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Public Radio's Environmental News Magazine (follow us on Google News)

Threatened California Oaks

Air Date: Week of

Cy Musiker reports on efforts to preserve California's oak trees, once some of the most common species in the state. Over a million acres of oak woodland have been felled by developers and ranchers over the past forty years, and early research indicates that some species may not be regenerating. Now a restoration project by the University of California is gaining the support of private landowners.


CURWOOD: This is Living on Earth. I'm Steve Curwood.

I was born a couple of years after World War II, and in my lifetime about two thirds of the world's intact forest ecosystems have disappeared. Most of this loss has come from cutting and burning, although acid rain and other pollutants have taken a toll as well. Almost no part of the globe is exempt from these forest losses. Today we'll hear from a correspondent in the tropical forest of Zambia, and take a look at the Clinton Administration's latest attempt to settle the forest dispute of the Pacific Northwest.

But first we go to California, where there's mounting concern over the oak woodlands that dominate the landscape from the coast to the Sierra foothills. Development is chopping away these oak forests at a rate of 30 to 50,000 acres a year, and some species of oak don't seem to be reproducing any more. From Oakland, reporter Cy Musiker has our story.

MUSIKER: Bruce Pavlik is pulling an acaceous seedling out from under an 80-year-old coast live oak growing on the Mills College Campus in Oakland. He might seem overly protective to be pulling a small week from under such a massive tree. But Pavlik says oaks are highly vulnerable to exotic intruders.

PAVLIK: Particularly on the urban edge, here, eucalyptus and acacias and some other very weedy trees begin to take over the habitat. And they eventually over-top the native oaks and they create a fire hazard, and on top of it a fire hazard that didn't exist when the oaks were there. And it's a big problem trying to keep natural communities natural.

MUSIKER: Pavlik is an associate professor at Mills College, and author of the book Oaks of California. Until recently, these dome-shaped trees and their surrounding grasslands were largely unprotected.

PAVLIK: Oaks tend to occur at low elevation, which is where we as humans like to set up our agriculture and our commercial developments, our residential developments. So very often, in the past, the oaks have been seen as weeds themselves, as sort of bulky inhabitants of priceless land. And they've been removed quite rapidly in some areas, as we've had urban, suburban expansion, agricultural clearing, range improvements.

MUSIKER: During the past 40 years, well over a million acres of oaks have been lost, over 10% of the state's oak woodlands. But these trees are now recognized to be keystone species that shelter over 300 native animals, from mule deer to acorn woodpeckers, wood rats, salamanders, and ringneck snakes. That's more variety than is found in any other California landscape, including the more famous coast redwoods.

(Forest footfalls)

Part of the difficulty in protecting California oaks is that there's been little research done on the trees, but seven years ago the University of California began to a new program to change that.

(Flowing stream)

McCREARY: What we have here is 2,000 feet of a perennial stream. This area was wooded probably until about 30 years ago, when most of the woody vegetation was removed here for range improvement and for some scientific purposes of creating some uniform pastures.

MUSIKER; Doug McCreary is an oak specialist at a University of California test site in the foothills of the Sierra Nevada, about 80 miles north of Sacramento. McCreary's ironic task is to undo the effect of recommendations made by the university in the 50s to cattle ranchers to clear all the oak trees off their range. They ultimately found that it wasn't bad just for the oaks, but for other aspects of the landscape as well.

McCREARY: One of the side effects of that was that the character of the stream was changed. There's now very little woody vegetation, mainly cattails, and from a wildlife standpoint it's not near as healthy. So what we're doing here is we're planting oaks and then other more riparian species such as willows and cottonwoods. And we really want to restore this creek.

(Flowing creek with lowing cattle)

MUSIKER: The creek is part of a model cattle ranch, where McCreary researches the best oak planting techniques and ways to keep cattle from grazing on saplings. That work is important because blue oak and valley oak aren't regenerating, even in some undisturbed portions of their range. McCreary and other researchers say they're not sure why. One factor may be that Mediterranean grasses have replaced native perennials since the arrival of the Spanish 300 years ago. There's also a theory that the California climate is becoming permanently hotter and drier.

McCREARY: Oaks perhaps haven't evolved fast enough to adapt to the changing environmental conditions. And they may be naturally being replaced by other vegetation, which is more suited to the changing climate. Now I don't know if that's valid or not, but in that sense, one might suggest that this isn't a bad or unnatural thing. It's just natural evolution.

MUSIKER: Still, McCreary is optimistic about oak survival, in part because UC's oak restoration program has gained the support of private landowners who control 80% of the remaining woodlands. Developers, for instance, are finding that they can charge more for home sites with mature oak trees. Ranchers find that oaks provide shade for their cattle and reduce erosion. But for some that support only goes so far. Jack Hunt manages over 150,000 acres of mountain and savanna oak woodlands on his Tahan Ranch near Bakersfield. He's worked with university researchers to study why oaks won't regenerate. But Hunt says he'd resist any laws designed to restore oak trees by restricting cattle grazing.

HUNT: In order for that to happen in a significant way, assuming it even works, is you're going to have to have some economic incentives and benefits associated with doing that. And if you're going to have a regulatory scheme, you're going to have to have one that works and not one like you have in LA County, that's become so politicized that no one ever makes a decision.

MUSIKER: Still, Hunt and the State Cattleman's Association are cooperating with public agencies and the California Oak Foundation, to keep development from fragmenting the state's remaining oak woodlands. UC researcher Doug McCreary thinks this may be a rare case where a consensus between private land-holders and environmentalists creates a lot of political momentum.

McCREARY: It's great that at this point, when the resource is still fairly viable, were trying to make some meaningful changes in how we manage these lands, so that the resource is conserved for future generations.

MUSIKER: The California Board of Forestry has begun an education program around the state to promote local protection for oak woodlands. For now, it seems people are making the necessary changes. But if it's not effective, the Board has promised to impose state-wide conservation standards. For Living on Earth, I'm Cy Musiker in Oakland.



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