Feature
by Suzanne Gavin
p>Recently, San Francisco Mayor Gavin Newsom announced that the city had exceeded its goal of getting 5,000 new trees last year, planting 5,265 trees between Arbor Day 2005 and Arbor Day 2006. But the mayor’s lofty goals for making San Francisco tree-friendly don’t stop there. He would like to see 25,000 new trees by 2010.In order to reach that goal, the city will need more than volunteers, saplings and educational planting programs. Property owners can take part in this citywide effort by joining nonprofit environmental groups like Friends of the Urban Forest in planting trees in front of apartment houses. But adding trees isn’t just a matter of civic pride; they can also prop up your property values. A recent study at UC Davis shows that street trees increase San Francisco’s property value by $6.7 million annually.
Trees Add Value 
Research shows that house prices are influenced by the presence of trees. Developers can maximize profits by retaining existing trees or replanting an urban forest after construction is completed. Several studies have analyzed the effects of trees on the actual sales prices of residential properties. Homes with equivalent features—square footage, number of bathrooms, location—were evaluated. In one area, a 6% increase in value was found to be associated with the presence of trees; an increase of 3.5% to 4.5% was reported in another study. In a survey, 86% of real-estate appraisers agreed that landscaping added value. An even higher percentage (92%) also agreed that landscaping enhances sales appeal.
Trees can also help you attract potential tenants. One study looked at 30 variables of potential importance in determining office occupancy rates. Results suggest that landscape amenities have the highest correlation with occupancy rates. We can assume that what is attractive to commercial renters is also attractive to residential renters. In fact, in another survey, small and medium-sized trees enhanced the public’s perception of a property’s value.
Trees also increase your property’s value in more intangible ways: by encouraging the upgrade of surrounding neighborhood sites, defining pedestrian walkways and contributing to feelings of safety, security and neighborhood pride. Plants, if strategically placed and cared for, can become a “living technology”: a key part of the urban infrastructure that contributes to a more liveable urban environment.
Energy and Environmental Savings
Trees can also help you save money on your utilities. A 25-foot tree reduces the annual heating and cooling costs of a typical residence by 8% to 12%. Also, buildings and paving in city centers create a heat-island effect. A mature tree canopy reduces air temperatures by about 5 to 10 degrees, influencing the internal temperatures of nearby buildings.
The canopy of a street tree absorbs rain, reducing the amount of water that will fall on pavement and then must be removed by a stormwater drainage system. In one study, 32-foot-tall street trees intercepted rainfall, reducing stormwater runoff by 327 gallons. Savings are possible since cities can install surface water-management systems that handle smaller amounts of runoff.
Trees are also a healthy addition to our communities. A typical person consumes about 386 pounds of oxygen per year. A healthy tree, say a 32-foot-tall ash tree, can produce about 260 pounds of oxygen annually; therefore, two trees can more than supply the oxygen needs of a person each year. Also, cooler air temperatures created by tree canopies reduce smog levels by up to 6%, producing savings in air cleanup campaigns. Finally, a mature tree absorbs up to 240 pounds of the small particles and gases of air pollution. In Sacramento, for instance, this represents a value of $28.7 million.
Unfounded Concerns
Despite all of the benefits of adding trees to your property, you may still have some concerns. Many owners believe that tree roots ruin the pavement and pipes, but in fact most tree roots grow in the top 24 inches of soil, well away from sewer lines. Water lines are made of plastic or metal and new sewer pipes are made of tight plastic designed not to break or leak. Tree roots may enter old sewer lines made of clay, but only if the pipe is already broken or cracked.
Over its 25 years, Friends of the Urban Forest has developed and updated a list of suitable species for street plantings. Trees that have a huge spread, aggressive water habits or are brittle are not recommended and outlawed from the list.
Many owners are also concerned that trees will be messy and expensive to maintain. But some species drop minimal fruit, flower and leaf litter. A group of neighbors may share the cost of seasonal cleanup by hiring a routine contractor, or you could give a tenant a small rent reduction in exchange for a periodic cleanup. And remember: the cost of maintaining your tree is a fraction of the amount it will add to your property value.
How to Plant
Once you’ve decided to plant trees in front of your property, contact the Friends of the Urban Forest at 415-561-6890 x 101 or check out www.fuf.net for more info. The organization requires that at least 30 properties sign on before it plans a planting day in the neighborhood. Many communities already have “planting organizers,” and you just need to let them know that you are interested in being part of the planting. If your neighborhood does not have an organizer, consider becoming one and help get the ball rolling toward raising property values in your neighborhood. Once your area has 30 properties signed up, it usually takes about two months before the planting date, with a community meeting after one month to discuss tree species and fill out the required city permit, which is free.
The plantings are almost always on Saturday mornings and are usually over by noon, with a celebratory potluck lunch following. The next planting will be in Noe Valley on May 6 from 9 a.m. to noon, and then Visitacion Valley on June 24. Upcoming planting sessions are also planned for the Marina, the Inner Richmond, the Mission and along 19th Avenue in the Sunset, just to name a few. Let your tenants know about the planting and encourage them to volunteer their time. After all, the trees will enhance their units just as much as they’ll boost your building’s value.
The opinions expressed in this article are those of the author and do not necessarily reflect the viewpoint of the SFAA or the San Francisco Apartment Magazine. Suzanne Gavin is the community outreach coordinator for Friends of the Urban Forest. She can be reached at 415-561-6890 x 101 or Suzanne@fuf.net. Copyright © 2006 by the San Francisco Apartment Magazine. All rights reserved.