Alnwick Area Friends of the Earth has raised concerns about tree felling in the town.
Last month, a number of 50 trees at Greenwell Lane car park were chopped down.
Landowner Northumberland County Council says it signed off the felling following a request from Northumberland Estates.
At February’s Alnwick Town Council meeting, councillors expressed their dismay that the work had been done without members being notified.
They demanded to know more and if further work was planned.
And now, Alnwick Area Friends of the Earth has made its views known.
A spokesman for the group said: “We are very concerned about the recent felling of more than 50 mature trees, which were of visual and environmental benefit.
“The group is worried that there has been no apparent mention of replacements for these trees within the town centre.
“Trees have many benefits which have been proved scientifically, time and time again.
“Trees are aesthetically attractive and make Alnwick a pleasant environment to live and work in.
“We urge the county council to recognise this and plant more trees to replace what the town has lost through this felling.”
A county-council spokeswoman said: “We were approached by Northumberland Estates, who wished to remove these trees because they were causing damage to their boundary wall and they were wanting to replace a damaged surface-water culvert to reduce the risk of flooding in that part of the town.
“We appreciate the points raised by the Friends of the Earth group and are in discussion with the Northumberland Estates regarding replacement tree planting.”