What happens, inside slow forest, is not much. Just the odd snap and crack, of a dry twig dropping, every now and then. 
I know sometimes there is a rook. And I know a raven too, if you've managed not to fall asleep. And echoes. Of passing people on the trail. And of seagulls and roosting wood pigeons too. Every now and then.  
No, not much happens, in slow forest. Apart from the wind in the trees. And the buzzing insects. And the distant farm. And the plaintive cries of what we might imagine is a lonely juvenile bird. 
But slow forest, is the place to go, if you want to hear a forest just being a forest. It's so huge. And so empty (not counting the trees) that most of what you hear is just, forest. Trees being trees. Leaves being leaves, in the changing wind. And the changing wind, just being a changing wind. 
* We captured this hour of forest time by leaving the Lento mics alone on an old tree last month deep in the Wyre Forest in Worcestershire. Two planes doing a loop-the-loop can be heard steeply descending around the middle section of the recording, and the echoing whistles of a passing steam train as it travels along the Severn Valley Railway can be heard towards the end.