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Perc removal


With Rubber Sidewalks, Trees Are on the Rebound

Bob Pool / LA Times 14jul01

Walkways: Panels pop out, giving access to roots, so removing ficus isn't only option.

The popularity of Southern California's most destructive curbside shade tree is starting to bounce back--thanks to rubber sidewalks.

Leafy ficus trees have helped cool neighborhood roadsides for decades. As they have grown, though, their stubborn roots have created safety hazards by pushing concrete sidewalk slabs out of the ground.

That has prompted repair crews throughout the region to chop down rows of the dense, green-canopied trees. Replacement trees have generally been slower-growing and scrawnier-looking.

But street maintenance workers in Southern California will soon be stretching the life expectancy of the ficus by using flexible sidewalks made from recycled automobile tires.

The rubber sidewalk gently bends when pushed from below by tree roots. It's also soft enough to cushion the landing of anyone unlucky enough to trip and fall on it. When the roots need trimming, the rubber panels can be popped out and then reused.

The panels are made from high-density, non-mushy rubber that is tough enough to handle skateboards and women's high heels. Around trees, they replace about a 10-foot length of conventional concrete sidewalk surface.

The rubber sidewalk has been a dream of Santa Monica street inspector Richard Valeriano for seven years. It came to him, in fact, while he was asleep.

"In my dream, sidewalks were all bending and twisting, but there was no cracking," Valeriano said. "I woke up and said, 'Wow! Elastic sidewalks! I wonder how we can make them?' "

Valeriano answered his own question a short time later when the West Los Angeles health club where he works out was remodeled. New flooring made of rubberized tile squares was installed. "That's it!" he exclaimed.

After some research, Valeriano linked up with a Rancho Cucamonga rubber mat manufacturing firm, U.S. Rubber Recycling Inc. With his help, the company produced a 30-by-12-inch tile from ground-up tires. When baked under pressure in a mold and dyed a red-brick color, the finished rubber tile has the look of five bricks arranged in a pattern.

New Pavers First Used Near Library Branch

Valeriano got the backing of his Santa Monica bosses to purchase a pallet load of the 2-inch-thick molded pavers and began experimenting with ways to glue them down. In 1999, he wrapped up two years of tests at the city street maintenance yard by replacing a badly cracked section of public sidewalk with rubber.

That walkway--beneath a ficus tree next to the city's library branch at Ocean Park Boulevard and 21st Street--was a success. Soon Santa Monica crews were installing the rubber pavers under ficus trees at half a dozen other places in town.

Santa Monica's rubber sidewalks got some unexpected bounce in April because of ficus tree-cutters near Torrance.

Lindsay Smith, a Gardena screenwriter and producer, spied a Los Angeles County work crew starting to cut down 26 ficus trees along Redondo Beach Boulevard near the Alondra Park Golf Course.

Smith persuaded the workers to hold up until alternatives to the cutting could be discussed. Then she got on the telephone and started calling arborists in hopes of finding a way to save the trees. One expert mentioned Santa Monica's rubber sidewalk experiment.

Smith managed to save 12 of the ficus trees after arranging a demonstration of Santa Monica's rubber walkways. Public works officials from the county and from adjoining South Bay cities showed up. A second demonstration drew officials from cities in Orange County as well.

Public works leaders from Hermosa Beach, Los Angeles, Long Beach, Glendale, Cerritos and the city of Orange were among those from 15 cities who pledged their own rubber sidewalk tests. Officials from a dozen other cities expressed interest.

The cities' walkway evaluations will cost about $1,000 per tree. But since recycled tires are used for the rubber, the tests could end up being underwritten by state grants financed by a $1 per tire recycling fee motorists pay when they replace their cars' tires.

At current prices, rubber walkways are about twice as expensive as concrete. But the cost evens out when sidewalks next to trees have to be repaired every five or six years, Valeriano said. He speculated that rubber sidewalks are tough enough to last for decades.

U.S. Rubber Recycling President Rick Snyder said the $6-a-square-foot cost of each rubber panel is likely to fall dramatically if they come into wide use.

"People call Lindsay a tree-hugger. . . . She's doing this from her heart. We're not paying her," he said.

Municipal officials are cautiously optimistic about taking rubber from the road and putting it on the sidewalk. Unlike Santa Monica--which has a no-cutting policy toward street trees--most cities routinely remove trees when their roots buckle sidewalks or threaten to do so.

"It's a new idea, and we're looking for new ideas," Jeff Porch, a Long Beach street maintenance supervisor, said of the rubber walkways.

Said Ray Torres, a Glendale public works official: "From what I've seen, it looks good. It might be something that can help us."

L.A. Considering Test of Rubber Sidewalks

In the city of Orange, officials planning to test about 100 square feet of rubber sidewalks are hoping the material will put an end to jackhammering and conventional concrete replacement, said Tara Finnigan, the city's business and public affairs manager.

Rubber sidewalk experiments are also being considered in each of Los Angeles' 15 council districts.

"We like the project. We like the possibilities. We want to see what happens," said Cora Fossett, a spokeswoman for the Department of Public Works. "We'll hopefully put them in places where property owners really want to save the trees."

Some arborists contend the ficus is the wrong tree for urban curbsides. But they say they are interested in how the rubber sidewalks handle its tough roots.

"I need to see it before I can imagine it," said Jim Summers, forestry director for TreePeople, a Los Angeles arbor group. "We want to preserve as many ficuses as we can, but there comes a time when resources can be better spent finding a different tree."

In Santa Monica, meantime, officials have invested about $40,000 in molds for the rubber pavers and in various types of adhesives for tests in gluing them down. Although other cities have asked for gray, concrete-colored rubber, Santa Monica favors red because it seems to fade less in sunlight, Valeriano said.

A recent survey of Santa Monica's 235 miles of sidewalks shows that even with rubber repairs, city resources could be thinly stretched. There are 664 places were roots have raised sidewalks 3 inches or more, and 1,800 other spots where the displacement is slightly less, Valeriano said.

Those who walk on the flexible sidewalks seem to like them. Outside the library on 21st Street, 10-year-old Isabel Spiegel had an unusual spring in her step as she skipped over the walkway. "It feels better than regular brick," she said.

Her father, Venice advertising copywriter Jeff Spiegel, said he's not surprised that cities are jumping on the rubber walkways.

"Big camphor trees tear up the sidewalk where we live," Spiegel said. "This seems like it would be worth a try in Venice."

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