If a tree falls in a forest and there's no one there to hear it, does it make a sound? *smile* I'm not sure that this qualifies as a "single tree" but, I like that you captured a natural happening in nature that not too many of us really think about.
This is a bit smaller than the size allowed for challenge entries, particularly for the advanced edit ruleset. There's a good tutorial under the "Learn" section for sizing pictures for challenge submission - you do want to take full advantage of the size you're allowed so people can see your photographs better.
Why so small? If you are new user, check out a DPC tutorial on how to resize yout picture. Even though there are many trees, the broken one still stand out. So, I would say it's still meets the challenge. I would have scored higher if it had enough pixels.
I like the way the tree moves your eyes around the photograph. i don't find the entire photograph to be unique enough. it's lacking a bit of focus on the single tree.