This study aimed to compile an inventory of remnant old growth trees that were planted along the border of homesteads as windbreaks, and to explore the conservation status of these old growth trees. Two survey sites in the southernmost part of Okinawa Prefecture, Japan, were selected. We found that the tree line at the north and east sides of homes have been protected and were better conserved than the tree line at the south and west sides. The average tree density was approximately 0.8土0.32 (SD) trees per meter for well-preserved tree belts. Moreover, a negative correlation between tree density and mean DBH size was found at both the east and north sides. The conservation and maintenance of old growth trees within the homestead depends on natural and human factors. Exposure to typhoons and monsoonal winds are among the most important natural factors that contribute to tree damage. However, human factors are also important in terms of tree cutting or conservation. The residents′awareness on tree conservation determined whether trees were preserved or felled.

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Suitable planting base is necessary for coastal tree growth. In this study, to accumulate the examples of investigation using a combined penetrometer-moisture probe (CPMP) for evaluating planting base of a coastal forest, soil moisture and soil softness observation using CPMP was conducted together with tree measurement in seven coastal Pinus thunbergii Parlat. stands in Oshamambe, Hokkaido Prefecture, Japan. While four forest stands were sound, three forest stands were declined. Declined forest stands tended to have higher soil water content at a certain depth than sound forest stands. However, differences in soil water content were not clear between sound and declined forest stands in some cases. Also, relationship between soil softness and coastal tree decline was not clear in this investigation. Thus, further research is necessary for establishing a method to evaluate planting base of coastal forests using CPMP, although we could confirm that CPMP has a potential to evaluate it.

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