The first human settlers arrived in what is now coastal Chile roughly 4,000 years ago. The Araucanian culture eventually became the largest indigenous group in Chile. This society of hunters, gatherers, and farmers lived in small villages and employed irrigation in central Chile. Human impact on the area remained relatively low in the precolombian era. But the arrival of the Spanish conquistadors in the early sixteenth century, however, led to rapid agricultural expansion and landscape clearance for grazing by goats and cattle. A lack of forested areas has led to four centuries of widespread cutting of matorral shrubs to produce charcoal for fuel.