Fire builds biodiversity in nature because no single fire is the same. How and where fires burn depends on a variety of factors like topography, fuel moisture, fuel accumulation, wind direction and velocity and vegetative types. These are just a few of the variables. These variables also give rise to different kinds of fire. A ground fire is a fire that stays close to the ground, while a catastrophic or crown fire moves from the ground up into the crowns of trees creating unstoppable wildfires. A back fire backs slowly with low intensity into the wind, while a head fire moves as an intense fiery wave with the wind.
Some ecosystems like artic or boreal ecosystems are adapted to and need catastrophic fire to survive with a period of burning of maybe a 100 years, while light fire ecosystems are adapted to frequent fire every one to three years. If fire is excluded by man from these ecosystems these systems begin to degrade in forest and grassland health by disease and old age losing biodiversity.
In wetter warmer climates as in the Eastern United States the fire adapted ecosystem under fire exclusion, logging and agriculture cause a shift from high fire type pines to low fire type hardwoods and softwoods. In turn this shift allows even easier fire suppression because these lowland low fire types have less flammable leaves than upland pine. Also, the overstory is not open allowing sunlight to the ground to nourish species rich plants and animals.
In dryer more arid climates as in the Western United States and parts of Australia, China, Russia and Southern Europe the result of fire exclusion is a build-up of debris in these light fire ecosystems. What results is that over years and decades of fire exclusion, eventually either lightning or man ignites this fire hazard. What results is the destruction or degradation of this type ecosystem by catastrophic fire along with loss of life and property.
Over time catastrophic fire type trees invade these light fire ecosystems. This is why it is time to quit working against nature and use prescribed fires and good thinning practices to bring these ecosystems back from the brink of extinction and to forest and grassland health. Do we really want to lose our Western Ponderosa Pine and Giant Sequoia ecosystems to invading catastrophic fire species and in the process doing great damage to lives and property?
In some boreal ecosystems what happens naturally, as in Alaska and Siberia over decades, is that catastrophic fires burn out a patchwork mosaic with each new fire being contained by other past fires not ready to burn yet. This creates biodiversity of plants at various stages of growth like willow where animals like Moose, Elk, wolves, bear, rabbits, lynx etc. move from one patch to another seeking out the successionary stages of vegetative growth needed for food or for their prey.
If fire is excluded what happens is that one gets less diversity as the ecosystem degrades with the whole system going up in flames eventually. The natural diversity of the fire mosaic is degraded and the plants and wildlife suffer. This is now well understood by good fire managers. In Alaska the authorities let fires burn where there is little damage to private property.
In the wetter climates as in the Eastern United States, light fires or prescribed fires to simulate natural light fires, are used to create the a natural type of diversity. These fires push back invading low fire species where upland pines like Longleaf and Slash Pine can be planted in their place. What these fires do depending on the factors already mentioned, is create a mosaic bio-diverse ecosystem of plant communities and the wildlife they support like Bobwhite Quail, Whitetail Deer, and Wild Turkeys.
In addition the light fires thin out pine reproduction so that the pines do not grow too close together and create a dense canopy of diseased stunted trees. Under good forestry practices, the forester thins out over time, the smaller diseased or damaged trees, just as nature would with fire leaving the best tallest and strongest trees to prevail.
By working with nature the good land manager provides income and a more healthy forest for future generations. This kind of sustainable forestry, rather than eco unfriendly clear cutting is known as the Stoddard-Neel method, and should be and is being expanded to our public lands. It creates a simulated natural biodiversity that clear cutting does not do.
So you see we can by working with nature end up with healthy forests and grasslands that simulate natural biodiversity and still create an income, forest products and a livelihood for people. Putting light fires back into our ecosystems benefits these ecosystems and us, rather than using fire exclusion to work against nature which is destructive both to us, our homes, property and nature.
To learn more about the importance of fire
in nature, my book Fire in Nature, A Fire
Activists Guide is free on its website. If you read this important new cutting edge
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fire in nature. :-) In the Western United States and Australia the book might even save you and your home from catastrophic wildfire, as you and your neighborhood learn ways to mitigate the danger from catastrophic wildfire.