South West Water (SWW) has been accused of being a "neighbour from hell" after a row of trees that blocked its sewage treatment works from residents in St Erth were chopped down without warning.
The company said the leylandii had to be felled because they had been damaged by roosting starlings, but residents are angry that the company did not inform anyone of the decision to remove the trees.
People living near the plants say the loss of the trees has led to more noise and light pollution.
Kerry Davis, who has lived on Cledma Bank, which faces the sewage works, for 15 years said: "They just seem to do whatever they want, when they want.
"They are a law to themselves really ... they are neighbours from hell."
John Cook, who lives nearby, said the first he knew about the plans to get rid of the trees was when he and his wife spotted them coming down.
"It is disappointing and very cavalier the way they did it," he said.
Resident Mike Matthews is also angry and said he estimated the decision had devalued his property by £150,000.
"They said they are going to replant trees next week but it is going to take a decade for them to grow," he said.
Mr Matthews can now see the sewage works, which he said looked like "Chernobyl", from his dining room, bedroom, living room and the new patio he just had built.
St Erth parish council has received numerous complaints from residents since the trees were cut down two weeks ago.
The council, which was not informed that SWW intended to undertake these works, has now referred the matter to Cornwall Council's enforcement section for investigation.
Parish council chairman, Ted Taylor, said: "SWW said that the trees had to be felled after being damaged by roosting starlings but everyone finds that hard to believe. I think that any damage to the trees was more likely to have been caused by the recent storms and that rather than carefully remove any damaged branches, it was probably cheaper to cut down the whole lot."
Parish clerk Peter Rylett added: "It is no wonder that SWW is regarded as a bad neighbour in the community and, hopefully, will be gracious enough to admit that it could have handled this better and not repeat its mistake in the future."
A spokeswoman for South West Water said the decision to fell the trees had been taken "reluctantly" and that replanting would start once the area was safe and clear of stumps.
She said: "A large number of starlings have been roosting in the leylandii trees at Hayle Sewage Treatment Works. Unfortunately the birds damaged the trees to such an extent that they were no longer safe to leave after several large branches fell onto equipment at the site.
"In the meantime, we have asked the operators on site to make sure that the lights are turned off at night so as not to disturb local residents and where this is not possible to redirect the lights so they are not pointing towards nearby properties."
