Last Saturday at an antique farm machinery show I fell in love with steam engines: the shiny copper complicated piping, the valves, the pistons, the throaty puttputtputting as the great iron beasts rolled into place. They ran on firewood and smudged the bucolic sky with their hoary breath, part smoke, part vapor. And here I was, tree-lover and conservationist, cheering them on.

One venerable steam engine powered an entire sawmill with a single, long belt. Three men helped feed a tulip poplar log to the screaming blade while below, an auger laddered the yellow chips onto a growing mound. The next engine over ran a cider press, carrying apples up a conveyor to be chopped and crushed by slow screws as big around as barrels. While one vat filled, the other sent fresh cider gushing through a hose — plastic, like the jugs that sold almost as fast as they were filled.

But for that detail, this could have been a vision of a post-oil future. I had some idea of what that might mean: the long sinuous ridges would go bluer in the thicker haze, and maybe we wouldn’t notice as their wooded slopes thinned into pasture for draft horses, and the remaining woods went back to woodlot, a “working forest” in the Nature Conservancy’s 21st-century euphemism, prized only for what’s of use to people: timber. Fuel. Pulp. Maybe chemicals again. Wild game. Water for steam and for mills. I thought of Shel Silverstein’s fable The Giving Tree, and the selfishness of that boy who grows old without ever growing up. The impossible contradictory demands he makes on the tree, both to go on nurturing and to sacrifice herself.

The men who tended the steam engines and the other old machines grinned and sweated like boys at play, breathing hard. It began to rain. We made our way quickly back to the car.