HOME IMPROVEMENT : An Efficient Housing Climate Management System? Try a Tree

Brazil and Malaysia aren’t the only ones removing trees faster than they’re replacing them; we’re doing the same thing to our urban forests, area arborists say.

Research by the American Forestry Assn. “shows us that cities are removing four trees for every one they’re planting,” says Tom Larson, a member of the group, president of Urban Forestry Consulting and founder of the nonprofit Tree Society of Orange County.

These are trees that we can ill afford to lose, he says. Our cities are already 5 to 9 degrees Fahrenheit warmer than surrounding areas, according to association statistics, and they’re predicted to heat up another 6 to 12 degrees within the next few decades if present trends continue.

Trees cool cities off directly by providing shade and reducing energy consumption for air conditioning. Indirect cooling results from trees reducing carbon dioxide in the atmosphere. (Carbon dioxide traps heat that would otherwise radiate into space.) We need more trees, not fewer, Larson says.

But that doesn’t mean we should all grab our shovels and go out and plant the biggest trees we can afford in our parkways. Putting the wrong trees in parkways in the first place--whether those plantings were done by citizens or municipalities--accounts in large part for the high incidence of tree removal that cities now face, tree experts say.

“Ninety percent of the trees available in the market do not belong in public parkways,” says Daryl Smith, superintendent of parks, trees and landscapes in Huntington Beach. “Their trunks get too big, and their roots are too invasive.”

If a tree is planted in an area too small for its root system, Smith says, it just seeks nourishment elsewhere. “The roots are attracted to the warmth of the soil under the sidewalk, the moisture and fertilizer in the lawn and the moisture and warmth in the rock and gravel under the asphalt in the street.”

When roots burrow toward these natural magnets, he says, they begin popping up sidewalks and breaking up curbs, leaving cities with just two options: breaking up the roots, which endangers the life of the tree, or taking the tree out altogether.

“The minimum space any kind of shade tree needs to thrive is 10 feet--and most of our medians aren’t even that big,” says Steve Holcomb, an arborist at Irvine-based Golden Coast Environmental Services. “That’s why cities find themselves having to cut down mature trees every 10 to 15 years. As soon as the trees get big enough to provide any environmental benefit, they tear up the hardscape.”

Trees in cutouts fare even worse. “The average age of trees in these 2-foot-by-2-foot cutouts--which, personally, I think are an abomination--is only seven to eight years,” says Alden Kelly, arborist consultant and member of Street Trees Seminar, a professional association of municipal workers, consultants and vendors dedicated to the promotion of street trees and improvement of street tree management.

“We’re treating trees like big potted plants,” he says. Or, as Holcomb puts it, “like long-term poppy beds.”

Cities have been working with the nursery industry, public utility plants and other concerned parties to find trees that will have a longer life span in restrictive parkways, without causing problems to the hardscape. But the narrow limit of choices under these constraints--in Huntington Beach, for instance, just 10 tree species are approved--can create other problems.

“When you have only a few species to choose from and start building up large host populations, those host populations will inevitably attract insects and encourage them to multiply,” Holcomb says.

Ornamental pear trees, for instance, which were planted heavily in many parts of the county over the last eight to 10 years, are now struggling with white fly infestations, he says. And palm trees, another widely used choice in narrow parkways, are developing “some real sophisticated diseases we don’t know how to treat.”

Pest problems are causing many cities to take a fresh look at their lists of street trees to see whether more can be added. Working with a committee of citizens, consultants and city staff people, Anaheim recently doubled its previous species list.

“We had maybe 25 varieties for the entire city before,” says Al Epperson, tree services coordinator. “And lots of single varieties in certain areas.

“I worked in Chicago in the ‘60s when the Dutch elm disease struck, and we took out 10,000 trees a year, so I know what can happen. If you have only a few varieties, these diseases can wipe you out. The white fly infestation affecting the ash and evergreen pear is bad enough as it is.”

