It's a neat concept!
The windmills are a little rough, but once you set them up it's pretty satisfying to see everything go down.
I don't see the point of the rain mechanic as you just push the fire to the lake.
There is no lose screen and no cost of windmills so I can just place the windmills all over the screen, not care about the trees and just progess to the next level with 20 negative points.
I also noticed that the music doesn't loop. Once it plays the whole thing it goes silent till the next level.
I think the idea is good enough that id could be a very fun game with some fixes and polish.