Marked for death: Owners required to remove trees with Dutch elm diseaseSeveral elm trees around Jamestown are spray-painted with orange spots. That means Dutch elm disease has taken hold in those trees.
By: Ben Rodgers, The Jamestown Sun
Several elm trees around Jamestown are spray-painted with orange spots. That means Dutch elm disease has taken hold in those trees.
So far this year 115 elms have been marked with the disease, which has wiped out thousands of trees here in the past three decades.
The good news is that number is down from this time last year when the number was 130. The mild winter and recent warm weather mean the effects have also been detected earlier.
“The symptoms develop quicker in hot, dry weather so we’re going to see more whether it’s a result of more disease or not, probably not,” said Jim Walla, forest pathologist in the plant pathology department at North Dakota State University.
A number of factors can lead to when Dutch elm shows up in trees. Some include the weather, the tree variety’s natural resistance, and removal of infected trees, Walla said.
“Usually with a lower number the first thing I think about is somebody did a good job of sanitation,” he said.
That’s why certain trees are marked in orange. The mark means the property owner has 30 days to remove the tree. If not removed the city will remove the tree and assess the cost on the owner’s property taxes.
Only trees that line city streets and boulevards that are a hazard because of DED are tagged.
Dutch elm disease is a fungus that latches onto borer beetles. When the female beetle bores into an elm it lays its eggs and they hatch outward, Jamestown City Forester Vern Quam said. This is why elms that show the disease show it on the outer parts of the trees first.
According to Quam, a diseased tree has the potential to produce 100,000 borer beetles that could carry the disease. Of those, 25,000 have the chance to infect other elm trees in the area as the other beetles will likely die or not carry DED.
Quam estimates there are 4,000 elms left in Jamestown, along streets, in yards or near water bodies.
“A lot of the spread we see in town comes from this, the delay of getting rid of some major trees,” he said.
Another main way the disease spreads when elm firewood is not debarked as the bark beetle that carries the disease resides under the bark.
“If a homeowner finds a dead elm tree and cuts it down and brings the wood into town to burn in his fire place, and if that would was infected with DED, that can result in a big flare up of Dutch elm disease in that community where the wood was brought into,” Walla said.
Certain weaknesses can also leave elms more susceptible to DED.
Most elms have some form of wet wood, which causes the tree to expand from the inside out at certain spots. Quam said most trees can live with that, but older ones with wet wood are more likely to contract DED.
A few elm trees were hit by lightning last year and that weakened them, which allowed DED to move faster. Drought stress can also take a toll along with native elm wilts, which cause leaves to be flaccid and droopy.
The warm early weather also allowed Quam more time to find infected trees. He started in May and plans to continue through the summer.
“I expected it. I just didn’t suspect it in the middle of May — the middle of June perhaps,” Quam said.
Similar conditions have led to the same results in Fargo, according to Walla.
“It’s my understanding that it’s also slightly down, but I’m hearing that they’re finding it’s developing a little more severely this year and there contributing that to the drought,” Walla said.
While DED moves fast Walla expects area elms could get infected late in the season and the disease’s effects could go unnoticed until next spring. An indicator could be an 8- to 10-foot die-off spread in the upper branches.
“Moving 8 to 10 feet is still fast moving for a tree disease, but a lot of times it’s difficult to detect,” he said.
Anyone that suspects Dutch elm disease should contact a forester or a county extension agent.
Sun reporter Ben Rodgers can be reached at 701-952-8455 or by email at email@example.com