Softimage ICE. This is an ICE compound that builds a complete tree in one hit, including leaves. Been dabbling with this for a while and it's starting to look interesting. At a basic level it can build a tree using no object inputs, just the default shapes, cylinder for trunk and branches and a disk for the leaves. These five examples use a cylinder slightly tapered at the top, to make the joins less visible. The leaves are the default disk scaled.