"And we estimate that that means we've lost approximately one third of Auckland's tree cover."
Barton showed NZH Focus a stack of approved consents by Auckland Council in 2013 and 2014. Many of those did not relate to just one tree, but several.
She says the rate of loss is accelerating.
"And we're not even seeing the impact of the Unitary Plan yet."
Barton expects more trees to be lost as intensification of the city continues.
"One of the main problems is the non-notified consent applications.
"So basically even if the trees could be accommodated in the development like around the outside or maybe they're going to be part of the reserve, as with the Snells beach tree, those trees still aren't being kept by the council."
She says Auckland Council is currently analysing remote sensing data on the city's tree loss.
"What we're anticipating is that when they get those results, they will back up what we've been seeing on the ground."
The Auckland Council says because of the 2012 changes to the Resource Management Act, it doesn't have a record of the number of now-unprotected trees chopped down.
And it did not answer NZH Focus' questions on exactly how many consents have been issued to cut down trees that are still protected under the Act.