The teen was arrested in relation to trespassing, but later released after being given a warning, a police spokesman said.
The teenager was the last thing stopping the removal of the tree - on the corner of Ash St and Great North Rd, in Avondale - where 117 units linked to the Ockham-Marutūāhu development are set to be built.
Azor's arrest comes after months of protesting efforts by residents in the community and those from protest group Mana Rākau.
The group earlier surrendered to authorities; saying the removal of the 120-year-old tree was the only way the apartments could go ahead.
Plans to remove it yesterday were halted as Azor continued to stay in the tree and refused to budge.
This morning's arrest comes after allegations of intimidation by someone who arrived at the scene in the early hours of today - about 1.30am - and climbed the ladder to where Azor was sleeping.
An Ockham spokesman confirmed the visitor was a member of staff but there was no intimidation.
A woman who was sleeping in a van not far from the tree, in support of Azor, told the Herald she was woken by a phone call from the teen.
"He rang me about 1.30 in the morning and said there was a man there - that he came up from behind him.
"He sounded worried."
The woman said she confronted the man - who quickly told her he'd done nothing wrong.
Ockham spokesman Peter Malcouronne said their site manager went up the ladder.
"Our site manager did climb the ladder with a bag of fruit I gave him to give to Caleb. He wasn't asleep - we'd been talking to him for two hours prior.
"Our site manager – who had talked with Caleb for several hours over the preceding day – then had a brief conversation with him."
The conversation was initially calm, but Azor became slightly upset and called the "sleeping woman", Malcouronne said.
"We did not wake Caleb, we did not intimidate him or, as has been alleged on several Facebook forums, take any of his possessions.
"We have a lot of respect for Caleb – he's a kind and very idealistic young man – and we urged the police not to press charges when he came out of the tree."