Tree that killed woman ‘tolerable’ risk
Daisy Hudson
An oak tree toppled during a storm in January was described as being of a “tolerable” level of risk, months before it killed a Rotorua woman.
Documents released by the Rotorua Lakes Council under the Local Government Official Information and Meetings Act (LGOIMA) show an independent arborist assessed the tree in February 2017 and found it was showing “signs of decline” but was not a high risk.
But concerns raised with the council in August led to braces being replaced and weight reduction work taking place in September and October.
A few months later, Trish Butterworth, 56, was killed when the tree fell and crushed her during a storm.
The tree, known as Spencer’s Oak, split in two during the storm on January 5, falling on to the Te Arawa House building and across the road, crushing a car Butterworth was driving. She died at the scene.
Police say they are still working on their investigation on behalf of the coroner.
The just-released documents also reveal concrete was poured into the tree.
The council acquired the tree in 1991, after the owners of the land it stood on decided they no longer wanted to own it. The tree was of historical significance so the council was obliged to acquire the land to ensure it survived.
The tree was planted in 1863 from one of four acorns Queen Victoria sent to Reverend Richard Taylor.
In March 2002, law firm Wakeling & Associates presented a tree report to the council.
The report found the tree was mostly in good health.
But it did identify a “large cavity” in the main fork.
“Since that time the tree has formed a sound ring of healthy wood around the outside, but has not fully occluded [closed up] — in fact the wound will never heal over,” the report stated.
The cavity that formed below that wound was “very deep”, and had been filled with concrete and pumice. The concrete surface was about 600mm below the opening.
“The internal part of the cavity extends into the heartwood of the main leaders. I am unsure as to how far this decay has spread up the leaders. The width of the cavity inside the tree exceeds 600mm,” the report stated.
The trunk was found to be in a stable condition.
The report recommended further investigation of the fungal bracket and the extent of decay near the base of the tree.
In February 2017, arborist company Arbor Care presented a visual tree assessment of the oak.
It found there were “several old wire rope cables” installed in the tree, some of which appeared to be “under a lot of tension”.
The assessment detailed three possible risk categories — broadly acceptable, tolerable, and unacceptable.
The oak tree fell into the tolerable category. The removal of deadwood would reduce the risk to broadly acceptable, the assessment stated.
According to a report released under the LGOIMA, in late August council open space operation adviser (horticulture) Mark Paget met arborist Thomas Rika, where he raised concerns that one of the oak’s bracing cables was giving way.
Upon inspection in early October, Paget observed that one cobra brace had been installed to replace the fraying cable brace, and an additional cobra brace had been installed to assist another existing brace.
The council has been approached for comment.