Ok, stubs/branch collar. There was an aproxomatly 1 cm collar on the largest removed branch towards the house, but nothing I gave any thought about while standing on the ground.
The piece wasn't given any push, the climber actually held it back so it wouldn't fly far (He has had a habit of pushing a bit much, and had few pieces landing a bit out the "comfort landing zone") The piece then flipped arround and skidded down the trunk, before hitting the stub/branchcollar and leaped right into the roof.
Anyways, we're all good now, and the roof is beeing taken care of, so everyone is happy.