Linda Benedict, Gautreaux, Craig, Blazier, Michael
Craig Gautreaux and Michael Blazier
Southern pine forests are a major part of the Louisiana landscape, covering nearly one-third of the state’s land. This abundant resource is the predominant source of timber for Louisiana’s forestry industry, which provides the Louisiana economy with $3 billion to $5 billion per year and nearly 21,000 jobs.
Louisiana has not always had the plantations of southern pines. This is especially true for the hills of north central Louisiana. Before World War II, this area grew cotton and corn but struggled because of fertility and topographical issues. As the demand for housing increased after the war, much of this land was converted to timber through incentive programs provided by the federal government. Because of this increase in acreage, forest production has grown 800 percent from the levels of the late 1940s. This growth is partially due to research conducted at the Louisiana Agricultural Experiment Station.
Early research focused on growing timber efficiently. Thomas Hansbrough, forestry researcher at the Hill Farm Research Station, studied the effects of planting density on the establishment of pine plantations. His findings indicated that a rate of 400-500 trees per acre yielded better results than the conventional wisdom of “plant ‘em thick” of the time of more than 700 trees per acre.
In the 1960s, Robert Merrifield, forestry researcher at the Hill Farm Research Station, determined the optimum time for fertilizing loblolly pine. Hansbrough and Merrifield collaborated on pruning techniques and established that removing limbs lower than 16 feet resulted in wood relatively free of knots.
Rodney Foil, forestry researcher at the Hill Farm Research Station, focused on thinning practices as related to pulpwood. His recommendations of thinning trees when the diameter of the end of the log was 2 inches as opposed to the industry standard of 4 inches proved to enhance the growth of pine plantations. This earlier thinning proved beneficial to the trees because of reduced competition for light, nutrients and water at a crucial stage of development.
AgCenter research also examined coastal wetland forest stands and the benefits provided by them. Scientists found that cypress-tupelo stands in permanently flooded conditions or exposed to salinity failed to regenerate if harvested. These stands would convert to marsh or open water reducing the long-term sustainability of these forests.
In 1993, the LSU AgCenter established the Forest Products Development Center in an effort to add value to the forestry industry through the use of wood in nontraditional ways. The center serves as an incubator of ideas of how wood products can be used as medicinal plants, in the energy sector and the role of recycled wood products.
Many wood products such as telephone poles and treated lumber possess chemical components. Hui Pan, assistant professor in the School of Renewable Natural Resources, is conducting research that would keep these chemicals from entering landfills. One process involves liquefying the wood to facilitate the removal of harmful chemicals such as chromated copper arsenate. The liquid wood can then be turned into other products such as biodegradable polyurethane foam that can be used to manufacture products such as spray foam insulation.
Craig Gautreaux, Communications Specialist, Communications, LSU AgCenter, Baton Rouge, La.; and Michael Blazier, Associate Professor, Northwest Region, LSU AgCenter, Homer, La.
Read more on the history of forestry research at the Hill Farm Research Station.
(This article was published in the spring 2012 issue of Louisiana Agriculture magazine.)