Abert's squirrels in the US make almost exclusive use of ponderosa pine for cover, nesting, and food. In Mexico where ponderosa pines are absent, the species is found in stands of the closely related "Pinus arizonica". Optimum Abert's squirrel habitat is composed of all-aged ponderosa pine stands with trees in even-aged groups, densities of 168 to 250 trees per acre (496–618/ha), and 150 to 200 square feet per acre (34.4–45.3 sq m/ha) basal area. In optimum habitat average diameter of ponderosa pines is , with Gambel oaks in the 11.8- to 14-inch (30–36 cm) diameter at breast height (d.b.h.) range. Optimum habitat has some ponderosa pine over d.b.h., which are the best cone producers. Larson and Schubert report that ponderosa pine d.b.h. produced an average of 446 cones per tree per crop. Trees less than d.b.h. produced fewer than 100 cones per crop.