This spring found U.S. Forest Service scientist Joe O’Brien helping to set a prescribed fire in the Turks and Caicos, a small Caribbean island chain that’s a British Overseas Territory. O’Brien, research ecologist with the Forest Service Southern Research Station Center for Forest Disturbance Science, was there to help save a unique rockland pine habitat from disappearing.
As a member of the Caicos Pine Recovery Project, O’Brien plans and trains crews to conduct the prescribed burns needed to help restore Caicos pine yards on the islands. O’Brien draws from years of research on controlled burning and specifically from his work on the increasingly rare pine rockland habitats of Florida and the Caribbean.
“Controlled burning – or prescribed fire – is the primary tool used in these habitats to suppress competing hardwood growth, prevent the buildup of excess fuel, and add nutrients to the thin soil,” said O’Brien. “Prescribed fire is already used extensively in the pine rocklands of the Bahamas and Florida, where the habitat can cover thousands of acres.”
The Caicos pine (Pinus caribaea var. bahamensis) is the national tree of the Turks and Caicos and the foundation or keystone species of the Turks and Caicos Islands (TCI) pine yard, a fire-dependent rockland habitat found only on low-lying areas of North Caicos, Middle Caicos, and Pine Cay, where it serves as habitat for a number of other plants, birds, reptiles and insects. Without the pine, the entire ecosystem ceases to exist.
In 2005, pine tortoise scale was discovered on Caicos pines and identified by a scientist from the Kew Royal Botanic Garden (Kew). An invasive soft-scale insect that probably hitched into the islands on Christmas trees from the northern U.S., pine tortoise scale quickly escalated in the warm climate. By 2010, nearly 95 percent of TCI’s Caicos pines were dead, many destroyed in a 2009 fire in North Caicos, where there were numerous dead trees and dense flammable undergrowth.
Recognizing that the Caicos pine ecosystem faced near extinction, a range of collaborators from Kew, the U.S. Forest Service, the TCI Department of Environment and Maritime Affairs, and other organizations started planning the controlled burns needed to improve the health of the remaining forests.
O’Brien helped with the extensive training for TCI’s first controlled burn on Middle Caicos on May 9, 2012. Since then, team members conducted additional controlled burns on small rocky patches – some only a few acres – of Caicos pine in North Caicos. During the burns, O’Brien took thermal images to study fire temperature, intensity, and behavior, and investigated different treatments. Other team members tracked tree health and pine survival after the burns.
“Caicos pine is fire dependent, which means that it needs fire to stimulate germination and to reduce competition from shrubs and hardwoods,” says O’Brien. “After the three controlled burns we conducted in 2012, we found tree health greatly improved, with trees once stunted by insects growing quickly and producing cones within a year. We expect the same from these latest burns. “
Last month’s controlled burn was the second in a new series that started in December 2014. The December burn was conducted on a two-acre plot that contains some of the healthiest remaining trees and was overseen by O’Brien and other fire experts. In May, project members burned in a core conservation area in the Middle Caicos pine yard. O’Brien and fellow project members again took thermal video images of the fire to chart burn temperatures. They’re also recording time lapse images to monitor the recovery of burn plots, expecting the gains in tree health to be as heartening as those from the 2012 burns.
As a researcher, O’Brien is also interested in how other stressors impact these fire-dependent rockland pine systems. In his research in the Florida Keys, he saw stands of slash pine, the foundation species in that ecosystem, destroyed by storm surge and sea level rise after a hurricane.
“This caused an instantaneous change in the state of the system that will likely persist,” said O’Brien. “In the Turks and Caicos, I’ve started a project investigating the interaction of the invasive pine tortoise scale with trees stressed by sea level rise. So far, the results are similar to those in the Keys. The results of these studies will inform efforts to restore both of these species-rich ecosystems.”
For more information, email Joe O’Brien at email@example.com.