The impact of fire suppression on ecosystems with long fire return intervals has been considered negligible. It is argued that, since fire suppresssion has been effective for only the last 30 to 50 years, fire suppresssion could not possibly have had much of an impact where the natural fire return interval is longer than that. This poster paper presents evidence to the contrary. First, consider lodgepole pine and spruce-fir age-class distributions in the Gospel-Hump Wilderness. As expected, they are negative exponential distributions, but they are shifted to the right. There is an absence of young age classes. Second, consider fire occurrence and area burned data from the Moose Creek Ranger District in the Selway-Bitteroot Wilderness, where a prescribed natural fire program has been in effect for the last 10 years. In 20 years previous to the prescribed natural fire program, 716 fires burned about 5,000 acres. In the last 10 years, 56% of the fires were not suppressed. The resulting 200 fires burned over 100,000 acres. Comparing the last 10 years with the previous 20, about one-fourth the number of fires have burned 20 times the area. Much of the area burned supports ecosystems with long fire return intervals. By keeping fires small, especially during drought years, fire suppresssion has had a substantial impact in a short period of time. If the stand and environmental conditions that must come together to create a high intensity fire are rare, fire suppression when those conditions coincide can have substantial ecological impact.