Is biomass boom an environmental bust? (WI)

Ashland Daily Press
October 28, 2008
By Chad Daily

Traditional timber harvesting focused on extracting the trunks and left the messy tops and branches, and some unmerchantable or downed logs behind in the forest or on the sawmill floor.

For decades, large-scale harvesting of biomass just wasn't profitable, and the benefits to soil and wildlife kept Mother Nature from complaining. Which is why, as pellet plants sprout up across the northwoods of the Midwest and utility companies see a power-generating product amidst the slash, Wisconsin seeks to encourage the economic potential of biomass without harvesting itself out of commission.

The state Department of Natural Resources (DNR), along with the Wisconsin Council on Forestry, is working on harvesting guidelines that aim to provide balance through general recommendations and site-specific provisions for harvesting biomass.

Government and industry officials and environmentalists all say a healthy forest is for the benefit of all. Yet opinions across the state differ on how much biomass can be harvested.

"Can the sites really sustain the spectrum of values that really are part of the sustainable forestry equation; sustainable forestry being everything from aesthetics to biological diversity to protection of water quality, soil nutrient availability and long-term fertility, and forest products," said Darrell Zastrow, bureau director of the Wisconsin Department of Natural Resources' (DNR) Office of Forest Sciences. "That's the package we're looking for from an ecological, social and economic standpoint."

The DNR, along with the Wisconsin Council on Forestry, is working on harvesting guidelines to provide general recommendations and site-specific provisions for harvesting biomass.

With increased harvesting of biomass there is the potential for dueling economic interests over the resource — increased pressure on the state's pulp and paper industry for feedstock from pellet and power plants being one conceivable example. But its use raises ecological concerns as well.

Biomass is a vital component of the forest ecosystem that, if removed in large quantities and not allowed to replenish, could within a few generations deplete resources needed for future generations or even cause a biological collapse of the forest, said Charly Ray, executive director of the Living Forest Cooperative in Ashland.

"You can't just shampoo, rinse and repeat as desired on the ecosystem and expect that it's going to respond the same way forever; it just doesn't," he said. "That's one of the basic rules of ecology."

Dave Zaber, vice president of the Madison-based Habitat Education Center, said large extractions of biomass haven't occurred since the first wave of deforestation in the country's history. It's never really been allowed to restock, Zaber said, which is why he dubbed the biomass craze the next step of the "boom and bust ideas."

And David Mladenoff, Beers-Bascom professor of conservation at UW-Madison and member of the committee drafting the harvest guidelines, said a large body of research shows more, not less, of at least the downed wood should be left in place.

"The research of forest ecology pretty much for the last 20 years has really shown that our forests are in a deficit in terms of decomposing wood for several different reasons," he said. "It's pretty hard after finding out for the last couple of decades that we need to leave more wood in the forest, it's hard to see how we can take more out."

Zastrow also said that the forests may have hit their limit.

"I get the general feel that the existing systems aren't capable of taking it all," he said, but added that some areas may adapt to more frequent harvesting of biomass.

Terry Mace, a forest resource analyst for the DNR, agreed and said the agency has been surprised before about the quick response in growth when additional wood and biomass is removed from the forest.

Mace said the state has set a goal of not harvesting more than 75 percent of the annual growth across all land, including the Chequamegon-Nicolet National Forest.

Although he said that benchmark was arbitrarily chosen, harvests of the growth or base stock have not topped 70 percent and it's usually kept in the low 60-percent range. But even when the envelope is pushed, nature seems to push back, he said.

"We've been adding to our forest stock, and our forests historically in my career; we get close to what we think our forests can sustain and I'll be danged, the little critters will grow better and we have more growth than we expected," he said.

Friend of soil and wildlife

The downed logs, branches and leaves that compose biomass have a two-fold benefit of enriching the soil with nutrients and providing habitat for certain wildlife species.

While harvesting must take into account not only commercial and recreational demands, addressing ecological needs means also adjusting for different soil types and the various trees that grow in those soils, Zastrow said, and the result would determine how much biomass is produced and how much can be extracted, he said.

