Trees aren't so hard to shoot, main trick to keep in mind is basically using the same rules you'd use in any fine art shot. For it to be successful you gotta nail the composition first, create interest with the setting, use the lines of tree branches, use golden ratio/rule of thirds etc. It's all in the details. I try to get away from the 'boring' look you might see in a snapshot (I've done it myself: you get to the place, see a tree and start shooting without thinking, then realize it sucks), try to see the tree as a potential portrait. It's like taking a photo of a person, you can capture their essence, beauty, their unique feature or you can do a snapshot. You can focus on a specific feature or you can take in the whole crowd.