Permalink : http://hdl.handle.net/2115/84965

JaLCDOI : 10.14943/EJFR.22.39

KEYWORDS : Coastal restoration;Japanese black pine (Pinus thunbergii);Root growth;Soil compaction;Waterlogging

Due to the disastrous tsunami which occurred along the pacific coastline of eastern Japan, 3660 ha of Pinus thunbergii Parlatore (Japanese black pine) coastal forests were heavily damaged. To restore and recover the functions of these coastal forests, artificial growth berms are being constructed to secure enough space for root growth, especially in the vertical direction. However, due to the use of heavy machinery, the surface soil of the growth berm was packed down and significantly compacted. Compacted soil results in hard soil and is often reported to negatively affect root growth of seedlings. Additionally, in some cases, waterlogging after rainfall is not promptly discharged due to low soil permeability and drainage. As oxygen availability becomes severely limited under waterlogging, this can also negatively affect root growth. Considering these problems, studies have been made to elucidate effects of soil compaction and waterlogging on root growth of P. thunbergii seedlings and broadleaved species which are new candidates for introduction to coastal forests. Furthermore, at some of the restoration sites, plowing of the surface soil is being experimentally done to soften the surface soil and improve drainage. Here, we review results obtained from several field surveys and pot experiments which suggest important key points to realize the healthy root growth of P. thunbergii seedlings at coastal restoration sites.