Double-trunk style – A double trunk occurs if a tree develops two trunks out of a single root base. The junction of the trunks at the base must be sharply “V”-shaped and not “U”-shaped. One of the trunks dominates because of its length or thickness. The smaller tree must be no more than two thirds the height of the larger. Together they form a common crown, just as we see in nature.
In nature, trees are forced into all kinds of shapes under the influences of weather, wind and placement. Consequently, bonsai trees can have many shapes and sizes and, depending on their way of growing, they are grouped into various styles and shapes.
Maybe some shapes seem strange and unnatural, but they are all based on the way trees grow in nature. Each tree, however, has its own character and within a certain style there is still an enormous variety. Usually a bonsai tree is given its name according to its shape or the number of trunks it has.