My power went out soon after the Santa Ana winds began to howl around midnight last Wednesday. The next morning revealed tree debris everywhere. A large branch from a city tree smashed the back window of my wife’s car, fences collapsed, and roofing material blew off the neighbor’s garage. We had no heat or hot water, thanks to our energy-saving tankless water heater that relies on electricity to operate. We were blacked out for three-and-a-half days. The frozen fish was history. But it wasn’t all bad. It was an adventure with candlelight romance, an excuse to eat ice cream before it melted, and plenty of chit-chat with neighbors while raking leaves. We had lots of company. Last week’s Santa Ana--with 70-100 mile per hour wind gusts--left about 1.5 million other people across the Los Angeles metropolitan area in the dark too. There was extensive damage to utility distribution systems. Meteorologists ranked the wind storm as a one-in-ten-year event. I took a walk through my South Pasadena neighborhood after the winds died down last Thursday. As a “Tree City U.S.A.,” South Pasadena was one of the hardest hit communities, though it received little media play compared to the bigger city of Pasadena. It quickly became apparent that this disaster, like so many others in recent years, was caused as much by the force majeure of the people as it was by Mother Nature. Santa Ana winds have blown in these parts since prehistoric times. What’s changed in the last 100 years is that the foothill area on the southward base of the towering San Gabriel Mountains has become populated by a million people and their trees. Enamored of their beauty--as I certainly am--South Pasadena and other foothill cities have planted trees on the narrow parkways between sidewalks and curbs shared by power poles and lines. Residents have planted them in their yards. The beautiful resulting canopy, along with the old houses, gives these communities the look of Anytown U.S.A. That’s why these charming neighborhoods are constantly used to film movies and television commercials that look like they’re set in New England or the Midwest. After decades of growth, the trees people love are fully crowned and becoming senescent. And because they probably never should have been planted in these areas once dominated by sage and brush--except for trees along water courses--utilities, cities, and residents can expect future one-in-ten-year wind events to produce similar, or even greater damage. My walk through the town (where I serve on the Natural Resources & Environmental Commission, which helps administer the city’s tree ordinance) revealed some of the striking reasons the threat is likely to grow in the future. I saw: -Uprooted trees with crowns spanning 40 or 50 feet across supported by shallow, instead of deep, root systems adapted to getting their water from lawn sprinklers; -Roots trimmed to repair displaced sidewalks and roads, in effect undercutting the structures supporting trees easily 40 feet in height, or taller; -Trees assiduously trimmed by local utilities to maintain clearance around power lines, but not necessarily trimmed (including those in private yards) to eliminate dead or stressed branches or to reduce the mass of their overall crowns to keep them proportionate to their root structures. These common conditions resulted in branches or whole trees falling onto power lines. I saw within blocks a towering pine on private property--perhaps 70 or 80 feet tall--that crashed down over utility lines, appearing to snap a pole and completely cover the street, making it difficult for repair crews even to access the area with their equipment. What can be done? The urban forest should not be cleared to eliminate threats to the power distribution system when the winds blow again. Nor should people’s love of trees where they live be denied. Instead, it’s time for cities, residents, and utilities to team up to do a better job of managing the aging canopy. Southern California utilities and cities should form urban forestry partnerships--similar to existing energy efficiency partnerships. In these partnerships, cities would get some resources in exchange for better managing their urban canopies to minimize future damage to the utility distribution system. With its incentive for utilities to carry out urban forestry projects in exchange for carbon emission reduction offsets, the state’s climate protection law, AB 32, presents one good opportunity for forging such partnerships. It’s a logical nexus too. After all, global warming is supposed to produce more violent weather events, similar to the wind storm that occurred last week. It’s time to be prepared, like the Boy Scout’s motto. Auction revenue from emissions rights under AB 32 is one potential source of funding for city participation in such partnership programs. Utility rates are another source, though one that must be limited and tightly managed. Goals the partnerships should work towards include: -Getting cities to rethink what species to plant when they replace parkway trees. Unless cities have an adequate budget for tree trimming--including periodic crown thinning and reductions when there are no alternatives--it likely is best to plant replacement trees that do not tower above power lines when they mature. -Watering new trees to make sure their root structure grows deep instead of spreads at the surface. This means keeping trees destined to grow large away from lawns. Better yet, in dry Southern California it’s better to keep lawns away from trees. This will save water and energy used to pump it too. -Providing funds to cities for more staff to maintain public trees and to educate residents about what trees to plant and how to care for them on their own property. Utility tree trimming budgets also must be adequate and utilities need better on-the-ground information about potentially threatening trees throughout their sprawling territories. The time to pursue it is now while the wind storm of 2011 is fresh in the mind and the ice cream is once again frozen.
