Ryegrass Is Losing Ground as Way to Cover Charred Hills

When Los Angeles city officials decide this week whether to plant grass seed on the charred hillsides of O’Melveny Park, they will face questions that go beyond the issues of aesthetics and ecology.

Managers of the 714-acre city park north of Granada Hills say they must carefully balance the needs and future of the park against those of its neighbors.

It is not merely a question of turning blackened hills green again, but also of taking into consideration legal, political, environmental and public safety factors.

“It is not a simple decision,” said Patrick Kennedy, a senior maintenance supervisor with the Los Angeles Recreation and Parks Department. “We are in the middle.”

The debate is over the use of ryegrass, a fast-growing grass planted for decades by many governmental agencies as a temporary Band-Aid to prevent erosion after wildfires burn off chaparral.

Alien Plant

The trouble is that ryegrass is not native to California. Although it has been planted here for more than 50 years to prevent mudslides after fires, some environmentalists and others have been increasingly critical of its use. They believe that introducing alien vegetation to areas where natural species have been preserved does more harm than good.

The Dec. 9 fire burned all but about 15 acres of O’Melveny Park. It headed west to Porter Ranch, where it destroyed or damaged 40 houses. All told, it singed about 3,200 acres of brush and grasslands, most of it county land.

After a week of studying the damage, county authorities concluded that it was unnecessary to seed their land with ryegrass because the fast-moving fire had left an undamaged, well-stocked bed of natural grass seed. County officials have recommended that the city make the same decision about O’Melveny Park.

Before the fire, O’Melveny Park, the second-largest park in the city, offered hikers a pristine mix of mountainous terrain, natural chaparral and wildflowers bisected by a network of trails.

Chaparral Slow

Though the natural grass and wildflowers will begin to return by spring, it may take as long as 3 years for the chaparral to return to its full pre-fire growth, said Don Mullally, senior gardener for the park.

The city’s decision on whether to seed with ryegrass may be more critical than the county’s because of the homes that surround O’Melveny Park. Should winter rains become heavy, water and mud could run off the park into nearby neighborhoods, Kennedy and others said.

“We are right up against the developed areas,” Kennedy said. “So we have to consider damage to park property, private property and the overall ecology of the park.”

Opinion and policy on ryegrass seeding varies from one public agency to the next.

The county Fire Department remains a proponent of its use and plans to use it this month in areas besides Porter Ranch that recently have been hit by brush fires.

Inside the federal government there are differing views:

Tim Thomas, a ranger and botanist for the National Park Service, said his agency does not recommend ryegrass seeding as a post-fire land management tool.

“There is always an immense seed bed left behind after a fire that will automatically replace the vegetation,” he said. “Throwing seeds on a slope that already has seeds is not needed. Nature does it better. Man can’t improve on it.”

Meanwhile, the U.S. Forest Service has often used ryegrass seeding after wildfires and only recently has started to look for other grasses and regeneration methods. Just this month, the agency began seeding a 3,000-acre burn area north of Sylmar with rose clover and zorro fescue, two native California grasses, said Steve Bear, a resource officer with the Forest Service’s Tujunga Range District.

“We are trying to get away from ryegrass because it is not native,” he said. “It has become in vogue to use native seeds.”

Different Circumstances

Many authorities say it is hard to draw a policy on the issue of seeding because each burn area is unique, said Ken Leigh, chief ranger of the state parks department’s Santa Monica Mountains District.

“State parks generally do not prefer to use it,” Leigh said. “Our biggest objection is that parks are supposed to be natural, and ryegrass is a non-native plant. But in some cases it is certainly better to have ryegrass instead of having the bank cave away.”

Whether ryegrass planted on a slope actually helps prevent erosion and mudslides is unclear, authorities say. So is the question of whether it hinders the regeneration of native vegetation.

Steven Hartman, president of the local chapter of the California Native Plant Society, cited ecological studies that suggest ryegrass does not significantly decrease erosion, that the root systems of native vegetation are the best hedge against soil loss. Hartman said many experts also believe that ryegrass suppresses native plants because they compete for the same soil nutrients.

Little Research

But Joe Ferrara, head deputy forester for the county, said ryegrass dies and disappears within 3 years, leaving hillside vegetation uninhibited and in its natural state.

“We’ve been planting rye seed for 50 years in this county,” he said. “If it doesn’t die away, then how come you don’t see it everywhere?”

The one thing most authorities agree on is that there has been scant research on the subject.

“Unfortunately, there have never been any extensive studies that would be conclusive one way or the other,” said Jane Kertis, an ecologist for the U.S. Forest Service.

Two years ago Kertis was part of a team that began what is expected to be the most extensive study ever of the effects of ryegrass seeding in the mountains of Southern California. The study, in which several seeded and non-seeded burn sites are being observed and compared over long periods of time, is expected to last until the early 1990s.

“In the meantime,” Bear said, “the argument rages--seeding or no seeding.”

Use Traditional

Authorities suggest that grass seeding continues to be used by some government agencies because of politics and tradition. The practice has been used for decades, and is considered by some to be politically prudent because it shows a government is not afraid to act.

“It is an emotional cause, purely emotional,” Thomas said. “ ‘There is going to be a mudslide!’ is the call. Then this becomes a way for a public agency to show they did something.”

By undertaking the seeding, a government agency also may be relieving itself of legal liability in case water runoff and mudslides occur, Thomas suggested.

The legal issue is just one consideration the city will have when deciding what to do at O’Melveny Park, said Kennedy, who reported there was slight flooding of park roads during the rains of the past few days.

“We have been researching what the impact will be” of seeding or deciding not to seed, he said. “We don’t have an answer yet.”