Over thirty years ago I planted a mesquite tree in my front yard. Actually, I threw mesquite bean pods on the ground and waited. I got the seeds from a friend’s trees. Or I got them from his neighbor’s trees, I don’t remember. But since my friend Lance’s trees were robust specimens of mesquites and his neighbor was noted botanist George Brookbank, I figured I win either way.
My intent was to provide shade for my kitchen, easily the hottest room in the house, using a native tree species. Three decades later I have succeeded magnificently, sort of. The mesquite quickly put out roots that located my sewage water line and drawing on that source, grew huge and healthy. Of course periodically I have to invite a plumber to bring a power router with him to clear my pipes but that is the price we pay in Tucson — anything for shade.
One of my greatest professional recognitions as an archaeologist came from Julian Hayden, a man who knew both his mesquites and his shade. We were arriving at a summer luncheon lecture and round-table discussion when I drove across the entire parking lot to park beneath the shade of a handy mesquite. Julian looked at me, in that way he had of not letting you know whether you were in for a lecture or accolades, and said, “You know, for an archaeologist you show a remarkable turn of intelligence.” Golden.
Despite the fact that mesquites are ubiquitous in the Sonoran desert and especially in and around Tucson, my belief is that they were once more confined in their occurrence as a secondary riparian tree, growing only near water sources. This is supported by the location of prehistoric resource use areas which are localized near known water resources.
The reason for their extensive spread in the historic period is simple. Mesquite trees produce a delicious pod, full of complex carbohydrates and it is sweet. Cattle love chewing the mesquite pods. Since the seeds within those pods are as hard as BBs the cattle eventually redeposit them along the way with a lot of moisture and fertilizer. Voila, mesquite bosques!
But cattle weren’t alone in their desire for mesquite bean pods. For centuries man has looked upon the early summer production of a plethora of the delicious pods as a windfall and a natural hedge against starvation. There is ample evidence that the prehistoric population of Arizona were well aware of the bounty that lay around them, available for the picking.
At Ventana Cave 1), there is a large volcanic rock sitting just outside the spring area. Hand-drilled into this rock are numerous deep holes. These holes are the remains of mesquite processing activity.
Pods would be dumped into the holes, acting as mortars and then the pods would be crushed, probably with wooden pestles made from the local hardwood — mesquite. The mush that resulted was then either dried into a powder-like flour or formed into cakes that could also be dried and preserved against later need.
Los Mortreros, a site that owes it’s preservation to the efforts of many Tucsonans, is named for the numerous bedrock mortars that were left behind by the prehistoric inhabitants.1)
Mesquite, while not a staple, was certainly an important food resource for the people living in the Sonoran desert in prehistory.
Children probably just grabbed the fresh seed pods off the tree and chewed them up enjoying the mild, sweet, molasses-flavored treat and spitting out the quid. Julian told me that the dessicated remains of those quids were found thousands of years later in Ventana Cave. 2)
Often while on surveys in places like the Sierrita, Rosruge, Coyote and Silverbell mountains I would find similar evidence of mesquite pod processing anytime we came upon sites that had water and the right kind of stone. Igneous, basaltic rocks, because of their rough surface, vesicular nature (it often has little holes in it) and hardness was the rock of choice, just as it was for manos and metates used in corn grinding.
Personally I think there may have been an added benefit that the prehistoric people discovered over the long run. Corn as a dietary staple has certain nutritional inefficiencies, one of which involves iron. The iron acquired from the the grinding of the pods in an iron rich stone would help ameliorate those problems. (Same reason I still cook with a cast iron skillet.) In other areas granite also serves as a ready replacement for basalt as a grinding stone though it doesn’t offer the same benefits.
In Tucson we have had something of a mesquite renaissance. Going online or perusing the regional news outlets you can find recipes for using mesquite flour in cooking and baking (it needs no sugar!) and there are some local producers of mesquite based cookies, cakes and pancakes.
1) Sites that will be discussed at length in future posts.
2) Julian Hayden personal communication