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Ponderosa pines in Bigfork suffering from a diplodia fungus outbreak

Bigfork Diplodia Outbreak Screen Shot 2022-09-04 at 12.41.21 PM.png
Posted at 1:22 PM, Sep 04, 2022
and last updated 2022-09-05 10:16:04-04

BIGFORK - If you’ve been in the area from Woods Bay to Echo Lake over the past few weeks, you may have noticed that the ponderosa pine trees have developed red or brown foliage.

After numerous calls from concerned citizens and landowners, the Montana Department of Natural Resources and Conservation (DNRC) and the U.S. Forest Service (USFS) did some investigating and found an interesting phenomenon had occurred.

“July 9th was a day that I'll never forget. It was a storm that probably did more damage than I've ever seen. The devastation that ripped through the trees, the deciduous trees, the pinecones, the needles that were everywhere. It was a three-day cleanup," said Eagle Bend Golf Club Superintendent Shane Bigelow.

The massive hailstorm that hit the area on July 9th caused damage to the ponderosa pine trees. Combined with the hot dry summer, activated a diplodia, or shoot blight fungus infection in the ponderosa pines.

Severe weather events put stress on trees, allowing fungi that are always present in forests to attack.

“We aren't sure how many of these trees can survive the outbreak but the fungus spores are on the pine cones, there's evidence of it and it's been verified by our pathologist in Missoula," said DNRC Forester Holly McKenzie.

But the diplodia outbreak isn’t the only thing people need to worry about. “So we're expecting that if we don't see severe mortality in the pines, people will want to monitor for bark beetles the next few years," said McKenzie.

Although diplodia is only found in ponderosa pines, there is concern that the bark beetles will attack the vulnerable ponderosas and move on to other species of pine. Bark beetles burrow through and colonize under the thick outer layer of bark causing widespread mortality in affected pine trees.

“You know, watch for symptoms of bark beetle attacks because as bark beetles regenerate and spread they'll move to other trees in the area that maybe were not impacted by the diplopia or the hailstorm in the first place but might take advantage of other stressed trees in the area. So it's something that will probably be here with us for a few years and that is unfortunate for this little part of Bigfork down here," said McKenzie.

The real fate of the ponderosas will probably not be known until the spring of next year. Citizens in the affected area are concerned that these trees will die, leaving a scar on the community.

“I feel very sad. Bigfork will not be Bigfork without these ponderosa pines and all the other trees. I mean, that's what feeds a lot of our people here on vacation and whatnot and those of us who live here, we live for trees, you know? We just want them to be healthy and I hope something can be done," said Judy Kennedy, a resident of Bigfork.

The USFS is asking people to monitor the trees and leave them standing until the spring to see if they will recuperate and survive. People who have affected trees on their property and are not sure what is causing the trauma, contact the USFS or the DNRC to have a forestry consultant come to inspect the trees.

The symptoms of a bark beetle outbreak and diplodia infection are very similar. In both cases, the needles will brown. It will be extremely important for people to monitor for bark beetles in the already brown, infected trees.

“The hard part with the bark beetle is going to be identifying bark beetle when the trees have already browned up on the tops and along the bowl of the tree. So what do you look for if you can't find brown needles and the needles are already brown? How do you know if you have bark beetle in there as well?" said McKenzie

"The things to watch out for would be some little bit of pitch streaming from upper portions of the tree as well as some boring holes and sawdust in the bark. But it's going to be a little more of a challenge to verify that so talking to a forester or getting a forestry consultant in if you have a few acres of these trees that maybe need to be salvaged or even call your service forester and other specialists," said McKenzie continued. "They should be able to verify or point to bark beetle versus the diplodia."

To verify if the tree has a diplodia infection there may be black spots on the brown needles. “Or, people could look around the base of the pine cones, the actual ponderosa cones themselves to look for black spots and fungal spores that are active," said McKenzie.

People can contact the DNRC or the USFS for more information and additional help distinguishing between bark beetle damage and diplodia infection.