From 1947 to 1975, Croker’s Brewton project (named for town nearest to the experimental forest), was devoted almost entirely to developing the shelterwood system, which has proved highly successful for regenerating longleaf pine. Yet despite regeneration research, longleaf pine plantations were dwindling by the 1960s. “There were so many failures of longleaf plantations throughout the South in the 1950s and 1960s that most foresters considered the practice too risky and switched to slash and loblolly pine,” Croker wrote in his seminal study on longleaf pine. Landowners and managers needed more evidence that longleaf pine could be grown productively.

A New Generation of Champions

William (Bill) Boyer had never seen a longleaf pine before he started working on Escambia studies in 1955, but he soon became a champion of the tree, and continues (even though he officially retired in 1998) to study ways to improve longleaf pine regeneration and survival. In 1975, Boyer and Croker published the guidelines for longleaf pine natural regeneration still followed today.

In 1964, Boyer and fellow SRS researcher Robert Farrar started the Regional Longleaf Growth Study (RLGS) on the Escambia, installing additional study sites in Mississippi, Florida, Georgia, and North Carolina over the next 3 years. RLGS was started to build a database of growthand- yield information for naturally regenerated, even-aged stands. Originally made up of 185 plots, the study was designed to cover a range of ages, stand densities, and site qualities. Every 10 years RLGS adds new plots in the youngest age class. Today the study consists of 305 plots; nearly half of these are located on the Escambia.

Over the decades, Boyer and Auburn University’s John Kush have worked to keep this unique study going and to make sure data is recorded. All RLGS plots are remeasured every 5 years; in 2009, the 45-year remeasurement will be taken. The science-based knowledge of natural stands of longleaf pine generated by Boyer and Kush is unprecedented, their influence on the field continued through new generations of graduate students, researchers, and forest managers. The long-term datasets from the study have been invaluable. Researchers have shown, for example, that naturally regenerated longleaf pine trees catch up and surpass planted trees in 33 years. For a landowner with natural stands of longleaf pine, this means planting costs could be greatly reduced or eliminated.

In recent years, Kush and students have been using RLGS plots and databases to look at the impacts of increased levels of atmospheric carbon dioxide on longleaf pine growth. This new research came about because Boyer, while analyzing long-term data, noticed significant differences between second- and third-growth stands in the study. Now researchers are starting to explore whether the carbon storage capacity of longleaf pine could encourage incentives for planting the tree to mitigate climate change.

Rekindling the Flame

To remain healthy, longleaf pine forests need periodic fires to reduce midstory competition from hardwoods. In 1947, a large wildfire in the Escambia area prompted managers to burn another 26,000 acres of land in and around the newly established experimental forest. Observing the successful regeneration of longleaf pine seedlings on the burned areas led scientists and others to promote fire, long considered an enemy to U.S. forests, as necessary for establishing longleaf pine stands. Croker observed that most of the regeneration in his seed tree plots was due to fire rather than the presence of seed trees; the seed tree method was abandoned on the Escambia as prescribed burning became an accepted management tool.

Boyer began experiments with fire in the 1960s, and found that longleaf pine was surprisingly tolerant to lowintensity fire. Fire studies have now been in place since 1973, including studies on the long-term effects of season and frequency of prescribed fire, as well as effects on forest floor vegetation. Dale Brockway, SRS research ecologist, tests prescribed fire as one of a suite of tools managers can use to restore and manage longleaf pine forests. He’s developed uneven-aged management methods for landowners who are interested in creating wildlife habitat, restoring understory plant diversity, aesthetics, and other values.

Although much is now known about even-aged management of longleaf pine stands, little is known about the long-term results of uneven-aged management, which promotes regular regeneration by creating the types of gaps that would normally occur from disturbances such as lightning, insects, fire, or wind. Since 2004, Brockway has been testing singletree and group selection methods for regenerating longleaf pine. He and fellow researchers have developed and tested a new silvicultural technique that managers and field personnel can easily learn and cost-effectively apply to manage forests for a broader range of structures and values.

Today, a little over 80 percent of the Escambia is in upland longleaf pine stands, the rest in slash pine and hardwood bottoms. Since management began in the 1940s, about 1,200 acres have been naturally regenerated to longleaf pine. What makes the Escambia unique is that it now shows longleaf pine in all stages of development, from newly germinated seedlings to mature trees up to 160 years old.

“The combination of stand ages, sites, and conditions exists nowhere else,” says Boyer, who started working on the Escambia in 1955, and is still collecting data from a study he installed in 1957. “The long-term silvicultural and fire ecology study sites provide ‘living laboratories’ available to other researches working to unravel some of the many fascinating mysteries lurking within what was once one of the most extensive forest ecosystems in North America.”

 

 

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