When it comes to sites with hardwood like aspen, there's a question mark about whether managing stands in shorter rotations depletes certain minerals like calcium, said Ray of the Living Forest Cooperative.

Mladenoff said calcium deficiency is also a concern among softwoods like red pine.

"Even on the soils that are not the poorest, but they're still pretty sandy. The data pretty much shows if you go a couple of rotations of red pine into the future and don't leave anything behind from biomass harvesting, you're really going to go into a deficit with soil nutrients (such as) calcium and phosphorous," he said. "We can only squeeze these systems so much."

Harvesters in Michigan's Upper Peninsula seem to be testing that theory, harvesting some pine sites on a 20-year rotation, rather than 40 years, specifically for use as biomass, said Jeff Chandler, natural resources and ecosystems group leader for the Chequamegon-Nicolet National Forest.

Mace said the DNR and Council on Forestry, which are using Minnesota's best management practices for biomass harvesting as a model, are considering advocating for more retention of biomass due to recent research showing Wisconsin soils to be lacking more magnesium and other minerals.

Decomposing logs and snow-covered slash also provide critical habitat for wildlife species, particularly members of the weasel family like fishers and marten, said Jonathon Gilbert, wildlife biologist for the Great Lakes Indian Fish & Wildlife Commission (GLIFWC).

A downed log often can provide just enough space for wildlife to slip into and avoid attacks from raptors and other predators, Gilbert said, and also offer shelter by keeping small spaces free of snow.

Those "nurse" logs are required by plants that need a place to grow and germinate, and the insects that burrow through the middle are part of the diet for birds on up to bears, he said.

Government and industry officials do say, however, that removing more biomass could have the added benefit of removing fuel for future forest fires.

In a 2006 report on "Why biomass is important," Dr. Ann Bartuska, deputy chief of research and development for the U.S. Forest Service, said many of the nation's forests are "unnaturally dense," increasing the likelihood of large-scale fires.

"Removal of biomass can help restore forest vitality and reduce crown fires, and protect and improve habitat for certain species," she wrote.

But she also wrote that greater use of renewable resources, rather than fossil fuels, presents an environmental challenge.

"Ensuring sustainable production systems that protect and enhance the environment is a hurdle for transitioning the country to biobased, renewable fuels in sufficient quantities to significantly reduce fuel imports and benefit our economy," the report states.

Crystal ball for the forest

Knowing the benefits of biomass left in place and some potential drawbacks of its removal give state and federal agencies, the timber industry and others a better idea of ecosystem sustainability.

Hoping to head off any irreversible impacts, by the end of the year the DNR plans to establish harvest guidelines specifically for biomass. The agency's Secretary, Matt Frank, said the state and stakeholders involved in the process must do their best to establish a balance, and erring on the side of caution is the right approach.

"There's a lot of the slash that was just left out before and there's potential to use that, but the question is, how much?" he said during a July 22 meeting in Ashland. "We have to get that right — we can't afford a mistake there — and we want to be conservative from an environmental sense to make sure we haven't overestimated what we can take out."

The guidelines, now in their fourth draft and available for public comment, are recommendations, not requirements. They aim to cover both general and site-specific guidelines.

For instance, the general guidelines advise that each acre includes retention of at least nine trees: three snags, which are standing dead trees; three partially-hollow cavity trees that provide habitat for wildlife; and three mast trees with fruit and nuts that feed wildlife.

However, the draft guideline suggests considering leaving three trees per acre that may grow into larger, old trees that satisfy requirements for mast and cavity trees. Conceivably that could reduce the total number of trees per acre. Zaber of the Habitat Education Center said the difference could be significant.

"When people talk about biomass, I ask the difference between a pound of bricks and a pound of feathers? There's a big difference, but they both weigh a pound," he said. "A 1,000-year-old tree is not the same as 1,000 1-year-old trees."

The guideline does make a distinction between "coarse" woody debris, defined as 4 inches or more in diameter, and "fine" woody debris that is anything smaller. Both are dead material "on the ground in forest stands or in streams."

The recommendation is to "retain and limit disturbance" to coarse woody debris, but it does not offer suggestions on how to limit disturbance.

