Husband and Wife tree

A Husband and Wife tree or Marriage tree is formed from two trees which have branches that have been artificially or naturally conjoined together or inosculated. Such trees may represent a deliberate 'romantic' act or will have attracted the name due to their physical appearance. The plural isn't applied as they are 'joined as one.' Osculation itself is the act of kissing.

The Origin of the name

The straightforward application of the term comes from the obvious unification of two separate individual trees, however a more humorous use of the term relates to the suggestive appearance of some natural examples.
The name Husband and Wife tree also comes in more detailed form from an analogy of the material and natural world that can be used to describe a married couple’s relationship:
A married man and woman are like two separate trees planted in different holes at the same time. They are a permanent fixture in the landscape and together watch the years and seasons pass. They are the same size and one does not hinder the growth of the other. Because they stand so close together they are not as subject to wind or ice damage as a single trees is. The two together are more likely to survive adversity. They grow very close to one another but they are truly separate. There is space enough between them for the wind and air to pass. Their roots are entangled from beneath and how they are joined is hidden from the World. They derive their sustenance from the same source. One can not be separated from the other without risking them both

Examples of Husband and Wife trees

Eric Sloane describes Husband and Wife trees in A Reverence For Wood in which he says The big trees appeared two at a time, placed as ‘husband and wife trees’ when a house was built. They were usually on the east side of the house or at each side of the entrance; you could pick out farmhouses on any New England landscape by these double clumps of green.[3] Most of these trees may not have become physically conjoined.
At the ruined Lynncraigs Farm in Dalry, Scotland a blackthorn (Prunus spinosa) stands in the old farm garden which shows signs of having been deliberately grafted.
Inosculation customarily results when trees are pleached.

Natural
A fig tree
On his 'Tour of Scotland', published in 1800, Garnett notes a tree near Inverary that the locals called the Marriage tree, formed from a lime tree with two trunks that have been joined together by a branch in the manner of a person putting their arm around another (see illustration) as would a married couple.[4]
On the way to the Heavenly Lake near Urumqi in China are a pair of trees that local people have called the Husband and Wife trees because they are connected together by a living branch.[5] The Tatajia Husband and Wife trees are in Taiwan[6] and in Yakushima, Kagoshima-ken, Japan, are a pair of Husband and Wife trees formed from conjoined cedars.[7] The Marriage Tree on Wassaw Island, Georgia, was named by the family who vacationed there and consists of a Bay and a Palm fused at the root.