This week California celebrates Arbor Day, a nationwide campaign to spruce up the country by releafing its streets, adding shade overhead, and injecting a little arboreal calm into our busy lives. So it is probably not the best time to take a poke at Los Angeles Mayor Antonio Villaraigosa's Million Tree Initiative. Then again, there's really not a better moment to examine its unchecked presumption that trees will save us. Can this, should this dry place support all that projected growth?
Launched in 2006 with considerable éclat, the program got a quick rhetorical jump-start: "I am committed to making Los Angeles the largest, cleanest and greenest city in the United States," the new mayor declared shortly after his first election. "Today, only 18.09 percent of Los Angeles is covered with trees. I ask all angelenos to work with me and engage in this effort to grow our canopy cover for the future by planting one million trees today."
Villaraigosa's ambition was heartfelt, his gesture of no little symbolic import: by this policy he expected to make a definitive statement about his environmental convictions and the priority they would hold during his mayoralty.
His bold aspiration even had some eye-popping scientific data (.pdf) to support it. Urban-forest researchers at the U. S. Forest Service, for instance, suggested in 2007 that planting one million trees would reduce storm-water runoff, decrease the city's carbon footprint, cut the use of air conditioning (and thus of electricity), and make for a much more beautiful community, with all the attendant psychological and health benefits that would flow from an enhanced and expanded tree canopy. Over 35 years, the per-tree savings would range from $1,100 to $1,600, an estimate that totaled a staggering $1.1 to $1.6 billion. What politician could turn his or her back on such a rate of return?
Perhaps this one should have. Or at least Villaraigosa might have paid a bit more attention to the concerns that even local tree activists raised about the program's feasibility. Such as the worry that it would prove impossible to calculate the real--as opposed to the potential--payback for planting such an astounding number of trees. How, some asked, would the city determine if the many seedlings it freely handed out at parks, educational fairs, and schools actually made it into the ground? And if they were planted, how would anyone know whether they survived? The whole scheme resembled a shell game.
Another gamble involved the amount of water needed to nourish so many trees to maturity. Nowhere in the Forest Service's calculations or the city's analyses was there any mention of this potential complication, which is a bit surprising in a city whose annual rainfall is less than 15 inches, which annually imports tens of thousands of acre-feet of water to sustain itself, and whose drawn down of northern California streamflow is constantly threatened due to endangered-species concerns in the Sacramento Delta. To green up the city would require a good deal more white gold, making Los Angeles ever more complicit in state-wide environmental degradation.
There was one aspect of the Villaraigosa campaign that seemed beyond reproach. As proposed, it would correct an environmental injustice reflected in the distribution of trees across Los Angeles. The Forest Service's analysis of the city's then-current tree canopy had revealed that such wealthy enclaves as Bel Air, and the hills of Beverly and Hollywood, had a thicket of woods that shaded their swimming pools and cooled off their movie stars. But head south down Robertson, La Cienega, or Fairfax, and even before you roll beneath the thunderous Santa Monica Freeway the trees begin to thin out and the sun's heat intensifies. As the federal researchers noted, the percentage of canopy (what they dub TCC), when set within city-council districts, "varied from lows of 7 to 9% in districts 9 and 15 (Perry and Hahn) to a high of 37% in CD 5 (Weiss)." This led them to conclude that canopy "was strongly related to land use. As expected, low-density residential land uses had the highest TCC citywide (31%), while industrial and commercial land uses had lowest TCC (3-6%)."
The same troubling results emerged when comparing neighborhood councils: the density of the existing canopy was vastly different between Bel Air-Beverly Crest (53%), Arroyo Seco (46%), and Studio City (42%) and those neighborhood councils with the lowest TCC, including Downtown Los Angeles (3%), Wilmington (5%), and Historic Cultural and Macarthur (6%). The poorer the community or the more industrialized the landscape, the fewer the trees.
Righting that wrong, by greening the city's most shade-starved and concrete-hardened districts, makes good sense and good politics. Yet it also depends on an assumption that the wide-scale planting of trees throughout Los Angeles is ecologically sound and sustainable. This query is peculiarly appropriate during Arbor Day, because for more than 120 years the Arbor Day Foundation has promoted tree planting--everywhere and anywhere--as an unalloyed social good and environmental benefit.
The upshot, though, has been a homogeneous landscape: because trees are beneficial, activists have asserted, they should be given root even in terrain that does not naturally support them. It is telling in this regard that Arbor Day got its start in a (largely) treeless Nebraska; telling, too, that its guiding genius, J. Sterling Morton, had grown up in the humid east. Morton's tireless advocacy was designed in part to turn the prairie into a well-wooded land. Call it agro-imperialism.
Anglo-Americans unfurled this same imperial banner when they poured into late 19th-century Los Angeles, this land of little rain. Its coastal-sagebrush ecosystems, so spare and sparse, seemed alien to those who had come of age in the Mid-West pineries, lush southern forests, or among the hardwoods of New England. Because there is no place like home, they immediately set about domesticating the local environs: they dug countless holes in the rocky soil, inserted and patted down by the thousands seeds and seedlings from their natal homes, and watered the young growth with abandon.
As they planted these trees, ornamental in name and function, in every town that sprouted up along the rail and trolley lines that crisscrossed the valley floors, these migrants were Americanizing Southern California. Each tree became a symbol of the powerful civilization that had forcibly supplanted the older communities, whether native, Spanish, or Mexican, and that had managed this landscape with a lighter hand. Environmental transformation thus was linked to political domination. Whites liked green streets; shade marked the arrival of the American Colossus.
This troubling history also colors early 21st-century programs like as LA's Million Tree initiative. True, its ideological arguments are framed in contemporary scientific discourse, for example that these many trees will sequester so many tons of carbon in the fight against climate change. Yet the idea that we must increase the region's level of canopy cover flies in the face of more compelling scientific constraints--the levels of heat and precipitation, quality of soils, and amount of light--that determine a tree's capacity to grow. By ignoring these technical details, the Villaraigosa program evokes an earlier generation's deliberate rejection of environmental realities in favor of imported cultural norms.
Perhaps this willful disregard is inevitable in a city whose official tree is the coast coral, an introduced species from southeastern Africa. But, really, we should know better.
Char Miller is the Director and W.M. Keck Professor of Environmental Analysis at Pomona College, and editor of the just-published "Cities and Nature in the American West." He comments every Wednesday at 2 p.m. on environmental issues.
The coral tree image used on this post is by Flickr user Floyd B. Bariscale of Big Orange Landmarks and was used under a Creative Commons License. The image of J Sterling Morton is from Wikipedia and is under public domain.