Akio Tsuchiya

The relationship between stem vessel parameters and the development of strata in the early stages of secondary forest succession in Amazonia

In order to compare the development of strata in the early stages of secondary forest succession with vessel parameters of the tree species, a forest inventory was carried out in 4-year (Q1: 48 m2), 11-year (Q2: 400 m2) and 20-year (Q3: 400 m2) forests and vessel parameters were investigated from stem cross sections of 18 species obtained in Q2. Thirty three species (21 families), 77 species (35 families), 39 species (20 families) were found in Ql, Q2, Q3, respectively. The percentage of dead individuals, dead stems and the percentage of individuals with multiple stems increased with time after clear cutting. Also, the total D2H of Q3 was 26.1 times that of Q1, and the development of strata started in Q2 and Q3. The image analysis of vessel size, area and number of vessels revealed that species which reach the forest canopy had a large D2H value, vessel diameter and area, while species which remain near the forest floor had smaller ones. Poecilanthe effusa (Huber) Ducke is an example of the latter case, with a large number of individuals and abundant sprouting of new stems from stumps, but with high mortality.

Forest biomass and wood consumption in the lower course of the Amazon: a case study of the Urubueua Island

Florestas de varzea e de terra-firme na foz do Amazonas foram comparadas, com relacao a sua estrutura, incrementos de volume madeireiro e biomassa florestal. O volume madeireiro de floresta de varzea e menor que o de florestas de terra-firme, especialmente quando se considera a intervencao humana (o cultivo da palmeira acai) na referida analise. Esta diferenca e ampliada na comparacao de peso florestal, pelo fato das arvores de varzea apresentarem uma baixa densidade madeireira. As arvores de florestas de varzea nao sao diretamente influenciadas pela escassez caracteristica do periodo prolongado de seca, devido a madeira de alta densidade ser formada em arvores de terra-firme. Na ilha em estudo, cuja area e de 36.200 ha, o desaparecimento anual da area florestal devido as queimadas provocadas pelas olarias, e cerca de 276 ha. Assumindo-se que as florestas tem um periodo de rotacao de 25 a 30 anos, a area total deflorestada esta entre 6.87-69480 ha/25 anos a 8.244-8.337 ha/30 anos. Este resultado demonstra que o balanco entre a biomassa e sua utilizacao nao esta em crise; entretanto este balanco pode sofrer alteracoes, caso nao sejam substituidos os meios de producao de energia na regiao.

Climatological and Geographical Characteristics within Inversion Layers in the Presence of High NO2 Concentration

High concentrations of NO2 may accumulate in the upper regions of the atmospheric inversion layers. In this study, the climatological and geographical characteristics of two cases where a high nighttime NO2 concentration appeared in the inversion layer were studied, one on a slope on the Seto Inland Seacoast and in the Saijo Basin. On the Seto Inland Seacoast, the inversion layer appeared at 160 m a.s.l. There were remarkable differences in the concentration of NO2 and saturation deficit across the boundary of the inversion layer. In Saijo Basin, the inversion layer covered almost the whole basin up to 500 m a.s.l. The cold air lake appearing below 290 m contained an especially high level of humidity and NO2 concentration. In conclusion, it appears that the inversion layer plays a significant role as a cover preventing atmospheric NO2 from diffusing outside the layer. In both cases, it seemed that the water vapor pressure almost reached saturation in the high NO2 concentration zone.

Micrometeorological environments and biodiversity in a closed forest and at a tree-fall gap in central Amazonia.

Micrometeorological parameters were measured in a closed forest (CF) and at a tree-fall gap (LG) near Novo Aripuana, AM, along the Madeira River in dry season (August to September 2003) and rainy season (March 2004), and were compared to the number of species per family and the number of seedlings obtained from forest inventory. The daily averages of net radiation (W/m 2 ) between CF and LG were 9.5:168.0 during dry season and 3.6:125.9 during rainy season, and these averages were influenced by the difference in shortwave radiation between the sites (CF<LG). Likewise, the diurnal range of soil heat flux, soil temperature, air temperature, and saturation deficit were all CF<LG. These site differences were explained from the sky-view factor (CF: 14.8±3.9%, LG: 43.6±6.0%). Frequently-occurring tree-falls and recoveries resulted in increases in the numbers of colonizer species, such as Burseraseae, Cecropiaceae, Meliaceae, Myristicaceae, Simaroubaceae, Violaceae, and Sterculiaceae. From the comparison of the number of seedlings at mini-plots, some genera, which have established themselves in response to improvements in environments at gaps, were found, such as Pourouma, Parkia, Tachigalia, and Orbignya , meanwhile genera peculiar to closed forests ( Protium, Chrysophyllum, Micropholis ) were also found.