Reseeding Hills Cheers Laguna, If Nothing Else : Environment: A number of studies question whether it really prevents erosion, but all agree it helps people feel better.

The relief was almost palpable as the helicopter slowly lifted skyward, dangling its 1,000-pound bucket of seeds.

In the open field serving as a staging area, a handful of observers leaned on piles of seed bags with smiles on their faces. At last, they seemed to be thinking, something is being done.

The scene last week was a cornerstone of a $2.1-million restoration effort by federal, state, county and local authorities in the wake of last month’s devastating Laguna Beach fire. The helicopter, operated by the California Department of Forestry and Fire Prevention, was bound for nearby Emerald Canyon, where it dropped its load of seeds on charred hillsides in the belief that the resulting vegetation would help prevent erosion.

But it might not work out that way. In study after study, including one partially funded by the forestry department itself, a chorus of experts have questioned whether reseeding really prevents erosion after fires. The real purpose it serves, some critics have concluded, turns out to be simpler: to put those smiles on the faces of anxious fire survivors.

“It has community value because people feel that something is being done,” says John Tettemer, a professional hydrologist who has helped the Irvine Co. design water resources projects and participated in many of the company’s discussions on reseeding. “That provides good political comfort, but the question is, does it really help and is it worth the effort?”

Officials of the forestry department, which has been reseeding in California for years, answer with a tentative yes. When conditions are right, they say, new seeds dropped from the air or sprayed on in a mulch can sprout more quickly than natural seeds, providing a cover and root system that will hold the fragile soil together and help prevent erosion during the rainy season.

“I don’t want to paint the picture that it’s always successful,” said Dave Neff, the department’s deputy chief resource program manager for Southern California. “There are times when it works and times when it doesn’t. Our position is that if we can effect any kind of protection, even minimal, we ought to try.”

Given mild rains and temperatures that are not too cold, the seeds--called zorro fescue--dropped on Emerald Canyon and its nearby environs ought to sprout in seven to 14 days to provide good cover, Neff said.

Experts in a variety of fields, however, question whether the potential positive effects of reseeding outweigh the potential damage to the environment.

To begin with, they say, replanted seeds don’t always grow more quickly than the natural seeds left in the ground after a fire. And if they do, many experts say, it is only by competing with the natural vegetation for space, moisture and nutrients, a process that often hinders the natural vegetation’s ability to regrow.

“It’s the competition that hurts,” said Elisabeth Brown, a local biologist and outspoken critic of reseeding. “What you want is to encourage the native plants to come back as quickly as possible and (reseeding) doesn’t seem to be the way to do it.”

That point of view is supported by a number of scientific studies, one of them, ironically, partially funded by the Department of Forestry and Fire Prevention itself. In that ongoing study--begun in 1986--state and federal forestry researchers are conducting a series of controlled fires in various areas, followed by reseeding in the hopes of monitoring the results to draw some conclusions.

While the study will not be concluded for several years, said Susan Conard, the U.S. Forest Service ecologist overseeing it, some preliminary findings can be made. First, she said, in the burn areas observed so far, reseeding appears to have had no significant impact on erosion control. And in general, she said, it does not appear to result in a significant increase in the vegetative cover.

The newly seeded plants, Conard said, “just basically replace the natives. As the cover goes up, the number of natives goes down.”

While her study focuses on rye grass--a popular reseeding plant not being used in Laguna Beach--Conard believes that its findings can be applied to other reseeding plants as well. But she is quick to caution that her observations--so far gleaned from only three burn sites--are preliminary and not yet statistically valid enough to be considered scientifically conclusive.

“If I were working for a management agency and had to make a decision on seeding,” she said, “I would probably go ahead if it were an area of high risk because if I got hauled into court, I wouldn’t have enough hard data to defend not seeding.”

The authors of another study, however, drew conclusions similar to Conard’s with what they considered to be hard scientific evidence.

Observing the results of reseeding after the 1991 Oakland fire--mostly the hydraulic application of seeded mulch to hillsides below burned houses--a group of researchers at UC Berkeley published an article in the current issue of California Geology. Among other things, it concludes that “Reseeding burn areas and the heavy application of hydromulch appear to be inappropriate responses on burned slopes not having severe ground disturbances. The most appropriate response after a similar urban/wildland burn may be to do nothing. However, intense public pressure to ‘act’ may not permit this response, even when it is correct.”

Laurel Collins, a researcher in the Department of Geology and Geophysics at UC Berkeley, who helped conduct the study, said, “We didn’t get any immediate benefit from the seeding. It made no difference with regards to surface erosion and no difference with regards to landsliding.”

The same company that applied the seeded mulch in Oakland is now engaged in a similar process in Laguna Beach. Unlike the aerial seeding conducted in open areas by the state Forestry Department, however, the mulch--specially treated with a kind of polymer glue to hold the seeds in place--is being applied hydraulically only to slopes in urban areas within city limits.

Carol Forrest, an erosion and sediment control specialist with Woodward-Clyde, the company doing the seeding, disagrees strongly with the Oakland study’s conclusions.

“We have a lot of evidence showing that the areas that were reseeded responded quite a bit faster than the areas that were not,” she said, directly contradicting one of the study’s findings. “What the mulch did was provide short-term erosion control until the new vegetation got established.”

Even Woodward-Clyde, however, admits that some of its work in Oakland was primarily cosmetic. Speaking at a recent Laguna City Council meeting, Michael Harding--another erosion and sediment control specialist with the company--showed slides of a highly visible hillside in Oakland which, he said, had been reseeded primarily at the behest of the city’s mayor even though it posed no immediate threat from erosion.

“What we basically did,” Harding said, “was paint that hill green. It made everyone feel a lot better.”

And indeed, some say, that is no small thing.

If reseeding “turns the soil green a little bit faster than nature would and people get comfort from the idea that the grasses are binding the soil together,” Tettemer said, than a useful purpose has been accomplished. “It’s quite understandable,” he said, “that a political body would choose to reseed for reasons of community comfort.”