England 16th-17th century deforestation and energy crisis

There were some very interesting things going on in England in the 1500s. Ironmaking required charcoal back in the 1500s. They hadn't started using coal. They would take trees and turn them into charcoal. Anybody know how you make charcoal from trees? You burn it in an oxygen-poor environment. You fell the trees, make a big pile, put dirt over that, and limit the amount of oxygen that can get in. You start the fire in this chamber like a brick kiln, limiting the amount of oxygen. As the thing heats up in this oven, you're burning off all the volatiles — the lignin and other things in the wood — and you're left with charcoal, which is basically carbon. The charcoal is relatively strong compared to wood, doesn't give off a bunch of smoke because you've smoked it out. Charcoal was the way to make iron.