These are mountain maples.
My family and I drove up Provo canyon to walk along the Provo River trail between Vivian Park and Bridal Veil Falls a couple weeks ago. It was a beautiful day to enjoy the fall color.
The fall season is a beautiful season in Utah, as it is in many areas. Just be sure to pack your camera if you decide to take a drive or walk so you can capture the beautiful fall color before it is gone for another year. The best time to take your photos is two hours before sunset or early morning, or if you are really lucky, bright overcast days are perfect for photography. You get even light and the colors are not "washed out" and look much richer.