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Natural Fire

 
 

Some ecosystems depend on periodic fires to maintain the habitats which make up the ecosystem. In these fire adapted areas, fire promotes plant and wildlife diversity and burns away accumulations of live and dead plant material (leaves, branches, trees).

FIRE DEPENDENT ECOSYSTEM MAP

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Ecosystem Map
  • Common in the southwestern mountains as far north as Washington and Oregon, and east to the Dakotas.
  • Natural Fires in this ecosystem usually occur every five to 25 years.
  • These fires tend to be low intensity ground fires that remove woody shrubs and favor grasses, creating open, park-like ponderosa stands.
  • The life history of ponderosa pine is well-adapted to high frequency, low intensity fires. These fires burn litter and release soil nutrients, thus providing a good seedbed for ponderosa pine seeds.
  • Ponderosa needles on the ground facilitate the spread of low intensity ground fires, and minimize the dander of crown fires, which can kill ponderosa.
  • In ponderosa pine stands, fire is generally prescribed on five- to ten-year intervals to reduce fuel loads. Shorter burn intervals have insufficient fuel built up to maintain the fire, and longer periods may run the risk of causing tree-killing crown fires. Prescribed fires usually result in maintenance of stand composition.
  • Common in the forests of the Great Lake states.
  • Natural Fires in this ecosystem usually occur approximately every 125 to 180 years.
  • Jack pine is well adapted to fire.
  • Jack pine seeds have been known to still be viable after exposure to heat at 1000 degrees Fahrenheit.
  • That heat, however, opens the scales of the cone and releases the seed onto the ground where the fire has removed much of the existing vegetation and litter.
  • Jack pine seeds require contact with mineral soil to germinate, so fire serves to prepare the seedbed, reduce competition from other plants, and release the jack pine seed.
  • Common in Southern California, Arizona, New Mexico, and parts of the Rocky Mountains.
  • Natural Fires in this ecosystem usually occur during 5- to 25-year cycles.
  • Variations in species in these areas are attributed partly through the frequency of wildland fires.
  • Fire adaptations include vigorous stump sprouting after fires by many shrubs, including the Manzanitas, Ceanothus, and Scrub Oak. Chamise produces dormant seeds that require fire for germination; these seeds create a large seed bank during non-fire years.
  • Many of the shrubs, especially Chamise, promote fire by producing highly flammable dead branches after about 20 years.
  • After a year, the plant community is dominated by annual grasses. Five years after a fire, chaparral shrubs once again dominate the ecosystem; for this reason, more frequent fires favor grasses over shrubs.
  • Common throughout the Rocky Mountains of the western United States, generally found in unmixed stands at higher elevations.
  • Natural Fires in this ecosystem usually occur at intervals of 200 to 300 years.
  • Each subsequent stage of a lodgepole pine community displays different reactions to fire.
  • Fire suppression, however, creates a fuel buildup that is difficult to manage, and suppression is not consistent with maintaining ecological communities, creating more intense fires.
  • Common in Nebraska, Illinois, Iowa, and Kansas and the Ohio Valley.
  • Natural Fires in this ecosystem usually occur in five- to ten-year cycles.
  • Primarily made up of grasses and forbs, with some shrubs and trees.
  • Growth of native species such as big bluestem, little bluestem, and Indian grass all increase significantly following a fire.
  • Fire in tallgrass prairies acts to burn aboveground biomass, killing woody plants, allowing sunlight to reach the soil, and changing the soil pH and nutrient availability.
  • Because grass provides a low quality of fuel, grassland fires usually are not intense.
  • When fire is removed from a prairie ecosystem, woody shrubs and trees eventually replace grasses and forbs.
  • Common in areas from Texas east to Florida, and north to Maryland.
  • Lightning ignited fires in southern pine communities are common.
  • Longleaf pine requires mineral soil for seed germination, and thus ground fires prepare the seedbed by removing litter and releasing soil nutrients.
  • Different pines react different to the frequency of fire. Longleaf pines favor frequent fires; shortleaf and loblolly pines favor less frequent.
  • In cases where fire does not occur for 25 years or more, such as when fire is removed from the system or on wet sites where fire seldom occurs, hardwoods such as oaks and hickories gradually replace the native pines.
  • Boreal common in southern Alaska extending as far north as Fairbank, Tundra is found in the higher elevation of this zone. Tundra extends from the Brooks Range north to the Arctic Ocean.
  • Because of Alaska's cool year-round temperatures, vegetation decays at a very slow rate, thereby releasing nutrients at a very slow rate. Following a fire in the boreal forest or tundra, large amounts of nutrients are released.
  • Fires in the boreal forest and tundra typically burn in a patchwork leaving a mosaic across the landscape.
  • Plants exploit this opportunity, especially the early successional plants. In turn, wildlife exploits the lush growth. Consequently, Alaska's plant and animal communities are highly dependent on fire regimes.
  • Oak-hickory forests are common in Pennsylvania, West Virginia, Kentucky, Tennessee, and many other states.
  • Natural fires occurred in oak-hickory forests at intervals of 25 years or less.
  • Native Americans burned some of these forests very often, possibly every year or two.
  • Most oaks have thick bark so they can survive surface fires. Both oaks and hickories sprout from the base of the trunk after fire.
  • Fires remove shade and deep litter on the forest floor, creating perfect conditions for oaks and hickories to reproduce.
  • Oaks and hickories don't reproduce well in shade, so other tree species take over if the forest doesn't burn for a long time.
  • Common in the northeastern states, especially on sandy soils.
  • Natural fires occur in pitch pine barrens every 6 to 25 years.
  • Many of these fires are severe, pushed by the wind from one tree crown to the next.
  • Pitch pine has thick bark that protects it from heat. It can sprout back after fire, and it reproduces from seeds in cones that are opened by fire.
  • Pitch pine barrens are home to many rare plants and insects, turtles and frogs. Some of these organisms require fire to shape their habitat or to survive competition from other species.
  • If many years go by without fire, pitch pine barrens accumulate large amounts of dead wood and pine needles, which can make the next fire too severe for the pines and other fire-dependent species to survive.
Northwest Great Lakes California Rocky Mountains Midwest South Alaska Oak-hickory forests Northeast
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Fire is Nature's Housekeeper

Fires have burned regularly, consuming vegetation, accumulations of insects and diseases, and triggering a rebirth of forests.

Many plants have evolved adaptations that protect them as a species against the effects of wildland fire, and some are even strengthened by it.

Nearly every region in the country has some kind of fire dependent plant or tree.

Some ecosystems such as deserts are not fire dependent and fire needs to be put out quickly to reduce damage.