Westerham, Kent-based Acacia Tree Surgeon’s Adam Baldock fell six metres from a tree after the chainsaw was forced into the left side of his neck as he worked in Mitcham, Surrey.
It is thought that he was trying to remove a large branch which sprang back on the chainsaw and pushed it back towards him.
His death is not being treated as suspicious.
A police spokesman said: "He was fatally injured while working as a tree surgeon.
"It seems he was trying to cut a branch and it pushed the chainsaw back at him."
A health and safety team is also investigating his death because it was an accident at work.