Decide on the size of your tree sculpture. The tree sculpture can be pocket-sized or 12 or more inches tall. An even larger sculpture is possible as well. Draw your design and plot the dimensions on a piece of paper.
Select a block of wood for the base. It does not need to be perfectly square. Indeed, an irregular shape will give interest to the project. The size of the block should correspond with the overall size of your proposed sculpture. If you want to making a small sculpture, the block of wood should not be very large. If it is larger, then use a larger block of wood or two pieces of wood glued together.
Decide on the gauge of the wire to make your tree sculpture. For larger sculptures, you need to use a larger gauge of wire, such as a 9 or 10. For smaller sculptures, the gauge can be smaller, such as 20 or less. You could even work with picture wire which has a nice texture as well, as it is very easy to work with.
Create the tree. If you are making a larger tree, such as one that stands on the floor and is 6 feet tall or more, you would probably want to start with a support upon which to wind your wire. Find a steel rod that's the height you want, drill a hole in the center of the block, and insert the rod.
Wind the wire around the rod, wrapping it completely with the wire to form the trunk. When you create the branches, you can wrap the wire around itself, and it will be able to support itself without a rod inside them. Add as many branches and twigs as you would like.
Do not use a support with a smaller tree sculpture. When you are making a smaller tree, you can wind the wire around itself to create the tree's trunk. Make the trunk by having one straight piece of wire, then wrap wire around it until the upright piece of wire is hidden from view. Continue the process to make branches and twigs that reach out from the trunk. Drill a hole in the base and insert the trunk.
Create leaves by cutting out leaf shapes from tissue paper. Attach the leaves to the ends of the branches by wrapping wire around the bottoms of the leaves. The leaves can be any color you like, or use more than one color on your tree.