I found a way do complete…
Some trees have separatists up there, you need to punch this trees to make then fall down…
But this trees dont have HP Bar, so you need to punch then with melee weapons…
you will know who is the correct tree when it you complete the autoattack combo (but you need to press the 1 the three times to combo be completed).
Sometimes 2 ou 3 separatis will fall down… sometimes you will receive exp (aparently you killed him up the tree).
That was my way to complete this heart.
