In Jeffrey Donovan's neighborhood, in Portland, Oregon, there's a beautiful pagoda tree.

It's around 50 years old, and it towers above the homes on the street.

There was a little seedling brought home from Richard Nixon's inauguration, and it's been

planted opposite my house that's one tiny sapling that somebody probably carried home on a plane

with them. They put it in the ground and 50 years later it's providing this kaleidoscope of benefits.

It's just magical. It's one of more than four million trees in Portland's urban landscape.

They're beautiful to look at, but they're also a valuable resource.

What do I see when I look at a tree? Well, I still see it as a beautiful thing. You know,

I'm still technically human. But I also see something that people are willing to spend a lot of money on

to plant and maintain. Donovan is the owner of Ash and Elm, a tree consultancy. Before that, he spent

25 years working as an economist for the U.S. Forest Service. What I'm trying to do is quantify

the benefits of urban trees. There's the classic dilemma in economics. You know, if you can't

count it, it doesn't count. What I'm trying to do is count it.

So when a city government is deciding on its budget, it's not just thinking about roads and

things like that. It also thinks about the benefits that trees provide.

When you start doing cost-benefit analysis on trees, it becomes laughable.

The benefits to the city are so much higher, often orders of magnitude higher than the costs.

For the Freakonomics Radio Network, this is the economics of everyday things.

I'm Zachary Crockett.

Today, urban trees.

There are an estimated 5.5 billion trees in cities across the U.S. They line commercial corridors, parks, busy intersections, and residential streets,

and they come in all shapes, sizes, and species, maples, sweetgums, palms, furs, and pines.

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