Is there any way to smash things for wood in the Long Dark?

Solution 1:

Hit Tab to open the survival panel. One of the options is "Forage Wood":

If you're outdoors, you get three options: Tinder, Softwood (i.e. Cedar firewood) or Hardwood (i.e. Fir firewood).

If you're indoors, you get two options: Tinder or Reclaimed wood.

You don't appear to need any tools to forage for wood, and I haven't noticed any furniture disappearing when I do it indoors.

Solution 2:

In the current version (December 2017), if you have a hatchet, you can break up crates, planks, pallets, tables, chairs for "reclaimed wood" which is usable for fires or for constructing snares.

Outside you can use a hatchet to break up fir and cedar branches for firewood.

I think you can also use a heavy hammer to break up lumber indoors.