This is a technique where an entire tree is grafted to deadwood to create an illusion of great age. First the living tree is stripped down to the cambium layer along one side. Young trees are best for this as they still have small enough caliper to be easily pliable. Then attach the tree to a prepared piece of deadwood following the natural contours as you wrap the living tree around. To fasten the tree many opttions are available. First you may wrap the entire thing in raffia and allow it to sit for the entire year before checking it's progress. You may also use copper or brass nails or screws to affix the graft. (copper nails are refered to as weatherstripping nails in the US). And finally you may use cable ties padded by some material that won't rot and harm the bark or graft. In a season or two the living tree should callouse to the old and become one single tree.
My name is Don and I'm a bonsaiholic.
If at first you don't succeed, stop growing Serissa.
Jimothy has quite a lot to add to this subject too, if we can tempt him in. He refers to it as 'Tenuki' or phoenix graft.