A new method for thinning Pinus thunbergii coastal forests was proposed in order to solve the overcrowding problem. We considered the lowering of disaster prevention functions and the vitality of coastal forests caused by thinning, the importance of the first thinning, and the thinning schedule on the basis of existing research. The proposed procedure is as follows. The area where the canopy height is lower than 3.0 m is excluded from thinning. Line thinning consisting of cutting down one out of every four lines in an early stage is proposed. The reference canopy height is 3.0 m for the first thinning, 3.5 m for the second, 4.5 m for the third and 5.5 m for the fourth. For canopy height of 6.5 m or above, trees that prevent the growth of predominant trees which will compose the future forests are cut.

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Remote sensing technology using earth observation satellites and ground penetrating radar are employed as a method for surveying the growth and soils of coastal forests. Surveys of vegetation and forests using these technologies use data in which the physical quantities of the reflection characteristics of above ground and underground electromagnetic waves are the criteria. These technologies not only enable objective surveys founded on a scientific basis, they also offer the advanced capability to provide information in a visual format for evaluation. This research evaluated the results of explorations of forest soils in the Kujukuri coastal black pine forests using ground penetrating radar compared with the results of onsite research into soil structure and for root system distribution.

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We studied the vegetation and made three mesh charts to understand the health situation of black pine (Pinus thunbergii Parl.), mixture situation of black pine, black locust (Robinia pseudo-acacia L .) and broad-leaved trees in Shonai coastal dune forest. As a result, it has been understood that black pine maintains healthy condition by about 74 % of Shonai coastal dune forest and gets pine-wilt disease easily on forest edge of national road along and inland side. As for forest type, forest of only black pine account for about 53 %. Since coastal disaster prevention is confirmed with the mesh of about 59 %, it is necessary to exterminate black locust.

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Growth condition in the past and age of alive large-sized pine trees were estimated from radial growth of trunks of dead and fallen Japanese black pine trees in a coastal pine forest preserved as a scenic beauty. Annual radial growth of pine trees younger than 80 years old ranged from 2.0 to 6.0 mm. On the other hand annual radial growth of pine trees older than 95 years ranged from 1.4 to 2.0 mm. Correlation between age and diameter was extremely high with older than 95 years of dead pine trees. The age of oldest trees was estimated to be 350 years old. The growth condition seems to have been severe from 1650s to 1900s.

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Considering the features of areas, Broad-leaved tree can carry out the function of coastal disaster prevention forest against sea breeze damage. Euonymus japonicus Thunb. were identified along the shoreline on the outskirts of Matsuyama City. Therefore, the purpose of this study was to examine the adaptability of Euonymus japonicus Thunb. as a protection forest against sea breeze damage. The study was carried out by doing comparative study of salinity density of watering and part of watering in tree. The results showed that when the watering was done on above-ground part, salinity density of leaf section was high. The salinity density of the trunk and the root was 1/2 or less of the leaf section. When the watering was done in the root part, salinity density of trunk and root parts was higher. In addition, salinity density of the soil was proportionate to the salinity density of the watering. Coastal soil salinity was 0.2 % and the concentration of salt spray was 0.01 % in the coastal area. Hence it is considered that Euonymus japonicus Thunb. could grow in the coastal areas.

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