A contractor working for Welwyn Hatfield Borough Council has cut down 11 trees at a park in error.
The tree contractor Maydencroft was originally meant to go to two other parks in the Welwyn Hatfield area last week, but ended up cutting down poplars in Moneyhole Lane Park in the Panshanger area of Welwyn Garden City.
"We're normally known for our exceptional quality of work, but on this occasion we very much missed the mark," Maydencroft's managing director Tom Williams said.
"We deeply regret this error, I personally and all the team at Maydencroft are very sorry for our actions."
WGC resident TK Choo came across the trees being felled while out for a stroll on Friday.
TK then endeavoured to get in contact with the council, but was unable to reach the person responsible over the weekend so trees were cut down on Monday.
"I reprieved a further 11 after contacting the council and councillors," he said.
Mr Williams said Maydencroft will offer the council compensation - in the form of tree planting - at sites of the WHBC's choosing, "and for any works associated with what we have done".
He added: "We are hugely saddened to hear about this most regrettable error at Moneyhole Park - we know how important trees are to our environment and to our communities."
Maydencroft was carrying out the tree felling as part of the borough's programme to replace mature Lombardy poplar trees that are in decay.
Felling has been carried out since April and the plan is to replant the poplar trees in November this year when the winter planting season begins.
A spokesperson from the council said the tree felling, under the poplar replacement programme, is reaching an end but that "the trees at Moneyhole Park should not have been included in this project".
The spokesperson added: "Regretfully, our contractor felled them in error; there was no instruction to include them in the programme."
The council has said it will work with local residents to find out "what they would like to see in place of the Lombardy trees and where, in time for the next planting season come autumn".
Welwyn Hatfield Borough Council lists on its website all the tree removals it undertakes here: welhat.gov.uk/treeremoval.
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