Walnut Canyon National Monument is at the junction of the Pine with the Pinyon and Juniper belt. Ponderosa Pine trees grow on both sides of the canyon and have golden brown bark. The shorter trees are Pinyon and Juniper, four species of which are known to occur on the Monument. There are scattered clumps of Gambel Oak, and several perennial shrubs of smaller size. One hundred and sixty plant species have been collected, identified, and filed in the herbarium. Several varieties of Penstemon are seen in summer and the Evening Primrose is common.

In addition to the animals mentioned elsewhere, visitors in the warm months may see two kinds of Squirrels and numerous birds including the Raven, Turkey Vulture, Stellar Jay, Nuthatch, and others. In summer, lizards are common and are often found on the outside walls or benches of the museum where they study visitors with considerable interest.