Fungus harming area trees
September 15, 2009
A fungus is suspected of harming stands of trees in the Park City mountains, a City Hall official said, overturning an assertion made recently that the cause was something else.
Brooks Robinson, a planner for City Hall and the local government’s tree expert, identified the fungus as marssonina, a condition that causes leaves to drop before they normally would. He said warm, wet weather causes the fungal spores to be put into the air. They then infect the trees.
It is unclear how many acres of trees have been infected, but Robinson said trees on between 10 and 20 acres of land downhill from Empire Pass in Deer Valley appear to be victims of the condition. He said there are trees at Park City Mountain Resort, in Thaynes Canyon and in Iron Mountain that also are suffering.
The determination comes quickly after Robinson indicated that the trees had suffered from another condition, known as sudden aspen decline. Robinson had said trees that suffer from sudden aspen decline are killed by insects. The trees become stressed through circumstances like drought and age, allowing the insects to move in, he had said.
The affected trees are "very noticeable," at Deer Valley and PCMR, Robinson said. He said the view of the aspen stands is diminished and there is a greater risk of wildfires since the trees provide fuel. Robinson said he hopes there is sufficient regeneration of the trees to make up for the losses.
The trees could be killed off if the condition returns year after year, he said.
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Robinson on Tuesday planned to visit the site with Park City Councilwoman Liza Simpson and others.
Lisa Wilson, who lives on Silver Lake Drive close to the area of the affected trees, also expected to go to the site with the officials. Wilson is pressing for information about the cause, wondering whether drain pipes might somehow be responsible.
She said people who are not aware of the affected trees would not pick them out from afar.
"Most people probably wouldn’t notice it. You walk right by," she said, explaining that there is "collateral damage" being done as well and adding, "When you point it out, it’s so obvious."
Erin Grady, a spokeswoman for Deer Valley Resort, said resort officials had noticed that trees were affected, but she was unsure when the resort became aware. She said it was not immediately determined whether the trees are on resort property. She said Deer Valley has engaged state forestry officials in discussions.
"The forest is our greatest asset," Grady said.
Leaves become infected in the early spring, and wind and rain spread the fungal spores to leaves that are just emerging.
The fungus will last through the winter in the infected leaves and twigs, and leaves that fall should be raked up and turned into compost or thrown out.
Sprinklers should not be used to water the trees, since the water spreads the fungal spores and increases the humidity.
Source: Utah State University For additional information about the fungus, visit the USU Web site, http://utahpests.usu.edu/plantdiseases/htm/ornamental/aspenspot/