An Old Growth Goal
4:00 am
Thu September 5, 2013

Science and Social Values in the Van Vliets

In the far reaches of Northern Wisconsin, a remote stand of old growth hemlocks has been cast into the public eye.  The 400-acre Van Vliet Hemlocks are known to many as one of the few old growth stands left in Wisconsin.  Over the past century forest managers have mostly taken a hands-off approach.  But a proposal from the state Department of Natural Resources to log part of the area has community members up in arms.

Even small diameter hemlocks can be hundreds of years old.
Credit Natalie Jablonski / WXPR News

With the sun streaming down through the old growth trees on a quiet summer day, it’s easy to understand why the Van Vliet forest inspires words like “jewel” and “treasure”. Slender hemlocks tower over a springy carpet of ferns and brown needles. 

“You can’t age a hemlock by its size.”

John Bates is a writer and naturalist who has led dozen of hikes through this forest. 

“Some of these skinny hemlocks over here are probably just as old as these larger hemlocks beside us.  Hemlocks grow very, very slow in the shade.  So you can have not uncommonly a 2-inch diameter hemlock that’s 100 years old, a 3 inch diameter hemlock that’s 200 years old.”

Even 400 hundred years is not uncommon for a hemlock’s lifespan.  

Writer and naturalist John Bates thinks the entire Van Vliet parcel should be left to its own devices.
Credit Natalie Jablonski / WXPR News

And at one point the trees nearly dominated the landscape in northern Wisconsin.  But they all but disappeared in the timber boom around the turn of the twentieth century.  Hemlocks now make up about two percent of Wisconsin’s forest.

“Then we have this beautiful yellow birch here.  Most people have never seen a yellow birch that looks like that.  It changes its face as it were – the bark changes, just as when we get old we get a little craggy looking, the yellow birch get pretty craggy as well.”

Old growth stands like this one are rare.  It’s for that reason that the Department of Natural Resources  wants to designate the parcel as a State Natural Area…a conservation status for sites relatively unchanged by human activity.  But along with that designation, the agency has a plan upsetting to many in the community: to log part of the Van Vliet forest.  

“If we didn’t manage it, it would succeed naturally, and slowly.”

Steve Petersen is State Forest Superintendent for the Northern Highland American Legion State Forest.  He’s talking about a 70 acre section of the Van Vliet forest that looks very different from the rest.  Instead of big hemlocks, it’s mostly smaller, younger maples. 

“We believe that through management we can have a better influence over what its future condition could be.  Hemlock hardwoods, big yellow birch, big sugar maple big hemlock.  Different sizes and different ages.  And it might seem kind of counterintuitive that we can manage to that kind of complexity, but we really can.”

That’s true, according to one scientist from the University of Wisconsin Madison.  

Low-lying areas in the Van Vliet forest form ephemeral pools in the spring.
Credit Natalie Jablonski / WXPR News

Craig Lorimer is on the forefront of research on how management techniques can speed up the process of old growth development.  His study shows thinning 20-30 percent of a young forest can nearly double the growth rate of remaining trees.

“We can’t speed up the aging of trees, that’s for sure.  All we can do is speed up the structural characteristics of old growth forests.  We can’t speed up the internal decay of trees…But there are some things you can accelerate, the development of large trees…and the complex layering of the forest.”

Lorimer says deciding what to do with a particular forest depends on the specifics of the site.  But as a general concept, he says putting a forest on the fast track to old growth is valid, and maybe even necessary. 

“we’ve got a lot of this younger second growth forest, and a real paucity of old growth forest.  And little by little the old growth does get destroyed by natural disturbances.  And so come 50 years and we might not have any of it left.”

But the public doesn’t necessarily buy that argument.  Community members have responded to the DNR’s active management proposal with a flood of letters and phone calls. 

“The public up here is totally in favor of maintaining this little part of Presque Isle township as not being logged.”

That’s Tom Olson, president of the nonprofit Friends of the Van Vliet Hemlocks.  Olson isn’t satisfied by the level of detail the DNR has provided in its proposal, and he’s worried that logging activity could impact the public trail network that Friends of the Van Vliet has spent countless hours constructing.  But even more than that, Olson thinks managers should respect the integrity of the Van Vliet parcel. 

 Olson: “We have no argument with logging lands that are expected to be timber lands, on a reasonable basis in the northern highland state forest.  I support the management team that’s doing that, I think they’re doing a wonderful job.  It’s just this parcel that we’re concerned about.”

Bates: “And again it’s only those 70 acres, it’s not the whole stand.  I fully understand that.  Life won’t come to an end either way, whether it’s managed or unmanaged.  It’s a tiny aspect of that site.  But again state natural areas are intended to provide natural functioning first and foremost, and that’s what we study on state natural areas.”

Naturalist John Bates says another scientific perspective would argue letting the maple stand evolve on its own is actually more valuable, because it provides researchers with data on how forests naturally develop. 

“Ultimately in many ways it’s not a scientific judgment as much as it’s a value judgment.  Because it can be a toss-up between how one might approach it.  And those are hard.”

The DNR says it will be considering public concern when it makes that decision in October.