Bottomland Forest Ecosystem

1. Bottomland Forest Ecosystem

2. Description • Bottomland Forests are deciduous, or mixed deciduous /evergreen forests • They form closed-canopy forests on riverinefloodplains and in shallow depressions • They are found in situations intermediate between swamps which are flooded most of the time and uplands which are usually dry

3. Description • The canopy may be quite diverse with both deciduous and evergreen trees, ranging from hydrophytic to mesic. • Bottomland forests may be the oldest natural community type in Florida • Pollen core evidence indicates hardwoods existed in Florida from 25 to 100 million years ago.

4. Description • Bottomland forests represent a transition between drier upland hardwood forest and very wet river floodplain and wetland forests • While trees and plants in this ecosystem cannot tolerate long periods of flooding (as in a swamp), they are periodically flooded when water levels rise

5. Description • There is much variety among bottomland hardwood forests, based on slope of the land, soil type, water availability, and climate • The diverse communities of bottomland forests are known for their species richness and may support from two to five times more species of plants and animals than either pine forests or upland hardwood forests.

6. Description • Bottomland hardwood forests constantly change and are altered over time by natural disturbance and climatic changes • They are characterized by infrequent, low-intensity fire and poorly to well-drained soil

7. The nutrient content of the soil is determined by the amount of leaf litter and other organic material present on the forest floor • Because the forest often has deciduous trees resulting in leaf litter on the ground, the nutrient levels of the soil increases as the litter decays • While most Florida soils have low nutrient content, bottomlands have some of the best soils in Florida • Forests with nutrient-rich soils generally have a greater variety of plant species

8. The role of fire • Wildfires do not affect bottomland forests very often, but they still contribute to changes in the trees and plants that grow there • When the forest is dry enough to burn, the fire can remove built-up leaf litter and groundcover and release nutrients back into the soil • The dead leaves are fairly moist and burn slowly, unlike the dry, flammable leaf litter in sandhill or scrub forests

9. The role of fire • Infrequent fires allow the establishment of many slow-growing hardwoods. • However, long-term exclusion of fire can lead to an excessive accumulation of plant material • This build-up of organic material may result in high-intensity fires that damage the tree canopy and endanger wildlife and humans

10. The role of fire • If the fire is severe enough, it may destroy the dominant hardwoods and provide opportunity for other types of plants and trees to establish • This would change the ecosystem from bottomland hardwoods to a community of faster growing plants such as pines and herbaceous plants

11. Dominant species • Dominant species include sweetgum, spruce pine, loblolly pine, sweetbay, swamp laurel oak, water oak, live oak, swamp chesnut oak, and sugarberry • More flood tolerant species often present include American elm, red maple, swamp tupelo, and bald cypress • Evergreen species include loblolly bay and sweetbay are often mixed in the canopy and understory

12. Dominant Species • Smaller trees and shrubs include American hornbeam, swamp dogwood, possumhaw, dahoon, dwarf palmeto, swamp bay, red bay, wax myrtle, and highbush blueberry • The understory is either dense shrubs with little ground cover, or open, with few shrubs and a groundcover of ferns, herbs, and grasses

13. Occurrence of bottomland forest • Bottomland forests along smaller streams are prone to periodic flooding • In floodplains along larger rivers and tributaries, bottomland forests are subject to short seasonal floods

14. Management Considerations • Nearly all bottomland forests have suffered from timbering operations, which frequently leave long-lasting scars from soil disturbance • In addition to clearcutting, some bottomland forests have been converted to pine plantations • Clearcutting of bottomland forest in the Panhandle often leads to a secondary growth canopy dominated by loblolly pine and sweetgum • Sweetgum is often favored by disturbance due to its ability to sprout following damage to the tree