By now it's no secret that the Butte Fire was likely sparked by a tree coming into contact with a PG&E overhead line. Jaxon Van Der Beken of the San Francisco Chronicle (who, by the way, won awards for his investigative reporting of the San Bruno PG&E fire), broke that news a week ago.
But PG&E makes a point of saying that the tree was a live tree. PG&E really wants us to know that.
Does it matter? Not really. Certainly, PG&E's lawyers will point out that there are many regulations requiring PG&E to clear away from it's overhead electrical lines trees that are dead or rotten. For example, the California Public Utility Commission rules say
When [PG&E] has actual knowledge . . . that dead, rotten or diseased trees or dead, rotten or diseased portions of otherwise healthy trees overhang or lean toward and may fall into a span of supply or communication lines, said trees or portions thereof should be removed.
But PG&E's responsibilities don't end there. The law requires PG&E to prune as necessary to keep it's electrical lines clear of all trees, dead or alive.
Dead trees, old decadent or rotten trees, trees weakened by decay or disease and trees or portions thereof that are leaning toward the line which may contact the line from the side or may fall on the line shall be felled, cut, or trimmed so as to remove such hazard.
If, as PG&E says, it inspected many times since 2014 the live tree that sparked the fire, it presumably should have noticed that the tree could contact the electrical line, just as might a dead or rotten tree, and "felled, cut, or trimmed" the tree so as to remove the hazard.
PG&E's lawyers might argue the point, but on its own website, PG&E seems to acknowledge that its responsibility extends to all trees that might come in contact with one of its lines, whether that tree is dead or alive.
Utilities are required to maintain clearance between vegetation and high voltage power lines at all times in all areas for public safety and electric system reliability.
It's just common sense.