PROMPT:On August 5, 2021, a fire ignited beneath energized power lines owned and operated by NorCal Utility Company (NorCal) in forest-covered and brush-covered land near Windy Road about 10 miles away from the community of Rural in High County, California. The High County Fire Department responded to investigate the fire. The investigator found a gray pine tree (Gray Pine) beneath the power lines in the origin area of the fire. He noted that a 1-foot section of the trunk about 2 feet from the top of the Gray Pine was charred.

After a thorough investigation, the investigator concluded that the Gray Pine contacted one of the power lines (the Power Line), exposing the tree to the electrical current conveyed through the Power Line. The heat of the tree-on-line contact burned the tree's bark and needles. Burning embers caused by the contact between the Gray Pine and the Power Line dropped into the dry and dead vegetation below the Power Line, igniting the Windy Fire. Images of the Gray Pine, taken by the investigator, are linked below.

The Windy Fire burned approximately 70,000 acres in High County. The fire damaged or destroyed approximately 950 structures before it was contained and suppressed.

The Gray Pine was part of a stand of trees near the Power Line. As of August 2020, it was more than 50 feet tall and 5 inches in diameter at its base, and it was tall enough to strike the Power Line if it fell. That month (August 2020), a NorCal vegetation management crew (tree crew) inspected the stand and identified for removal three trees on the outer edge of the stand that stood between the Gray Pine and the Power Line. In January 2021, Nor Cal Utilities' tree crew removed those three trees, but not the Gray Pine. This exposed the Gray Pine, which had been on the interior of the stand. Removal of the three trees on the outside of the stand left the Gray Pine without support on its side facing both the Power Line and the path of the sun.

As part of its investigation, the High County Fire Department had a tree expert (called an arborist) examine the scene and the facts. The arborist's report explained that trees that grow on the interior of a stand are weaker and are prone to failure if stable, exterior trees are removed. She concluded the Gray Pine was extremely thin for its height; trees with wider diameter and shorter height are more stable, while taller, thinner trees, like the Gray Pine, are less stable. She also noted that the Gray Pine's height-to-diameter ratio was more than 100-to-1, indicating extreme instability and high risk of failure.

The arborist concluded that exposing this weak and unstable tree by removing the other trees from the stand left the Gray Pine prone to leaning or falling in the direction of the Power Line. She also found that a range of other factors, including new growth on the thin Gray Pine, and the wind conditions, also played a part in the tree's toppling into the Power Line.

As part of its vegetation management program, NorCal utilizes aerial imagery to identify and prioritize areas for treatment, including trimming and falling hazard trees. It also has a tree hazard rating system. Within that system, it had assigned gray pine trees, as a species, a "very high" potential for failure, because preceding the Windy Fire, NorCal recorded many occurrences of gray pine trees failing into power lines and causing outages. Aerial imagery taken prior to the Windy Fire shows the Gray Pine leaning towards the Power Line.

A. First, summarize the facts, issues, holdings, and rationales from the County of Ventura v. Southern Cal. Edison Co. (1948) 85 Cal.App.2d 529 (County of Ventura) and Beresford v. Pacific Gas & Electric Co. cases.