Why they do controlled burns

The Chicago Park District periodically burns conservation areas throughout the city because the prairie we built the city on evolved with fire. Last fall, they burned some of the prairie-reclamation areas in Winnemac Park, close to my house:

Here's the same area yesterday, clearly benefitting from the burn:

And just because everyone loves her, here's a photo of Cassie enjoying the random pats and treats she got at Spiteful Brewing about two hours after we passed through the park:

Happy Monday.