The vegetation dynamics of Korean red pine (Pinus densiflora) forests were investigated at Mt. Seorak, Korea. Our Detrended Correspondence Analysis (DCA) classified the forests into four types: ridge top, upper slope, lower slope/hill, and streamside. The ridge top forests were likely to sustain themselves, as suggested by the large proportion of seedlings and saplings (89% at <25 years old) and the relatively high density of P. densiflora (2388 stems $ha^{-1}$). Periodic disturbances, such as flash floods, made the streamside inhospitable to late-successional species. Such conditions may have provided a favorable environment for the recruitment of P. densiflora seedlings through increased solar radiation and decreased competition with other species. On the upper slopes, the dominance of Quercus seedlings and saplings (63% at >25 years old, and a density of 3263 stems $ha^{-1}$) suggests a transition from pine to oak forest. Extensive human interventions appeared to arrest the natural succession from pine to oak forests on the lower slope/hill, while encouraging invasions by forest-edge and introduced species (e.g., Rosa multiflora and Robinia pseudoacacia).