In honor of Arbor Day, a few words on the small forest growing in our backyard. No, not the weeds, although some of them are tall enough to qualify for small-tree status, I’m afraid. No, I’m talking about the nether reaches of our backyard, which were smooth and green and grassy when we bought this house but are now a tangled, briar-filled forest incubator. I was just back there this morning, checking on Copper, who’s in dog-digging heaven, when I noticed how tall some of our volunteers are. We have several fledgling oaks and hollies and a few trees of uncertain lineage. They’re the lusty newcomers, racing to catch up with the old grandfather oaks, which are dying at an alarming pace. I mourn the old trees, especially the one that came crashing down a year ago, the first day Suzanne was home from college, 100 feet and double-trunked, so that one half narrowly missed our neighbor’s house and the other half narrowly missed ours. But I take comfort in the accidental forest that grows to replace these venerable giants. Some day the new trees will be old and tall, too, and I can say, I knew them as babies.