A "gap in the system" was blamed after a tree toppled in a downtown Auckland square, crushed a car, and narrowly missed people.
After the melia tree collapsed in St Patrick's Square, council documents suggested the tree had not been maintained for at least six years, despite visible decay.
Auckland Council information disclosed after Herald enquiries showed a council legal consultant raised concerns about the quality of tree inspections.
But the contractor said multiple steps were in place to reduce the chances of another incident like that of November 12 at St Patrick's Square.
"We are in the process with Auckland City Council Team to revise these processes and systems to ensure that this doesn't happen again."
Treescape Executive Chair Ed Chignell said there was an initial misunderstanding about the fallen tree's location and species but a detailed investigation followed.
"Treescape and Auckland Council identified that the tree had not been previously inspected for a number of years," he told the Herald today.
"This highlighted the need to review the Auckland Central inspection zone and how inspections are conducted in Auckland Central and to what detail."
He said the contractor would annually review the Auckland Central inspection zone list in collaboration with the council.
"All trees in Auckland central are inspected on a regular basis by a qualified arborist. The inspection results are audited by Auckland Council staff," he added.
"Treescape and Auckland Council are continually working on improvements to tree risk evaluation whilst balancing the need to maintain and enhance the Auckland urban forest."
Council legal and risk consultant Agnes Banta expressed concerns on November 17 to four colleagues about "deficient" tree inspection recordings.
She said the tree's last recorded maintenance was in February 2014.
"Given that there was visible decay and a cavity on the tree, it is a sensible expectation to have shorter gaps in between the scheduled maintenance," she added.
The driver wrote to the council about the destructive incident, saying it was distressing.
"I truly believe that if I had not taken the swift action to slam on my brakes and reverse the car, we would either be in the spinal ward of the hospital or worse."
He spoke at the time of complaining to police but today he told the Herald the issue had been resolved.
A services schedule for thousands of Auckland trees showed Grange Rd had 88 trees on the list. Agonis melia was the dominant species.
All the street's trees were inspected every 12 months and maintained every five years, according to the schedule.
After the Fiesta was damaged, a council arboriculture manager said the melia's stem decay wouldn't have been noticed in the last planned street inspection in July 2020.
"Prior to the failure there was no indication of poor tree health, it still having a full vigorous canopy."
He said the street's maintenance history showed the tree was last fully maintained in November 2017 and was halfway through its next pruning cycle.