Decision trees can be made using several common software packages, including Microsoft PowerPoint, most word processors, and many drawing programs.
Essentially any program that allows you to link boxes and arrows can be used to communicate the decision tree.
A specialized program from Microsoft called Visio is specifically designed to create charts and diagrams that can be saved and shared in a wide number of formats, including other Microsoft programs. The examples that follow were built using Visio. This program can be tested for 30 days and purchased at: http://office.microsoft.com/en-us/visio/FX100487861033.aspx 
Decision trees are stepwise graphical representations of a decision process. They are especially useful in the following:
The situation is complex and has many steps to reach a solution.
There are many potential conclusions or categories that answer the decision to be made.
The decision can be broken down into discrete parts that have “yes” or “no” answers.
When a complex situation occurs infrequently, and important considerations or inputs might be forgotten in the interim.
To illustrate and simplify a new concept to employees or peers.
To help an individual check the quality of their own decision by reviewing the parts for consistency and agreement.
When answers to previous questions suggest additional or different criteria that should be considered in subsequent steps.
To provide consistent and predictable management decisions among many different operators.
Steps in the Process
Brainstorm the list of input information that is relevant to the decision being made and formulate these as questions.
Consider the potential answers to these questions.
Organize questions in order of importance.
Order questions so that more general questions are asked earlier in the process than very specific ones.
Use one of the software programs to present the questions or decision steps in graphical manner. Software programs that allow “drag and drop” construction from menu of shapes and arrows are easiest and quickest to use.
Link dependent questions to previous questions so that the reader is directed to the next important consideration in the process based on the answer given to the previous step.
Test the resulting decision tree with someone who has little knowledge of the likely answer for clarity and completeness.
Refine the decision tree as new information is found that can simplify the decision or has an impact on the correct conclusion.