When do events start?

Two Doves in a Wild Plum Tree, by Onda Tokuju, late 1920s

From Saving Time by Jenny Odell

The trees of Pando and the visible mushrooms of a fungal network are both examples of bodies that are also totally embedded in some other kind of body. Events can take on a similar ambiguity. When John McPhee writes about the San Gabriel mountain debris flow filling up a house in six minutes, it's difficult to see this event in isolation from its preconditions: for example, an earthquake that broke up the rocks, or a fire on the mountain during an earlier summer. Indeed, McPhee describes a summer fire in 1977 that prompted Hidden Springs officials to warn residents of the possible resulting debris flow in the coming winter (to no avail, even though they ended up being right). Did the debris flow start when the rocks moved? Or did it start when the chaparral caught fire?  (p. 268)

Later... 

Trying to draw a line around myself, I am forced to ask, Am I Jenny or am I my mother's daughter, my grandmother's granddaughter? and so on. If I am an event, when did I start? Thirty-five years ago? Hundreds of years ago? Thousands? Am "I" not like the visible mushroom growing out of a substrate outside which I would be incomprehensible, even impossible? Though my episodic memory goes back only so far, my existence is explained by older things: my mother's immigration, a war whose exigencies threw my grandparents together, and the fish swimming off the coast of Estancia, on the eastern tip of Iloilo. The people who fished there have something to do with me, just as I continue to have something to do with them.