I recently completed some exploratory designs for a new cheese product that unfortunately will not be going ahead, and some illustrations for interpretive signage at Mariposa Grove that will. Here are a few of them.
The Phymatodes nitidus borer beetle and Douglas squirrel both have symbiotic relationships with Giant Sequoia trees (cross section shown) in that they speed seed dispersal from cones (also shown) that otherwise may remain closed for 20 years. The squirrel eats the cone scales and discards the seeds, and the beetle severs vascular connections to the scales, which dry and release the seeds.
Even then the seeds are unlikely to germinate in the rich organic matter around the trees until fire creates minerals that trigger the process.