| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2003: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2002: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
In this study, the growth of trees which had been lightly stressed was investigated in a small treefall gap formed in 1999 (CP, 400 m^2) and a large gap formed in 2001 (CG, 2500 m^2) in a super-canopy-projected lowland forest along the Madeira River of central Amazonia, and the relations to microclimatic parameters at the two sites were examined and compared to a man-made open space. The thickening growth abruptly increased in 1999 at CP, but it decreased gradually during next year. At CG, the growth kept a higher level even after an increase in 2001 than that before the gap formation. At both sites, the percentage of vessel area in stem transection approximately doubled, meaning that the tree height also increased. The downward short-wave radiation, a source of input energy, was CA>CG>CP, and other parameters such as net radiation, photosynthetically active radiation, ground surface soil heat flux, and atmospheric and soil temperatures also showed similar phases, however, relative humidity, dew-point temperature, and absolute humidity had a reverse pattern (CA<CG<CP). This is explained by the sky-view factor which says that a small-sized gap with a dense canopy exists in low temperature and high humidity environments with small diurnal fluctuations, whereas an open space with no coverage accompanies in high temperature and low humidity environments during daytime and radiative cooling or easily water-vapor-condensed environments during nighttime with large fluctuations. However, even a small gap is influenced by direct solar radiation, and it works to the advantage of small individuals in the gaps
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