If you are in the Northeast, I must suggest Bark by Michael Wojtech (www.knowyourtrees.com/). This book is comprehensive and very well laid-out, and focusing on identification primarily through the properties of the tree's bark. I like that it gives you the skills to identify trees year-round, which is particularly useful in the winter when many trees are leafless.

If you are in the Northeast, I must suggest Bark by Michael Wojtech (www.knowyourtrees.com/). This book is comprehensive and very well laid-out, and it gives you the skills to identify trees year-round, particularly useful in the winter when many trees are leafless.