This Demonstration produces fractal trees in 3D. At each iteration, new branches are added to the outermost branches; each new branch is scaled down from the previous length by half. If the pattern were to go on forever, it would result in a tree with finite volume but infinite surface area. You can control the level of iteration (up to 4), the number of branches added at each iteration, the angle at which the branches point and the shape of the leaves.