The historic ‘Aspen' necklace poplar, cottonwood tree at the McLean Street reserve is set for its next major chop.

The already shortened tree is being further truncated on Tuesday to make the reserve safe for Tauranga Jazz Festival patrons.

The ‘Aspen' tree is about to be further cut.

The plan is to cut 7-10 metres off it, weather permitting, to ensure the safety of the event.

The remaining trunk and stonewall will be completely removed after Easter.

The historic tree's decline became apparent on January 17 when an eight tonne branch fell onto McLean Street – narrowly missing parked cars.

The 146 year old tree is being cut down before it falls down, an arborist's report on the tree reveals.

Independent arborist Paul Kenny says the tree is in decline and in increasing danger of collapse.

The necklace poplar is rotting inside and the roots that hold it up are also failing.

Structural roots on the southern and western sides of the tree are 'in significant decline” says Paul.

The internal rot is so severe that in spite of 30 tonnes of weight being removed from the tree by Arbor Care in the days after the branch fell, still more has to be cut to make it safe.

The trunk is hollow and too weak even to support the significantly reduced branch structure.

If it's not cut down, public access to the reserve will have to be restricted, and the height of the tree severely reduced to prevent it striking adjacent buildings should it fall.

Regular pruning and inspections will be required to monitor the risk of a structural failure and further drastic pruning may still be required.

The total cost of the branch failure, clean up, the ensuing cut back and independent assessment has cost $9817.64 plus GST.

A Tauranga City Council decision was required because felling the historic tree requires resource consent.