A work group in the Black Hills is doing some math that could influence the long-term health of the Black Hills National Forest and its timber industry.
The Timber Sustainability Work Group consists of six members from the 32-member Black Hills National Forest Advisory Board.
The assignment for the work group is to study new data about the forest, and then recommend how much timber should be cut for the next five years.
“Really it boils down to a couple of variables,” said Greg Josten.
He’s a member of the work group and the state forester of South Dakota.
“Those two variables are gross growth of ponderosa pine, and mortality of ponderosa pine.”
In other words, how fast are trees growing, and how fast are they dying? One minus the other equals net growth. If logging exceeds net growth, it's not sustainable.
That’s exactly the problem right now, according to Forest Service researchers. During the past couple of decades, a mountain pine beetle epidemic and several massive wildfires drastically altered the forest. But logging continued. At the current harvest levels, researchers say the Black Hills could run out of trees suitable for logging in the next several decades.
But if logging is reduced too much, loggers and sawmills might go out of business. And that could be bad for the forest. Wildfires once did much of the work to prevent an overly dense forest, but since humans began suppressing fires, logging has been a necessary tool in forest management.
So, Josten said the work group has to find a balance.
“We need to be real careful about how we choose these figures,” he said, “not only from the standpoint of protecting our forest, but also protecting our industry.”
The group has agreed on a mortality rate of 0.26 percent. That’s the lowest rate from a range proposed by Forest Service researchers, who described 0.26 percent as “optimistic.” At the other end of the range is a mortality rate of 1.04 percent, which researchers described as “long-term conservative.”
Josten said the work group assumes the mortality rate will be relatively low for the next several years, because the mountain pine beetle infestation in the forest has subsided below the level of an epidemic.
The work group’s choice of a low mortality rate could be a win for loggers. But the group has not yet decided on a number for gross growth. And that could still influence the group’s recommendation about the amount of logging that should occur during the next five years.
The Forest Service, meanwhile, is considering whether to revise the master plan for the forest. That would affect longer-term logging rates in the Black Hills, beyond the five years covered by the work group’s recommendation.
- Seth Tupper is SDPB's business and economic development reporter.