After the Great East Japan Earthquake, tree-planting areas on the artificial ground, such as tsunami evacuation hills and road embankments have expanded. Since the properties of the artificial ground would depend on several factors such as embankment materials and construction methods, these would cause the variation of growth of planted trees by sites. In this study, the relationship between the growth of planted broad-leaved trees and the several ground properties were investigated at tsunami evacuation hills and road embankments constructed in Iwanuma City, Miyagi Prefecture, to make clear the main tree growth differentiated factors. Growth of tree seedlings in five embankments differentiated in times of construction and planting were measured over several years and its ground properties such as hardness, texture, nutrient content, and pH, were compared. The growth differences among embankments were related to the properties of the embankment materials rather than ground hardness. The growth of evergreen tree species, such as Machilus thunbergii, Quercus myrsinifolia, Q. salicina, Q. glauca, Q. acuta, Camellia japonica, and Ilex integra, slowed down on the embankments with acidic or alkaline reformed soils that contain fewer clay particles, organic matter, and exchangeable Ca and Mg. It was also suggested that the ground hardness could explain partial growth differences within a site. Within an embankment with the same material, slow growth of planted trees tended to occur on extremely hard or soft grounds.

A 2-year planting test was conducted by using 12 tree species, including evergreen shrubs, subarboreal trees, and arboreal trees, to identify the appropriate tree species for the restoration of the Ozato-Matsubara coastal forest in Tokushima Prefecture, western Japan. This area was deforested by a typhoon storm-surge and suffered from sika deer appearance. The appropriate combination of tree species and countermeasures against deer for successful planting was discussed on the basis of seedling performance and deer browsing damage. Cluster analysis using variables related to seedling performance and deer damage revealed that 12 tree species were divided into two groups: one group of seven species with minor deer damage and another group of five with severe damage. Vigorous height growth was shown by the subarboreal species Morella rubra and Daphniphyllum teijsmannii among the minorly damaged species and by the shrub species Pittosporum tobira among the severely damaged species. Leaf discoloration that was likely due to photoinhibition was observed in arboreal species, such as Cinnamomum camphora, C. yabunikkei, Machilus thunbergii, and Elaeocarpus sylvestris var. ellipticus. The mosaic landscape of small forests and abandoned farmlands between coastal and interior forests could encourage deer appearance at the planting site. A planting scheme using a combination of arboreal species and nurse trees, such as M. rubra, D. teijsmannii, and P. tobira, and the installation of deer-proof fences in small plots was proposed for the restoration of deforested coastal areas under sika deer appearance.

We investigated sediment transport rates during 6 months after clearcutting of a 100-year old sugi (Cryptomeria japonica) plantation in order to compare its spatial heterogeneity of sediment transport an uncut stand. After clearcutting, the extremely large sediment transport rate (STR) owing to the possible formation of `the water path' contributed to the higher coefficient of variation (CV) of STR compared to that in the uncut stand. To examine the factors affected the variations in STR, we classified the STRs of the clearcut stand into two categories (high and low STR) based on positive or negative deviation from the mean STR, and compared the forest floor cover by forest residues (woody debris and litter: FCR), litter movement rates, and slopes inclination between the categories. The low STR (negative deviation) had significantly higher FCR and smaller litter movement rates. STR showed a strong negative correlation with FCR. A decision tree analysis demonstrated that STR was low (negative deviation) when the FCR was less than 44.5%. These results suggested that the increase of STR due to the formation of water paths by skidding and the control of sediment transport by scattered forest residues contribute to the heterogeneous sediment transport in the clearcut stand.