Eliminating parkways as they now exist would allow for more options, and that’s exactly what arborists would like to see.

“The concept of parkways comes from the Midwest, where snow-removal equipment needs space to dump snow when it clears streets without putting it on sidewalks,” Holcomb says. “We kept the concept--even though we don’t have the snow--but reduced the parkways. And just kept reducing them until now we’re down to 18 to 20 inches in some cases.”

Holcomb would like to see these parkways in which narrow green strips separate roads from walkways replaced by an arrangement where walkways are right next to the curb: “You’d plant the tree where the sidewalk is now--it would still technically be on easement--but it would have the whole yard to root in.”

This would be healthier for trees and permit more species to be planted, he says.

Kelly would go further: “If I were king of the world, I’d make most streets one way and take out sidewalks on one side of the street. Let people go to a little trouble on the behalf of trees for a change.”

But these solutions, both admit, are not politically popular. “It means starting over,” Holcomb say, “and people are reluctant to give up existing trees in the interim.”

Another way to increase the tree varieties in the urban forest is planting them somewhere besides parkways. Holcomb, for instance, would like to see trees planted in all those little odd-shaped plots too small to build on but large enough to support a substantial tree. “It would have to be a tough tree that could pretty much exist on its own, but there are plenty of those around.”

And Larson, with the Tree Society, would like everyone living in a private home to plant three trees around it.

“If people planted three deciduous trees around their homes--we call them ‘passive solar trees’--energy consumption could be reduced by millions of megawatts,” he says. “The trees would leaf out in spring and summer and shade the house, reducing the amount of air conditioning needed, and would lose their leaves in the winter, letting the heat from the sun in.”

Air-conditioning bills in the summer could be reduced up to 30%, he estimates. Planting trees with “some dimension and scale” whenever possible would also benefit the environment by cleaning the air, Larson says.

Though all trees absorb carbon dioxide and produce oxygen, thereby benefiting the environment, tall trees with sweeping canopies do this more effectively than such dwarf species as crape myrtle, he says.

Larson’s arguments for planting trees of consequence where appropriate should not be construed as lack of support for parkway trees, however. One of the Tree Society’s functions as the regional coordinator for California Releaf is supporting groups of citizens who wish to help their cities plant more trees--most of which will be, by necessity, in parkways.

One such group is Releaf Anaheim. This organization--the first of its kind in the county--has the goal of planting 20,000 trees in Anaheim by the year 2000 and is cooperating with the city’s Parks and Recreation Department to meet it.

When enough requests for trees come into the department from one area--or can be combined with known vacancies--to suggest a good candidate area for a community planting, the information is relayed to Releaf Anaheim. According to parks superintendent Jack Kudron, Releaf then contacts homeowners in the area, gets them and other community members--such as Boy Scout troops or high school ecology classes--involved and generally plans the event, he says.

Actual planting is by citizens of the community, with initial training and supervision by city staff.

Having planted the parkway trees themselves, citizens become more protective about them, Kudron says. “They water them more carefully, watch out for pests and just generally take more interest.”

The arrangement also has the advantage of saving the city money. Two city staff members worked with Releaf Anaheim to plant 15 camphor trees on Alice Street in the group’s latest project, he says.

“If the same two guys had planted those 15 trees, at, say, 1.5 hours per tree, it would have cost the city 45 man-hours,” he says. “But since volunteers did most of the work, all the city had to provide was eight hours’ labor for two staff members for one morning. We’re going to be able to plant a lot more trees this way.”

He heard about a similar project at an American Forestry Assn. conference about a year ago, he says. (The association started Global Releaf, the parent project behind all the other Releaf groups.)

Community plantings are what Larson likes to see: “I want to turn the chili cookouts of the ‘80s into the tree-plantings of the ‘90s.”

The society will provide the opportunities, he pledges. More plantings are scheduled.

“Call ((714) 449-7170) to find out how to participate,” he urges. “We want to get as many people involved as we can, because we need every tree we can get.”