Study on Vegetation Changes Following the Management of Oak Wilt Disease in Quercus mongolica Forest of Namsan (Mt.), Seoul†

This study aimed to analyze the characteristics of vegetation changes in the <italic>Quercus mongolica</italic> forest on Namsan (Mt.), influenced by shifts in the urban natural environment and the management of oak wilt disease. In addition, predictions and appropriate management strategies for the ecological succession patterns of oak forests were presented. The urban environment is predicted to impact vegetation, including the growth ranges of <italic>Quercus mongolica</italic> and <italic>Quercus serrata</italic>, and trends in foreign species and pests, such as <italic>Platypus koryoensis</italic> and <italic>Raffaelea</italic> sp. By 2019, 24,237 damaged trees had been recorded and managed through various methods: 54% used sticky roll traps, 37% involved felling and fumigation, and 17% employed techniques, such as tree stem injections. The <italic>Quercus mongolica</italic> community on Namsan (Mt.) has been declining since 2007 due to both oak wilt disease management and urbanization. Intensive management in the early stages of the oak wilt disease outbreak, around the ridge, transformed the <italic>Quercus mongolica</italic> community into a deciduous broad-leaved forest, including species such as <italic>Prunus sargentii</italic>. The vegetation structure of this forest has been altered by felling and fumigation to control oak wilt disease, leading to a decline in the dominance of <italic>Quercus mongolica</italic> and Sorbus alnifolia. In contrast, there has been a significant increase in the prevalence of <italic>Acer pseudosieboldianum</italic>, a species well-adapted to urban environments, in the opening of the canopy areas. The dominance of <italic>Fraxinus rhynchophylla</italic>, which thrives in fertile and moist areas, has decreased due to urban environmental changes, such as alterations in water systems. Among oak species, <italic>Quercus serrata</italic>, which has a high growth niche under climate change, has increased in dominance. The outbreak and subsequent management of oak wilt disease have further weakened <italic>Quercus mongolica</italic>’s dominance. The opening of the canopy has improved light conditions, facilitating the emergence of <italic>Quercus mongolica</italic> and <italic>Quercus serrata</italic>, both shade-intolerant species, in the sub-tree and shrub layers. This suggests the potential for secondary succession towards a community of <italic>Quercus serrata</italic>, <italic>Quercus mongolica</italic>, and <italic>Zelkova serrata</italic>. Considering the impact of climate change on the suitable distribution of <italic>Quercus mongolica</italic>, a cold-tolerant species, the succession trend indicates a potential shift towards <italic>Quercus serrata</italic>, the dominant species in southern Korean forests.