The future of Tauranga's iconic 147 year old 'Aspen tree' remains uncertain after one of its large branches fell on Monday morning – temporarily blocking McLean Street in the central city.

A contractor cleans up the mess left on McLean Street after a large branch fell from the historic 'Aspen tree'.

Tauranga City Council arborist and parks coordinator Joshua Trafford says they will do everything to save the black cottonwood tree, often referred to as the 'Aspen tree', but the state of its health is being assessed this week.

He is unsure what caused the large branch, estimated at about one metre in diameter, to plummet to the ground shortly after 9am, although when arborists arrived to survey the scene on the corner of Willow Street and McLean Street, they detected a large amount of rot and decay where the branch was joined to the tree.

Joshua says the tree was planted in about 1864 and is protected under the district plan.

The council's principal tree contractors, Arbor Care Limited, will complete its testing on the tree by the end of Tuesday.

Council will seek a second option from another tree contractor and those tests should be known by the end of this week.

'Because the tree is such an iconic tree, it's worthwhile taking the time to get all the information we need to make a decision on its future,” says Joshua.

Jean Doust heard the loud crack and witnessed the branch crash to the road from her office across the road.

It landed near her car and other vehicles parked on McLean Street.

No vehicles were damaged, but Jean says a truck did sustain a minor scratch.

'It was so quick. We were just looking out and we heard this great crack, we thought it was a car crash.

'It shuddered when it landed on the ground. People in the offices thought it was an earthquake,” says Jean.