A study was initiated in 1995 to measure landscape changes in forest structures between 1900 and 1995. A systematic sampling system was used to collect data on three forested faces on the Bitterroot Front. Over 1,200 tree cores were taken on 216 plots between the elevation range of 4,500 to 7,500 feet. Historic forests were reconstructed through quantitative techniques. Changes are presented in three elevation zones: lower (4,500 to 5,800 feet), middle (5,800 to 6,900 feet), and upper (6,900 to 7,500 feet). Dramatic decreases in fire dependent species and increases in fire intolerant species are shown throughout all elevation zones. Ponderosa pine (Pinus ponderosa) has been reduced from 52 percent to 26 percent of total basal area in lower elevations. Douglas-fir (Pseudotsuga menziesii) increased its relative percentage of total basal area in the lower zone from 19 percent to 55 percent over the past century. Western larch (Larix occidentalis) abundance has declined from 26 percent to 11 percent in lower elevations (4,500 to 5,800 feet) and from 24 percent to only 6 percent in middle elevations (5,800 to 6,900 feet). Lodgepole pine (Pinus contorta) has increased its relative percentage of landscape basal area 6 percent in middle elevations and 13 percent in upper elevations (6,900 to 7,500 feet). Whitebark pine (Pinus albicaulis) decreased from 39 percent to only 11 percent of total stand basal area in the upper elevation zone.