Speaking at The ARB Show, he said: "There's been more cutting of corners, though we can't easily get a handle on numbers. It can be lack of training, not using proper kit, not having a ground crew, pulling trees down with ropes, charging over the odds or just doing a bad job.
"Often workers only have a mobile number. Customers will have paid them in cash then want to know what we are going to do about it." But he urged people to report cases to local HSE offices.
According to Arboriculture Association director Nick Eden: "The industry isn't Government-regulated so anyone can buy a chainsaw and call themselves a tree surgeon - and in a recession, more people are tempted to do that. But it's bad for safety, bad for trees and bad for the committed industry members."