He has sold more than 500 blueprints of his solar kiln design. People from as far away as Russia, Chile and England--as well as from New York, North Carolina, Washington state, Minnesota and Wisconsin--have come to Spring Green for his weeklong crash course in full vigor forestry.
"I want to give enough information to a person so they can actually do [the whole process] themselves," Birkemeier says. "Within one week they think, 'We can do this.'" He estimates that about a dozen farms have implemented full vigor forestry.
Wallace Baird, a retired physical chemistry professor, owns a farm near Winston-Salem, NC. A majority of his land is enrolled in a state tax program that requires him to periodically log his forest in exchange for low property taxes.
"We have two five-acre tracts of Virginia Pines that need to be harvested. The trees are small, about 14 inches in diameter," Baird says. "I was torn about having the pulpwood guy come in and take our trees."
Baird worried about possible damage to his land caused by conventional logging, as well as the economic waste of feeding his trees into a pulp mill. "I read somewhere about people using 8-inch trees for lumber," he says, "and then I found Jim's Web site, which jives with what we want to do."
In mid-September Baird, along with his wife and two adult children, spent a week with Birkemeier. On Monday, the group toured Timbergreen Farm. On Tuesday, they cut down a few trees. Wednesday was spent sawing trees into boards and stacking them in the solar kiln. They made floorboards on Thursday, then spent Friday installing the flooring into an unfinished hallway in the basement of Birkemeier's home.
Baird declares the course a success and plans to re-floor homes owned by various family members: "We have all the equipment that Jim has. We are going to do essentially everything he is doing. We've already got two friends interested in new floors." He plans to recommend Birkemeier's course to some of his neighbors.

Gene Francisco, executive director of the Wisconsin Professional Loggers Association, spent a day at Timbergreen Farm with Birkemeier in the late 1990s, when he was chief state forester for the Department of Natural Resources. Francisco thinks full vigor forestry can work, although he mentions a few caveats.
Safety, for one, is an issue when forest owners cut down their own trees, as Birkemeier's program recommends. "It takes a lot of skill to harvest trees in a safe way," says Francisco.