The Tree Diagram is one of the Seven Management and Planning Tools.
The Tree Diagram is a tool to explore exactly what needs to be done in order to achieve a goal. The tree starts at the left with the goal to be achieved, and then branches to the right into progressive levels of detail as to how each objective and task breaks down into more detailed objectives and tasks.
The Why-How Chart is a form of the Tree Diagram, but it tends to develop the trunk of the tree out of the branches (ie to arrive at the top-level objective by thinking through more detailed objectives).
The Tree Diagram should culminate at the far right in a complete list of all the tasks that are required to fulfil the main task or objective listed on the left
Further information on the Tree Diagram (and indeed on all of the Seven Management and Planning Tools) can be found on the ASQ website..
Track your progress to ensure the efficacy of this strategy.