Single tree blamed for devastating blaze

A devastating bushfire that razed nearly 200 homes in the Blue Mountains and destroyed 3600 hectares of land might have been avoided if Endeavour Energy had chopped down a single rotting tree, a NSW Supreme Court judge has been told.

Resident Sean Johnston and a number of his neighbours have launched a class action lawsuit against the power company.

They allege it failed to take reasonable steps to properly monitor and clear vegetation around power lines in the mountains west of Sydney.

The plaintiffs allege the huge blaze that burned through the lower-mountains suburbs of Winmalee, Springwood and Yellow Rock in October 2013 was sparked by a wattle tree falling onto power lines at Linksview Road in Springwood.

Justice Peter Garling on Wednesday listened to a triple-0 call made by nearby resident Marilyn Stubbs after she looked out her window on October 17 that year to see "trees exploding into flames".

The fires burned for weeks, destroying 194 homes and damaging hundreds more.

"For members of the group who were caught in the path of the fire, the experience was life-threatening and terrifying," the plantiffs' barrister Tim Tobin SC told the court in his opening address.

He said the dangers of trees and scrub around power lines were well known across Australia, particularly after the deadly Black Saturday bushfires in Victoria and subsequent royal commission.

Endeavour's own records showed that trees and branches falling onto powerlines were a major cause of fires started on the company's electricity network.

"The risk was not only foreseeable, it was foreseen," Mr Tobin said.

Mr Tobin said that as at early 2011, Endeavour's internal guidelines required that "scopers" identify dead, dying, dangerous and visually damaged vegetation and hazard trees around its poles and wires.

But Endeavour's contractors handed that task to workers who were classified as labourers and had little - if any - specialised training in tree inspection, the plaintiffs will allege.

"The evidence will establish that the contractors did not inspect for hazardous trees," Mr Tobin said.

"Endeavour knew they didn't, expected they didn't, and acquiesced in it."

In the years leading up to the 2013 blaze, Mr Tobin said, Endeavour had significantly underspent on vegetation management - by almost $100 million less than the amounts approved by the Australian Energy Regulator.

"The plaintiffs' case is that, had Endeavour taken the precautions, an appropriately trained inspector would have conducted a walk-by visual inspection of the tree (at Linksview Road) and would have observed signs in the tree that would have caused him to take a closer look at the base of the tree, which inevitably would have led to the tree's removal," Mr Tobin said.

The case is expected to last nearly two months.