I photographed a cabbage tree (Cussonia spp) that had seeded itself in the trunk of a palm tree. It appeared to be healthy with a smaller one growing below it.
Five years later, both appear to be thriving.
You can clearly see how the top one has firmly anchored itself to the palm tree.
The roots of the lower one have also got a firm grip on the ‘host’ tree.
It is difficult to spot any roots actually making their way down to the soil at the base of the tree, yet there must be, for it is otherwise difficult to comprehend how else these trees would get the nutrients they need to survive.