DIY Charcoal Producing Hiking Stove

Here is a good description of a wood gasifier hiking stove made from some cans.

According to the author, the total weight is just 14oz and you don't have to carry any fuel.

The author recommends to completely burn the fuel to ashes. However, if you pour water over the fire after you have boiled whatever you have intended, the charcoal left can be buried in the soil as a soil improving agent as well as carbon sink.