Transcript Bottomland Forest Ecosystem

Bottomland Forest Ecosystem
Description
• Bottomland Forests are deciduous, or mixed
deciduous /evergreen forests
• They form closed-canopy forests on riverine
floodplains 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
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.
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
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.
Description
• Bottomland hardwood forests constantly
change and are altered over time by natural
disturbance and climatic changes
• They are characterized by infrequent, lowintensity fire and poorly to well-drained soil
• 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
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
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
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
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
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
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
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