Fuel

Who says you have to buy expensive hardwood to fire your earth oven. Where wood is scarce in many parts of the world, there are alternative fuels. Right here in Maine (where hardwood is readily available) there's no reason to disregard free alternatives. Whatever you use, however, must be dry, really dry.
The key to using fuel, any fuel wisely, is oven insulation. The more insulation the better. Extra insulation translates to less air pollution and more trees left standing.

Garlic stalks from the garden

There they go

School Oven

Here are some images of a 36" floor diameter, earth oven that's being constructed at a school in Maine. The work is being done by a couple of extremely dedicated teachers and some students.

 Working on stone base

Using template

Brick arch to protect oven opening

Searching for sand

 First fire