抄録
Objective. Wood material is widely used for building. Large amount of co-products are generated in sawmill when a log is converted to lumber. Therefore LCI of lumber was implemented based on 3 allocation procedures (allocation to only lumber, volume based allocation and price based allocation) to know the effect of allocation methods in LCI results and which method is desirable for the LCI of lumber.
Results and Discussion. CO2 emission allocated to lumber on volume based allocation is 30% lower than that on allocation to only lumber. On the contrary, CO2 emission allocated to lumber on price based allocation is just 3% lower than that on allocation to only lumber. CO2 emission allocated to each co-product on volume based allocation is 5-30 times of that on price based allocation. From the results of this case study, adapting volume based allocation to LCI is not proper since it is tend to underestimate the environmental load of lumber. Adapting allocation to only lumber and price based allocation are acceptable from a viewpoint of evaluating the environmental load of lumber. Furthermore, price based allocation is better from a viewpoint of evaluating the both environmental loads of lumber and co-products. In case of using sawmill residue for fuel in boiler to dry the lumber, similar results were recognized.
Conclusions. Adapting price based allocation is considered most desirable for the LCI of lumber, and allocation to only lumber is acceptable to evaluate the environmental load of lumber. Future work is to investigate the inventory of other wooden materials (e.g. plywood and laminated wood etc.) and to decide which allocation procedure is the best for the inventory of whole wooden materials.
