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Yamane, Towa*; Inatsu, Masaru*; Kawano, Jun*; Sato, Takuto; Kusaka, Hiroyuki*
Agricultural and Forest Meteorology, 379, p.111052_1 - 111052_9, 2026/03
Times Cited Count：0 Percentile：0.00(Agronomy)This study aims to obtain fundamental information on birch pollen deposition data by field observation for the high-resolution, accurate pollen modeling. On the peak dispersal day in 2024, simple pollen collectors were installed just below and at three downwind points of an isolated birch tree line in Ebetsu, Hokkaido, Japan. Meteorological observation were also conducted at the site during the days. The birch pollen captured on slide glasses was imaged by a microscope. We first developed the automatic pollen counting technique by applying a machine learning algorithm YOLO to the images. This technique was validated by comparison with subjective counting, and we successfully achieved the automatic counting that has never been done before. The results suggested that the pollen count was highest in the point 200 m downstream from the tree line and diurnal variations were observed at all distances. A simple linear regression analysis of pollen count and meteorological factors revealed a significant positive correlation with temperature. Additionally, a positive correlation with wind speed was also found only at the point just below the tree line. The large-eddy simulation with the pollen advection supported the observation results, though the pollen deposition position was more concentrated near the tree in the simulation.
Ueyama, Masahito*; Iwata, Hiroki*; Nagano, Hirohiko; Tahara, Narumi*; Iwama, Chie*; Harazono, Yoshinobu*
Agricultural and Forest Meteorology, 275, p.196 - 207, 2019/09
Times Cited Count：42 Percentile：91.60(Agronomy)Fire is the major disturbance in North American boreal forests, and is thought to be the most important process that determines the carbon balance in North American boreal forests. This study conducted four years of tower flux measurements in a burned ecosystem from one to four years after a fire, and nine years of measurements in a young regeneration from five to 13 years after a fire in interior Alaska. The fire scar acted as a source of 248 g C m
yr
one year after the fire, and the annual CO
emissions continuously decreased until seven years after the fire. At the final year of the study period, 13 years after the fire, the older forest became a CO sink. During the 13 years after the fires, the total post-fire emissions were 767 g C m across both sites. Gross primary productivity (GPP) and ecosystem respiration (RE) recovered to those of mature black spruce forests 10 years after the fire. The successional recovery of GPP was mostly explained by the recovery of the leaf area index (LAI). Anomalous weather, such as a cold spring, hot summer, and high summer rainfall, increased the CO emissions rather than the uptake. In interior Alaska, the post-fire CO emissions (35-48 Tg C) were estimated to be approximately one third to fourth of the direct CO emissions (156 Tg C) by combustions from 1998 to 2017, which indicates that post-fire emissions are important to the regional CO balance. The forest successional trajectory at young age still contains large uncertainties due to lack of data, and thus adding new data improves our understanding of the post-fire CO balance.
Katata, Genki; Hayashi, Kentaro*; Ono, Keisuke*; Nagai, Haruyasu; Miyata, Akira*; Mano, Masayoshi*
Agricultural and Forest Meteorology, 180, p.1 - 21, 2013/10
Times Cited Count：22 Percentile：64.46(Agronomy)A multi-layer atmosphere-SOiL-VEGetation model (SOLVEG) was modified to calculate the NH
exchange fluxes over a paddy field. The heat transfer at the paddy water layer and the dry deposition of water-soluble gases such as NH and SO onto the wet canopy, as well as the emission potentials of NH from the rice foliage and the surface of floodwater or soil were incorporated into the model. The modified model reproduced the observed surface and NH fluxes, paddy water temperature, and soil temperature and moisture during both the fallow and cropping seasons. The "recaptured fraction" was defined as the ratio of the amount of volatilized NH recaptured by the foliage to the total amount. Numerical experiments using the modified model with varying emission potentials of NH showed that the recaptured fraction increased with an increase in the leaf area index (LAI) and saturated when LAI 
1 because of the limitation of stomatal uptake.
effluxes from surface litter, soil organic carbon, and root-derived carbon estimated using radiocarbon signaturesAtarashi-Andoh, Mariko; Koarashi, Jun; Ishizuka, Shigehiro*; Hirai, Keizo*
Agricultural and Forest Meteorology, 152, p.149 - 158, 2012/01
Times Cited Count：40 Percentile：82.75(Agronomy)Radiocarbon (
C) signature was used to partition soil respiration in a cool-temperate deciduous forest. Heterotrophic respiration strongly correlated with soil temperature, but the magnitude of the response to soil temperature was different between SOC decomposition and litter decomposition. Autotrophic respiration appeared to correlate strongly with the phenology index rather than soil temperature. The information on the seasonal change about the contribution ratio of each source to the soil respiration is essential to understand the intrinsic temperature sensitivity of each source and the other factors controlling soil respiration.
Katata, Genki; Nagai, Haruyasu; Kajino, Mizuo*; Ueda, Hiromasa*; Hozumi, Yu*
Agricultural and Forest Meteorology, 150(3), p.340 - 353, 2010/03
Times Cited Count：32 Percentile：74.99(Agronomy)The aim of the present study is to evaluate fog deposition on vegetation and its contribution to water and energy balance in arid regions using a detailed land surface model including fog deposition on vegetation under meteorological conditions simulated by a meteorological model. The results of estimated fog deposition indicated that fog deposition provided a more effective water source for plant growth as compared to heavy rainfall in arid areas. Evaporation from leaf surface water eases the plant's water stress via reducing transpiration. Latent heat of evaporation from the leaf surface water and soil causes temperature reduction of soil and leaves during the daytime. Moreover, decreased transpiration rates as a result of increased evaporation from the leaf surface water due to fog deposition, yields an effective water source to be used for photosynthesis for those plants suffering from severe water stress in arid environments.
Furuno, Akiko; Chino, Masamichi; Otsuka, Akira*; Watanabe, Tomonari*; Matsumura, Masaya*; Suzuki, Yoshito*
Agricultural and Forest Meteorology, 133(1-4), p.197 - 209, 2005/11
Times Cited Count：24 Percentile：57.75(Agronomy)Transoceanic migration of rice planthoppers was precisely simulated by incorporating several parameters related to the flight behavior with a high performance atmospheric dispersion model. The model consists of an atmospheric dynamic submodel and a particle random-walk submodel for atmospheric dispersion. The model also functions in specifying the release area of the migration of planthoppers. Using this model, we carried out a case study simulating the migration of planthoppers to western Japan in mid-June 1998. In the simulation, 56 areas each with a width of two degrees of latitude and longitude were set as tentative take-off areas. The calculated density of immigrants was compared with each observed density by rank correlation coefficients. Possible migration release areas which showed a high correlation to observations were distributed around 23-27N, including Fujian and Taiwan. An air temperature that allowed the planthoppers to fly continuously and flight duration were critical parameters for the simulation results.
