Indonesia experienced severe deforestation and forest degradation over few decades. In order to clarify why and how Indonesian forest had been lost in the past half-century, we investigated a wide range of statistics, such as forestry, population and land-use, or GIS data.

As late as 1900, Indonesia was still a densely forested country. However, the deforestation speed accelerated since 1970s. As a result of this, the forest cover was decreased to Forest area decreased from 162.3 Mha (83.8% of the land area) in 1950, 119.7 Mha (61.8%) in 1985 and 94.4 Mha (48.7%) in 2010 at least half of which is believed to be degraded by human activity. Especially forest cover loss on Sumatra and Kalimantan is significant.

Major direct pressures of the forest loss are classified into 1) logging operations by forest logging concessions to family farmers, 2) oil palm and other agriculture expansion, and 3) forest fire. In addition, 4) agriculture and forestry prices, 5) policy and institutional factors, such as financing foreign debts by exploiting natural resources, 6) privatization of timber and tree crop estates, 7) corruption, and 8) land tenure conflicts, 9) domestic population growth and 10) economic growth are also imoprtant underlying driving forces. The cause of deforestation was composed by complex factors through the history.