The forested slopes of Capulin Volcano are covered in pinyon pine/juniper woodland. This short-statured forest is dominated by pinyon pine, juniper, sumac, wavyleaf oak, Gambel’s oak, and mountain mahogany.

Some ponderosa pines are found in the monument. These large pines usually occur in mountains in pure stands. They are more solitary and mixed through the other woodlands in the lower elevations of Capulin Volcano.

A grove of several Aspen trees lights up the base of the volcano each fall as the leaves turn a yellowish orange.