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The combination of a giant branch - weighing between three and five tonnes - and high winds may result in a young Taiwanese woman losing her life.
The branch fell on the Waikato University student - understood to be on a "bridging programme" before undertaking an undergraduate degree - crushing her late on Wednesday afternoon.
The 20-year-old, in her second year of studies at the university, suffered severe head and pelvic injuries and is on a life support system in hospital. A source there has said it is unlikely she will recover from her injuries.
Hamilton arborist Ron Shea has estimated the weight of the branch at between three and five tonnes, saying: "I didn't realise from the picture how big it actually is."
He said the strength of the branch had been worn down by an "inclusion", caused when two branches grew into one another.
"It's the mechanical action of the wind that weakens it," he said.
"Years of leaf fill, soil and water then decompose and there's a bit of rot there. So it's water, wind, dirt and weight that have caused it to tear away."
Aborists have cut up the branch, which was awaiting removal from the scene of the accident yesterday.
The tree, an ailanthus, is situated on the inside fence of an industrial welding business and is about 15m from the border of the Ruakura Rd property, which is owned by Tainui but leased to AgResearch.
It is believed the student was making her way home along the rural road, which only has grassy verges, on the outskirts of the city at the time of the accident.
People who were the first at the scene on Wednesday were reported to have not initially known that somebody was underneath the branch.
The young woman's parents are on their way to New Zealand and her host parents, believed to be close friends of the Taiwanese family, were too distraught to make any comment at the hospital yesterday.
