A method of implementing a user integrated circuit (IC) design in a tree representation includes the step of introducing the tree representation for the user IC design in a partitioned manner including at least one sub-design to form a design abstraction of the user design. At least one sub-design can include a sub-design providing for multiple levels of implementation hierarchy. The method can further include the step of traversing the design abstraction in a top-down fashion to provide functions selected among floor planning, port assignment, and timing budgeting for at least one sub-design, and the step of traversing the design abstraction in a bottom-up fashion to facilitate at least one among resolution of resource conflicts and parallel processing of multiple sub-designs. Traversing the design abstraction in the bottom-up fashion can facilitate a re-budgeting of timing for the integrated circuit design.