"I" == Iris Cohen writes:

I Bamboo is a very rapidly growing plant. You are probably hearing it grow. Out
I in our Midwestern corn belt, they say you can hear the corn grow in midsummer.

But from 200 meters away, about one pop per 10 minutes per clump on a
hilltop, from several hilltops, for a hour or two a few days a year?

No, they weren't on fire. Perhaps it might be sudden dryness of the
air though... but I don't have a humidity meter to tell, oops. No
barometer either.
--
http://jidanni.org/ Taiwan(04)25854780