On the heathland being restored at the Nysdam reserve where I was volunteering yesterday, a Silver Birch (๐ต๐๐ก๐ข๐๐ ๐๐๐๐๐ข๐๐) and a European Larch (๐ฟ๐๐๐๐ฅ ๐๐๐๐๐๐ข๐) have grown together, resulting in physical leaning and crown interlocking. Although aboveground we see them embracing, the relationship is perhaps best understood in terms of coexistence, shared habitat preferences, and potential underground ecological interaction, rather than any physical fusion. Locally the common names of these trees are Bouleau verruqueux/Ruwe berk and Mรฉlรจze/Lork.
Both species are ectomycorrhizal hosts, commonly associated with fungi such as Amanita, Laccaria and Russula, (Agarics, Deceivers and Brittlegills). Possibly both trees are connected indirectly through a shared mycorrhizal (fungal) network, a system that can facilitate the transfer of water, nutrients (particularly nitrogen and phosphorus), and carbon compounds between neighbouring trees.
From a successional perspective, Silver Birch functions as a pioneer species, capable of rapidly colonising open, nutrient-poor, acidic substrates such as heathland. Its leaf litter and root activity contribute to organic matter accumulation and soil structure improvement, which helps the establishment of later-arriving conifers, including larch. Larch is well adapted to similar soil chemistry and benefits from the improved microclimate created by early colonisers, especially in exposed, wind-affected landscapes. Being fast growing, it soon catches up, height-wise.
The physical contact observed between trunks and branches appears to be the result of phototropic growth, with both individuals adjusting crown orientation towards available light rather than an actual structural graft (inosculation) which doesn't really happen between distantly related trees.