Dallas-area environmentalists warn invasive beetle could be latest threat to Trinity Forest

Steve Houser was the guy to rail against felling trees for decades. If anyone could be called a “tree keeper,” it would be Houser, a certified arborist in the Dallas area for over 40 years and a board member of the Trinity Coalition, a nature-related nonprofit based in Dallas.

A dreaded beetle, the Emerald Ash Borer, has been found in north Texas and it is only a matter of time, maybe months, before it is discovered in Dallas, Houser said. The insect, no larger than a dime, has destroyed hundreds of thousands of ash trees in the United States since it was discovered in Michigan 18 years ago.

In Dallas, the beetle has the potential to seriously damage the Great Trinity Forest, considered the largest urban hardwood forest in America and nearly six times the size of White Rock Lake. About 40% of the trees in Trinity Forest are ash trees and studies have shown that they are therefore susceptible to the beetle.

Steve Houser, a certified arborist, looks at an ash tree in Reverchon Park in Dallas on Wednesday, January 6, 2021. Houser draws attention to the Emerald Ash Borer, who kills ash trees and was recently confirmed in Fort Worth and Denton. Research shows it could be in Dallas soon. (Juan Figueroa / employee photographer)

Houser, whose career included high-profile battles to keep trees from being felled for development, thinks differently this time around.

“I’m the one who wouldn’t recommend removing healthy trees. I’ve spent way too much time saving trees, ”said Houser, a longtime Trinity Forest attorney.

“But just sitting by and watching them die is the worst thing we can do,” he said.

Slow pest

The emerald ash drill (EAB), native to Asia, was unknown to the United States until 2002 when it was discovered in southeast Michigan. The invasive species has since spread to 35 states.

In 2016, the insect was first discovered in Texas near Caddo Lake in Harrison County and then spread to adjacent counties in East Texas. In 2018, the insect was discovered near Eagle Mountain Lake, 150 miles away.

Most likely, the EAB beetles found in Tarrant County were not from East Texas. The insects, which can travel up to 12 miles per year, couldn’t have moved as fast, said Mike Sills, an urban forestry expert with the Texas A&M Forest Service. Sills believes it is more likely that the beetles were brought to the area with freshly cut firewood or timber from states to the north.

Since 2012, the Texas Forest Service in Texas has been looking for EAB and using traps to track down the pest. Since it was first discovered in Harrison County nearly five years ago, the Forest Service has found more EAB beetles in Cass, Marion, and Bowie Counties of East Texas and Denton County of North Texas.

The traps are set in late winter and early spring when the insect is most active. “We have been monitoring the situation here,” said Sills. “It hasn’t been found in Dallas yet.”

How ash trees die

Adult EAB beetles lay their larvae in the bark of the ash trees. The larvae then feed under the bark. “They will starve the tree by not allowing any water or food to get to the roots,” Sills said.

After the infestation, the beetles kill an ash within two to three years, according to an information sheet from the Texas Forest Service.

Homeowners looking to save their ash trees should discuss their options with a certified arborist and weigh the cost of preventive treatments versus removal, Sills said. There are insecticides that can be applied before the beetle is discovered in a community.

“We recommend treating trees only within 15 miles of an active sighting,” Sills said.

The Trinity Forest

While homeowners can save individual trees, the challenge for Dallas, who owns the Trinity Forest, is very different.

The urban forest follows the Trinity River about 11 miles from the Santa Fe Trestle Trail near Corinth Street and Riverfront Boulevard on the southeastern edge of downtown Dallas until just past Interstate 20.

The Great Trinity Forest as seen from the sky in 2013.The Great Trinity Forest as seen from the sky in 2013.(GJ McCarthy / employee photographer)

On February 1, the city’s Environment and Sustainability Committee will hold a briefing on the threat posed by the emerald ash drill.

One of the problems is figuring out how many ash trees there are in the city.

“That’s honestly one of the big challenges,” said Bret Johnson, certified arborist for the city of Dallas.

Estimates that 40 percent of Trinity Forest are ash trees are based on previous studies. But that doesn’t explain anywhere else in town – including parks, Johnson said.

Plan needed

Councilor Chad West, vice chairman of the committee, saw the need for a management plan to address the threat.

West sees three options towards the city. The first is to do nothing and let a huge strip of forest die within three years of the infestation.

But Johnson and other tree experts said thousands of fallen trees pose a major fire hazard. A lightning strike or human negligence can cause wildfire.

A forest fire could pose a health threat to densely populated areas near South Dallas, downtown, and Oak Cliff.

“When we’ve had a fire in Trinity Forest, especially in the summer, all the smoke goes through downtown Dallas,” said Houser. “At that point, people will be very excited about it and ask why no one told us about it and why no one did anything about it.”

Large-scale use of pesticides to save the trees would be both costly and environmentally harmful. “When you’re talking about thousands of trees, it’s just not realistic or feasible to treat them with an insecticide,” said Houser.

FILE - This file photo dated Oct. 26, 2011 highlights the markings of larvae of emerald ash diggers on an ash tree in Saugerties, NY.  First found in Michigan in 2002, the emerald ash drill is now in 30 states and has killed hundreds of millions of ash trees.  Forests from New England to the west coast are at risk from invasive pests that defoliate and kill trees.  Scientists said the pests are causing some tree species to become extinct, causing billions in damage every year.  (AP Photo / Mike Groll, File)FILE – This file photo dated Oct. 26, 2011 highlights the markings of larvae of emerald ash diggers on an ash tree in Saugerties, NY. First found in Michigan in 2002, the emerald ash drill is now in 30 states and has killed hundreds of millions of ash trees. Forests from New England to the west coast are at risk from invasive pests that defoliate and kill trees. Scientists said the pests are causing some tree species to become extinct, causing billions in damage every year. (AP Photo / Mike Groll, File)(Mike Groll / AP)

The only sensible option, say West and Houser, would be selective felling of the ash trees. That would make it possible to sell the wood to fund the replanting of new trees, Houser said. Decaying trees also release more carbon, which adds to air pollution, Houser said.

“There is no wand solution,” West said. “We must consider the path of least destruction.”

The priority is to work out an action plan while there is still time, he said. City officials will investigate how other cities have dealt with the infestation.

“We’re not the first to invent the wheel here,” he said.

The city needs to be briefed on the issue quickly so that action can be taken, Houser said, conveying a sense of urgency.

“It’s a devastating pest,” he said. “That’s why I’m pushing for a management plan.”

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