Guiana Shield is equally rich and 13,367 species of vascular plants have been found, approximately 40% of which is considered endemic. The shield is overlain by the largest expanse of tropical forest on any Precambrian shield area in the world. Guianan rain forest is similar in nature to Amazonian rain forest and known protected areas include the Iwokrama Forest of central Guyana, Kaieteur, Kanuku National Park of southern Guyana, the UNESCO World Heritage Site Central Suriname Nature Reserve of Suriname, the Guiana Amazonian Park in French Guiana and the Tumucumaque National Park in the Amapá State of Brazil. In Venezuela the forests
British Guiana in the Anglo-Dutch Treaty of 1814. The UK continued separate administration of the individual colonies until 1822, when the administration of Essequibo and Demerara was combined. In 1831, the administration Essequibo-Demerara and Berbice was combined, and the united colony became known as British Guiana. The economy of British Guiana was completely based on sugarcane production until the 1880s, when falling cane sugar prices stimulated a shift toward rice farming, mining and forestry. However, sugarcane remained a significant part of the economy (in 1959 sugar still accounted for nearly 50% of exports). Under the Dutch, settlement and economic activity was concentrated