Trunk-borne fruits are unusual, but include the well-known papaya, the commercially-marketed durian, and the largest of tree fruit, the jackfruit. The location of flowers and fruit on the branches or trunk is likely a response to the need for high levels of water transport, and fruit weight that could not be borne by leafy smaller stems. It is also possible that variants with the fruit in this location benefit from increased transport of their seeds, as fruits are accessible to heavier climbing animals, rather than falling from the trees when ripe.
The tree trunks are cylindrical because they grow from the center and outwards. They grow uniformly and this is evident from the rings when the trees are cut.
Tree trunks are straight and branchless in their lower parts in their efforts to grow tall.
marijuana
Not a plant it can be any tree. And no plants grow on any trunks
The wind, objects that prevent the tree from growing upwards.
Different species of different fruits or plants grow differently. For example, a blueberry tree would grow to about 50cm maximum when a mango tree would grow to about 5m.
Some are, some are not.
Tree trunks are straight and branchless in their lower parts in their efforts to grow tall.
Watermelon
The mangrove trees can have many trunks, but the banyan tree has both multiple trunks and above-ground "prop roots" that can grow vertically and horizontally.
Many plants which are called epiphytes grow on tree trunks. They are adapted to grow there as orchids , lichens etc.
the roots underneath the trunk let the tree grow