 ), quaking aspen ("Populus tremuloides"), and Douglas fir ("Pseudotsuga menziesii").Findley and others mention that Abert's squirrels are common in mixed conifer canyons in New Mexico.In Durango and Chihuahua the squirrels are said to inhabit high altitude ponderosa pine stands, however, the ponderosa pines of Mexico have relatively recently (since at least 1997) been reclassified as a separate species "Pinus arizonica" (syn.