Monday, 13 May 2013 08:51

Sakatah project marries prairie restoration with bioenergy

When Molly Tranel Nelson was watching crews cut down large trees, buckthorn and other shrubs from an area of Sakatah State Park last winter, an elderly man stopped by to talk.

"He said he remembered when his father grazed cattle on the land before it was a park. So you know it was all prairie," said Nelson, Department of Natural Resources regional resources specialist for parks and trails.

Getting the land back to prairie was the goal of a major project that only came about because of large grants that aimed to tie habitat restoration with bioenergy.

Over the years the prairie had been invaded by trees due to a lack of natural fires that kept prairies open in the past. "A lot of it was invasive species, Amur maple, box elder, buckthorn, honeysuckle — just a lot of invasive trees that don't provide good habitat."

Restoring the 45 acre site was long a goal of the park, but funding for a major project was elusive. But the DNR was able to get $58,000 in funding from a program aimed at restoring habitat while using the woody materials removed to expand the market for biomass. Trees and brush that were removed from the site were picked up by District Energy, a St. Paul company that burns biomass to convert to electricity.

"They took 44 semi loads so far and there's another 30 loads sitting there waiting for (highway) load restrictions to be lifted," Nelson said.

When such prairie restorations have been done in the past, the brush and trees were usually burned on site. That's partly because few people wanted the wood and partly because of the invasive species being removed.

"With things like buckthorn, you don't want to transport it and dump it somewhere else because it's invasive and you just spread it," Nelson said. "And you hate to just burn it and not get a benefit from it."

Barb Spears, who coordinates the DNR's Linking Habitat Restoration to Bioenergy program in St. Paul, said that's why her program is a win-win.

"It's great because you get to see (the material) get into the utilization stream rather than being wasted."

The program started in 2007 with $500,000 funding from the Legislature. Later, the Legislative-Citizen Commission on Minnesota Resources, which oversees Legacy Amendment money, added another $600,000 to the fund, which is awarded in competitive grants for projects like the Sakatah restoration.

District Energy has taken much of the biomass produced by such project around the state, but Spears said they've also found other customers for materials. A pine plantation on one prairie was cut down with a Wisconsin mill paying $10,600 for the logs. And the Amish have purchased wood for use in pallets.

In other cases, the state wasn't able to sell the woody material, but found companies that would pick it up and chip if for landscaping mulch. That, said Spears, is still better than simply burning it on site.

Nelson said the restoration of prairie at Sakatah will take several years to complete. "We'll have a flush of invasives coming because it's open and these seed beds are there. We'll use some herbicide this spring and then replant those areas (with prairie seeds)."

Nelson said she wished she could have gotten grant money to do a similar prairie restoration at Minneopa State Park on the west edge of Mankato. But the park is too far from the District Energy plant in St. Paul to make it worthwhile for them to truck material to their plant.

The campground side of Minneopa Park was originally all prairie, but park staff have fought with an invasion of cedar and other invasive shrubs and trees.

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