French President Jacques Chirac gathered with African leaders in Republic of Congo on Saturday at the start of a two-day summit aimed at finding ways to preserve the world's second largest rain forest. The forests of the Congo Basin _ an area that comprises 10 countries _ are home to more than half Africa's animal species, including the world's entire population of lowland gorillas. Nearly 20 million people depend on the forests for food and shelter. African leaders attending the summit are expected to sign a treaty to better control poaching and illegal logging which threatens the basin's vast 200 million-hectare (500 million-acre) ecosystem. The 10 nations that make up the Congo basin are Angola, Burundi, Cameroon, Central African Republic, Congo, Equatorial Guinea, Gabon, Republic of Congo, Rwanda and Sao Tome and Principe. Despite improved conservation efforts in recent years, environmental groups warn the forest is still shrinking at an alarming rate, due mostly to illegal logging. Poaching and a rampant illegal bush-meat trade also threaten the ecosystem. Chirac arrived in Brazzaville after a two-day trip to Senegal. He is due to return to France later Saturday.