One of the easiest and least expensive ways to build lintels over doors and windows is with small diameter wood poles. Poles are typically gathered inexpensively from local forests, sometimes with a firewood permit. In comparison, milled timbers, dimension lumber, and concrete and steel timbers are more expensive than pole lintels. Pole lintels are fast and easy to build, and provide a pleasing natural appearance.
Important considerations include selecting strong wood free of defects of suitable diameter (size depends on span and type of wood), providing 12” minimum overlap onto earthbags and securing the poles with rebar pins to prevent shifting.
Photo source: La Purisma Mission