Leaf-fall phenology was studied in a cooltemperate deciduous broad-leaved forest in central Japan in relation to the topographic environmental gradients that occur along a short mountain slope. Leaf-fall phenology was described quantitatively using data from leaf litter collected along the slope. In autumn, leaf fall at the study site tended to occur slightly earlier on the upper slope than on the lower slope. This pattern was found at both the stand and the species levels. Our results suggest that leaf-fall phenology may be affected by difference in microclimatic conditions, because environmental conditions are thought to be more severe on the upper slope than on the lower slope. The less intensive methods used in this study, the litter trap method, and Dixon's model succeeded in quantifying the phenological patterns of leaf fall within stands and within species along the short mountain slope.

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Palm kernel shell (PKS) utilization for power generation has greatly increased in Japan since the introduction of the feed‐in tariff (FIT) in 2012. However, the FIT fails to consider the entire palm industry while evaluating the environmental impacts of using PKS. Therefore, this study aimed to elucidate the life‐cycle greenhouse gas (GHG) emissions of power generation using PKS. We targeted two PKS‐firing power plants as these are the first two instances of the use of PKS in power plants in Japan. A system boundary was established to cover palm plantation management in Indonesia and Malaysia, as both power plants import PKS from these countries. The GHG emissions were derived from land‐use change, palm plantation, oil extraction, PKS transportation, and power plants. Six scenarios were examined for the emissions based on the type of land‐use change and the existence of biogas capture in oil extraction. CO2 emissions from PKS combustion were also calculated by assuming that carbon neutrality was lost because of cultivation abandonment. The GHG emissions in one scenario, where the plantations were replanted and continuously managed and no biogas capture implemented in oil extraction, exhibited an average of 0.134 kg‐CO2eq/kWh reduction in a plant in Kyushu District, and 0.043 kg‐CO2eq/kWh reduction in a plant in Shikoku District for liquid natural gas‐fired steam power generation, respectively. More than 65% of life‐cycle GHG emissions originate from biogas generated during oil extraction; thus, biogas capture is an effective strategy to reduce current emissions. In contrast, in the case of accompanying land‐use change or collapse of carbon neutrality, the emissions considerably exceeded those of fossil fuels. These findings indicated that the FIT fails to consider the risk of increased emissions or further substantial emission reductions. Therefore, the feasibility of FIT application to PKS needs to be re‐established by evaluating the entire PKS life cycle.