While hiking around some cinder cones at 9500 feet, we followed the rim of a crater and came upon a number of chunks of petrified wood:

Mauna Kea erupted a million years ago, but there were many more recent cinder cone eruptions from 250 000 years ago to as recent as 4000 years agp, one of which would have buried a small forested area.

We spent quite a bit of time exploring this area, pleased to have made this discovery, not noted in the literature that we could find.