The wood gliders and training planes of World War II are fragile antiques today. But during the war they met a need and were an example of wood product ingenuity and research.

At the outbreak of the war when the U.S. needed planes but lightweight metals were in short supply, University of Minnesota researchers working at the U.S. Forest Products Laboratory in Madison, Wisconsin, helped retool the furniture industry to meet the need.

The average glider carried 15 people and their equipment or a vehicle. Built with one-eighth-inch wood veneer skinned wings, they were lightweight, inexpensive, built from material readily available, and suitable for landing troops under cover of darkness.

The phenolic resin glues and techniques developed then are used today in waferboard and other wood products. Wood veneers were also impregnated with phenolic resins. The resin-impregnated wood was compressed to the density of a soft metal and used like metal. After the war, it found use in golf club heads, knife handles, and in tennis racket frames. These advancements help extend our previous wood resources.

And a compliment was paid to U of M researchers when billionaire Howard Hughes asked them to conduct a feasibility study of building a fleet of planes similar to his giant wood airplane known as the “Spruce Goose.” However, plans were scrapped when a cost-benefit analysis concluded it wasn’t practical.

Birch and aspen occupy about one-third of Minnesota’s forest land. With a shortage of harvest-sized aspen over the next several decades, Minnesota scientists in the 1980s developed processes to incorporate birch into panel construction. Wood from aspen and birch has very different properties, but U of M research overcame those differences, showing how birch could be used to supplement aspen in oriented strandboard production. Today, that research is being used to fill some of the gap in the aspen supply.

University of Minnesota scientists in aquatic toxicology worked closely with the Environmental Protection Agency to examine the effects of various pollutants on fish and invertebrates. Through research in fish growth and reproduction, they helped shape the initial federal Clean Water Act regulation of hydrogen sulfide and cyanide. Today, researchers investigate more subtle effects of endocrine disrupting compounds on fish reproduction.

Researchers continue to investigate ways to use wood residue for products, yielding profits while reducing the amount heading to landfills. Wood waste can be shredded and used for animal bedding, composted to improve soil, chipped for mulch, or burned as fuel. But University wood product researchers have explored other uses of by-products since the beginnings of the paper industry in Minnesota.

Early studies of the chemistry of cellulose and lignin (a by-product of paper manufacturing) were made in the 1930s. It appeared impossible to make a functional plastic containing more than 25 to 40 percent lignin until 1998 when a U of M wood chemist created a material composed of 100% alkylated kraft lignin that is similar to polystyrene in tensile strength. Methods were devised to injection-mold the material into tough pieces. Creating plastic from lignin provides a profitable use for surplus kraft lignin that cannot be used in pulp mills. And properly formulated, lignin-based plastics are easily biodegraded by common fungi. Finally, wood is renewable, while petro-chemical plastics are not.

More recently, techniques developed by U of M scientists use waste wood, kraft lignins, and waste plastics to create a durable product that can be extruded for windows, doors, siding, and building materials for decks.

University marketing researchers worked with the world’s largest window maker in the world, located in Minnesota, to track prospective customer contacts and develop a highly successful “Prospect Management Plan” for windows manufactured with the extrusion technology.

In 1904, University researchers started testing the durability of treated and untreated fence posts—testing continued for more than 30 years. From a 1908–09 report: “About three thousand fence posts composed of basswood, cottonwood, willow, birch, hard maple, red oak, and ash have been treated with preservative . . . . The possibilities in the way of using our cheap woods . . . with preservatives will last as long or longer than our best cedar posts. If the farmers of our prairies can be shown how to treat these . . . it is an important matter.” The findings found wide application throughout the wood products industry.