The Cold Hill Silvicultural Assessment

Research-management partnership in action

Upland hardwood forests mature slowly – it can take as long as a century. It can also take years to answer research questions about these forests, which are often dominated by oaks and hickories.

SRS Forest Technician, Ryan Sisk, re-measures competing vegetation on the Daniel Boone NF. Photo by Callie Schweitzer, USFS.

In 2003, the U.S. Forest Service Southern Research Station (SRS), Northern Research Station, and Southern Region (Region 8) of the National Forest System initiated a long-term cooperative project on the Daniel Boone National Forest in Kentucky.

The project, named the Cold Hill Silvicultural Assessment, combines applied management with a large-scale research project to evaluate different silviculture methods to increase forest health and resilience.

“The first phase of the study addressed silviculture strategies that would be most effective to increase resiliency and resistance of upland hardwood forests to the pending threat of spongy moth infestation,” said Callie Schweitzer, research forester and lead scientist on the project. “Long-term studies such as this one can also be used to examine trending issues that come along during the ongoing studies.”

Schweitzer (in yellow hard hat) describes the Cold Hill project plans with Daniel Boone NF staff and the general public. Photo by Andrea Felton, NEPA Planner, London Ranger District, Daniel Boone NF.

An example of this is the heightened interest in regenerating white oak for use in the cooperage industry to make staves for whiskey barrels.

White oak stave logs are used for the production of white oak barrels, which are in high demand because of the growth of whiskey and wine industries. In 2016, wooden casks (or barrels) were the top Kentucky wood export at $89 million worth of exported barrels. But regenerating white oak and maintaining white oak growing stock are major research challenges on all lands, regardless of ownership.

One of the treatments used in Phase I was a shelterwood prescription designed to enhance the oak regeneration process. The initial treatment created canopy conditions that allowed small oaks to successfully grow into a more competitive position.

“We found red maple trees to be so prominent that we decided additional treatments during Phase II to target the reduction of red maple were warranted,” says Schweitzer. “We worked with the Daniel Boone National Forest staff to make necessary adjustments to the prescription.”

Schweitzer said that having a goal to increase forest health means that stands are managed to benefit all native species. This includes species that are more desired than others, such as oaks and black cherry. It also includes abundant species like red maple and species that are almost absent from southern hardwoods – namely, the American chestnut.

Silviculturalist Jared Calvert (in blue hard hat) describes stand treatments during a tour of the Cold Hill project. Photo by Andrea Felton, NEPA Planner, London Ranger District, Daniel Boone NF.

Another treatment from Phase I was planting American chestnut hybrid seedlings bred for blight resistance on three national forests across the Southeast.

American chestnuts were extirpated in the early 1900s by the ‘perfect storm’ of chestnut blight, root rot disease, and land clearing for pasture and farms. The blight has prevented chestnut re-establishment, and research continues to test strains for blight resistance and competiveness.

Stacy Clark, SRS research forester, and partners at the University of Tennessee’s Tree Improvement Program have been conducting chestnut research since 2007. “Planting high quality seedlings is a critical step to overcome ecological challenges to restoration,” says Clark.

Phase I concluded in 2017, and Phase II will address the increased competitiveness of red maple. Researchers and managers will intensively target red maple stems before and after commercial harvest.

In November, researchers and managers organized a field day to engage the public, Kentucky Heartwood members, and faculty from the University of Kentucky on the Cold Hill Assessment.

Phase II will continue the American chestnut study, along with additional treatments for improving oak recruitment, managing competition from maple, and continued assessments of forest health and vigor.

For more information, email Callie Schweitzer at

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