California's Capital Sees Big Benefits in More Trees

Sacramento, Calif., claims more trees per capita than any other city in the world. It's now embarking on a 40-year plan to double the city's tree canopy. The potential benefits of urban forests include lower temperatures, improved air quality and — perhaps surprisingly— a calming effect on drivers. KQED's Jason Margolis reports.

MADELEINE BRAND, host:

This is DAY TO DAY. I'm Madeleine Brand.

Sacramento, California. It's not widely known for much aside from being the state capital. Well, now it's being compared to another capital: Paris, France. By some estimates, Sacramento has more trees per capita than any other city except Paris, and it's getting even greener. The city wants to double its urban tree canopy. Jason Margolis of member station KQED reports.

JASON MARGOLIS reporting:

Strolling through midtown Sacramento, great magnolias, English elms and sycamores line the streets, providing shade for entire city blocks. Their leafy branches arch like the ceiling of a grand cathedral, enveloping the street below.

Councilman RAY TRETHAWAY (Sacramento, California, City Council; Head, Sacramento Tree Foundation): We're walking beneath now the valley oak. The native tree grows a hundred feet tall and such.

MARGOLIS: Sacramento City Council member Ray Trethaway heads the nonprofit Sacramento Tree Foundation, which is widely considered the most prolific urban tree-planting organization in the country. He's spearheading a new project called The Greenprint Initiative. The goal is to double the tree canopy in Sacramento and five neighboring counties over the next 40 years. According to a recent study by NASA, these trees can lower urban ground temperatures here by 36 degrees on a hot day, making the Sacramento summers actually quite pleasant.

Councilman TRETHAWAY: We always meet people in Sacramento that still do not have air conditioning on 110-degree days because they live beneath the canopy of the trees.

MARGOLIS: And the more trees you plant, the more benefits. NASA scientists say if Sacramento doubled its tree canopy, it would improve air quality and cut the number of smoggy days in half. But Trethaway says getting these perks means planting big trees.

Councilman TRETHAWAY: We're underneath two pear trees right now that don't give a lick of shade compared to the large-canopy trees that we have been strolling under. And so this would not be the choose of trees in the future.

MARGOLIS: According to the US Forest Service, a large-canopy tree will add $48 in benefits, saved in lower electricity use and improved air quality. A small tree, by comparison, saves only a dollar. But there are challenges to building a forest amidst a city. Trethaway points to a young sapling about five feet tall.

Councilman TRETHAWAY: Anything smaller in an urban setting--boy, they can get run over by skateboards, eaten up by dogs, run over by cars or lawn mowers and such. So you have to start with a pretty good size tree. Most trees are normally two to three years old when you put them in the ground.

MARGOLIS: And urban forests need regular maintenance, pruning and watering. It's crucial that young trees are watered regularly the first three years. After that, the expansive root system helps a tree find water on its own. All this is expensive. Local governments and the US Forest Service are helping pay for The Green Print Initiative, but it won't be nearly enough. Trethaway says the only way these trees will get planted and nurtured is through a massive volunteer and community-education effort. So his tree foundation is organizing 250 communities into what he's calling NeighborWoods.

Councilman TRETHAWAY: It's an investment in the future. You--nobody plants a tree for today or for personal gratification. It's all about tomorrow.

MARGOLIS: And while Sacramento may have the most impressive program in the nation, smaller-scale ventures are being launched across the country, from Los Angeles to Minneapolis to New York City. For NPR News, I'm Jason Margolis in Sacramento.

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