I enjoyed this--read it episodically over the last few weeks. Some great stuff on the trees, and I wish there'd been more, but the book was really focused on those folks obsessed, in love with the trees. There, too, I enjoyed the portraits, but didn't so much understand as bear witness to such passion.
Still, as my friend Dayna noted, the book arouses one's own passion, too. It's the kind of book that knee-deep and bone-frozen in mid-February Minnesota made me long (I was going to write pine) for the sweeping green of a huge old-growth forest.