What’s plant inosculation? It’s the process of natural grafting, like what created this wonderful tree ‘porthole’ in South Australia.
Although this example is between two branches on the one tree, as also happens when you have twisted or braided stems on an ornamental fig, occasionally branches on separate but adjacent trees will also grow together. Usually this is between plants of the same species and they’re often called ‘marriage’ trees or ‘husband and wife’ trees.
Inosculation occurs when two branches rub together in the wind, removing the thin outer layer of bark and exposing the cambium layer below. As the cambium layers fuse, bark begins to grow around the wound and thicken into a normal branch.
As you would expect, trees that are easily grafted, such as apple, peach, pear and olive trees are known to conjoin this way, often when they are too closely spaced in orchards and not regularly pruned. Beech trees, which often grow very close together in thickets, or are deliberately closely-planted as a pleached hedge, also often inosculate.