BELEM, Brazil — Eight Amazon nations agreed to a list of unified environmental policies and measures to bolster regional cooperation at a major rainforest summit in Brazil on Tuesday, but failed to agree on a common goal for ending deforestation. It is not possible that, in a scenario like this, eight Amazonian countries are unable to put in a statement — in large letters — that deforestation needs to be zero,” said Marcio Astrini of environmental lobby group Climate Observatory. Beyond deforestation, the summit also did not fix a deadline on ending illegal gold mining, although leaders agreed to cooperate on the issue and to better combat cross-border environmental crime