Remember a little more than a month ago when I implied that spring had arrived in Chicago despite the insistence of the natives that I was being laughably optimistic? Well, the natives were right, and I was wrong. Since then we've had our fair share of plunging overnight temperatures and frigid rainy mornings. But now I'm hoping I can safely say that spring is really here, and our first brutal Chicago winter is behind us. Since leaving Los Angeles, where weather is stubbornly perfect 95 percent of the time, I have enjoyed the seasons despite the difficulty getting acclimated to bad weather. In LA it's green all the time, but here watching the leaves appear on the trees has been an enjoyable novelty. And yesterday, which may have been the best day of the year thus far, I decided to dust off my tree books, unused since I left the east coast for California five years ago. I was curious to see what kinds of trees line our street, and what's living in our back yard. (I was partly inspired to do this by the Talk of the Town piece in this week's New Yorker about the guy who's running New York City's "tree census.") So, using my National Audubon Society Field Guide to North American Trees and Trees of North America, I discovered that we've got a Northern Catalpa and an American Elm in the front and some kind of Maple in the back yard. If the thunderstorms stop today, I might go back out and see what else is growing around here.