Rock and tree fallsRock and tree falls

Rock and tree falls

Little is known about the influence of rockfall and surface instability on the population dynamics of the Wollemi Pine, but it is thought to be an important factor. The sandstone on which Wollemi Pine occurs is known to be unstable. Indeed, rockfalls have been observed in situ. Rockfalls may cause mortality and injury to different plant species at different rates, mediating competitive interaction and influencing community composition. Injury through rockfall may also trigger coppicing. That Wollemi Pine exists on steep slopes may indicate it is more tolerant of, or better able to withstand, substrate instability than co-occurring species (such as, via physical protection from bark, or differences in root deployment and penetration into the sandstone). Tree and rock falls damaged several Wollemi Pine individuals during the 2019–20 fires, and the incidence of such disturbances has increased since the fires.

Immature wollemi pine stems sprouting from the base of the burnt trunk of adult wollemi pine trees.