There were still green needles in the ponderosa pine's canopy when the fire finally passed by.
But then the beetles came.
No. 52 fought back.
The battlefields are marked in orange pitch turned hard with time along the pine's blackened bark. The tree tried to repel the invaders - pushing them backward with a dose of tar-like pitch. But in the end, the fire-weakened tree was overwhelmed.
Two years later, it died.
In 2005, the dead tree snapped five feet above the ground and landed with a heavy thud onto the forest's floor.
Brian Long saw the struggle unfold.
On this sunny October afternoon, the Montana Department of Natural Resources and Conservation technical services section supervisor replaced the shiny aluminum tag on No. 52's stump.
A bright yellow “M” is painted on its blackened bark.
“The beetles were probably drawn to this tree due to the large amount of damage it sustained in the fire,” Long said. “This tree's ability to survive a beetle attack was significantly reduced by the fire damage.“
No. 52 is one of 131 trees that Long and other state researchers have been tracking since 2000 in an effort to learn about how ponderosa pine and Douglas fir survive the impacts of wildfire.
In August 2000, about 377,000 acres of state, federal and private forest lands burned in the Bitterroot Valley. The fires scorched about 8,000 acres of the Sula State Forest.
The wildfires had barely cooled before the state began making plans to salvage log burned areas in the Sula Forest, hoping to recoup some of the value of the wood.
At the time, there was considerable debate among foresters and specialists over which trees were likely to survive and which would die. Because of that uncertainty - and strong public opinion - the state chose not to harvest any trees with green needles.
Instead, researchers established the mortality study.
They sought out areas where the fire had burned at different intensities. And then they carefully recorded the physical damage that occurred to each tree within the 11 study plots.
Each tree was marked with a yellow “M” and tagged with numbers.
Every year hence, except one, the researchers returned to see how the trees had fared.
“We knew that a certain number of trees with green needles would survive,” Long said. “And there were people concerned that we might cut too many trees that would live. There wasn't really any good research that we could go on.”
Operating under a mandate to manage for the long-term health of the forest, as well as to bring in revenue for schools and other public entities, Long said it's important for state foresters to understand which trees will live and which won't following a wildfire.
“We don't want to have to go in a second time to harvest more dead trees,” he said. “We want to reduce the amount of disturbance on any individual site.”
And so Long and others watched and recorded the trees' progress over the years.
They learned that the fate of most of trees in the study was determined in the first four years. By the end of 2004, 62 percent of all the trees in the study were dead. Another 3 percent died by 2007.
Not surprisingly, Douglas fir fared much worse than the more fire-resistant ponderosa pine.
Less than a quarter of Douglas fir trees survived the impacts of the 2000 fires. Nearly half of the ponderosa pine lived.
“We knew that ponderosa pine were going to do better, going into this study,” Long said. “The pine were more resistant to fire than fir. That's a fact that all textbooks will tell you.”
The intensity of the fire played a dramatic role in the trees' ability to survive.
In places where the fire burned with high intensity, 90 percent of all the trees died. In other areas, where the fire crept along the ground and torched a tree here and there, close to 75 percent of the trees in the study survived.
The fir were more susceptible to damage to their root collars. A high-intensity fire killed nearly every Douglas fir, while close to 20 percent of the ponderosa pine survived.
“We've found that fire intensity is something our foresters need to be aware of,” Long said. “The relationship of the amount of heat occurring in an area makes a big difference in how many trees will live.”
The researchers also found that mountain pine bark beetles were deadly on fire-weakened ponderosa pine.
More than 70 percent of the pines that died were infested by pine beetles.
“Trees weakened by fire can attract large numbers of beetles,” he said. “We found that when trees are already stressed, they often don't survive a beetle attack.”
Long and others took the information gleaned from the study to develop guidelines state foresters are now using to determine which trees will be cut and which left following fires on state lands across Montana.
Plans call for developing the same type of studies around Seeley Lake and Rock Creek following this summer's wildfires.
“We want to see if these same trends continue to happen in other locations,” he said. “We're going to continue to learn from this study we have in Sula as well.
“What we've learned so far is giving our foresters a much better idea of what trees are likely to survive and which aren't,” Long said. “That's going to be important for us in the future. Š From the way things seem to be headed, it looks like we're going to be salvage logging almost every year for some time to come.”
Reporter Perry Backus can be reached at 1-800-366-7186 or at pbackus@missoulian.com.
|
 |
 |
Add your comment now! Write your comment in the form below.
(Email address is for verification only. If you'd like to email a story, look for the link above)