Horseshoe Bend's Forests, Counted: The 2022 Vegetation Baseline

In August 2022, National Park Service ecologists marked out ten permanent plots in the forests of Horseshoe Bend National Military Park, in east-central Alabama, and counted everything growing in them. It was the first time the park had been measured this way. These numbers are the baseline that every future survey will be compared with.

The vegetation plots set up in August 2022.

Why count plants

Plant communities keep changing, pushed by the environment and by disturbances natural and human. On the southeastern Coastal Plain and Piedmont, their variety supports wildlife, provides ecological services, and is most of what a visitor sees. Tracking how the vegetation changes, and what is stressing it, tells the park how healthy its land is and what to do about it.

The park

Like most of the southeastern Piedmont, the park's land was cleared for farms and timber after European settlement. Where its forests stand today, and what grows in them, still follows those old patterns — and the soil moisture that each slope holds:

• Dry (xeric) forest on convex upper slopes;
• Submesic to dry forest on mid-slopes;
• Moist (mesic) forest in sheltered, concave lower slopes;
• Alluvial forest on the flats beside rivers and streams.

How it was measured

The Southeast Coast Network follows a peer-reviewed protocol (2019), like other eastern NPS monitoring networks and modelled on the Carolina Vegetation Survey. Plots are placed at random within the main habitat types — those covering more than 30 percent of a park — and each one records:

1. every vascular plant species, native and non-native, and how abundant it is;
2. for woody plants, basal area, density and health;
3. fuel on the forest floor;
4. disturbances, including insect pests and disease;
5. the site itself: landform, soil nutrients, canopy cover and height.

At Horseshoe Bend, the ten plots cover two habitats: Piedmont Upland Forest (six plots) and Piedmont Alluvial Wetland (four).

What they found

Average species richness (± standard deviation) by growth form and habitat.

Non-native plants are common in the wetlands. Chinese privet (Ligustrum sinense) was in all four alluvial plots, and Japanese honeysuckle (Lonicera japonica) in three.

Mean occurrence of native and non-native species, by habitat.

Other signs

• Fire. Three of the six upland plots and one of the four alluvial plots had fire scars. The park has burned on purpose since 2002, to help longleaf pine regenerate, cut fuel loads and manage stands damaged by the southern pine beetle.
• Deer. No sign that white-tailed deer were overbrowsing young trees, in either habitat.
• Dogwoods. Of nine flowering dogwood stems measured, three were dead and four showed leaf symptoms likely from dogwood anthracnose (Discula destructiva).

Next survey: all ten plots are due to be measured again in spring and summer 2026.

About the monitoring

Since 1999 the NPS Vital Signs program has tracked the condition of more than 270 parks with significant natural resources, to spot trends, give early warning of trouble, and show whether management is working. The Southeast Coast Network covers twenty park units across North Carolina, South Carolina, Georgia, Alabama and Florida — seashores, historic sites, monuments, military parks and more — over some 184,000 acres of federal land.

The full report, Terrestrial Vegetation Monitoring at Horseshoe Bend National Military Park: 2022 Data Summary, is in the NPS DataStore. See also the Southeast Coast Network and its reports.

Sources

Written from "Terrestrial Vegetation Monitoring 2022 Data Summary for Horseshoe Bend National Military Park," a resource brief of the Southeast Coast Inventory and Monitoring Network, National Park Service; a work of the United States government in the public domain.