In even-aged rotations and complete salvage operations, leaving five tons of oven-dried, fine woody debris behind is recommended, and it could be a combination of pre-existing and cut debris. Intermediate treatments and uneven-aged rotations need a minimum of one ton per acre of fine woody debris that occurs as a result of the harvest and not including what is already on the ground.

The average Wisconsin tree crown has between eight and 10 oven-dried tons of fine woody material, which is also less than 4 inches in diameter but can be living or dead, according to the guidelines.

Don Waller, professor of botany and environmental studies at UW-Madison, said both coarse and fine woody debris are important.

"You don't get course woody debris if you're not letting the trees grow more than a few inches in diameter, so that fundamentally changes the character and the understory of the forest," he said. "On the other hand, you have most of the nutrients in the fine woody debris, and if you take that away too, you've potentially got issues of nutrient depletion."

The guideline also suggests not removing stumps, root systems and the "forest litter layer," which the draft defines as debris such as leaves, needles, bark and wood in different stages of decomposition.

That might not be specific enough for GLIFWC's Gilbert, who said one opinion of the draft so far is that it does not address the different stages of decomposition.

"If you cut down a tree today it's a log, and if it lays there for 75 years, it's going to be a different log than the one you cut today," he said. "...One of the impacts is, all that rotten debris will be gone and there won't be anything to fill in behind it so you lose that flow of woody debris."

"None of that is addressed in these guidelines," he said.

Zastrow of the DNR countered that discussions so far have leaned toward a "leave it there" approach.

"Do we leave that if it's on the ground? In our draft discussions, that's been yes, if it's on the ground you leave it on the ground," he said. "Subsequently, those residual trees that we're recommending (to leave) would add to that course woody debris and replace that course woody debris over time."

The harvest guidelines are recommended, but the state's Council on Forestry compiled its own list of recommended policy changes through the legislature to encourage the production and utilization of woody biomass.

To reduce competition with the pulp and paper industry, the council defined sustainable woody biomass as that which does not meet "the utilization standards for pulpwood, posts, bolts, or sawtimber."

It also recommended amending the Managed Forest Law to include biomass as an objective to consider on private forest land, along with recreational uses, watershed protections and other objectives.

Since creating a blanket policy for all national forest land would be next to impossible, each area is looking to develop their own guidelines for biomass harvesting. In the Chequamegon-Nicolet, the U.S. Forest Service would generally follow the state's recommendations, Chandler said.

"We have chosen in the past, and I'm sure we'll choose in the future, to voluntarily comply with the state guidelines so that our practices are consistent with all of the other land ownerships in the state," he said. "Technically, we don't have to comply with them, but being a good neighbor, we choose to."

Chandler added that the agency still would conduct site-specific investigations and consider whether to place additional requirements on a harvest beyond state guidelines.

He also said the Forest Service has already had inquiries about biomass in the context of existing timber sales, but held off because the impacts were not considered during an environmental assessment.

"By and large, we have deferred those (biomass harvests) at this point in time because we didn't analyze the effects," he said. "We had not disclosed in the environmental documents that that may be happening because we didn't know at the time that the loggers wanted that material."

Since loggers will typically be the ones on the ground deciding what stays and what goes, they will be at the front line of the future of biomass. As harvesters put in practice the state's guidelines, Zastrow said the results likely won't be immediate, but he knows the signs to look for.

"It takes time for that whole process to work, but when you see improvements in implementation on a voluntary basis, when you see strategic investments into research on really tough questions that haven't been researched, that's when the system is working well," he said.

Waller of UW-Madison said giving proper guidance to the timber industry requires flexibility to ensure sustainability, so the guidelines need to remain a breathing document, especially the first time around.

"What I want to see (in the guidelines) is more attention to the uncertainty we have here, the fact that we haven't done this before — certainly over several rotations — and we just don't know what the consequences might be," he said. "We need to monitor and we need adaptive management feedback and to benefit from our learning."

NOTICE: In accordance with Title 17 U.S.C. Section 107, this material is distributed without profit to those who have expressed a prior interest in receiving this information for research and educational purposes.

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