Wes Dempsey’s tree tales

Here’s something readers probably don’t know: There are no cedar trees in Cedar Grove. There are several Italian cypresses in the popular Bidwell Park picnic spot, but not a single cedar. As far as Wes Dempsey is concerned, “It should have been named Cypress Grove.”

Dempsey, a retired Chico State University botany and genetics professor, is the dean of local naturalists, having led nature tours in Bidwell Park and elsewhere for more than 40 years. Go on one of his jaunts, and you’ll harvest many interesting kernels of knowledge, as a group of about 30 people learned during a Monday morning (March 10) exploration of the trees of Bidwell Mansion State Park and the Chico State University campus, known collectively as the campus arboretum.

Are you aware, for example, that a common garden weed popularly called “sticky plant” was the inspiration for Velcro, an invention that earned a certain Swiss engineer a billion dollars?

Or that California pioneers dried the weed and, because it retained its springy nature afterwards, used it in mattresses? Or that, as a member of the coffee family, it can be used to make a coffee-like drink containing caffeine?

And do you know that confusing a horse chestnut with an American chestnut can be fatal? Both trees are found on the Chico State campus. The American chestnut is “delightfully edible,” as Dempsey put it, but eating a horse chestnut would kill you.

Or this: The reason why Norway spruces are a common farmyard tree in the Midwest is because years ago traveling sewing-machine and Bible salesmen carried seedlings with them and offered them to farm wives as gifts for listening to their sales pitches.

To accompany Wes Dempsey on one of his tours is to be regaled with stories and information of this sort. As one woman said to her companion, “It’s a lot to take in.”

In 2004, when the CN&R named Dempsey one of its “local heroes” for his decades of volunteer service in educating and exciting people about nature, we wrote, “When it comes to local plant and tree life, it’s safe to say that Wes Dempsey is one of the most important local figures since, well, John Bidwell himself.”

That’s because for all these years he has been the most direct link between Chico’s founder, who was famous throughout California for the extent and quality of his amateur horticulture, and the thousands of people who have wanted to learn more about the community’s rich natural history. And, at 82 and retired for 17 years, Dempsey is still going strong, teaching willing students about the natural world around them.

Monday’s tour began in front of Bidwell Mansion, near a magnificent Southern Magnolia tree directly in front of the house. Gen. Bidwell planted it in 1863, Dempsey said, about five years before he built the mansion. Its purpose was to shade the house’s porch, which shows how thoroughly he had planned ahead.

Indeed, there was a magnolia theme to the tour. In addition to several Southern magnolias, we visited an original saucer magnolia from China, a star magnolia, a tulip tree (also known as a yellow poplar) and several others.

There are quite a few interesting trees on the mansion’s front lawn—a couple of Turkey oaks, a monkey puzzle tree from Chile, a California fan palm, an Italian cypress and a giant Sequoia. Each was presented to us with an accompanying story.

The palm, for example, is a granary tree in which acorn woodpeckers stash their nuts. A single family of birds controls this particular tree, Dempsey said. “The family may be two or three sisters, with their mates, and half a dozen fledglings from last year,” he explained. All the parents participate in incubation, and every member of the family helps in feeding the chicks. They all defend the tree, as well, fending off other woodpeckers as well as squirrels. In this way they control a territory of about 20 acres.

Perhaps the most interesting plant we saw wasn’t even a tree, but rather a vine—the California pipe vine, named after its flowers that look like a calabash pipe, the kind Sherlock Holmes smoked. Dempsey pulled off one of the flowers and pried it open, revealing dozens of tiny gnats inside that were fertilizing the flower.

A series of red lines on the flowers serve a fascinating function, Dempsey explained. They reflect ultraviolet light, which the gnats are genetically encoded to see, thus attracting them to the flower.

By the same token, the plant’s leaves give off a smell that is attractive to the pipevine swallowtail butterfly, which lays its eggs on the leaves. Its larvae feed on the leaves, which contain a poison that the larvae ingest. This poison doesn’t harm them, but it does protect both the larvae and the mature butterflies from predators by making them poisonous to eat. Dempsey called it “an interesting series of adaptations.”

Who knew?