The factors that contributed to the vegetation we see on Cumberland Island uplands today are complex and not necessarily apparent. The maritime forest was severely disturbed during the early agricultural period (1786-1880). Torres (1977) mentions that in 1741 there were a few plantations on the island. They no doubt had small gardens, and “fields of rye” were mentioned in 1759. A map dated 1800 shows only land ownership and houses, while the McKinnon 1802 map shows cotton fields. By 1845, there were extensive gardens at Dungeness and by 1889, many apparently treeless fields were scattered throughout the island. Livestock numbers and activity plummeted during the Civil war but soon recovered. On the island in the 1970s, there were 400 head of free-roaming cattle (NPS FMP 1979), the last of which were rounded up in the late 1980s. It was not until that time that natural succession could proceed and the maritime forest could finish its recovery.
Natural succession follows recognized patterns. In the maritime forest, following the original clearing, fallow fields are invaded by grasses and forbs, and trees finally get a foothold. First come pines, being known as a pioneer species. Eventually, a pine-oak-hickory association follows, and then mixed oak-hardwoods gain the upper hand and squeeze out the pines and other sun-loving species as the understory thickens. Live oak is the dominant species in our maritime forest, along with water and laurel oak, holly, hickory, red bay, and magnolia. Presently, the forest is mostly in the pine-oak-hickory stage. In the latter stages, it resists fire quite successfully. Only in unusual circumstances are large live oaks killed by fire.
The understory on Cumberland had been cleared by cattle for at least a century, which interrupted natural succession and allowed continued pine reproduction. However, since the removal of the cattle, the forest understory has gotten dense enough to stop pine reproduction, which will allow the maritime forest to reach its climax stage by eliminating some species, including pine.
Naturalists have looked at pines with relation to maritime forests and agreed that the presence of pine on the Atlantic barrier islands may be a good index of human disturbance (Meyers & Ewel,1990). In further support, Johnson, et al. (1974) said island pine typically occurs where original live oak forests have been cleared and Schwartz & Travis (1995) that the pine-oak hickory association was a mid-successional grouping of recent origin and not a natural community. Harper (1911) added that pine was scarce or absent on the South-Georgia islands. On Cumberland Island, the conclusion was reached that in the absence of disturbance, a maritime oak forest would presumably form a homogeneous cover over the upland portions of the island (Turner & Bratton,1987).
The 1979 NPS Cumberland Island Fire Management Plan stated that cattle were having a serious impact on island vegetation. The plan advised that “documentation and research need to be conducted before the Park engaged in any prescription burning, lest it become a decision by default and possible existing unnatural conditions be perpetuated.” Which is exactly what happened in the Fire Management Plans to date.
Cattle
The Spanish brought cattle to Florida in the 1500s. As homesteads increased, so did the number of cattle. Excess livestock of plantations could be marked and released to go feral Before the number of residents rose significantly, barrier islands were a place to secure feral livestock. The pressure of their grazing has influenced coastal communities for centuries.
Cattle are browsers, feeding on leaves, twigs, and young shoots of shrubs and trees, and can succeed in the island environment better than horses, who are grazers, eating grass, sedges and forbs. Cattle do greater damage to the vegetation and communities. Their browsing affects species composition, growth, and soil properties of the forest.
The pressure of cattle grazing has influenced coastal communities for centuries.
Looking back at the last few centuries, we see much natural and unnatural disturbance to Cumberland Island. About one-half the uplands were in agriculture during the mid-1800s (White, 1849), drastically disturbing the maritime forest. Livestock numbers plummeted during the Civil war but soon recovered. We are reminded: “Knowledge of the historic patterns of anthropogenic disturbance is critical to an understanding of the patterns (or lack thereof) and the processes of ecological systems” (Hamberg & Sanford, 1986) i.e. the current state of the island’s maritime forest.
On Cumberland Island in the 1970s, there were 400 head of free-roaming cattle (NPS FMP 1979). The last of these were not rounded up until the late 1980s. Only then could natural succession proceed and the maritime forest truly continue its recovery. As the understory recovers from the lengthy impact of cattle, the forest has become thicker which sets the stage for continued natural succession.
References
- Bratton, S.P. & S.G. Miller. 1994. Historic Field Systems and the Structure of Maritime Oak Forests. USNPS Cooperative Park Studies Unit, Institute of Ecology, UGA.
