What Causes Forest Fires?

Understanding the basics of forest fires involves not only knowing the source of the initial spark, but also why they happen and what determines their level of severity. Devastating effects of fire draw copious amounts of attention. Beneficial aspects and the natural causes of these events are just as important; though do not garner as much focus. An out of control fire that begins in a forest is coined a wildfire.

Natural Causes

Naturally occurring blazes have different igniters. These include lightning (most common), volcanic activity and according to gisdevelopment.net sometimes "rolling stones and rubbing of dry bamboos with each other in the strong wind".

Anthropogenic Causes

Referring to the U.S. a Northern Arizona University website states "Nationwide, humans cause almost 80% of wildfires." Human causes can be accidents and arson. Many "accidents" are a result of negligent actions such as discarding cigarette butts, out of control campfire, unsafe use of fireworks, and use of faulty electric wiring. Sparks generated from tracks as trains pass over them are all too common in some forests. Intentional arson includes spillover of fires set to structures within and adjacent to forests. Creating or renewing pastures involves burning of land; this can spiral out of control without proper precautions.

Anthropogenic or Natural?

In determining anthropogenic or natural causes the line can sometimes be blurred. Examples are when man built structures act as the ground that initiates the lightning spark, and introducing of non-native, less fire resistant plant species.

Geography

Climate plays a huge role as drier areas are more susceptible to combustion and intensification. Drought in areas that are normally relatively wet can pose even bigger problems as the vegetation here is often not as naturally resistant to the effects of fire. Tree species such as the ponderosa pine with their thicker bark are more resistant and tend to reside in drier forested areas such as those in the American Southwest. High wind areas are more prone to have blazes increase in magnitude. Areas that are closer to human habitats are also at higher risk for anthropogenic fires.

Effects

Bringing conditions that encourage biological diversity as a sort of cleansing mechanism is a natural benefit of forest fires. Having said this, abnormal amounts of human induced and accelerated fires can have disastrous effects on both the forest ecosystem and human habitats. The U.S. Government Accountability Office points out that the forest fire problem has worsened since 2000. This is despite the fact that federal money going to agencies responsible for wild-land management has "doubled since the late 1990's."

Climate Change

Scientists theorize that climate change is playing a role in exacerbating the problems. This is due in part to changing climate patterns that bring less rainfall and higher winds to some areas that would otherwise not have these conditions.