... trees with a lot of orange and yellow in their leaves are... the aspen of the Rockies

The aspen can glow yellow when back lit. My favorite black and white photo of fall colors was printed in the Arizona Daily Sun, the newspaper of Flagstaff and Northern Arizona. Most of the native trees around Flagstaff are ponderosa pines, but, up the sides of the San Francisco peaks, just below the tree line, there are aspens and in fall they are golden.