With careful management and modern forestry techniques I believe sustainable (or close to sustainable) charcoal production is possible, I can remember seeing CSIRO do a study using Australian Mallee trees. These grow fast enough such that you can rotate which part of the plantation you are harvesting to enable something close to continuous production. I can't find paper https://publications.csiro.au/rpr/pub?pid=csiro:EP115427 is closest thing google turns up.
You also get eucalypt oil as a by-product from harvesting these trees wikipedia tells me this has a high enough octane rating to serve as a fuel in it's own right.
Enough people know that Wootz steel is possible through mixing wrought and cast iron in the right sort of vessel that we'd have at least some steel with decent carbon content. Or pattern welding will be fine for most things.
True, it wouldn't support anything close to the scale of steel production today.
But it could be a step in a bootstrap process. Build some hydro/nuclear/wind power plants, then you can start looking into hydrogen reduction for steel production.
