When wildfires are suppressed, opportunities are foregone to create fuel breaks, reduce fire regime departures, and decrease future extreme fire behavior by modifying fuels. To our knowledge, no one has yet attempted to systematically quantify these foregone opportunities. This general technical report describes a methodology to measure the cumulative impacts of suppression over time by modeling the spread of ignitions that were suppressed. We illustrate a set of analysis steps to simulate where ignitions would have spread had they not been suppressed and to assess the cumulative effects that...