original forests of the wet zone. The government has attempted to preserve sanctuaries for natural vegetation and animal life, however. Ruhunu National Park in the southeast protects herds of elephant, deer, and peacocks, and Wilpattu National Park in the northwest preserves the habitats of many water birds, such as storks, pelicans, ibis, and spoonbills. During the Mahaweli Ganga Program of the 1970s and 1980s in northern Sri Lanka, the government set aside four areas of land totalling 1,900 km2 as national parks. Land use and settlement patterns The dominant pattern of human settlement during the last 2,500 years has consisted of village farming communities. Even in the 1980s, the majority of people lived in small villages and worked at agricultural pursuits. Traditional farming techniques and life-styles revolve around two types of farming--"wet" and "dry"—depending upon the availability of water. The typical settlement pattern in the rice-growing areas is a compact group of houses or neighborhood surrounding one or several religious centers that serve as the focus for communal activities. Sometimes the houses may be situated along a major road and include a few shops, or the village may include several outlying hamlets. The life-sustaining rice fields begin where the houses end and stretch into the distance. Some irrigated fields may include other cash crops, such as sugarcane, or groves of coconut trees. Palmyra trees grow on the borders of fields or along roads and paths. Individual houses also may have vegetable gardens in their compounds. During the rainy seasons and thereafter, when the fields are covered by growing crops, the village environment is intensely verdant. The nature of agricultural pursuits in Sri Lanka has changed over the centuries and has usually depended upon the availability of arable land and water resources. In earlier times, when villagers had access to plentiful forests that separated settlements from each other, slash-and-burn agriculture was a standard technique. As expanding population and commercial pressures reduced the amount of available forestland, however, slash-and-burn cultivation steadily declined in favor of permanent cultivation by private owners. Until the 13th century, the village farming communities were mainly on the northern plains around Anuradhapura and then Polonnaruwa, but they later shifted to the southwest. In the 1970s, wide expanses of the northern and eastern plains were sparsely populated, with scattered villages each huddled around an artificial lake. The Jaffna Peninsula, although a dry area, is densely populated and intensively cultivated.