Optimizing species selection for the structural timbers of traditional farmhouses in a snowy rural area of northeastern Japan

Abstract

Vernacular houses constructed using local woods contain information about forest‐resource use. To clarify how timber was used to construct wooden farmhouses, we identified the timber species composition of 11 houses built between 1845 and about 1940 in Tadami, a snowy rural area in northeastern Japan, and interviewed 70 residents. We recorded 2004 timber parts (99–308 parts per house) and 171.2 m3 (1828 parts) of known species (14 taxa). Cryptomeria japonica (cedar) and Pinus parviflora var. pentaphylla (white pine) were used for all essential structural parts and accounted for 44% and 39% of the total timber volume, respectively. Fagus crenata (beech) was the third most commonly used species (7%), for roof supports, beams, and girders. The interviews revealed that the timber was typically sourced from local private or common woodlands within 1 km and that local craftsmen selected and hauled the trees. Considering the region's unique and complex vegetation, as land‐cover distribution is strongly influenced by frequent avalanches, the timber was likely managed within local stands of tall trees, and the most available species would have been cedar (although whether native or planted is unknown), followed by native white pine on mountain ridges around settlements. In comparison, beech stands that could supply sufficient amounts of timber might have been limited. Based on the characteristics of the trees used as house timber in Tadami, we conclude that despite the surrounding harsh, snowy conditions, locally available species of tall trees were historically selected for timbers.