My Pearson 31 sailboat has balsa cored decks in a fiberglass sandwich. End grain balsa coring is common in fiberglass boats (but lately foam is taking over).
Balsa is actually somewhat difficult to propogate.The seeds cannot be stored and pregermination treatments are required to ensure germination rates greater than 10 percent. The fibers must be removed by hand or by burning.The seeds are then placed in boiling water and the heat source is removed. After soaking in the water for 15 minutes, the seeds must be planted immediately.
Makes you wonder what the feral trees do in the wild?
"Honey, time to boil the kids".