If you need an efficient stove that burns gathered material here is how to make one. link
Very few people will have heard about turbo-stoves before.
A turbo-stove uses gasification and combustion of the gases produced to achieve clean efficient use of a fuel such as wood.
Essentially we have a chamber containing a smoky fire and a secondary flame which burns the smoke.
Almost all natural fuels and many synthetic ones will burn very cleanly under the right conditions.
A properly functioning turbo-stove burns wood and most other bio-fuels so cleanly that they can be used indoors without a chimney. They can be used for cooking in a similar manner to a gas flame.