- Hamburg, S.P. and R.L. Sanford. 1986. Disturbance, Homo Sapiens, and Ecology. Bull. Ecol. Soc. Amer., Vol 67, No. 2: 169-171.
- Harper, R.M. 1916. The Relationship of Climax Vegetation to islands and peninsulas. Bull. Torrey Bot. Club, 338(11):515-525
- Johnson, A.S., H.O. Hillestad, S.F. Shanholtzer, G.F. Shanholtzer. 1974. An Ecological Survey of the Coastal Region of Georgia. NPS Monograph Series, Number 3.
- Kirkland, Z. 1979. Fire Management Plan, Cumberland Island National Seashore.
- Ruckdeschel, C. & H.B. Jordan. 1982. Observations on the Cumberland Island Fire of 16 July-24 August, 1981, and subsequent Recovery. Final Report. NPS contract PX 5630-1-531.
- Torres, L. 1977. Historic Resource Study CINS, NPS. Historic Resources Division, Denver, CO.
- White, G. 1849, Statistics of the State of Georgia. Savannah, W.T. Williams. Other references in Volume 33, Number 1.
NPS and FIRE
The National Park Service (NPS) operated under a total fire suppression policy until 2015, but there were many wildfires on the island during that time, the most noteworthy ones in the scrub. The 1981 fire burned over 1640 acres (Ruckdeschel & Jordan 1982), and during that entire period, thousands of acres burned.
Fire Management Plan
Between 1977 and 2002, the NPS reported 50 fires. To date, based only on my (CR) files, there have been at least 62 fires. Information from 2002-2024 was not available from NPS. The point is that the long-term impact of that fire suppression policy on the plant communities was likely negligible since thousands of acres did burn while the total suppression policy was in effect. Yet the 2024 Fire Management Plan (FMP) justifies introducing deliberate burns on its assumption that natural fire had been excluded from the maritime forest and scrub.
Lands on the north end of Cumberland are officially designated Wilderness, except the area which special interests, Greyfield, had removed from that protection. Fire there threatens no structures, so human manipulation is unnecessary and contrary to the purpose of Wilderness. The fuel loading, both in maritime forest and scrub, serves as an important factor in perpetuating those ecosystems. In fact, altering the understory and combustible material might change the trajectory of their development.
The FMP acknowledges “structure and composition of the plant community has been altered over the past century” (p57) also that…”effective planning and management must be grounded in our comprehension of past dynamics….” Yet there is no explanation as to how the plant communities were altered by early human manipulation or of the tremendous impact hundreds of free-roaming cattle had on the vegetation.
Fire in the Wilderness on Cumberland Island threatens no structures, so human manipulation is unnecessary.
The FMP, guided by the many mandates for CUIS, stresses “maintaining natural ecosystem processes,” which includes natural succession. Guidelines say justification for introducing fire must be based on sound principles.
The maritime forest is only now beginning to enter its final, climax stage on the north end. The impact of cattle essentially stopped the natural succession of the upland maritime forest at the oak-pine stage for over a century. It is thrilling sight indeed to see the recovery now occurring. But introduced fire risks setting that recovery back to the oak-pine stage or ultimately, if carried on for too long a period, perhaps even altering its final goal?
The FMP refers to “hazardous fuels,” which are down and dead vegetation. This debris is part of the natural cycle and is used by the plant communities in different ways. By not recognizing individual communities’ relationships to fire, the NPS does a disservice to the resource. The recovering maritime forest resists fire and needs a thick understory to proceed with its natural succession. The scrub wants an inordinate amount of dead and dying debris, up to 20-35 years of it, so it can burn catastrophically to mineral soil. They have an opposite relationship with fire.
A flaw in the FMP is not considering historic land use, and assuming NPS fire suppression, instead of the more detrimental impact of cattle, as the cause of change in vegetation. A disturbance history must be available to help us understand the status of the various plant associations, their trajectories, and the importance of fire to them.
The 2024 FMP never acknowledged the maritime forest is not mature; that most of it is still in a stage of natural succession. Instead, the emphasis is on restoring fire into the ecosystems, which shows a lack of understanding of maritime forest succession and the dynamics of the scrub.
The only caveat we are given from the NPS is in the 1979 FMP: “Research needs to be conducted before the park engages in any prescribed burning. This should be an important, active research effort lest it become a decision by default and possibly existing unnatural conditions be perpetuated.” And today, 46 years later, this remains to be done.