Oak Resprouting Survival and Competition for 19 Years after Wildfire in the Republic of Korea

Abstract

In the Republic of Korea, forest fire occurred at a rate of more than 400 events yr−1 from 2000 to 2016, and the burned areas are concentrated in the eastern coastal region. In this region, pine forest is extensively distributed, and pine forest is converted to oak forest through natural succession or stump-sprout regeneration following forest fires. However, there is a lack of research on oak competition and survival during the regeneration process in burned areas. Therefore, this research was carried out to evaluate the effects of oak survival ratio of Quercus serrata (glandbearing oak), Q. variabilis (oriental oak), and Q. mongolica (Mongolian oak) in burned areas. The investigation plots were set to survey tree height, diameter at breast height, sprout survival, and composition in Goseong-gun, Kangwon province, Republic of Korea. The mean tree heights of Q. serrata and Q. variabilis were approximately 9.8 m and 9.1 m, respectively, which were higher than the approximately 5.8 m heights of Q. mongolica stands 18 years after a forest fire, and the trend for tree diameter at breast height was the same for all three species stands. In the early stage of regeneration after the forest fire, the survival probability of the Q. serrata sprouts decreased at a rate of 1.7–2.0 times higher than that of other oak species in the Q. serrata-dominant stands, and this tendency was found to the survival probability in Q. variabilis-dominant stands as well. The median survival time of Q. variabilis sprouts in the Q. variabilis-dominant stands was approximately 10.1 years, which was similar to Q. serrata-dominant stands. However, the dominant stand of Q. mongolica was different from that of other dominant stands since the stand mostly located in the ridge and the upper part of the mountain where topography and soil conditions were considerably dissimilar from the other stands. The decision of dominant species seems to be determined by the survival and occurrence of sprouts during the early stage in post-fire regenerated oak forests. Therefore, it would be more desirable to coppice sprout for dominant species productivity and rapid dominance after a forest fire.