Botany Question - Tree Limb Fusion

[Mag]

Whats the word when two tree limbs fuse together?

And why does it happen?

 

A small tree in front of my house has this, where it seems two tree limbs got too close together and became sort of one.

Both are fully grown, but where they touch there is a lump of wood surrounding it.

 

I can get a pic if you need.

 

thanks

[Glider]

The word is grafting and the lump is a callus. Technically, it's grafting when done artificially, i.e. by a person. Certain types of apple tree have been developed that produce really nice apples, but the tree itself doesn't do well on its own roots, so these cultivars (cultivated variants) are usually grafted to the rootstock of more vigorous apple trees when they are seedlings.

 

Another example is where a tree has grown a bit long in the trunk and you want it to have branches lower down. You can take a shoot from higher up the tree and heel graft it to the trunk exactly where you want it.

 

In bonsai, you can use thread grafting to place branches precisely where you want them. You allow a shoot to grow freely so it forms a long whip, then you drill a hole through the trunk exactly where you want your new branch and in early spring, you thread the whip through the hole and 'glue' it in place using grafting wax. As the whip grows and expands, it begins to swell where it is constricted. Also, the wound in the trunk begins to form a callus as the cambium begins to close the wound. Eventually the callus formed by the trunk and that formed by the constricted whip grow into one another and graft together. You can then cut away the whip at the other side.

 

Basically, if two areas of the same (or related) trees rub against each other to a point that the cambium layer (the living, growing part of a tree) in each limb is exposed, then the swelling callus caused by the healing of each branch (as long as they are held together), will merge and grow into one as the cambium layer covers the entire wound and lays down more wood, resulting in their healing together, or grafting.

[Mag]

ah, thank you very much - very informative

[Glider]

You're welcome