Few people associate Arizona with “oak-land” yet the very name of our state is derived from the Basque term haritz ona or “the good oak,” named for an immigrant settlement of folk in the 1700s that was full of oaks. It’s not surprising then that Arizona has an impressive diversity of oaks.
An important and common species here in southern Arizona is the Emory oak, Quercus emoryi. This tree reaches a height of 30 to 60 feet and is the predominant oak species you see as you travel around Santa Cruz County. This oak gets its name from William H. Emory who first described it in Texas, during the boundary survey following the Mexican-American war.
Emory oaks are typically found in oak woodlands, foothills, mountains and canyons at elevations between 4,000 to 7,000 feet. Their distribution is confined to parts of Texas, southern New Mexico, southern Arizona and south to central Mexico. Emory oaks have rounded crowns giving them a very distinctive shape on the landscape.
One of the most important aspects of these oaks is their unique acorns, or bellotas. These bellotas are very special and have been highly sought after by humans for millennia. What makes them so special is that they can be eaten right out of the shell because they lack the high concentration of bitter tannins found in most acorns. The taste has been characterized as sweet and slightly bitter. They are usually harvested in the first week of the rainy season to prevent infestation of worms as the season progresses. Bellotas are harvested by placing a plastic tarp on the ground under the tree and shaking the limbs, or simply leaving the tarp and gathering the nuts over time. The acorns are usually stored in the freezer to kill any worms.
Many Native Americans, and later immigrant families, would gather at harvest time to collect the bellotas. The nuts, about the size of a pinion nut, can be eaten raw, roasted, dried or ground into flour for use as a thickener in stews and soups. Bellotas can be substituted for pinion nuts or other nuts in most recipes.
Turkey, quail, squirrels, javelinas and bears also eat bellotas. The Emory oak is also a host species for the oculea silkmoth. Cavity nesting animals use hollows in oaks for homes, and the acorn woodpecker uses these oaks as granaries to store acorns.
Emory oaks do not always produce acorns. Production is determined by the amount of winter rainfall and whether there is a late spring frost. Sometimes Emory oaks produce mast crops (a seven-year cycle in which a large quantity of acorns are produced).
While this iconic tree is not endangered or listed as threatened, as the climate becomes warmer and drier these grand trees suffer. This is apparent throughout the history of the landscape through both oral histories as well as photos.
Many different conservation/restoration groups including Borderlands Restoration Network (BRN) are working on improving conditions for oaks by keeping water on the landscape to recharge groundwater levels.
Deliverables for a currently funded project that BRN just started in 2019 include planting of at least 1,000 acorns of Emory oak across 250 acres of total restored habitat and completion of shadehouse construction for future oak propagation with at least 250 trees started during project period. Project success will be evaluated through the survival rate of the seedlings.
Emory oaks play a significant ecological role in our local environment, and we should do all we can to ensure they remain on the landscape. It is easy to see why early English poets coined the phrase ‘Mighty oaks from little acorns grow.’ The Emory oak reminds us that from all our planting efforts, regardless the scale, the growth is exponential in both our awareness and our wild home.