effect rather than the competition for moisture. Therefore, removal of gambel oak would be likely to improve the ranges.
Bird communities of gambel oak: a descriptive analysis
