The Harrison Experimental Forest

Pine genetics comes of age

by Zoё Hoyle, SRS Science Delivery Group

Located in the lower Coastal Plain in southeastern Mississippi, the Harrison Experimental Forest (Harrison) was established on the Desoto National Forest in 1934. By that time, vast stands of southern pines, mostly longleaf pine, had been cut from the estimated 31 million acres that made up the southern Coastal Plain forest. Located just north of Gulfport, Mississippi, the 4,111-acre experimental forest continues to provide critical information about the genetics of longleaf and other southern pines.

Measuring tree roots for study on the Harrison. Photo by U.S. Forest Service.

Measuring tree roots for study on the Harrison. Photo by U.S. Forest Service.

In 1955, the SRS Southern Institute of Forest Genetics (SIFG) was located on the Harrison, with research studies focused on forest genetics and pathology. SIFG research on the genetics of growth, form, and pest resistance of forest trees has guided tree improvement programs across the South.

In 1961, researchers installed experimental plots on the Harrison to test responses to fertilization of three different pine species—longleaf, loblolly, and slash. Along with a surprisingly strong response to one-time fertilization in all three species, the long-term experiments showed that after about 25 years, longleaf pine catches up with loblolly pine in terms of growth and productivity. In 1999, at mean age 39, mean timber volume per acre was actually greatest in the longleaf pine plots.

When Hurricane Katrina hit the Harrison in 2005, the experimental plots took a beating. In 2006, researchers measured the damage, comparing their data to 1999 records. They found that the damage from Katrina was over 30 percent greater in the loblolly pine plots than in the longleaf pine and slash pine plots. Findings from the damaged plots have provided important information for land managers trying to decide how to replant hurricane-damaged areas along the Gulf Coast while taking into account the increased storm activity predicted under climate change.

During the same period, the SRS Forest Genetics and Ecosystems Biology team based in North Carolina started taking data from the Harrison plots as part of their research on carbon sequestration and tree species adaptation to climate change. In spring 2008,  then team leader Kurt Johnsen, research biological scientist, present team leader Chris Maier, and plant physiologist John Butnor drove out to the Harrison to map tree roots and measure soil respiration for research on the differences in carbon storage among the three pine species.

Johnsen and his team also started designing and preparing a companion study to the one established in 1961. Seedlings for the new study were grown from seeds harvested from the original study and from genetically improved seeds. Various fertilization and prescribed fire treatments have been applied, and instruments to measure carbon efflux installed on the site so that scientists can study the interplay among genetics, silviculture treatments, and carbon sequestration.

Together, the old and new studies will continue to provide land managers the science-based knowledge they will need to manage and adapt Coastal Plain forests as the climate changes over the next decades.

Read more about findings from the original plots and the design of the new study plan.

For more information, email John Butnor at

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Posted in Experimental Forests, Forest Products, Genetics, Longleaf Pines, Southern Pines, Threats

Faces of Innovation: Chuck Burdine at the Southern Institute of Forest Genetics

Persistence pays off for a Mississippi youngster

by Teresa Jackson, SRS Partnerships & Strategic Initiatives


Chuck Burdine at the Harrison Experimental Forest. Photo by U.S. Forest Service.

Chuck Burdine at the Harrison Experimental Forest. Photo by U.S. Forest Service.

Charles “Chuck” Burdine is a biologist with the Southern Research Station’s (SRS) Southern Institute of Forest Genetics (the Institute) located on the Harrison Experimental Forest (HEF), in Saucier, Mississippi. Chuck started his Forest Service career in December 1999 in the Student Temporary Employment Program (STEP) while still earning an Associate degree in forestry at Jones County Junior College (JCJC) in Ellisville, Mississippi.

How did you come to work for the Forest Service?

During my penultimate semester at JCJC, I began looking for a job and applied at the Institute. It did not happen right away, but after being persistent and making routine visits to the office, support service specialist Andrea Gilich eventually accepted me as a field student. I was hired as a field technician and immediately began fieldwork planting and measuring trees, and cleaning up research plots.

How did you transition from fieldwork to the lab?

In June of 2000, after working in the field for six months, a lab position became available. Glen Johnson, the technician running the labs at that time, thought I would be a good candidate and asked if I would be interested. I told Glen I would try it for two weeks and see how things went. After working in the lab for six months, my supervisor, Dr. Tom Kubisiak, was successful in converting me from the STEP to the Student Career Experience Program (SCEP), which allowed me to further my education and guaranteed me a permanent position upon graduation. I earned my Bachelor of Science Degree in Biology from the University of Southern Mississippi in May 2004, and was converted to a full time employee.

What led to your interest in forestry?

Spending most of my childhood outdoors in order to camp, hunt, fish, hike, ride a bike, float in a canoe, and anything else outside is what has always made me appreciate and love nature. I knew (or at least thought) that I wanted to work outside, and forestry seemed to fit in with that type of career. As a youth, my dream job was to become a ranger at a National Forest, anywhere, but preferably in the western part of the U.S. Reflecting back, a forestry degree was not the best path to achieve my dream job, however, the opportunity to work for the U.S. Forest Service has been extremely rewarding and something that I am very proud of.

