Rust surmised the "selfish" act occurred because someone thought the pōhutukawa tree was detracting from a sea view. He personally believed such trees enhanced the view.
"I think there's nothing worse than just a bare landscape and the sea; in particular the pōhutukawa is just such an iconic tree and when they're in bloom, they're spectacular."
Rust's views were shared on social media, with dozens of people sharing their dismay to his post on the Doubtless Bay Noticeboard Facebook page.
Rust hoped the attention would put off anyone from poisoning a replacement or any other trees.
"There are a few others I would hate to see killed."
The Far North District Council - which was responsible for trees on reserves, roadside berms and beachfront esplanades - had not yet received a report of any trees being killed on Dudley Cres, spokesman Ken Lewis said. But such matters were taken seriously.
Under Section 76 of the Resource Management Act, anyone who damaged or cut down a tree protected under that act without consent could be fined up to $300,000. Similar financial penalties were contained in the Reserves Act.
"Trees provide ecological and amenity values in urban centres. They provide shade along footpaths and roadways, and may be associated with historical events or people. They provide habitat for wildlife, help control rainwater flows and erosion, and help moderate local climates," Lewis said.
"Pōhutukawa, in particular, are an iconic tree for New Zealanders and are now at risk from myrtle rust disease."
Lewis said anyone who noticed damaged trees, not obviously on private land, should to report this to council on 0800 920 029.
"It is important that damaged trees, or trees that seem unwell, are reported as it may be possible to repair damage or prevent further damage if arborists can tend to these quickly."
It's the latest in a spate of tree poisonings in the Far North.
Four pōhutukawa trees were poisoned in November last year in Opito Bay, in the Bay of Islands, angering and frustrating locals from the area. Those trees were now responding well to a home-grown treatment by Kerikeri expert Phil Walesby.
And Paihia couple Lisa Harris and Daniel Gonin returned to their Sullivans Rd home in January after a nine-month stay in Australia to find several trees on and around their property were dead or sickly after being poisoned.