January 11, 2006

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Publication Date: Wednesday, January 11, 2006

Open space district launches war on a weed

By Sue Dremann

Palo Alto Weekly

A weedy "slow-motion explosion" that threatens to overwhelm Midpeninsula native plants will be combated in a 10-year, $1.2 million effort by the Midpeninsula Regional Open Space District.

The invader, known as "slender false brome," is a non-native grass that is extremely aggressive and destructive to the native forest ecosystem, according to Cindy Roessler, the district's resource management specialist.

False brome is a perennial (all-year) grass that is dark green in winter and spring and light green in summer. It has distinctive seed stems.

The grass has a major problem in western Oregon, where it has taken over an estimated 10,000 acres of forest and grasslands.

In January 2004, district officials identified false brome as a grass they had earlier noticed growing on nearly 60 acres of district land, mainly at its Thornewood and La Honda open space preserves along Highway 84 and in patches at El Corte de Madera preserve along Skyline Boulevard.

Ms. Roessler said the infestation could cover as much as 100 acres when private land is taken into account.

The district is being extra aggressive because, unlike other infestations such as yellow star thistle, there is an opportunity to eradicate the plants while the infestation is still in a relatively limited area. Ms. Roessler said false brome can remain confined to smaller patches for years, then proliferate and overwhelm an entire ecosystem.

The grass was first seen in Oregon in 1936, but it didn't become a problem until the mid-1990s. The plant forms stands so dense native plants and tree seedlings are choked out, she said. It now threatens western Oregon's economy, which depends heavily on logging.

On a trip to Corvallis last summer, Ms. Roessler saw the extent of the infestation first-hand.

"It was everywhere," she said. Locally, "it's more spotty. There's a half-acre here, a trail there. You don't see it everywhere." She said when she described the spotty growth patterns to the Oregon foresters, they replied, "Oh, yeah, we remember that."

But they waited too long to combat it, she said: "I'm not willing to risk it."

"It's growing in even very shady redwood forest," said Ms. Roessler. "I'm alarmed at how flexible it is -- it grows in sun and shade. It's very tolerant."

Its presence among redwoods above Woodside is particularly alarming because of the light undergrowth that allows it to easily take over.

If the weed is allowed to flourish, "it could cause ecosystem conversion and change the fire ecology," she said. It would reduce available forage to native animals and affect the habitat of creatures living off decaying redwood trees and in the forest soils, she added.

Ms. Roessler first thought false brome had been introduced in hay from Oregon for Woodside area horses. But genetic testing has found no link to the Oregon brome.

In early skirmishes, hand-weeding along creeks and using simple herbicides have worked best, she said. Some funds will assist neighboring private landowners.

Photos are on the district's Web site, www.openspace.org. Anyone who sees a suspect plant should contact the district for proper identification, she said.

The district also has earmarked $30,000 annually for 10 years to research sudden oak death, a fungus that kills oak trees, to find out why some trees are showing resistance. The district will survey resistant trees.

"Our 50,000 acres are like a giant laboratory. We have a good chance to develop potentially resistant trees," Ms. Roessler said.
INFORMATION

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