It's a nice game! Really cool ideas!
I think that the graphics could really use some improvement though.
For example, having the character face the direction that I am moving it goes a long way, or having something like a watering can whenever you need to water a tree would also be really cool. I guess that the old trees are supposed to break the rocks too? If so, some feedback on that would be nice. As it is, I really don't see the correlation between the trees and the rocks. On a puzzle game, stuff like that is very important.
Also, I only found choping necessary for only one part of the game. Maybe by making the old tree "choppable" instead of falling over a certain time you could improve the amount of action the player have in the game. Further on that, I always think it's awesome a puzzle game that have multiple ways to solve the same puzzle. That did happen once, but I'm not sure if it was on accident.
The WASD controls don't work on my end, but that might be just me. But just in case it isn't, always add secondary controls when it's available, When I first played your game, I was stuck for about half a minute trying to move the character, didn't even ocur to me that you control it with the arrow keys. I am very, very, stupid, I know, but I guess I am just used to playing games with WASD.
Anyway, I'm sorry I dragged on for a little bit. I am relatively a begginner, so I am also sorry if I didn't make myself clear in some point. It's a cool game, really! It was fun! I look forward for what you guys make in the future!