We have some thoughts:
We are trying to stay away from the tree idea, because we have an organization in town that has a similar logo:
http://caseytrees.org. We like the overall layout of #2, but would like to see the font from #16. Also, we would like to see some options with a focus on plants/flowers rather than trees.
The entry we ranked 16 is more what were are looking for, the style is a little more artsy.
For entry 16, could you put something very simple related to flowers. plants inside the box?