Native to Asia, the emerald ash borer 20 years ago found its way to North America, where it was first spotted in Michigan. In May, Texas A&M Forest Service sounded the alarm that its monitoring traps in Dallas had for the first time caught the sucker. The beetle has arrived.
The EAB, as it is known by tree people, tunnels under the bark of every ash species and gobbles the part of the tree that moves water and nutrients up the trunk, thereby starving it. If a tree goes untreated, it will die in two to three years.
In 2015, the nonprofit Texas Trees Foundation conducted a survey of the city of Dallas’ entire tree population. It found that 13 percent—about 2 million trees—are some variety of ash. In the 6,000-acre Great Trinity Forest, what has been called the lungs of the city, the percentage is even higher, about 23 percent. We could lose all of it. Based on environmental impact, Texas Trees puts the value of the city’s ash population at $890 million.
Trees are essential to a healthy urban environment. They clean the air, reduce the heat island effect created by concrete, and help prevent flooding. Studies have shown that just looking at trees lowers people’s blood pressure and improves mood. So let’s talk about how to save them.
How to Spot Ash
Look for compound leaves, with each leaf having an odd number of leaflets. The leaflets are directly across from each other, except for the terminal leaflet at the end. Each leaflet is pointed. You’ll know there’s trouble if you see dead branches at the top of the tree, if you see leafy shoots sprouting from the trunk, or if you see splitting bark that exposes “larval galleries.”
Stop the Spread
The Texas Trees Foundation estimates there are 150,000 ash trees on city property. That’s a huge problem, as it would cost about $10 million to inoculate them all. For you personally, depending on the size of the tree, it costs $150 to $300 to protect an ash tree with an insecticide injection that lasts a few years. If you wait too long and let the beetles do their dastardly work, your only recourse is cutting down the tree. Compromised trees can come apart in unpredictable ways, putting inexperienced crews and property in peril. So work with experts. And that tree will need to be mulched on-site, because hauling ash basically serves as giving EABs an Uber ride to their next meal.