"They paved paradise and put up a parking lot" is no longer a sentiment relegated merely to the lyrics of a 1970 Joni Mitchell song.a
Environmentalists are now armed with the facts, thanks to a new study released last week by a Washington, D.C., conservation organization.
In San Diego, and indeed in most large metropolitan areas nationwide, trees have been vanishing from the landscape at a steady pace for decades. From 1985 to 2002, San Diego's urban forest coverage shrank by 27 percent, the group American Forests concluded in the five-month, $150,000 study.
During that same period, the city's urban areas grew by 39 percent. After studying high-resolution satellite photographs, the organization found San Diego to be made up of the following: 110,044 acres of urban sprawl (51 percent of the total), 48,674 acres of grassland (22 percent), 32,956 acres of shrub land (15 percent) and 14,738 acres of tree canopy (a dinky 7 percent).
Sadly, the group reported that water, wetlands, sand and bare land made up such a small percentage in the overall picture-5 percent-that it was "considered too small to be a factor in the calculations of this study."
Gary Moll, vice president of the group's Urban Forest Center, came to San Diego last week to meet with city staff and Mayor Dick Murphy, who has produced the most cheerleading of late-at least politically-on the value of tree planting in San Diego's urban jungle. Moll thinks city leaders have gotten the message.
"One thing you ought to realize is that you have a fairly positive attitude emanating from the mayor's office, even though I don't know if they realize the extent" of the problem, Moll told CityBeat after his visit.
Well, that's a start, but the road to tree revivalism in San Diego will be a long and arduous one, said Drew Potocki, the city's urban forester and a long-time champion of the environmental and financial benefits of tree planting, particularly along city thoroughfares.
"It used to be everybody thought about trees as, "Oh yeah, they're nice for shade and the birds.' Well, trees aren't just a pinstripe on the street," Potocki explained. "They're actually a functional part of our infrastructure, especially in San Diego, because you've got a storm-drain system that does not get filtered. Where's your filtration device? Well, it's all the street trees."
Potocki acknowledged that he often gets strange looks from storm-drain advocates for remarks like that, but American Forests backs him up on his thesis. If San Diego were to boost its tree coverage from its current 13 percent to 25 percent, the group insisted, the city could save "nearly $23 million a year in the areas of stormwater management and air quality alone."
As the group explained in a statement: "Trees intercept rainwater on their leaves, branches and trunks. Some of it evaporates, and some slowly soaks into the ground, reducing total volume of runoff as well as peak flow after a storm."
The mayor chimed in, noting that "planting trees cleans and cools the air, reduces runoff to our beaches and bays, and can unify a community."
City officials seemed hesitant to blame encroaching development as the main culprit in San Diego's vanishing urban forest. Moll, however, said the cause "does seem to be development."
Potocki said the city will take the next three or four months to break down the study's data into more detailed findings for each of San Diego's community planning groups, giving each community the ammunition it needs to push for more aggressive tree-planting efforts. The city has vowed to plant 100,000 trees in the next 20 years.
Potocki suspects that the city will find that tree loss will be greatest in older neighborhoods, where trees have grown too large for their locations, wreaking havoc with sidewalks and creating "a negativity toward that tree from the property owner who probably has no interest in revisiting that negativity by putting another one in."
American Forests has now studied about 40 metropolitan areas. "We're seeing some good results from it," Moll said as he headed back home. "The key thing [for city leaders] is to set a target. They're going to find that it's probably harder than they thought."Meanwhile, Potocki has advice: "Where can residents get free trees? Call 236-TREE."