The sight pulls me up short. It looks like something out of myth or a book of spells. Here is a miniature Scots pine growing 6ft up, right in the fork of a shaggy old birch. It delights and baffles me in equal measure. In further wanderings, I discover more examples of this strange magic. A rowan and a birch appear to sprout from the same stem, while a holly and a hawthorn are so hopelessly intertwined that I spend ages tracing back down through leaves, twigs, branches and trunks just to figure out how deep this union goes. At the bottom, this odd pairing have drawn a rusted fence into their inter-species embrace.

Investigating, I learn that there are a few wonders at work here. First, trees can grow so closely together that they become entangled and appear joined. Occasionally, though, limbs do repeatedly rub against each other in the wind, wear away the bark and fuse. Some even share vascular systems, passing water and nutrients between them. It is a natural grafting process called inosculation and can happen anywhere from the base of the trunk up to higher branches that form a linking arm. In folklore, it is called “a husband and wife tree”. Mostly occurring within species, it does sometimes cross divides.

But my high-perched pine is a different phenomenon entirely; it is an epiphyte. Here, a seed falls into decaying wood or a mossy crevice on a tree and germinates. It doesn’t draw nutrients or water from the host like a parasitic plant, but survives on the accumulated organic debris, along with sunlight, rainwater and air. Ferns, mosses and orchids are common epiphytes, but the “flying tree” is rare. Its growth and lifespan will be limited unless – even more rarely – it sends roots down through the host to the ground, usually splitting the trunk on the way.

Though this sounds vampiric, the host is usually already decaying. I discover a version of this in an elegant young birch rising from the gnarled root claw of an ancient, felled Scots pine. In a striking reversal of the little pine high in a giant birch, here is the union not just of two species, but between the living and the dead.