(calm music) - In Wisconsin, we celebrate our seasons as really the foundation for our natural diversity.

And autumn sets the stage for one of our hallmark phenomenon, and that is the fall colors.

In Wisconsin, we're positioned at about 42 to 47 degrees, north latitude.

And that combined with the inclination of earths' axis, as we're revolving around the sun, leads to climatic patterns, mostly temperature and precipitation among others, that dictate what we have in our Wisconsin forest.

Our Wisconsin forests are typical of a deciduous temperate biome, including a lot of maple trees, Oak trees, Beech, Birch, Aspen.

These deciduous trees are those that lose their leaves annually.

As we head towards winter and earth is leaning away from the sun and winter's coming, these trees receive signals, shorter days or declining photo period, coupled with cooler temperatures, which are really like a call for preparedness that winter is coming.

And the first things that the trees do is stop a production of chlorophyll, which is that magic pixie dust required for photosynthesis.

When they stop producing chlorophyll, all the greens turn to yellow, orange, brown hues, and we also see a lot of bright reds, pinks due to chemical changes within the tree and within the leaves that are required to retain nutrients throughout the winter.

Now, because earth has a pretty consistent physiographic location, we tend to see that same change in the leaves every year, okay?

The only variability would be related to maybe some cooler temperatures from one given year to another.

But that peak fall color in the Northern half of the state is going to reveal itself around the first or second week of October.

And in the Southern half of the state, it comes shortly thereafter, maybe about the third week of October.

What really leads to the most brilliant fall colors in our Wisconsin forest are a wet spring, moderate summers, and then cool evening, not freezing, but cool evening fall temperatures.

The reason our deciduous trees lose their leaves is really threefold.

Number one, during the growing season, the leaves are harnessing energy and sharing that with the rest of the trunk and the branches.

And during the winter, they want to shut that valve off and shut that passageway off so that the rest of the tree, the branches, the trunk can conserve that harnessed energy.

So they lose their leaves to shut that off.

And secondly, it's a way for the tree to conserve and preserve moisture within the branches and in the trunk.

And lastly, the tree needs to lose its leaves because without the leaves on the branches and the trunk, it can withstand the strain of the strong winds associated with Wisconsin's storms.

While we see these colored and fallen leaves often as a nuisance, as they're clogging our rain gutters and our storm sewers and cluttering the lawn, being tracked into our house, they're actually a really vital part of our Wisconsin Woodland ecosystem.

They support biodiversity and they provide an intangible resource.

First of all, the leaf letter protects plant roots and conserves soil moisture during the winter.

And it also suppresses the invasion of non-native species and ultimately that leaf litter and the mulch breaks down into plant food for the next year's growing season.

The fallen leaves also provide important winter habitat for all kinds of Woodland animals, small mammals to microbes, spiders, amphibians, insects, other pollinators, all depend on that leaf litter and the associated stems and pieces of bark as critical nesting material and in insulation all winter long.

And the intangible value of our fall colors to Wisconsin residents may not be as easy to determine because we truly can't grasp it or contain it, but the scenic beauty that they provide is there.

I mean, we know it when we see it.

Wisconsinites and friends from neighboring states take day trips, or even weekend getaways from the Southern Kettle Moraine, northward to the Eagle River Managua area, from Door County, westward to the Bluffs along the Mississippi River, specifically to take in and enjoy the turning leaves and the fall colors in our forest.

So because of that, we really need to recognize that our fall colors are truly an important part of our ecological culture.

And they're an important intangible resource whose value can't be over appreciated.