תרגום - אנגלית-אספרנטו - Only when the last tree has been cut down, Only...

In general this is a good translation, but there are some things that I think would improve it.
/perceptos/konstatos/
/estas mangxebla/mangxeblas/
All of the "estos ..ita" forms could be changed to "..itos" to make them pithier.

Hi, stevo! I see you got back as well.

"Konstatos" and "manĝeblas" seems OK to me, but the verbs in "...itos" sound quite strange...

They do to me too, because they are used so rarely, but they are still correct. It's a way to make the message more direct, more immediate. Rather like saying "kill" instead of "take a life".