Deforestation can be explained based on the idea of the Tragedy of the Commons, introduced by Garett Hardin in 1968 (Hardin, 1968). The tropical forest was initially a common resource that could be accessed by anyone in the society. The cost of taking resources (timbre) out was less than the benefit (reaping profits) that followed. When everyone held their self-interest as top priority, people would not have a reason to stop utilising these resources. This was driven by a worldwide population growth from 2.6 billion to 5.3 billion between 1959 to 1990 (Rishi, 2009), as improving healthcare helped to increase life expectancy while decreasing infant mortality rate. This eventually became a social dilemma when the rate of reaping off the common resource pool exceeded that of the self-replenishing rate. Theoretically, no one would stop utilising the resource as self-interest is in top priority. Even if one tried stopping, others would continue and in the end, the one who stopped would lose out. Also, when people did think about the impact, often the damage had been already done. Another reason why deforestation became widespread was due to the fact that it was tied to prosperity and affluence. Also, other secondary benefits involved improved health in the country and standard of living (Butler, 2008).
(Photo Credits: http://worldissues-zozo.blogspot.com/2009/01/tragedy-of-commons.html)