Forest Fires

A forest fire is an unwanted fire in a forested area. They can be caused by natural events, but they are usually caused by people.

Heat sources include the sun, lightning, volcanic activity or sparks from rockfalls. Sometimes humans are deliberately involved in setting fires which remove dead material that is of no use for human purposes and burns away dry underbrush.

A wildfire begins when sufficient dead matter has accumulated on the ground to form a combustible fuel source burning seasonally as it does so through autumn and winter months. The root cause of wildfire development is heat! Fire will spread if there is nothing to stop it. Items heated above approximately 400° Celsius (or 752° Fahrenheit) give off enough flammable vapors to burn. These vapors will mix with the surrounding atmosphere and be ignited if a flammable material is nearby to catch fire from them, or by radiant heat from flames.

In Australian English, the word “bushfire” refers both to forest fires and grass fires . In American English “forest fire” usually refers only to wildfires in forests , while a grass fire is generally called a “grass fire”. [paragraph] The phenomenon we call wildfire today was not clearly understood in prehistoric times and it is likely that early people actively cleared fires from their environment through deforestation and wood-harvesting. As human populations increased and trees became scarcer near human habitations, wildfires were viewed as threats and land without care was set ablaze with abandon .

Today, it is thought that wildfires are caused by a number of factors including lighting, spontaneous combustion, dry thunderstorms ,  and the activities of man.  Each year in the United States, more than 2 million acres are destroyed in forest fires alone with billions of dollars in property damage.  Many plants in temperate regions require fire for reproduction.

Fire dangers are often given for areas with risk levels at “very high”, “high”, “moderate”, or “low”. Forest types are considered when determining if an area has a higher risk level. If one was to step outside during the day time and let their eyes adjust they would be able to see the light spectrum, if they let their eyes adjust at night time they would be able to see stars. Light travels in a straight line while heat will disperse in all directions. When observing fire danger during different times of day, it would be easier to see the larger areas with higher risks during the daylight hours because of the light dispersing through out the area. Around 6 p.m., there are not enough photons available for detection by human eyes without an infrared camera or other detectors that are sensitive to longer wavelengths.

A fire can move very quickly depending upon its intensity , topography, fuel availability and weather conditions .  Areas which have recently seen logging operations,  Some species such as the jack pine (Pinus banksiana) and lodgepole pine (Pinus contorta) depend on fire to release their seeds from cones .  Many plants that bear fruits, nuts or berries require fire to spread their seed.  

Today, humans are the most important cause of wildfires and since we don’t want uncontrolled fires, we actively start and stop them. We build houses in wild areas and protect our homes with suppression systems where we can afford it. Many human-caused fires originate from unattended or poorly extinguished campfires , burning debris or arson. Humans can also accidentally cause a wildfire by touching off a spark when welding, grinding, or brushing against flammable material.

Fire is used as a tool to manage forests for timber , and also as an instrument to manage the landscape and protect other valued resources and structures .  One example is controlled burning which minimizes fuels to decrease risk of uncontrolled fire .  This technique stimulates the germination of some desirable forest trees such as loblolly pine (Pinus taeda), shortleaf pine (Pinus echinata) and ponderosa pine (Pinus ponderosa) , while promoting shrubs such as sumac (Rhus glabra), huckleberry oak (Quercus vaccinifolia) and cherrybark oak (Quercus pagoda) .

Wildfires typically start by accident and quickly change to a natural process that can be beneficial for ecosystem needs .  This is why we try our best not to fight fires when they happen because we want the fire to do its job which will help shape and benefit the landscape in future years.