Differences in Wood Utilizaiton among Species in Construction Timbers for Pit Houses in Satsumon Culture at Oshima 2 Site, Kitami City, Hokkaido, Japan

Abstract

Morphological features were examined for a total of 166 charred wood specimens of which estimation of use and wood identification had already been reported after unearthing from four pit houses in Satsumon culture located at Oshima 2 site (Kitami city, Hokkaido, Japan). It was possible to estimate the diameter classes of tree stems from which the wood specimens were taken, and trimming mode of timbers from the stems for 97 of the 166 specimens. They were divided into round woods from stems of small diameter and split timbers from stems of large diameter. The round woods were mainly used for flooring/bench seats and approximately two-thirds of them were Populus. The split timbers were mainly used for rafters, and approximately two-thirds of them were Quercus. These results suggest that size and trimming mode of wood are closely related to construction components and the choice of species. Average annual ring width of Quercus specimens was 0.58 mm; much narrower than that of other species/taxa examined. It is likely that Quercus woods were collected in natural forests around the site and widely used because the woods were easy enough to trim and strong enough.