The plan for shade in Phoenix
This is KJZZ's Morning Edition, I'm Dennis Lambert. As you've been hearing in our series "Heat Wave," temperatures here in metro Phoenix are expected to increase in the years ahead. And that has city officials taking action. As you heard Monday in Peter O'Dowd's story, the city is planting trees to increase its shade canopy. Phoenix has planted 115 trees to reduce the urban heat island effect at Civic Space Park in the downtown area, and that's where I am to discuss the plan with the city's forestry supervisor, Richard Adkins.
DENNIS LAMBERT: How extensive is this tree shade plan?
RICHARD ADKINS: Well it covers the whole city, all 520 square miles of the Phoenix area. We're trying to work with other municipalities in the Valley to extend across all political boundaries.
LAMBERT: What's the goal?
ADKINS: Well the goal is to increase the shade canopy for the whole Valley. Right now we probably sit at about 10 percent as far as vegetative shade canopy here in the Phoenix area.
LAMBERT: That would be pretty low as far as cities across the country?
ADKINS: Well for the desert southwest it's not too bad. There's been an established goal in the desert southwest for about 25 percent, so that's kind of the goal that we're angling for. It's fairly ambitious.
LAMBERT: What steps have been taken so far to reach that goal?
ADKINS: Well so far we're trying, we've set up an inventory, because first if you don't know what you have you don't know how to manage it. So we're just about completed with a complete inventory of trees that the city maintains. So that will set me up with what kind of shade canopy we do actually have, what our species mix composition is, our age distribution and our conditions so then we can manage it from there.
LAMBERT: Do you have particular kinds of trees that you're putting in?
ADKINS: Well we've just started to identify like the top 10 species and you don't want to have too many of one species, we try to limit it to about 10 percent of either one so that we can move forward with that. We try to use a lot of natives, of course, but some applications, especially down here in the urban core, you know a thorny spate of mesquite or palo verde is probably not the appropriate species.
LAMBERT: Now we're standing here in Phoenix Civic Space Park, a place that used to be a parking lot a few years ago but now is pretty green.
ADKINS: Yes, it's actually a very good example of urban infill. It's a little over three acres here. As you said, we've got 115 trees. We have some shade canopies with photovoltaic cells on top of them. By the time this matures out as far as the trees growing in about 15 years we should have about 70 percent shade cover here.
LAMBERT: But a problem with grass growing.
ADKINS: It can get that way. We have some areas that are still open for the students from ASU, you know, they can lounge in the grass and there still can be some playful activity, but yes, that is a consideration when you're talking about shade.
LAMBERT: Is the goal that you've set, is it realistic?
ADKINS: It's very optimistic. It's fairly aggressive. I feel if we have an aggressive goal that's something that people can get behind. If we don't set it high enough, perhaps people won't take it seriously and we won't get the movement and the support of the community to move forward.
LAMBERT: How do you measure what you've done?
ADKINS: By number of trees planted versus number of trees removed. We do have a lot of senescence older trees in the Valley that, you know, it is their time and they need to be removed. So we kind of weigh that in trying to get a positive on the planting versus the removal, and trying to get the right tree in the right place. That's probably one of the most important. It's more than just "let's go out and plant 100 trees." Well, let's plant 100 trees and have the resources to maintain them as well as put the resources in the right place so they can reach their genetic potential.
LAMBERT: Well, Richard, thanks for joining us.
ADKINS: It was my pleasure, you have a nice day
LAMBERT: Richard Adkins is the forestry supervisor in the City of Phoenix.