Similarly one may ask, why do bromeliads grow on trees?
Their roots are anchored in the soil to provide stability and absorb nutrients and water. Epiphytic bromeliads grow attached to other plants, usually trees. They non parasitic using their roots to anchor themselves to the host plant. Epiphytes gather water and nutrients from the air with small hairs called trichomes.
Regarding this, how do you attach bromeliads to wood?
Wrap the soft root ball with sphagnum moss. Choose an indented spot on the driftwood and tuck the bromeliad in, holding firmly. Wind a length of fishing line or wire around the wood, covering the base of the plant at the root system. Wrap it around 6 times and tie firmly in the back.
Almost all bromeliads are native to tropical climates. Their original habitat is humid and they grow on shady forest floors or attached to trees. This means bromeliads are adapted for warm, wet, shady climates. If you live in an area that will not freeze, you can safely plant your bromeliad outside.