How has your job evolved through the years?

When I first started working at the HEF, our unit was much larger. Over the past 15 years, many employees have left, leaving vacant positions that were never filled. This provided an opportunity for other employees, including myself, to take on their responsibilities and duties. The unit’s project leader and my supervisor Dana Nelson, introduces me to visitors as the person who “runs the labs.” Initially, I did not think of myself in this role, but now I realize that my position has evolved over the years. In addition to the labs, I am responsible for inbound/outbound sample tracking, refrigerator/freezer inventory, research network administration, etc. There are also routine duties I am responsible for that are important but not critical to our mission. These include being the National Oceanic and Atmospheric Administration (NOAA) weather data correspondent; coordinating space for the conservation and restoration efforts of local endangered species (mostly the Mississippi dusky gopher frog), led by U.S. Fish & Wildlife personnel; and, working with lab visitors.

What are some of your favorite projects?

The work we do on the American chestnut would probably be my favorite, and something that I started doing my first week in the lab. The fusiform rust research work would come in second. These two research areas have taken up the bulk of my time since starting in the lab. Nonetheless, I thoroughly enjoy working with visitors, which include PhD students, collaborative scientists, technicians from other forests or college institutions, etc. Often times, the smaller projects we work on with partners are related to the work we do on fusiform rust and the American chestnut. It is not unusual to host students and/or scientists from other institutes, both domestic and international, for weeks or even months in order to complete some aspect of their larger project.

You sound very energized by the work that you do?

Very much so, I love to meet and talk with people, and to learn from them. I have had the opportunity to work with people from different states, regions, countries, and cultural backgrounds for most of my career. The interactions with numerous people have been one of the greatest aspects of my job in the lab. I feel that I have friends, not just colleagues, all over the world because of the relationships that have developed through working together.

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Posted in Genetics

Genetics to Support Healthier Pine Forests in the South

Nine genes involved with fusiform rust resistance in loblolly pine identified

by Zoё Hoyle, SRS Science Delivery
Closeup of telia on oak leaf. The fungus that causes fusiform rust requires an alternation of hosts to complete its life cycle. Part of the cycle is spent in pines, the rest in green leaves of several species of oak. Telia are hairlike structures that form on the leaf and produce the spores that infect pines. Photo by Robert L. Anderson, courtesy of

Closeup of telia on oak leaf. The fungus that causes fusiform rust requires an alternation of hosts to complete its life cycle. Part of the cycle is spent in pines, the rest in green leaves of several species of oak. Telia are hairlike structures that form on the leaf and produce the spores that infect pines. Photo by Robert L. Anderson, courtesy of

Fusiform rust, caused by the fungus Cronartium quercum f. sp. fusiforme, is one of the most serious diseases affecting loblolly and slash pines in the southeastern U.S. and causes an estimated $28 million in damages every year. As the primary source of pulpwood and saw timber for the U.S. forest industry, the economic importance of loblolly pine alone to the South and the nation can’t be overstated.

Developing genetic resistance in loblolly and slash pine seedlings is the only realistic way to manage the disease — since chemical control is expensive and impractical — and foresters have used artificial inoculation systems to select for rust-resistant pine families for years. But developing resistant seedlings is complicated by the interactions that take place between the pine host and fungal pathogen at the gene level, where the disease constantly evolves to disarm the resistance genes developed by the tree.

The genetic markers researchers develop to tag resistant genes in loblolly pine breeding populations provide managers with an effective tool to guide tree planting and to determine the best seedlings to grow on a given site. Developing genetic markers relies on decades of genetic research on the complex interactions between the loblolly pine and fusiform rust genomes.

In a recently published article in the journal Forests, scientists from the U.S. Forest Service and North Carolina State University detailed nearly two decades of research on the host-pathogen interaction between loblolly pine and fusiform rust. They describe nine fusiform rust resistance genes they found in loblolly pine, including the specific methods used to locate each gene on the reference genetic map of loblolly pine.

“Understanding how these fusiform rust resistance genes in loblolly pine and other pine-susceptible pines impact resistant screening and the selection of breeding stock is important to tree breeding,” said Dana Nelson, corresponding author of the article and Forest Service Southern Research Station research geneticist. “The documentation of these nine genes provides a key piece of information needed to improve breeding and site selection strategies.”

In 2010, Nelson and others found that gene-for-gene interactions between the pine host and the fusiform rust pathogen largely determine the formation of the galls on stems and branches that weaken and kill infected pines. For the recently published papers, the researchers used this gene-for-gene method to provide the analysis that led to the identification and genetic mapping of the nine fusiform rust resistance genes.

Researchers found that the nine identified genes occur in three groups on the loblolly pine genetic map. “Higher resolution mapping of these and additional resistance genes will lead to better gene testing for breeding programs and maybe someday eliminate the need for costly artificial inoculation testing,” said Nelson.

Read the full text of the article.

For more information, email Dana Nelson at

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Posted in Genetics, Insects and Diseases, Southern Pines