Eight-year monitoring of the height growth and survivorship of seedlings of Pinus thunbergii Parl. planted with sand fence and bush hedge protection in a coastal sandy environment in Korea

Abstract

ABSTRACTThis study aimed to examine the effect of distance at three levels (5 m, 15 m, and 25 m) of ranges of plots landwards from a sand fence and bush hedge protection margin on the height growth and survival of seedlings of Pinus thunbergii Parl. planted in a coastal sandy environment in Uljin, East Sea area of Korea. The purpose of the study was to investigate height growth and survival with distance from a bush hedge/sand beach boundary of pine seedlings in a coastal forest plantation. Seedling height growth and survivorship were measured annually in nine plots, with three plots each selected from three ranges of plots at distances of 5 m, 15 m, and 25 m landward from the bush hedge/sand beach boundary from 2007 to 2014, 8 years after planting. Annual averages in seedling height growth significantly reduced in the 2nd and 3rd years of growth but appreciably stabilized from the 4th to 8th year, indicating that the 2nd and 3rd years of seedling growth and survival in the study site were the most critical. We found no statistically significant differences in height growth and survivorship of the planted seedlings between the three ranges of plots at distances of 5 m, 15 m, and 25 m landward from the bush hedge/sand beach boundary in the microsite. This suggested that seedling height growth and survivorship were not significantly affected by the distance factor. This was attributed to the protective and stabilization functions of the bush hedges and sand fence barrier, which reduced near-surface wind damage to seedlings and fostered a relatively uniform height growth and survival of the planted seedlings in the microsite. Furthermore, wind speed (P = 0.014) and soil moisture at ≤ 12 cm depth (P = 0.014) were the most significant of the selected factors limiting the height growth of the seedlings in the study area, as they accounted for 94.4% (R2 = 0.944) of the insignificant variability associated with the distance factor. The results provide supportive evidence that sand fence and bush hedge micro-windbreaks can be reliably used to protect, stabilize, and sustain relatively uniform height growth and survival of seedlings of P. thunbergii planted in a windy coastal sandy environment and in other locations with similar soil and climatic conditions.