This was interesting, but once I got past the first third or so, I put it down and it honestly took a while to pick it back up. The first part was intriguing - he introduced a bunch of different characters each via their relationship with trees. They weren't connected to each other, so it read more like a bunch of short stories. But it was thought-provoking to see how all these things people go through can relate to trees in a greater context. He also drops little lines about how we are connected to trees even if we don't think or care about them - for example, his line about eating a piece of chocolate, an orange, and a cup of coffee - three miracles from trees.
But after the first third of the book, the stories started to converge and it became more like a traditional novel, which never really felt as great as the first part. It has a good message - we need to care for the earth - but after a point, I felt like he was just repeating it over and over and the book ended up feeling very long. I think I would have loved it a lot more if it were shorter.