"processing wood" means getting it ready to use as fuel for a fire, right? I have done it lots of times without using any tools at all. Sometimes I have used a big rock. Usually it takes about fifteen minutes or so to get enough together to last all night.

If I have logs that I can's break up, I feed them into the fire at one end, or burn them into two pieces. The critical step in fire building is getting the fie started and acquiring the tinder for that step. A chunk of esbit fuel or similar can simply that job.