The theme, the Vatican announced March 8, is "The Amazon: New paths for the church and for an integral ecology."

The Pope also named 18 members for the pre-synod council that will collaborate with the secretary-general of the Synod of Bishops in preparing for the special assembly next year.

A synod council usually prepares an outline and list of questions, which bishops' conferences and other interested groups in the church respond to. The responses are then compiled and analyzed before a synod working document is prepared.

The synod will seek to hear the voice of those living in the Amazon region and identify new paths of evangelization, especially for indigenous people who are "often forgotten and left without the prospect of a peaceful future, including because of the crisis of the Amazon forest," which plays a vital role in the environmental health of the entire planet, the Pope has said.

"We have to break with the historical paradigm that views Amazonia as an inexhaustible source of supplies for other countries without concern for its inhabitants," he said when meeting indigenous people in Peru in January 2018.

Rich in biodiversity, natural resources and cultures, the Amazon rainforest is the largest in the world, covering more than 2.1 million square miles in South America. The rainforest spreads across Brazil, Ecuador, Venezuela, Suriname, Peru, Colombia, Bolivia, Guyana and French Guiana.

Among the 18 new members of the synod council are three cardinals, 13 bishops, one nun and a layman -- the majority of them are from countries in the Amazon region.

Council members include: Brazilian Cardinal Claudio Hummes, president of the Pan-Amazonian Church Network (REPAM); Ghanaian Cardinal Peter Turkson, prefect of the Dicastery for Promoting Integral Human Development; Mexican Cardinal Carlos Aguiar Retes of Mexico City; British Archbishop Paul Gallagher, Vatican foreign minister; Sister Maria Lopes Dos Santos, a member of the Carmelite Missionary Sisters of St. Therese of the Child Jesus and delegate of the Confederation of Latin American Religious; and Mauricio Lopez, executive secretary of REPAM.