I conducted long-term vegetation change analysis in alpine and sub-alpine ecosystems around Yosemite National Park using repeat photography techniques. By identifying historic photo locations from the early 1900s and 1985 and re-photographing them in 2008, I expanded previous studies by adding another 25 years of change detection. Comparing more than 80 photo triplets revealed clear landscape trends, including increased density of krummholz and sub-alpine forest at the tree line, tree encroachment into meadows, reduced forest clearings, and more vegetation on rocky slopes and domes. The imagery also showed evidence of upslope tree line movement—consistent with broader patterns in the American West but different from earlier studies in this specific area. Building on research by Prof. Richard Vale, the project combined fieldwork, spatial documentation, and long-term visual datasets to better understand ecological change in high-elevation Sierra Nevada landscapes. I hope this study will be repeated again.