Here in Brazil we have a big problem regarding our forests and animals that are often ill-treated, exterminated or sold illegally to other countries.
So I usually work personally or financially with SOS MATA ATLANTICA ( http://www.sosma.org.br ), WWF-Brazil ( www.wwf.org.br ) and the PEA-Projeto Esperança Animal ( www.pea.org.br).
As far as I could see these organizations do a good work for the environment with responsibly and clarity, keeping their supporters informed about decisions and activities taken by them.

Gassho.