green-billed coucal and the Sri Lanka blue magpie. The untapped genetic potential of Sinharaja flora is enormous. Of the 211 woody trees and lianas within the reserve, 139 (66%) are endemic. The total vegetation density, including trees, shrubs, herbs, and seedlings, has been estimated at 240,000 individuals per hectare. The Minneriya National Park borders the Minneriya Tank, which is an important source of water for elephants inhabiting the surrounding forests. Dubbed "The Gathering", the congregation of elephants can be seen on the tank-bed in the late dry season (August to October) as the surrounding water sources steadily disappear. The park also encompasses a range of micro-habitats which include classic dry zone tropical monsoonal evergreen forest, thick stands of giant bamboo, hilly pastures (patanas), and grasslands (talawas). During the Mahaweli Program of the 1970s and 1980s in northern Sri Lanka, the government set aside four areas of land totalling as national parks. Statistics of Sri Lanka's forest cover show rapid deforestation from 1956 to 2010. In 1956, 44.2 percent of the country's land area had forest cover. Forest cover depleted rapidly in recent decades; 29.6 percent in 1999, 28.7 percent in 2010. Government and politics Sri Lanka is a democratic republic and a unitary state which is governed by a semi-presidential system. Sri Lanka is the oldest democracy in Asia. Most provisions of the constitution can be amended by a two-thirds majority in parliament. The amendment of certain basic features such as the clauses on language, religion, and reference to Sri Lanka as a unitary state require both a two-thirds majority and approval in a nationwide referendum. In common with many democracies, the Sri Lankan government has three branches: Executive: The President of Sri Lanka is the head of state; the commander in chief of the armed forces; chief executive, and is popularly elected for a five-year term. The president heads the cabinet and appoints ministers from elected members of parliament. The president is immune from legal proceedings while in the office with respect to any acts done or omitted to be done by him or her in either an official or private capacity. Following the passage of the 19th amendment to the constitution in 2015, the president has two terms, which previously stood at no term limit. Legislative: The Parliament of Sri Lanka is a unicameral 225-member legislature with 196 members elected in multi-seat constituencies and 29 elected by proportional