If you ever see a tree or shrub up and die for no reason, and you found no bug holes, no foreseeable trunk problems, no root girdle; you probably have a gas line break.
It doesn’t take much of a rupture in a high pressure gas line to flood enough roots with this plant killing gas. These lines are supposed to be three feet underground, which means you are not likely to smell it either.
Most times it is a larger tree that is affected. The roots over time grow down and out and begin to put pressure on the gas lines they are planted over
You may have never heard of a tree dying of this before, it is a rare occurrence, but common enough to be known by people in my line of work. Unfortunately there is no recovery from this; extra water won’t fix this problem.