By the 1930s, U.S. Forest Service researchers and others were developing silvicultural practices that small landowners and farmers could use to grow productive forests even in the southeastern U.S., where land use had led to widespread depletion and degradation of natural resources.
Forest Service researchers established Farm Forestry demonstration plots where landowners could see research findings turned into action. “Demonstration stands were usually 40 acres, and were often called ‘Farm Forties,’” says Don Bragg, research forester at the Forest Service Southern Research Station Southern Pine Ecology and Management unit. “They were intended to show small landowners how to use good silvicultural practices to supplement their income.”
In 1934, Russell Reynolds became director of the newly opened Crossett Experimental Forest in Arkansas, and three years later he established the “Good” and “Poor” Farm Forestry demonstration plots. They earned their monikers “Good” and “Poor” because the Good Forty had almost twice the board foot volume as the Poor Forty. For 32 years, Reynolds carefully tended these stands with an uneven-aged harvesting approach that, in the Good Forty, involved annually cutting a volume roughly equal to the annual growth. In the Poor Forty, Reynolds initially cut only a fraction of the growth, so that the stand could recover to full stocking like the Good Forty. This only took 15 years to achieve, much quicker than Reynolds expected.
“Today, the Farm Forties are remarkably similar,” says Bragg. “This selection method has proved to be an effective tool to restore stands and improve the quality of forest products over time.” Reynolds also improved the quality of the remaining pines by cutting the trees that were lowest quality or least likely to survive.
Although the Good and Poor Forties have been well-documented over the decades, no formal studies of the age structure had been done. Bragg and Jim Guldin, project leader at the Southern Pine Ecology and Management unit, recently studied stand age patterns and identified silvicultural implications for a study published inthe journal Forest Science.
To determine the age of trees, researchers collected small cylinders of wood and counted the growth rings. It is very difficult to tell how old a tree is without counting rings. Small trees can be surprisingly old, and large trees can be surprisingly young. “On the Farm Forties, as on many uneven-aged sites, the relationship between pine age and trunk diameter is limited,” says Bragg. “We found that 25-year-old pines could have a diameter at breast height of anywhere from 4 to 15 inches.”
A number of the large overstory pines turned out to be more than 70 years old, even though that hadn’t been a specific management goal. “Old, slow-growing trees are often especially valuable producers of ecosystem services and wildlife habitat,” says Bragg. For example, federally endangered red-cockaded woodpeckers excavate nesting cavities in old pines that have been extensively decayed by red-heart fungus, a condition rarely found in young pines. “Uneven-aged management practices could be used to retain these trees without sacrificing much sawtimber yield,” says Bragg. “Conversely, stand productivity can be increased while retaining uneven-aged structure by removing slower growing pines.”
More than 90 percent of the trees now standing in the plots germinated after the Farm Forties were established. “That speaks to a very unusual attribute of such stands. They grow and develop much more quickly than uneven-aged stands found in other forest types, such as Ozark oak-hickory or northern hardwoods,” says Guldin. “That gives us opportunities to study how treatments affect stand development relatively quickly, which is always an advantage in silvicultural research.”
Foresters and landowners are cordially invited to visit these stands at an upcoming forestry field day at the Crossett Experimental Forest May 16-17, 2014.
For more information, email Don Bragg at firstname.lastname@example.org