Country diary: Trees growing out of trees – the more I look, the more I find them | Merryn Glover

In Badenoch, within Scotland's Cairngorms National Park, the author discovered a remarkable natural phenomenon: trees growing directly out of other trees. This observation began with a small Scots pine emerging from a large old birch, approximately six feet up its trunk. Further exploration revealed more instances of this unusual growth, including a rowan and a birch appearing to sprout from a single stem, and a holly and hawthorn so intertwined that tracing their origins proved challenging. In some cases, these entangled trees have even incorporated man-made structures, like a rusted fence, into their growth.

Investigating this natural occurrence, the author learned about the biological process known as inosculation. This phenomenon occurs when trees grow so closely together that their branches or trunks become entangled. Over time, repeated rubbing from wind can wear away bark, leading to the fusion of the trees. In some instances, these fused trees can even share vascular systems, allowing for the transfer of water and nutrients between them. Inosculation can happen at various points, from the base of the trunk to higher branches that form a connecting limb. This natural grafting is sometimes referred to in folklore as a "husband and wife tree." While most commonly observed between trees of the same species, inosculation can also occur between different species, explaining the cross-species examples observed by the author.