I'm writing a scene that takes place in a forest. How do I research for it?

I find that when I'm writing about a setting that I'm unfamiliar with, I tend to write many similes to describe things. In the case of trees, I describe their branches looking like gnarled fingers, their roots like tangled hair, etc. But I feel this is almost a cop out. I don't know much about forests and trees and so I resort to how I perceive them to look, to create atmosphere, to paint a picture, without ever actually referring to them as willows, sycamores, oaks (that's as much as my tree knowledge goes). So how can I "know my stuff", so to speak, when I write, so that I'm more comfortable writing in a forest? Is it a bad thing that I don't specifically name the trees I'm describing? (I often have images of trees in my head, but I can never place their name) As you can tell, I'm a novice writer, so any help would be appreciated. Thank you for your time.