It turns out that newly sprouted seeds respond to soil-dwelling microbes near the tree’s roots. These microbes can harm a tree’s seedlings so the seeds need to get away from the mother tree.
This has caused trees to evolve methods of dispersal of their seeds by using fruits that get eaten and seeds that get blown on the wind.
There are also plants that fare better when they are surrounded by their own kind. Sagebrush, for example, sends out airborne chemical cues from its foliage and branches that play a vital role in protecting the plants against insect attack.
One study showed that two genetically identical sagebrush plants grown next to each other were more effective fending off caterpillars and grasshoppers than two unrelated plants.
So…the notion of “friending” started a long time ago.