Abstract
As a significant percentage of forestation problems in Japan can be traced to young trees not being properly or selectively culled, their effective utilization contributes to maintain a forest in prime condition. The goal of our research project is to utilize effectively medium and small sized timbers as value added material. Wooden space truss system using those timbers is one important application developed by us. In this paper, pullout performance of lag screw used in joint unit of the truss system is verified through a theory of pull-out properties parallel to the grain, experiments and FEM analysis.
