Hi! This is a very interesting photo and I personally feel a great choice for this challenge. The trees draw me in and take me out the top to the "brown" sky, LOL!
A few things that caught my eye right off the bat was the composition of the overall shot. There is really nothing that is keeping me in the shot, it's all fighting for my attention except for that tree in the front right. If you had cropped either that out or more around it to have it be the one for the most attention, not sure if I'm getting my point across. But what it basically comes down to, while a great overall choice for the challenge there is nothing that is standing out in the shot and telling me, "HEY LOOK!" I played with my magic envelopes a little bit and with some creative cropping, take the grass out of the bottom maybe and a little off the right to bring the front tree more on the thirds line might help with the overall feel of the shot.
I hope my comments help and wish you the best of luck in future challenges!