Toxic-Free City Spaces
A quiet revolution has been taking place in our city parks and public spaces. In 2004, the City of Santa Barbara officially adopted (although the groundwork had been laid for a number of years by then) an Integrated Pest Management (IPM) program that aimed to reduce the use of toxic chemicals in the maintenance of parks and urban forests. In the past, prophylactic applications of chemical agents to control disease and pest outbreaks were performed on a regular schedule with no regard to the actual presence of pathologic elements. IPM programs typically strive to employ the least toxic materials for treating pests and diseases in the landscape, based on evidence gathered during regular monitoring of the area. Initially this might lead to some drastic changes that reject the use of poisons to contain undesirable organisms in the landscape. In other cases, it might lead to finding a substitute that is less toxic to control a problem. Since this commitment was made, the use of dangerous pesticides and herbicides has been reduced by 90 percent in city spaces. City park staff relates that the amount of the most-frequently used herbicide, Roundup, has fallen from 35 gallons to under six gallons per year. Other materials have been totally phased out.
One key to the success of the program has been the further adoption of a zonal approach to reduce not only the hazards of toxic chemical use, but the public’s exposure to them. This Pesticide Hazard and Exposure Reduction (PHAER) system attempts to identify areas of maximum exposure and eliminate or reduce, as much as possible, the use of toxic materials there and substitute more acceptable treatments in each of the zones. Compatible materials to treat pest and disease outbreaks are listed for each of the zones. Treatments are limited to those on the list and are only applied when a problem is identified of a magnitude to justify intervention. Green zones are totally benign to their human occupants; yellow zones are areas with greater pest or weed problems requiring occasional use of materials that would be excluded from the green zone; and red zones (very few and slated to be phased out) are identified as those where serious problems still require somewhat conventional solutions to gain control.
The transition hasn’t been easy and many of the ultimate goals have not yet been reached. In fact, the City is following a path that many other institutions have discovered as they pursued these same targets. It takes time and money, to identify and implement change. In many cases, it comes down to redesigning landscape features so that they can be treated differently. These modifications occur slowly and in stages. The beauty of the PHAER plan is that there are concrete timelines and transitional states on the path to success. The City has prioritized its parks, slating those with the potential for the highest exposure rates, for early action. The target date for implementation of all the desired elements of this plan is 2012.
Let’s hope that it is easier and cheaper to implement the plan than this timeline predicts, but in general, this approach does require more labor to achieve the same result that chemicals used to do with just a squirt. Take these examples: Grassy areas adjacent to a popular swimming pool have over the years become invaded by clover. No big deal, except that clover attracts bees and barefooted swimmers were at risk for annoying or, in some cases life-threatening, bee stings. The selective herbicide that had been used is now no longer employed. Instead, the turf gets a little more nitrogen to pump it up and the maintenance crew has set the lawnmower a little lower to favor the grass instead of the clover, which doesn’t have the energy to flower if it is cut close to the ground. Another example: six years ago, park staff applied a ton of worm castings to an area of Alice Keck Park Memorial Gardens that was planted with various hibiscus species. The newly rampant giant whitefly that has recently made its way north from Mexico, find these plants particularly attractive, but the organically repellant nature of plants grown with worm castings has kept them at bay all this time. Additional applications of this magic elixir have reduced spider mites on other plants at this botanical park as well as Xylosma trees in Willow Glen Park and hibiscus shrubs at De la Guerra plaza.
Weeds throughout the purview of the parks department are more likely to be controlled by mechanical means now. Besides the old reliable methods of pulling and hoeing, devices such as the aquacide weeder, which uses super-heated steam, and a propane-fueled torch, both use heat to shrivel weeds in pathways and other areas dominated by hardscape elements.
It may not be uncommon for some of us to imagine that our civic bureaucracy is responsible for the greatest violations and infringements, in ours and many other regions. In this case it just isn’t so. The vast majority of pesticide and herbicide purchases, and therefore applications, are performed by Joe Average. Homeowners use an estimated 78 million pounds of insecticides, herbicides, and fungicides per year, 50 percent more today than 20 years ago. Of the 110 children in one major urban area that were tested, 99 percent were found to have chemical traces of such products in their blood. Runoff from lawns doused with “weed and feed” fertilizers is laced with pesticides and fungicides that end up in our oceans. In our attempt to control insects in the landscape, we kill an estimated seven million birds a year.
It is just such exposure that the City is striving to reduce. If the city parks can be beautiful and healthy to visit, why shouldn’t everyone else who gardens and tends landscapes take heart and learn from their example? No reason at all. It may take a little time, but any step in the direction of creating a more natural and balanced ecosystem will contribute to the overall health of our urban area. City spaces are becoming a shining example for us to emulate in this quest.