Stroll through Ames this weekend to catch the last days of Central Iowa’s peak fall colors.

The Iowa Department of Natural Resources predicts this weekend as the best time to see Story County’s autumn at its most scenic.

“Generally, we’ve had pretty good conditions here in Central Iowa,” said Jeff Iles, chairman and professor of horticulture. “It’s been so darn dry, though, the leaves are falling fast.”

As autumn makes its way from the north, trees enter their dormant stage.

The chlorophyll in leaves breaks down because of the shortening daylight hours and temperature changes, he said. When chlorophyll stops being produced, leaves are on borrowed time; they have produced food for the trees and have done their job for the year, he said.

“Not all trees turn at the same time; that’s the nice thing about fall. You have prolonged periods of color, and if you have a different mix of species, like we have on campus, it gives you a nice mix of colors. The maples on campus right now are spectacular,” he said.

Iles also suggests driving through the city’s older neighborhoods to see sugar maples and oaks, which are just beginning to turn.

Steve Lekwa, director of Story County Conservation, said Brookside Park; Inis Grove, located by Arnold Lake; and Ledges State Park are some of the popular places to visit in Story County.

“The colors we see in the fall were there all along – the green chlorophylls overpower during the spring and summer months. When fall comes, trees don’t maintain chlorophyll, which is broken down and replaced with the other pigments that were always there. The pigments are usually carotene, the same pigments in carrots,” he said.

Oak trees fall dormant late, he said, and show rich browns and dark reds. The hard maples, like sugar and black maples, feature yellows and shades of orange, but walnut, hickory and linden are already past their peak colors, he said.

Ed Moran, an outdoor horticulturist at Reiman Gardens, 1407 Elwood Drive, said fall color peaks change on a yearly basis and vary from species to species.

“[Peak times] change from year to year; it depends on the amount of moisture we’ve had, day and night time temps – they all affect the peak fall color. Wind can play a big part in that; it can blow off the foliage and then it’s done,” Moran said.

Certain species change colors at different times and it all depends on that species’ genetics, he said.

Ash and elms are some of the first ones to change; maples are just starting to turn now, and some oaks will carry their foliage long through the winter, he said.

“I really don’t know why they don’t all lose their leaves at the same time,” Lekwa said. “They just have different physiologies. Just like birds migrate sooner than others, some trees pick up on the changing seasons sooner.”