Prescribed Fires

Energy Transformations and Energy Transfer

Fire is one manifestation of energy.  Technically, energy is defined as “the ability to do work.” In the case of fire, that work is transforming landscapes.  There are two main types of energy: kinetic (the energy of motion) and potential (stored energy). In addition to these two types, energy manifests itself in other forms such as thermal and chemical energy. To learn more about the different types of energy check out the US Energy Information Administration.

reflected_radiationImage Credit: NASA Earth Observatory

The Law of Conservation of Energy states that energy cannot be created or destroyed, it only changes from one form to another. All the energy which fuels life on Earth originates with the sun; of all the sunlight which hits the earth, only 48% makes it to the surface. Trees and other plants absorb this incoming energy to fuel photosynthesis, producing molecules like glucose which store  chemical energy.

During fire events, the chemical energy of plants is transferred to the surrounding air as light and thermal (heat) energy. While we can see fire with our eyes, the smoke produced by fire often obscures our vision. The thermal and infrared imagery capabilities possessed by some satellites are able to detect the location of fires through smoke cover that human eyes cannot see through.

Veg-densityThe image above was taken before the fire which shows vegetation intensity; all the vegetation within the outlined area represents chemical energy.

veg-intensity-2After the fire, the chemical energy of the vegetation within the outlined area was released as light and heat.