In Defense of Trees

Let's talk trees for a moment. They're a bit like orphans or endangered species in that when people cry out to save them, there's little push-back, even if little action is ultimately taken. But in an op-ed piece in today's New York Times, one sentence amid an opus of tree-praise citing studies and data from around the nation caught our attention: "The Texas Department of Forestry has estimated that the die-off of shade trees will cost Texans hundreds of millions of dollars more for air-conditioning." Now that's something we haven't heard before.

With that, Unfair Park called Micah Pace, the regional urban forester who covers the Dallas area for the Texas Forest Service. We figured he could tell us how, exactly, trees affect air conditioning (and clarify whether that's a bogus statement), and let us know if and why we should care about trees in Dallas. Our chat is below.

The article went on to include that last year's drought killed more than five million urban shade trees in Texas, and another half-billion in state parks and forests. "We have underestimated the importance of trees," the article states plainly. We weren't aware that their importance was something in need of defense, but the tone of the piece was reminiscent of Michael Pollan's widely quoted In Defense of Food, which explains in very certain terms why people must re-evaluate what they eat and revert to actual food.

The writer credits trees with filtering and cleaning water and air, cooling the air, aiding the human immune system, lessening anxiety and depression and treating disease. Here, we should mention that the piece is written by a man named Jim Robbins, who penned an upcoming book called The Man Who Planted Trees.

Here's our chat with Pace, our local tree guru, who's less of a hugger and more of a pragmatist:

What is the day-to-day work of a regional urban forester? The regional urban forester of the Texas Forest Service works directly with municipal governments to help them increase the environmental benefits of their trees. What we do is, essentially, we look at their management plans. If they don't have one, we help them develop one. We work on inventory projects.

How does Dallas' management plan measure up to other cities in Texas? Um, well, they really don't have a public tree management plan. There's a management plan that was written for the Trinity Forest. As far as all the city trees, in the parks and along the streets, there is no current management plan, and it's something that the city really needs to consider. They're kind of a tough nut to crack ... not really the city forester or her coworkers, but it's more the leadership, the management.

Is it odd that Dallas doesn't have a management plan? Well, yeah, you would think the largest community in the region should set the standard. On the other hand, when you're as large as Dallas is, it's certainly a much larger undertaking to do a citywide tree inventory than, say, the city of Allen. It is a much larger investment of money and time and resources. But you should probably be trying to manage that important resource as effectively as possible.

How can trees affect our air-conditioning costs, as The New York Times article states? Oh, well that's just referring to the fact that trees shade our homes, so if you lose the trees we would have to run our air conditioning more to keep our homes cool. That's why every time you go to the store, you try to park beneath the tree. All that's referring to is one of the many benefits trees provide us is shade, not just that it makes us more comfortable, but that it saves us money.

That's it? They're all not only directly shading your home, but they're absorbing the energy rather than it being absorbed into the pavement itself which would then be radiated back into the atmosphere, which would keep everything much warmer. You might have heard of the concept of the urban heat island effect, and that's what that refers to. It almost creates an island effect to where the pavement is absorbing the heat from the solar energy all day long, and then at night it releases it. And that is why urban areas are so much warmer at night than the outlying rural areas.

So as far as the value ["hundreds of millions"] ... that's realistic. That's talking statewide. Again, that's just one of the many benefits that trees provide us, and it's a drastic one especially because of the economic times we're in right now.

When you connect something to money, people's ears perk up. There's a cool website you might be interested in looking at [National Tree Benefit Calculator]. What it does is it allows the user to put in their ZIP code and then list the type of tree that they have and the size of the tree, the diameter of the trunk. It will tell you an estimated value of the tree for certain environmental benefits.

[He stresses the significance of quantifying why trees are important] We all know trees are good. We get up in front of city council and we say, "Hey, save our trees," and they say, "Why do you want to do that?" And we say, "Because trees are so nice; we love them," but that only goes so far. I mean, everybody likes trees. How many people hate trees?

It's a pretty easy cause to get behind. It's so much more powerful when you say trees are good, and here's why. This is what they're worth, because money talks. There's also social benefits. Violence goes down in areas with trees. When there's trees outside in your neighborhood, you spend more time outside. You get to know your neighbors, by default. You're more willing to look out for each other and build that social bond. Also, shopping [who would have thought]. Research has shown that people will spend up to 15 percent more in a retail area where there's shade and trees.

The city of Dallas just bulldozed dozens of mature trees to make way for an extension of the Katy Trail. Is that a big deal? I realize that we live in a world where development is going to occur. I don't say don't go out and remove any trees. I mean, I live in a home. Things had to be plowed over in order to build the home, plus we needed wood with which to build the home. Trees are there to use, but the way in which we use them is the important part of the equation and we should do it sustainably. We shouldn't be removing more trees than necessary.

Do you think there's a way that the city could better utilize trees to take care of air quality issues? [If Jim's "modest proposal" of walls of greenery doesn't come to be, that is.] I think it's one of the factors in the equation. We can't plant our way out of bad air quality, I guess is what I'm saying, but it is part of it because trees do absorb pollutants and particulate matter, but trees also produce allergens. It goes both ways, and this time of year, especially people with allergies are having fits because there's pollen in the air.

There are strategies around the country that certain groups are starting to use related to strategic tree planting, and what I mean by that is analyzing those benefits that we talked about [related to air quality] ... and saying this area of the city has a heightened problem with asthma. So you say, we should be strategically planting trees that we know increase air quality. You look at a specific area's needs, and you identify specific species.

Are there any other local tree issues that may surprise people? Trees are constantly under multiple sources of stress. When you add to that record drought and record heat, which we just had, you're going to see a lot of mortality in the next coming years. We did a study recently in urban areas -- it estimates up to 10 percent of all urban trees will probably die. That's an average statewide. I would say that our area, North Texas, is the best in the state -- we've gotten a lot of rain.

You're going to continue to see those trees that were stressed struggling to come out this spring, and then hoping to survive as it starts to get hotter, and there is a possibility of trees continuing to die over the next several years. It's much like people. We always protect our young and our elderly because their immune systems are weaker. They don't have the strength to defend themselves the way healthy adults do. Trees are the same way. When they're stressed, they have less defense energy to fend off against pests and disease. They've used every source of energy they have to recover and avoid dying last year.

So if we're ever going to care about them, now is the time? Now is the time. So I guess the take-home story is this. People should be keeping track of their trees for any signs of dead in their trees. And this is mostly important from a safety perspective. Ultimately, we don't want to be hurt by our trees. If the trees are alive, and they don't see any issues with the trees, the best thing to do is continue monitoring the soil. Make sure the soil is moist ... we want to try and avoid any additional stress.

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Leslie Minora