This study identified the vegetation changes in the Hwaeomsa Temple forest in Jirisan National Park over the past 100 years by comparing the vegetation map of the "Jirisan Botanical Survey Report" of the Japanese Government-General of Korea in 1915 and the detailed vegetation map of the National Park Service in 2018. The 1915 vegetation map was digitized using QGIS 3.22 to quantify each vegetation type's area and spatial distribution. It was then overlaid and compared with the 2018 detailed vegetation map provided by the Korea National Park Service. The analysis showed that pine forests were the most dominant with 58.38% of the total area, followed by broad-leaved forests (29.53%) and grasslands (11.04%) in 1915. By 2018, mixed deciduous forests dominated by Quercus mongolica, Q. serrata, and Carpinus tschonoskii had significantly expanded. Specifically, about 65% of the former pine forests have been transitioned into broad-leaved forests, while grasslands were largely converted into forests dominated by canopy tree species. The elevation-based analysis revealed that pine forests remained dominant below 400 m above sea level, while the most active transitions to mixed deciduous forests occurred between 400 and 900 m. Above 900 m, forests dominated by Q. mongolica maintained stable conditions in the past and present. This research has academic significance in providing empirical evidence for long-term vegetation succession changes in a temperate forest ecosystem over approximately one century.