About 60 of the tree supporters had earlier this afternoon packed the board's public gallery in the HSBC Tower on Queen St as Waitemata Local Board chairman Shale Chambers warned of the risk to its reputation if it ignored community concerns.
Although his community board supported trimming the trees to provide clearance above a widened roadway, as part of an motorway interchange upgrade, he said it had taken the "unprecedented" step of opposing their removal.
"These notable, majestic, heritage trees provide a range of environmental services and amenity values," he said.
"They soften the impacts of the roading infrastructure, providing shade and protection, as well as being an iconic inner-city landscape feature in their own right."
He understood the trees, which extended 550 metres along Great North Rd, were planted on Arbor Day in 1934 in association with the development of Chamberlain Golf Course.
"Now over 80 years old, they have become a spectacular stand of native trees along the southern edge, forming a welcoming boulevard as intended at the time of planting."
Mr Chambers elicited gasps from the public gallery when he said a petition of 1475 signatures was among 54 submissions to the planning commissions ruled invalid by Auckland Council because of an incorrect reference number on submission forms, leaving just 10 to have been considered at a hearing in November.
Pohutakawa Savers representative Jolisa Gracewood spoke of the diversity of supporters including the Tree Council, tangata whenua and MPs from both sides of Parliament concerned about what would be a monumental mistake that would "leave a hole in the skyline for generations to come."
Auckland Transport's chief development officer Greg Edmonds said that if removing the trees could be avoided while achieving the objective of improving the transport network for general traffic, buses, bikes and pedestrians, "we would prefer that option" - but that was found not to be possible.
He was challenged from the public gallery on a statement that an alternative option which would save the trees would allow only one left-turning lane, before board chairman Lester Levy said his directors were able to make up their own minds without such interjections.
Dr Levy, who opened the meeting by noting the irony of its being held in the board's Kauri Room, promised those present that a decision would be reached behind closed doors before 5pm.