Let me tell you the story of this tree. It's around 7 years old--I know this because I pulled it out of a crack the first spring it popped up. I was walking with some students along the sidewalk, their chatter filling the air, and I spotted it: 3 or 4 sets of leaves waving like a mini flag right next to a car tire. It had rained a day or two before, so when I gently pulled on the trunk--which was more like a twig--it came up easily, roots and all. "What are you doing?" One of my students asked. "Saving this tree," I said. We headed inside to find a cup of water, and I explained just how I intended to save the tree. "It's dying." I assured them it would live. I explained--again--that if I left the roots in water and later planted and soaked it, it had a good chance. "It's dying." It's over seven years later, and every once in a while I remind one of the students with me that day that the tree is still alive. I've replanted it a