Burn Season

Early spring, mid-March, has traditionally been burn season for prairies in Southern Wisconsin the last few decades. Why do we burn? The pre-European settlement landscape around here was a lot of open savanna, with grassy park-like settings with scattered trees. It is thought this was maintained by fire, either naturally occurring or set by the local indigenous population at the time. The plants and animals adapted to that environment and became what we consider the "native landscape"many are trying to restore.

When the area was settled and turned into farms, the fires stopped, and the settlers brought new plants and animals from elsewhere that began to take over, which created dense woodlands and thickets.

The brush clearing and burning we do today is an attempt to restore that open, savanna landscape.

On Cave Bluff there are several prairies and savanna areas that are in different stages of restoration related to their history. The Manchester Prairie has been maintained by fire for a few decades and has a good population of established species.

The "horse pasture" to the south was a just that, a pasture. It has scattered trees, but was gaining an understory thicket of honeysuckle and buckthorn since the horses left many years ago. We've been clearing that, and this year is the third burn on that section. Already you can find sections of native grasses coming back.

Other areas like the star prairie at the top of the bluff have always been prairie going back to pre-settlement as far as we can tell, and have the best species diversity.

Balance

Nothing is simple, however. What we have found in our more established prairies is that frequent burns have actually diminished the species diversity in those areas. They are becoming grass-dominated, and other herbaceous plants are beginning to fade out. We don't want that. It could be that the combination of earlier springs starting the growing season earlier and later burns because of unstable weather are causing damage to these plants, allowing the tougher grasses to take over.

We might be experimenting with winter burns when we are snow-free or just mowing some years. Burning in the winter is tricky, especially since control with water is hard when it's below freezing!

Everything about the Cave Bluff project is a learning process, over decades and lifetimes.