A Natural Part of the Island Ecosystem
The scrub/flatwoods community on Cumberland Island is an association of fire-adapted plants (primarily palmetto, stagger bush, pine and bays) on poorly drained soil with little to no canopy, and composes a large portion of the north end of the island.
Scrub Fire, 25 June 2008
Without periodic hot fires, the community would change over time to one of stunted oaks with a thick palmetto understory, similar to the growth around Sea Camp today, and much diversity would be lost. Several island species are found only in the scrub. The island’s fire history shows a major burn every 25 to 30 years, but with changing global conditions, that schedule may shrink.
Helicopter Takes Water from Lake Whitney
To Fight Fire, 24 June 2008
The scrub area eagerly burns and encourages fire. Its thinly scattered tall pines attract lightning and thick grasses in the temporary ponds and crowded ranks of palmetto elsewhere facilitate fire’s spread. After several years of drought conditions, ignition is almost guaranteed, and suppression is difficult, if not impossible, once a fire gets going.
Defaulting to a total suppression policy is a breach of government responsibility
The usual scenario is for the fire to race to the edges of the scrub community and then creep into the less welcoming adjacent communities, such as those with an oak canopy, and from there it can reach extensive aquatic systems.
27 June, Shell Road
A stand of live oaks surrounds the Candler compound and has protected structures from the incendiary scrub for centuries. The Settlement/Subdivision is surrounded by a different vegetative association with a canopy and little understory, also one in which fire is less enthusiastic and more easily controlled.
The scrub burn of 1981 was notably different from the 2008 fire, even though much of the same area burned. Drought conditions prevailed for at least 2 years prior to the 1981 fire, and ground water level was extremely low. Unusually high air temperatures, low humidity, and strong winds combined to spread that fire quickly and much farther than in 2008. The low water table had dried vast areas of wetlands, which allowed accumulated organic material to be consumed by the fire and thus provide for more open water in the years to come. In 2008, the water table was significantly higher and restricted the natural burn much more than in 1981.
July 13 regrowth – Palmetto fronds
Natural fire did not access the Sweetwater slough system this time, and although some of that area was deliberately ignited, it burned only superficially. The only hot burn occurred in the open scrub, in almost exactly the same core area that burned hot in 1954 and 1981. Outside the scrub community, the recent fire burned lightly, killing palmetto fronds but not consuming them and leaving their petioles mostly intact.
The National Park Service has never finalized a fire management plan for Cumberland Island (1972-present) and is therefore under a policy of total fire suppression. Defaulting to a total suppression policy is a breach of government responsibility, since much of the north end of the island is a designated Wilderness Area and by federal mandate must be managed to promote natural systems. The only reason the scrub community has survived and continues to burn is because firefighters’ efforts to extinguish it are impotent.
Click map to view larger size version (PDF file – requires Adobe Acrobat Reader)
Other Cumberland Island communities are not so fortunate and are losing their character and ability to support species adapted to this particular natural regime. For example, the colonial nesting wading birds such as egrets, wood storks and ibises, no longer nest on the island due to fire-related habitat changes. Also, the sloughs are choked with shrubs so they offer no refuge to migrating ducks as they did in the past, and ground doves and kestrels are limited to interdune habitat.
Museum personnel expect to discuss the necessity for changing current fire suppression practices with the new superintendent, whenever he/she is appointed and with the new Southeast Regional Director as well. Perhaps we can convince them to develop and implement a fire management plan for the island which permits natural processes and facilitates natural evolution of the scrub community. Having a natural fire regime is important for maintaining the ecosystem and for compliance with Wilderness management guidelines.
Gator Hole – Lake Whitney, 18 July 2008
A little known aspect of government firefighting is the money involved. In the case of Cumberland Island, funds do not come out of the local park’s budget, but a special fund into which all the agencies contribute, and it is bountiful. Crews are expected to put in up to 16 hours a day, and the pay is generous.
While fires do smolder and may flare up at a later date, there is also perhaps a financial incentive to extend the process of securing an area once everything is under control. In the recent scrub fire, deliberate burning of an extensive area within the Wilderness fires was initiated subsequent to control of the natural fire. The area deliberately ignited did not burn in the 1954 nor the 1981 fires. Such manipulation of ecological processes in the Wilderness Area will be the subject of a later commentary.
Recent Newsletters explaining the immediate fire issue:
(PDF files – view with Adobe Acrobat Reader)