For Thailand in particular, the environmental changes caused by man during the last two decades are obviously terrible. Second only to deforestation, fire plays the most destructive role in the forest ecosystem which results in drastic deterioration of the environment as a whole. However, these changes over time seem slow to human eyes. For example, over 20 years of environmental degradation, people gradually get used to the deterioration of nature and actually accept new conditions such as annual flood and drought.

   From an ecological point of view, fire is considered as a non- biotic factor which, in general, works within the ecosystem to decompose, recycle and select. As an agent of decomposition, fire releases, in the form of a heat, the chemical energy stored in the available fuel. Fire liberates, in slightly altered forms, many of the constituent bio-chemicals residing in the litter. Somehow an ecosystem must cope with this discharge of energy and chemicals, with the eradication of some organisms and the introduction of others, and with the simultaneous processes of selective destruction and selective enhancement.

    It is therefore, evident that fire is not a minor factor, but a major one. Fire is and has been, for centuries, a part of terrestrial environments of the world. Consequently biotic communities adapt and compensate for this factor just as they do for temperature or water. Yet, as with most environmental factors, man has greatly modified its effect, increasing its influence in many cases and decreasing it in others. Through careless behavior, man has often so increased the effect of fire that a productive environment, is destroyed or injured.