Manipulating Bonsai Tree Trunks
The structure of the trunk is a primary element of a properly styled bonsai. There are a number of tricks to manipulate the trunk over the years.
The trunk, and branches, can be tied to the ground or to other anchors. The tie is then tightened over time to draw the trunk in one direction or another.
Anchor the wire in the soil at the base of the trunk. Use wire 1/3 the thickness of the trunk. Bend the wire gently to prevent breaking anything and allow the wire to secure the new shape. Make small changes each year until the trunk and branches reach the shape you desire.
Grow your tree outside in the ground for 2 to 3 years without any pruning. It will get taller than you want for a bonsai, but the trunk with thicken. When you replant the tree in a pot, cut the trunk to the bonsai height. Care for the tree until it puts out new branches that you can shape to suit the style you want.
Wrap a wire coil around the trunk. Push it down until it sticks against the bark near the base. Leave it there for a time to trap the sap low and thicken the trunk. As the trunk thickens, raise the wire to thicken the next section.