- 著者
- Akio TSUCHIYA Pedro Braga LISBOA
- 出版者
- The Association of Japanese Geographers
- 雑誌
- 地理学評論 (ISSN:13479555)
- 巻号頁・発行日
- vol.77, no.5, pp.321-335, 2004-04-01 (Released:2008-12-25)
- 参考文献数
- 45
Meteorological parameters were measured in mahogany (mogno)-black pepper (pimenta) agro-forestry sites at Parque Ecológico de Gunma in Santa Bárbara do Pará, Brazil in September 2001 in order to investigate the differences in microclimatic mitigation in relation to forest structure and growth. In site mogno africano (MAF) where African mogno and pimenta were planted four years ago, the tree height (H) was 14.9±0.9m and the canopy coverage (CC) was 59.40±9.22%. Likewise, in site mogno amazônico (MAM) where an agro-forestry of Amazonian mogno and pimenta has been tested for six years, H was 6.6±0.8m and CC was 35.48±5.36%. In site mato reservado (RES), which is a 30-year-old secondary forest with 24 woody species, H: 13.3±7.8m, CC: 72.39±8.23%, and in site rocado (ROC), which was clear-cut 10 months ago, eight perennial herbs and 21 pioneer woody species were found, but CC was the smallest (6.21±1.09%). With respect to the radiation balance, downward short wave radiation (SWdown) was ROC>MAM>MAF>RES, while upward short wave radiation was ROC>MAM>MAF_??_RES. Both net radiation and photosynthetically active radiation had a similar phase to SWdown. Temperature was also dependent on SWdown. But dew point temperature (Tdp) decreased faster in ROC and MAM than at the other sites because radiative cooling due to upward long wave radiation (LWup) was larger in the nighttime. When temperatures reached Tdp in ROC and MAM, the relative humidity became 100% and the absolute humidity kept decreasing as long as dew formation continued. From these circumstances, it is clear that the diurnal fluctuation of microclimatic environments near ground surfaces depends on CC, and it is believed that pimenta, which are fond of the shade, should be planted in RES with high microclimatic mitigation effects.
- 著者
- Akio TSUCHIYA Akira TANAKA Niro HIGUCHI
- 出版者
- The Association of Japanese Geographers
- 雑誌
- 地理学評論 (ISSN:13479555)
- 巻号頁・発行日
- vol.78, no.12, pp.794-811, 2005-10-01 (Released:2008-12-25)
- 参考文献数
- 51
Soil CO2 concentration and microclimatic parameters were measured at a primary forest and grassland in dry season (August to September 2003) and rainy season (March 2004) in central Amazonia in order to investigate the effects of infiltration of rainfall and evaporation of soil water upon the changes in soil CO2. The CO2 temporarily increased with infiltration, and decreased after soil water descended downward. Then, the increase and decrease moved to deeper soil. This phenomenon was found at both a primary forest and a grassland in the rainy season, and was found in the dry season as well at primary forest. At the grassland in dry season, the soil moisture change was positive during daytime, while the CO2 concentration change was negative. During nighttime, in contrast, the soil moisture change was negative and the concentration change was positive. It was estimated that the fluctuation of radiation between day and night reversed the relative position of soil water and CO2 in the soil. In the rainy season, there was not a large difference in the surface soil concentration (10-30cm: 20, 000-25, 000ppm) between the sites, while in dry season the concentration at the grassland was quite low (2, 500-2, 600ppm). From these findings, it was estimated that the soil CO2 was emitted or the root respiration was quitted due to the withering of herbs on the grassland in the dry season. In either case, it is thought that the decrease in soil CO2 was brought about by the exposure of naked land due to the disappearance of forest canopy.