Researchers test trees for answers

Libby Ranger District and Rocky Mountain Research Station officials are hoping to find answers among the trees during an operation that could begin any day now in an area behind Bighorn Terrace near Libby.

It all has to do with prescribed burning and the resilient nature of ponderosa pine.

“It’s a pretty good proposal from my point of view and it will reveal what happened to the root system from a lack of natural fire from the result of 90 to 100 years of fire suppression,” said Malcolm Edwards, Libby district ranger.

Research revealed that some ponderosa pine stands had a higher than expected mortality rate after prescribed fire efforts began following that century of suppression. Project officials believe the lack of fire has caused the fine roots of ponderosas to move into the upper layers of the soil and duff.

Those fine roots make up the bulk of the tree’s root biomass and its intake of nutrients. So, when fire managers reintroduced fire into the ponderosa pine stands during hazardous fuel reduction operations or to improve wildlife habitat and forage, complications surfaced.

“What they want to do is some very confined burning around the tree wells,” Edwards said. “They’ve already collected quite a bit of root materials and counting and sorting over last summer.”

Researchers found that the burning operations were killing the fine roots in the upper layers of the trees. That caused tree mortality in one to five years from the burn – an unacceptable outcome for land managers.

Researchers and district rangers plan to compare three different types of treatments during the testing – burning, raking and mixing – to see if the same results are accomplished.

“They’re trying to consume the upper one or two inches of litter layer there and not burn so hot that it destroys the roots,” Edwards said.

Bighorn Terrace’s steep features with old-growth trees sit along the north side of the Kootenai River near Libby. Reached by driving to the end of Kootenai River Road, the area features a boat launch and a popular hiking/horseback riding trail that begins at the parking area.

The study is part of an overall effort to complete research in that area. An element of controversy has surfaced in the past behind proposals there such as logging the steep landscape through the use of helicopters.

Sixty trees in the area behind Bighorn Terrace were identified to serve as test subjects. With 20 of the trees, the duff layer will be raked away. On another group of 20, the duff layers will be broken up and mixed. And with the last 20, the work will involve burning beneath each individual tree canopy.

“The idea behind the treatments is that it will cause the duff layers to dry out more quickly and retain less moisture, thus making it a more inhospitable environment for the fine roots,” the Libby Ranger District said in a release prepared by Janette Turk and Nikia Hernandez.

In other words, researchers are trying to “train” the roots to go deeper into the ground like they would have if allowed to burn every 10 to 30 years as they did before fire suppression efforts began.

The window of opportunity to complete the project may be limited. Officials said the tree treatments must occur while the roots are still dormant. Roots become active again when the soil temperature reaches approximately 40 degrees.

“It’s hard enough to get a burn window any more,” Edwards said. “When doing a project like this, you want exact temperatures and moisture so it really gets narrowed down.”

Researchers plan to begin burning, mixing and raking when the snow has melted away from the tree wells but before it is completely melted in the rest of the unit.

“It could be this next week – that would be a push – but possibly within two weeks,” Edwards said this past Friday. “I’m guessing April barring some big torrential rains or snow.”

Officials said that if the environmental parameters have not been met before the snow melts then a fireline will be constructed around each burn treatment tree. The fireline is designed to reduce any extra smoke production from the fire creeping around and it also reduces the risk of an escape.

Edwards said one of the biggest factors revolves around air quality. Burns only occur when air dispersion and weather forecasts are predicted to be favorable. Besides the issuing of a press release, signs will go up and residences in the area will be contact to be informed of the project.

“We work through the local county people with the air quality division,” Edwards said. “We will make the extra effort to monitor the smoke.”

Burning operations must comply with air quality regulations, guided and monitored by the Lincoln County Department of Environmental Health and the Montana/Idaho State Airshed Group. Forest Service officials said that because of the project’s location, some short-term smoke impacts to adjacent landowners could occur.

For those with questions or seeking more information, call Hernandez at the Libby Ranger District office, 293-7773.