It then fell to six of the protesters to look for a compromise.
It's not the first time the survival of trees has roused strong emotions in the River City.
Jay Kuten, who was at the December 2 meeting, remembered other examples of residents outraged at the sudden removal of trees.
In one incident in the 1990s former mayoress Delphine Turney climbed into Victoria Ave plane trees. There was a proposal to fell them because they interfered with the working of a closed-circuit television camera. In the end those trees were trimmed, and stayed.
Another furore broke out when the council began replacing London planes with the more compact autumn glory variety. The matter occupied many a column centimetre in this paper. The city now has a mixture of the two.
Some in the city are passionate about keeping any and every tree.
The council had it the wrong way round, Deidra McMenamin said at the December 2 meeting.
"The services are interfering with the trees."
She was upset at the recent felling of an elm tree at Pakaitore/Moutoa Gardens. It's also making way for the Taupo Quay upgrade. She said trees helped soak up stormwater and prevent slips, and also created shade and pumped out oxygen.
"They actually provide a structural job in the environment."
On the other side of the fence is Alex Garrett, who owns the shopping arcade at 45-47 Taupo Quay. He wants the gigantic planes gone, and wasn't pleased to hear that more may be planted outside his building. They were far too big, he said.
"It costs me at least $1000 a year for the constant cleaning of gutters. My gutters are all brand new, done to the highest normal standard, but they can't keep up with the trees being that big.
"The gutters have to be done every three weeks or after any wind of any significance - we are constantly on edge."
The council would not remove trees for no reason, Ms Main said. One of her fears about this particular plane tree fuss was that it would reveal how much trees are costing the city's ratepayers. Council roading manager Rui Leitao said it cost nearly $100,000 to replace 11 plane trees in Victoria Ave in the past financial year.
London planes are proven street trees and are allowed to grow large in cities such as London and Paris, even in narrow streets. The council's 2008 tree policy says they should remain a dominant tree for the city, but that keeping all of them is impossible, due to "size, disease and damage to infrastructure".
Those facing the axe in Taupo Quay were planted in the early 1880s, on reclaimed riverbank land.
The six people chosen to negotiate their future were Ms McKay, Colin Ogle, Phil Thomsen, Bruce Dickson, Cath Watson and Ross Mitchell-Anyon. They met council officers and deputy Mayor Hamish McDouall on Tuesday. It was a long meeting, and some had to leave before it ended.
Mr Mitchell-Anyon said most of the protesters were prepared for a compromise.
One of the elements of the discussion is that council was looking to dig a new service trench one metre from the trunks of the trees. One new element in the trench is a Powerco cable, the meeting heard. It would link two electricity substations and provide back-up power if one of them stops working.
Other services are already there, and Ms McKay said plane tree roots had never interfered with them in the 23 years she has lived in the street.
Running the services down a trench in the middle of the street instead of on the footpath would cost $750,000 and double the cost of the upgrade, roading manager Rui Leitao said.
There's more to the upgrade than just a service trench. There's also the need for 40 more car parks before the relocated Sarjeant Gallery opens in April.
"The parking layout is critical to the council's compliance with their own resource consent," Mr Mitchell-Anyon said.
One of the plane trees may also have to make way for a bus stop outside Wanganui's information centre.
The result of Tuesday's meeting is an agreement - grudging on Ms McKay's part - to fell two of the six plane trees, keep three and continue to debate the future of the sixth. It's the one that could make way for the bus stop. It's also one of those outside Ms McKay's building.
The two trees going are immediately outside the information centre and tram shed. In their place will be a raised intersection and a planting of four rata/pohutukawa hybrid trees, one at each corner.
Deputy Mayor Hamish McDouall says they will create a view corridor down Drews Ave, linking the city with the river, where there are more pohutukawa trees. It will be "quite legible in arboreal terms", he said.
The two condemned trees could go at any time, with no need for further council approval.
The three trees definitely staying can have the service trench put around them. They are the two opposite the Saturday River Traders' market, and the one closest to the Whanganui Bridge. Mr McDouall said they were the "grandest" of the six.
That leaves just the one contentious tree, the one between Ms McKay's building and the information centre. Mr McDouall says engineers are debating its future, and their conclusion may have to go back to the group of six.
Ms McKay will cease her protest if only two trees are felled. She's not sure how she will react if any others have to go.
After hearing all the arguments she still feels the main barrier to their survival is not the service trench but the council's arbitrary insistence on seeing through its plans for the area.
It's been hinted that she's being selfish about the trees, and she said that might be true.
"But I am a long-term resident, who has been there since before there was any council interest in developing the area. I also know there are many others besides myself that love them."
Mr Mitchell-Anyon is one of those. But he said what most worried him this time was the lack of consultation before the trees' removal. They were heritage trees, and he said everyone - not just local residents - should have had a chance to express an opinion. Under current policy the trees can be removed without a word to anyone - which is what happened when one was felled during renovation of the information centre building.
Mayor Main has promised a review of the council's tree policy early next year.
The huge old London planes in Wilson St and outside the former Wanganui Chronicle building are also in the gun. Ms McKay said anyone who wants to keep the city's large old trees should be vigilant about responding to that review.