Darren Bush
Fall leaf views from a canoe.
The fall color calendar in Wisconsin usually runs to late October.
When a tree is hungry, it takes six carbon dioxide molecules and six water molecules, and adds a little solar energy to create a glucose molecule. Fortunately for us, the reaction creates six molecules of oxygen. It can’t do it without chlorophyll.
That’s what we learn in middle school science. College chemistry professors may dive deeper into the chemical structure of chlorophyll a, C55H72MgN4O5, a beast of a molecule with a lone magnesium atom just for fun. I’m just happy chlorophyll exists, or else we’d all be dead. Not just that, the world would be uglier.
You could say that fall color is upon us. Actually, fall color never left us. The leaves of the trees that surround us are already colored: oaks are red and brown, aspens are golden yellow, beech leaves are an almost translucent light tan. Dogwoods and maples are red.
Each leaf is already pigmented with what you see after the chlorophyll slips back into the tree to save energy for spring. An aspen leaf may be bright green in the summer, but take away the pigment, and the golden yellow color is what was always there. That’s why they’re brighter than an oak tree leaf, whose substrate is dark red or russet colored. The chlorophyll can’t mask the underlying dark tone.
The changes in the colors are related to latitude, which means the northern areas get darker and cooler first, both of which serve to tell the tree it’s time to save energy and hunker down for winter. Stress can also cause a tree to pack it in a little early.
You can usually follow the changes with the calendar: In mid September, start way up north. I was in Boulder Junction a few weeks ago and there was just a hint of color in the trees that were a little more stressed out due to drought over the summer. When I got home the Fall Color Report website showed 10% color, which was about right.
The usual leaf color calendar runs from mid-September to late October in Wisconsin. I usually schedule a hike or paddle trip around the middle of October, where I expect to find a good balance of color here in the southern part of the state. I say balance, because I like a mixture of colors and a little residual green to complete the picture.
My favorite place to see fall color is the Driftless Area. Highway 14 from Spring Green to LaCrosse is lovely, but it really kicks in after Richland Center, heading toward Viola, LaFarge and Viroqua. Head up 131 toward Ontario along the banks of the Kickapoo River for another visual feast. Paddle the river for an even more intimate view.
Door County is beautiful; however due to its bottleneck at Sturgeon Bay and only two roads around the outside of the peninsula, it can get pretty crowded during what my western North Carolina friends call leaf peeper season.
State parks closer to home include Governor Dodge, which has about 40 miles of hiking trails. The White Pine trail has been a favorite of the family since the kids were young. Blue Mound State Park has fewer trails and less topography than Governor Dodge, but is as convenient as it gets. The bluffs of Devil’s Lake are even more spectacular when covered with changing leaves.
The UW Arboretum, of course, is lovely, and is about as accessible as can be. The Gallistel Woods canopy barely lets light through, which creates a stained glass effect when it’s sunny.
Our yard has ashes and maples, and our neighbors have ancient oaks that drop their foliage in our yard. Even on the ground, the leaves are beautiful. Oaks and their cousins, the birch, keep their leaves on until they’re pushed off by the new leaves or blown off by the wind; usually a combination of both.
After the leaves fall, their beauty isn’t over. They cover the forest floor, providing habitat for a myriad of creatures; toads, terrestrial turtles, salamanders, small mammals, invertebrates, and overwintering habitat for many insects.
Want to protect native pollinators? Leave the leaves. Many wild bees overwinter in the protected leaf mulch. If you’re worried about your lawn, don’t. You might have to explain to your neighbors that leaving them is beneficial. If you have an HOA, you may be fighting an uphill battle, but it’s worth the fight, especially if you can get a little coalition of people who care about the critters under the leaves.
The National Wildlife Federation claims that yard waste, including leaves, accounts for putting 33 million tons of refuse into landfills each year. That’s about 10% of the total trash buried, but the lack of oxygen there means the leaves make methane gas. So there are 33,000,000 reasons to leave them where they fall. The good news is that Madison composts the leaves it collects curbside.
The next time you venture out in the fall after the leaves are down, take a hand lens and turn over a chunk of leaf mulch. The critters you might find are marvelous.
