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Severe decay damages of bridges made of ekki (Lophira alata) wood known as a durable species
2000 - IRG/WP 00-10383
Bridges made of ekki (azobe, bongossi, Lophira alata Banks et Gaertn.) timbers were severely decayed only 10 years after the construction possibly caused from no maintenance for the periods. The reason of no maintenance is due to the misunderstandings on wood durability against wood-decaying fungi. Some civil-engineers and architectures understand "durable species" means "absolutely decay-durable ...
S Doi, T Sasaki, Y Iijima


Persistence and residual activity of organophosphorus termiticides in soil and prevention against the degradation of chlorpyrifos
1991 - IRG/WP 1518
The persistence and the residual activity of four comercial organophosphorous termiticides, Chlorpyrifos, Fenitrothion, Tetrachlorvinphos, Pyridaphenthion, in soil were studied under laboratory conditions. The persistence and the residual activity of four organophosphorous termiticides in two types of soil decreased with the lapse of time. These termiticides were mostly degraded by microorganisms ...
T Iijima, M Tanaka, M Higaki


The spread of technology in a simple wooden pile construction method to prevent shallow landslides
2025 - IRG/WP 25-20733
This study introduces the development and practical application of an innovative slope stabilization technique called the Wood Pile Root System Method (WPRSM), aimed at preventing shallow landslides, which have increased due to the rising occurrence of extreme weather events caused by climate change. This method effectively reinforces slopes using thinned timber, providing a sustainable and cost-e...
K Shimizu, K Tanaka, H Hashitani, A Yamaguchi, K Kabeno, Y Iijima, A Ito, M Jo, T Fujii, K Abe, H Ochiai


Considerations on how different preservation processing methods of logs would have different effects on wood structures
2025 - IRG/WP 25-41040
Azekura-zukuri style wood structures (hereinafter referred to as azekura-style structures) have been utilized in forest conservation projects in Japan as substitutes for concrete structures. We estimate that making use of thinned and small logs for azekura-style structures has positive impact on circular economy and carbon fixation and contributes to the biodiversity within their areas. In additio...
Y Iijima


Proposal for New Evaluation Criteria for Exterior Products to Achieve a Circular Economy
2025 - IRG/WP 25-50408
In recent years, the development of laws related to the promotion of wood use in buildings in Japan has led to a significant increase in wood demand, resulting in the widespread use of various wood materials in construction. In this context, the use of preservative-treated wood, selected based on the principle of using the right material in the right place, has been emphasized. However, a systemat...
K Murakami, T Fujii, Y Iijima, T Hikiji