We were driving through the endless northern expanses of Chicago, huge houses, huge cars, big money, and the last of the cicadas were whirring, and we turned and found ourselves on an elm lined street. It was a tunnel, really, the branches arching overhead, the sun dappling the street, and as we drove along I turned off the music and rolled down the windows and let the muggy air flow over us, the scent of elm, the bird songs, the chatter of squirrels, the cicadas. I was overwhelmed with deja vu. We had lived in so many towns up and down the Atlantic seaboard when I was a kid, and passed through so many more, that my days growing up were full of elm lined streets, and shade, and dappled sunlight. Every street of them was like stepping into a cathedral, hushed, dark, ethereal. Come fall the leaves came down like slow rain and filled the gutters. All winter long the branches creaked as the wind would howl through them. Come spring we’d wait for the hints of life, tiny specks of green, and by summer the elm hung over us again in great green arches. Most all are gone now. Disease swept slowly but inexorably, taking nearly all of them. Eighty per cent. They remain in small stands, on lanes full of carefully monitored trees, a mighty urban forest of a zillion trees all across America cut down, rotted away, dead. The sun glares down on the shady streets now, that particular magic is gone. We think of forests as unchanging, immutable, as if barring chainsaws they will always be there and have always been, the same forest. Like we could go back a hundred thousand years and pop out of a machine like Rod Taylor and all the trees would be the same. But it’s not so. Trees, like people, like anything living, really, are prey to plagues and parasites. Periodically something horrible and fatal fells them by the millions and other species, immune, replace them. So fell the elm tree. It had once conquered and become dominant, over the rotting trunks of spruce trees and now it survives in glades, tended by botanists and tree surgeons, so that those old enough to remember can be swept away by nostalgia driving down a shady street.