Deforestation is the removal of trees without reforestation. The main causes are wood for construction, agriculture,
urban development, grazing animals and wildfires. While many of these causes are needed there should also be an obligation of
these companies to reforest
Wikipedia
Wikipedia has a comprehensive article about what causes deforestation.
ACT
Amazon Conservation Team works with indigenous people in conserving biodiversity, health, and culture in tropical America.
c Global Environment
These organizations fight deforestation and help protect land.
RAN
Rainforest Action Network works to protect the Earth's rainforests through education, grassroots organizing, and non-violent direct action.
Forest Action Network
The Forest Action Network is a network of over 500 activists who maintain a year-round presence on the coast of British Columbia, Canada. They helped to defer logging in 9 valleys in the Great Bear Rainforest.
Alaka Rainforest Campaign
ARC is a coalition of national and Alaska-based conservation groups that work to protect the remaining wild lands of the Tongass and Chugach National Forests from clearcutting and other harmful development.