Tree Species Composition, Structure, and Aboveground Wood Biomass of a Riparian Forest of the Lower Miranda River, Southern Pantanal, Brazil

• Published in: Folia geobotanica 2008-12, Vol.43 (4), p.397-411
• Main Authors: Wittmann, Florian, Zorzi, Bianca Thaís, Tizianel, Fernando Augusto Tambelini, Urquiza, Marcus Vinicius Santiago, Faria, Rogério Rodrigues, e Sousa, Nathália Machado, de Souza Módena, Érica, Gamarra, Roberto Macedo, Rosa, Augusto Lisboa Martins
• Format: Article
• Language: English
• Subjects: Biomedical and Life Sciences; Floodplains; Floods; Forest ecology; Forest habitats; Forest stands; Life Sciences; Plant Ecology; Plant Sciences; Plant Systematics/Taxonomy/Biogeography; Riparian forests; Species; Species diversity; Trees; Tropical forests
• ISSN: 1211-9520; 1874-9348
• DOI: 10.1007/s12224-008-9022-9

The aboveground wood biomass (AWB) of tropical forests plays an important role in the global carbon cycle, and local AWB estimates provide essential data that enable the extrapolation of biomass stocks to ecosystem or biome-wide carbon cycle modelling. Few AWB estimates exist in Neotropical freshwater floodplains, where tree species distribution and forest structure depend on the height and duration of periodic inundations. We investigated tree species composition, forest structure, wood specific gravity, and AWB of trees ≥10 cm dbh in 16 plots totalling an area of 1 ha in a seasonally inundated riparian forest of the lower Miranda River, southern Pantanal, Brazil. The 443 tree individuals belonged to 46 species. Four species (Inga vera, Ocotea suaveolens, Tabebuia heptaphylla and Cecropia pachystachya) comprised more than 50% of the Total Importance Values (TIV), and floristic similarities between the plots averaged 38%. Although we detected an overall increase in species diversity correlated with decreasing flood levels, the most important tree species had almost identical distribution patterns along the flooding gradient. The stand basal area per plot (±s.d.) amounted to 3.0± 1.1 m² (47.8±18.1 m²/ha), and the tree heights averaged 10.9±1.4 m. Multiplying the individual basal areas by individual tree heights and a form factor of 0.6, we estimated the aboveground wood volume (AWV) for each individual, and for each plot (24.4±11.7 m³, 391.1±188 m³/ha). Wood specific gravity (SG) varied between 0.39 g/cm³ (Cecropia pachystachya) and 0.87 g/cm³ (Tabebuia heptaphylla), with a stand level average of 0.63±0.12 g/cm³. Multiplying the individual AWV with species SG, we estimated the plot AWB to be 16.2±6.4 Mg (259.4±102 Mg/ha). This value is comparable to that reported for late-successional forest stands of Amazonian floodplain forests, and it is close to the worldwide tropical average AWB. Because tree heights in the present forest were comparatively low when compared to other Neotropical forests, we found that resprouting of stems accounted for comparatively high basal areas. We argue that stem resprouting is an adaptation of tree species originating in non-flooded Cerrado to the seasonal inundations of riparian forests.