Fuel-stingy Z stove: Could it be the answer for fuel-poor third world?

Last summer, in the Quetico Wilderness region along the Minnesota-Ontario border, Martha Beidler of Lancaster, Ohio, cooked a meal on a small camp stove using a readily available fuel: dry moose dung. It was an experience that underscored again the versatility and efficiency of a little stove that has become, in her teaching experience, a potent ''more with less'' symbol.

Mrs. Beidler, a frequent speaker at nutrition conferences in the United States, specializes in outdoor cooking and ecological awareness. She contends that fuel efficiency is as important outdoors as it is inside the home. Thus, she is full of praise for the little stove.

Normally she uses forest litter - anything that can be picked up within a radius of about 6 feet. But on this occasion she wanted to put her little stove to a further test, so she turned to dung. It provided all the heat she needed to put a hot meal on the table for her camping family. In some regions where she camps - above timberline in the High Sierras, for instance - dung is one of the few readily available fuels.

In the backyard of my Weymouth, Mass., home, I have boiled potatoes and other vegetables from time to time, using only the dried canes that had been pruned from a raspberry patch. I used the same remarkably fuel-efficient little camp stove that Mrs. Beidler does on her camping and lecture tours. It will burn any solid fuel - twigs, bark, cones, wood pellets, peat, charcoal, coal, and, yes, even animal dung.

Its secret lies in the short chimney that is built into the stove to provide a self-induced draft. Preheated air boosts secondary combustion, while an insulating sleeve shields the burner bowl. The effect is to concentrate the heat beneath the pot or pan so that very little energy escapes unused. The point is, the Z stove can extract an abundance of heat from almost insignificant amounts of fuel.

Tests at Eindhoven University of Technology, near Appeldoorn in the Netherlands, showed the Z stove, as it is named, to be 31 percent fuel-efficient. That means that almost one-third of the heat contained in the fuel went into cooking, the rest escaping as waste heat. In contrast, the open fire used for cooking, whether at the backyard barbecue or as it is for every meal in much of the third world, is only 6 percent efficient.

The Z stove was designed primarily with the poorer nations of the world in mind. While economic well-being frequently turns on fuel-efficiency in the West, the very survival of many third-world families hinges on their ability to make meager fuel supplies stretch further than ever before.

Fred W. Hottenroth of the ZZ Corporation of Los Alamitos, Calif., designed a compact stove that could easily be carried in a backpack. If it could get widespread recognition among outdoorsmen in the US, it might well come to the attention of people who could get it to where it would do the most good, such as in the fuel-starved Sahel region of West Africa or equally fuel-short Katmandu, Nepal, where fuel-wood prices have risen 300 percent in just the last two years.

In many third-world regions, families now take six times longer foraging for fuel wood than they did a mere 10 years ago, while those who must buy their fuel often pay as much as 25 percent of their income for it. Imagine the cost of home-cooked meals if we had to lay out a quarter of our earnings just for the electricity that powers the stove.

Mr. Hottenroth has no wish to manufacture stoves for much of the world, but he would like the idea to get around. The stove is made of lightweight galvanized steel, a material that is readily available at low cost throughout the world.

Its design is such that it could be locally mass-produced by people with only moderate training in the use of tinsnips and a hammer. The key word here is ''mass-produced.'' Many fuel-efficient stoves have been designed for the third world using readily available materials such as mud and stone. The drawback is that they take time to build and cannot be moved if a family is driven away from a region by drought or the encroaching desert.

Meanwhile, the annual consumption of 750 million tons of fuel wood for cooking alone is devastating the forests of the third world. Within four years, it is estimated, demand will outstrip supply. Efficient stoves could cut that consumption by almost 80 percent. That would be enough to allow reforestation programs, woefully inadequate at the present rate of consumption, to get ahead of demand.

Where dung is burned as a fuel, far less would be consumed, and the rest used where it has much greater value - on farm fields.

If you are interested in the Z stove, either for your own backyard or in the quest to get it out to the less-developed nations of the world, write for details to Fred W. Hottenroth, ZZ Corporation, 10806 Kaylor Street, Los Alamitos , Calif. 90720.