Acorns an unstable food supply

Acorns were an important food source for Native Americans in the Rogue Valley, but just how reliable was this wild source of carbohydrates, fats and nutrients?

Ashland Parks and Recreation Department Head Gardener Donn Todt is trying to answer that question.

On a recent cool Sunday morning, he strode over the uneven terrain of an oak savannah north of White City, briefly pausing as he eyed individual trees and made notes about their acorn production.

A tree scores a zero if it has no visible acorns within 10 seconds of searching. The highest score is a three &

reserved for trees with branches that are weighted down by an abundance of acorns.

Rather than laboriously counting acorns on each individual tree, the quick classification system allows Todt to track more than 130 trees at five sites scattered from here to Emigrant Lake.

He has been tracking the trees in this way for nearly two decades.

"This is the 19th year. When I reach 20 years, then I think I might call it. But at first, I thought I'd call it at 10 years, then 15," Todt said.

The study began in 1989 when Todt's wife, Nan Hannon, studied acorn production for two years as part of her master's thesis. Now that the study has continued for many more years, a pattern is beginning to emerge.

Acorn production tends to rise and fall, rise and fall. Plentiful rainfall helps boost numbers, but acorn counts can be low even in years with good precipitation, he said.

Todt said he believes trees developed these boom and bust cycles in an evolutionary effort to thwart predators. A wide variety of creatures have historically feasted on acorns, including humans, squirrels, deer, birds and insects like the acorn moth and acorn weevil. Insect infestation of acorns can be as high as 75 percent.

Acorns usually begin dropping in mid-September, but in abundant years, enough escape their predators that some remain on the ground into April, Todt said.

Insects have come up with their own strategies for dealing with the cycles of acorn production. Many crawl out of acorns and into the ground, where they wait a few years before creeping back out in hopes of hitting the next boom year.

"Acorns and insects have been doing this dance for probably millions of years," he said.

Acorn woodpeckers have adapted by storing acorns in hundreds and even thousands of holes they bore in dead tree trunks. Todt motioned at a towering ponderosa pine snag, where the pale green of this year's crop showed in some holes while the tan of older acorns was visible in others.

Those peaks and valleys in acorn production meant that Native Americans had to be resourceful. They probably stored acorns to carry over into lean years, traded with distant groups where production was good and relied on other food supplies, he said.

Native Americans also had methods for maximizing production.

"Hunting and gathering is a very sophisticated way to make a living. You have to know the land," Todt said.

"People tended to modify the environment to optimize resources. Native Americans observed that acorn production from savannah sites was best. They used fire probably very effectively so they had good production."

Settlers of European ancestry who arrived in the Rogue Valley described it as looking like a vast orchard.

Regular burning by Native Americans reduced undergrowth around oaks, freeing up water and nutrients for the trees to use.

Underburning was also used for other wild crops. Tar weed, a two to three-foot tall plant with yellow flowers, is scattered throughout the dry grass at the study site north of White City. Native Americans burned away the plants beneath the fire-resistant tar weed. Todt shook a tar weed plant to reveal nutrient-rich seeds that fell into the palm of his hand.

Camas also grows on the site beneath the oak trees.

Native Americans usually dug its edible root in the spring when the ground was softer, he said.

All of that modification of the natural world means that Todt has to be careful in how he interprets the results of the long-term study. Until recently, the Rogue Valley's newest inhabitants have viewed fire as an enemy. In excluding fire, they have allowed brush and trees to take over the once-open oak savannahs, probably leading to a reduction in acorn production.

In choosing study sites that were still in a savannah form, Todt said he and Hannon may have picked locations with scarce water and poor soil. However, the study does include one site along Bear Creek, downstream from Phoenix, that has good conditions. It probably most closely approximates the oak tree stands where Native Americans would have concentrated their harvesting, he said.

For Todt, spending these weekends in the late summer and early fall monitoring trees that were once such an important food source provides a nice contrast to his job with the parks department, which involves tending mainly ornamental plants and trees.

Ornamental gardening is a relatively recent development in the Rogue Valley, having been introduced by photographer Peter Britt in the 1860s, he said.

But Todt has taught other parks workers how to sow tar weed and other native plants in spots like the North Mountain Park natural area.

An expert in native plants, he said in his younger days he sometimes spent time trying to survive on wild foods. But that go-it-alone approach helped him realize the importance of collective memory for Native Americans.

"Survival depended on the accumulated knowledge of not just one person, but on the group and generations over time," Todt said.

He said grandmothers and grandfathers represented treasure-troves of information, especially because they could remember how to survive during rare episodes of unusually harsh conditions. For example, each century the Rogue Valley suffers through, on average, three droughts that each last a decade or more.

Todt said tracking acorn production is one way to honor the legacy of what he calls the "old time gardeners" who cared for the land.

"It's important to slow down and look at the plants that were important to people here for thousands of years," he said. "This is a crop that has been around for thousands and thousands of years."

Staff writer can be reached at 479-8199 or To post a comment, visit

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