Bill Pramuk

I love the English language.

It never ceases to surprise me in the way simple words can have multiple and complex meanings. Here’s a good one to know at this time of year: mast. Not the tall vertical spar that rises from the deck of a sailing ship, and not a captain’s mast (a naval disciplinary hearing), the American Heritage College Dictionary defines it as “the nuts of forest trees accumulated on the ground, used especially as food for swine.” Why “mast”? As far as I can tell it has something to do with “masticate,” to chew, and there are plenty of animals that chew on acorns.

The oaks are being generous again this year. I’ve been walking in areas where the ground is thickly littered with acorns from valley oaks, and live oak branches are heavily laden and sagging with the weight of them. Some say that oak trees do this in advance of a cold winter. Personally, I have no idea how a tree could anticipate the future, but I have seen that oaks bear light crops of acorns in some years, often alternating with heavy crops in subsequent years. And some oaks require two years to set and ripen one crop of acorns.

Generous crops of acorns rarely serve as mast for swine in these parts. The woodpeckers and blue jays have more than their fill. For the trees, copious seed and the genetic diversity it generates serves the long-term survival of oak species. In “Oak, The Frame of Civilization” author and arborist Bill Logan presents the idea that oaks may thrive throughout the temperate zones around the world, not because they are specialized for an ecological niche, but because they are flexible, adaptable and diverse.

In “Circus of Quercus” by David Cavagnaro, oaks are shown to hybridize, producing leaf forms that defy identification because they show a broad range of variation. This can be quite puzzling to homeowners and arborists, when the leaf shape and color is somewhere halfway between a blue oak and a valley oak, for example, or a black oak and a coast live oak. That last example represents an actual species, the oracle oak Quercus X morehus.

Many oak hybrids, however, do not produce fertile acorns. Cross pollination between species of California native oaks produces fertile progeny only when both parent trees are of the same evolutionary lineage, of which there are three: white oaks, red oaks and intermediate oaks. 

In the white oak lineage, which includes valley oak and blue oak, acorns ripen in one season. In the red oak lineage, coast live oak ripens acorns in one season, while the other species in this group — black oak, interior live oak and Santa Cruz Island oak — require two years. Red, white, black and blue; it can be pretty confusing. 

On the practical side, it is much simpler to grow oaks from acorns than it is to understand their genetic diversity. To be frank, I’ve never been that good at propagating plants. I’ve experienced countless failures in attempts to root cuttings and grow plants from seed. In the vegetable garden even I can grow green beans from seed, and oaks are easier!

One of the more fun school projects I did as a parent of two young boys, when they were in elementary school, was to collect acorns and grow oak seedlings. Growing the seedlings was the easy part. I’m afraid most of the trees never found an appropriate home.

For that project I used an article published by the California Oak Foundation  “How to Collect, Store, and Plant Acorns.”  I’ve saved it and referred back to it for many years. It provides numerous helpful tips, but the essence of it is quite simple:

 • Collect and store acorns in the fall.

 • Store acorns for one month in a sealed plastic bag in the refrigerator.

 • Lay acorns on their side and plant one-inch deep in the soil.

 • Keep the area around planting spots free of weeds.

 • If possible, water several times during summer, and protect young seedlings from animals by using screen cages.

As we head into the festive days of fall and winter, the first for me this year will be  Acorn Day, a hands-on family fun day, learning about oaks, for which I will be one of many presenters. The event is Sept. 29, 9 a.m to 3p.m. at Pepperwood Preserve, a 3,000-acre permanent nature preserve located off Franz Valley Road, near Calistoga. Operated by the Pepperwood Foundation, the preserve has hiking trails, 30 miles of roads, and two astronomical observatories. It has been used by the University of California system many times for doctoral and post-doctoral projects on flora, fauna and ecology.

Acorn Day is an opportunity for all to learn about oaks, acorns, the birds and mammals that depend upon the oaks, and meet a variety of people who care for and about the native oak trees of California. 

Admission is free. Bring a bag lunch and join us under the beautiful oaks. For more information, go to www.pepperwoodpreserve.org

Bill Pramuk is a registered consulting arborist. Visit his Web site, www.billpramuk.com, e-mail questions to info@billpramuk.com, or call him at 226-2884)