DEGREE OF DETERIORATION OF LOG PILES BURIED IN THE TAMA RIVER LOWLAND MORE THAN 84 YEARS AGO

In Japan, various efforts are underway to achieve carbon neutrality by 2050. Reforestation and the use of harvested wood products are well-established and are considered to be reliable and realistic climate change mitigation measures. Therefore, using wood underground for countermeasures against soft ground is expected to provide substantial carbon storage. However, there is little academic data on the extent to which wood deteriorates under underground conditions; thus, the effect of this method of carbon storage has not been recognized internationally. In this work, log piles driven into the ground more than 84 years ago in the Tama River Lowland, Japan, near the mouth of the Tama River were excavated, and the degree of deterioration and the groundwater level were investigated. The degree of deterioration was low, and the half-life of mass loss was estimated to be about 400 years, even though the log piles had been above the groundwater level for a long period of time.