Tree Huggers: When Nature Takes It Literally

In the quiet corners of forests worldwide, trees are engaging in their own version of romance. It’s called inosculation, and it is nature’s answer to the artificial process of grafting. Inosculation and grafting are like botanical cousins. Both involve the fusion of plant tissues, creating a single, stronger organism. While grafting is a human-engineered process, inosculation is nature’s DIY version.

Gemels: The Forest’s Power Couples

These naturally grafted trees earn the charming nickname “gemels,” from the Latin for “a pair.” They’re living proof that in both nature and horticulture, two can indeed become one.

The Tree-mendous Union

When two trees grow so close that their bark wears away, their cambium layers touch. This intimate contact allows them to share nutrients and water, much like a successfully grafted plant. The result? A stronger, more resilient tree duo.

Such trees are often colloquially referred to as “husband and wife” trees, or “marriage trees”. The straightforward application of the term comes from the obvious unification of two separate individual trees, although a more humorous use of the term relates to the sexually suggestive appearance of some natural examples. There may be a degree of religious intent, as some cults are organized around beliefs that trees contain a hidden or sacred power to cure or to enhance fertility, or that they contain the souls of ancestors or of the unborn.

Thin-barked species like apple, beech, and olive trees are the most likely candidates for this arboreal union. Their close-quarter growth habits increase the chances of a successful merger.

-True inosculation: This involves actual self-grafting, where the cambium layers of two trees fuse together, creating a shared vascular system.

-Appearance of grafting: This refers to trees that are physically touching, rubbing, intertwined, or entangled without actually fusing their vascular systems. These trees may appear conjoined but aren’t biologically connected.

Both scenarios can be referred to as “conjoined trees,” “husband and wife trees,” or “marriage trees”. The appearance of grafting is included in this broader category, even though it doesn’t involve true biological fusion. It’s worth noting that:

Distinguishing between true inosculation and the mere appearance of grafting often requires close examination or long-term observation.

-True inosculation typically occurs between trees of the same or closely related species.

-The appearance of grafting can happen between trees of different genera or even families.

The Best of Both Worlds

While grafting allows humans to create specific plant combinations, inosculation showcases nature’s own ingenuity. It’s a testament to the adaptability of trees and their ability to thrive through cooperation. So next time you’re wandering through the woods, keep an eye out for these naturally grafted wonders. They’re a reminder that sometimes, the most beautiful unions are the ones nature creates all on its own.

Branching Out Together – Inosculation in living fences

Living fences can involve natural grafting (inosculation) when planted closely (4-8 inches apart)

-Branches grow and cross

-Crossing branches are often tied together

-Natural grafting occurs due to bark abrasion from wind movement

-Results in a strong, meshed barrier that strengthens over time

Some gardeners may encourage grafting by making small cuts where branches cross, but this isn’t always necessary.

Inosculation in living fences combines the natural phenomenon with intentional human design, bridging the gap between natural and artificial grafting. Not all living fences involve grafting; many are simply closely planted and pruned shrubs or trees.

When Inosculation Goes Wrong

Inosculation often results in stronger, more resilient tree couples. However, like any relationship, things can get complicated. Here are some of the potential downsides:

Disease Drama: When trees join forces, they also share germs. If one tree catches a cold (or worse, a fungal infection), the other might catch it too. It’s like when you and your partner both get the flu at the same time – not fun.

Structural Weakness: Imagine two trees holding hands, but their grip isn’t as strong as it looks. Inosculation can create weak points, making the trees more prone to breaking under stress. It’s like having a joint bank account – if one partner overspends, the other might feel the strain.

Growth Stunted: When trees are joined at the hip, they might start competing for resources. It’s like when you and your partner both want the last slice of pizza – someone’s going to go hungry. This competition can slow down the growth of one or both trees.

Double Trouble: If one tree in the pair starts to decline or dies, it can pull the other down with it. It’s like when your partner’s bad habits start to rub off on you – not a good look.

Wound Worries: Inosculation often happens through wounds, which can leave trees vulnerable to unwanted visitors like insects and fungi. It’s like when you get a cut and have to worry about infection – trees have similar concerns.

Uneven Load: Fused trees might grow unevenly, leading to a lopsided look and increased risk of toppling over in strong winds. It’s like when you and your partner have different spending habits – it can throw off the whole balance.

Despite these potential pitfalls, many inosculated trees thrive and become stronger together. It just goes to show that even in nature, relationships can be complex and require a little extra care.

The term inosculation is derived from the Latin roots in + ōsculārī, “to kiss into/inward/against” or etymologically and more illustratively “to make a small mouth inward/into/against”; trees having undergone the process are referred to in forestry as gemels, from the Latin word meaning “a pair”.

The term inosculation is also used in the context of plastic surgery, as one of the three mechanisms by which skin grafts take at the host site. Blood vessels from the recipient site are believed to connect with those of the graft in order to restore vascularity.

It is most common for branches of two trees of the same species to grow together, though inosculation may be noted across related species. The branches first grow separately in proximity to each other until they touch. At this point, the bark on the touching surfaces is gradually abraded away as the trees move in the wind. Once the cambium of two trees touches, they sometimes self-graft and grow together as they expand in diameter. Inosculation customarily results when tree limbs are braided or pleached.

Inosculation is most common among the following taxa due to their thin bark:

Apple, Almond, Ash, Beech, Crepe myrtle. Chestnut, Dogwood. Elm. Ficus. Grape. Hazelnut. Hornbeam. Laburnum. Linden. Maple, Norway spruce, Olive, Peach, Pear, Privet, River red gum, Sycamore, Willow. Wisteria