Councillors are warning members of the public to be on their guard about rogue tree surgeons.
People across Lincolnshire are being warned by councils and professionals to watch out for untrained tree surgeons offering discount services.
The Echo reported earlier in the year how the bogus callers were putting residents at risk of a £20,000 fine by chopping down protected trees.
Qualified tree surgeon Jacob English said he thought the crooks might be coming out of the woodwork now because of the recession.
"There are a lot of people suffering from the economic down turn and I think people are doing it now as a way of making money.
"It can be appealing because they do it cheaper than we would but the work they do will be poor and they won't have the insurance they need."
Mr English, who set up The English Tree Company after qualifying from the Riseholme campus of the University of Lincoln said the illegal tree surgeons were also eating into legitimate businesses.
"We were set up two months ago so it is hard to see an impact now but I'm sure in the long run it will have an effect."
Graham Penn, Doorstep crime co-ordinator for Lincolnshire trading Standards, said: "Rogue traders will often use gardening as a means of exploiting vulnerable residents.
"Recently a gang quoted a Lincolnshire resident £250 to lop trees and then demanded £750, saying the quote was £250 per tree and they had lopped 3 trees.
"They often use gardening as a method of gaining trust and then commit distraction burglary when an opportunity arises they sell information of their targets on to other gangs as well."
More details on the rules regarding tree surgery, see Monday's Echo.