Adult novel, young person who loves trees and learns about them

[Edith]

I don’t remember a lot, but it’s about a person (young man?) who loves and respects trees deeply, I think that a big part of the story is sort of following their path to knowledge about trees. I also believe there is some kind of mentor/person that the protagonist is inspired by and learns about trees from. There is possibly a big book involved where tree knowledge is documented. I vaguely remember something about a suicide attempt or a tree where someone once hung themselves. I believe this book was quite long.

[Sue]

One of Gene Stratton Porter's books? There's "Freckles" or "A Girl of the Limberlost" They're both set in virgin forest.

[El]

Freckles or A Girl of the Limberlost for Sue's suggestions

[Rainbowheart]

Still looking, Edith?