Seven fledgling Norfolk pines on the Awatoto foreshore have been cut down - with the vandals dragging several of them down the beach and dumping them in the sea.
"It is unbelievable," Napier City Council Parks and Reserves manager Tony Billing said of the attack which happened overnight Tuesday and Wednesday.
The trees were planted about nine years ago as part of the Keep Napier Beautiful programme and stretched along about 200m of the beachfront just north of the Awatoto Rd/SH2 intersection.
It was the second vandal attack on young Norfolk pines during the past year.
Last July a dozen metre-high pines were slashed and broken off along a stretch of seafront between Westshore and Bay View.
"It is so annoying and so upsetting for staff who work damned hard to look after the trees and gardens of this city," Mr Billing said.
"We are involved in a concerted campaign to plant trees and improve the landscape - then to have some people decide to do this."
Works staff were alerted to the damage early Wednesday morning and discovered that whoever cut them down had used a handsaw to mask the noise, and had dragged several of the pines 120 metres down the beach and pushed them into the sea.
"They didn't realise the tide would just bring them back in - real bright, eh?"
Mayor Barbara Arnott and city councillors first learned of the vandalism while in a meeting on Wednesday.
"The reaction was one of great displeasure - that is a mild way of putting it," Mr Billing said.
Mrs Arnott described it as devastating, and vowed that council staff and the police, who are investigating the incident, would do everything they could to find, and prosecute, the culprits.
"These trees have matured after years of struggling in this harsh environment," she said.
"They were planted for the city by Keep Napier Beautiful and it is devastating to see the results of peoples' criminal actions."
Mr Billing said the pines would be replaced in the next planting programme which was set down around the middle of the year.
Due to the costs involved there was a question mark over whether some form of protective caging would be erected around them.
"It costs several hundred dollars for each one," he said.
Mr Billing said police and council wanted to hear from anyone who may have seen any activity around the trees during the night, or has any information about what had taken place.