I've considered myself an "outdoor enthusiast" or whatever for a few years now, but only since last fall have I really began to feel quite aware of my surroundings. In that time I've also felt my connections with what's around me grow.
It's a little embarrassing to admit that even as recently as this spring I simply didn't know much about trees; I knew maples from oaks, beeches, birches, white and red pines, and as of a maybe a year ago hemlocks and cedars. So the last six months or so have been an explosive time as far as learning trees goes. I could try to list all of the trees I now know by sight and it would be pretty long, and I'm sure I'd forget some, but I don't know them all—not even close.
In the last two months or so I've been looking over different tree books, and all have helped me to some extent.
During the winter I spent about $30 on field guides of different subjects. I was buying on a budget to so I didn't exactly get the most helpful ones available. As far as trees went, I bought a book called
Trees of the Great Lakes Region by Steve Harrington for $7.95. It's 192 pages, pocket sized, and includes a pretty good array of species with hand drawn black and white pictures mostly of leaves, sometimes including twigs and buds.
It's helped me identify quite a few trees—sometimes just helping me distinguish between different species withing a genus, other times helping me with trees that were totally new to me. The images are somewhat lacking I guess, but they aren't bad. The book includes a key, but it's rather limited and hasn't helped me with identifying anything I don't think.
Overall, however, I feel like it's a decent book for what it is. Its small size make it nice for when I don't want to carry a bigger book around with me, and it still has pretty good descriptions of each tree's characteristics as well as its habitat and common traits.