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

Abstract

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 Folia Geobot (2008) /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 m 3 , 391.1±188 m 3 /ha). Wood specific gravity (SG) varied between 0.39 g/cm 3 (Cecropia pachystachya) and 0.87 g/cm 3 (Tabebuia heptaphylla), with a stand level average of 0.63±0.12 g/cm 3 . 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.

Age-related and stand-wise estimates of carbon stocks and sequestration in the aboveground coarse wood biomass of wetland forests in the northern Pantanal, Brazil

“…In Table 6 we compare our estimates of C-stock and Csequestration in AGWB with data from a riparian forest in the southern Pantanal region (Wittmann et al, 2008), different successional stages from central Amazonian floodplain forests (Worbes, 1997;Schöngart et al, 2010), and dry forests from Mexico (Vargas et al, 2008). The estimated Cstocks in AGWB of the four studied stands are lower when compared to the estimated C-stocks in a flooded riparian forest along the Miranda River in the southern Brazilian Pantanal.…”

“…An important parameter for the AGWB estimation is wood specific density (ρ, in g cm −3 ), which can vary considerably between tree species even in the same stand (Fearnside, 1997;Baker et al, 2004;Nogueira et al, 2005;Wittmann et al, 2006Wittmann et al, , 2008Schöngart et al, 2010). From 48 characteristic tree species of the Pantanal comprising 130 samples (cores and stem disks), ρ was calculated by the dry/fresh volume ratio after measuring the fresh volume in the field and drying the sample for 72 h at 105 • C (Schöngart et al, 2005).…”

“…With this data set (Arruda, 2006) we estimated ρ for 67-98 % of the individuals in the four stands. For another 4-31 % of the individuals we used published data for the mean values and standard deviations of ρ (Loureiro et al, 1979;Worbes et al, 1992;Fearnside, 1997;Ter Steege, 2001;Schöngart, 2003;Baker et al, 2004;Wittmann et al, 2006Wittmann et al, , 2008Chave et al, 2009). For the remaining trees (<1.6 % of all individuals) we estimated ρ by using the mean value of the analyzed tree species (Table 2).…”

Stand dynamics of the drought-affected floodplain forests of Araguaia River, Brazilian Amazon

“…Other studies found a negative relation between diameter growth and the height and duration of annual inundations, e.g. in the igapó forests along Rio Negro , Amazonian várzea forests (Nebel et al 2001a(Nebel et al , 2001bSchöngart et al 2010) and riparian forests in the Brazilian Pantanal (Wittmann et al 2008;Schöngart et al 2011). Worbes (1997 confirmed with dendrochronological methods that the floodplain trees typically reduce wood growth during the aquatic phase and then remain in a state of cambial dormancy.…”

Development of Allometric Equations for Tree Biomass in Forest Ecosystems in Paraguay

“…In Atlantic Forest, Cecropia pachystachya is a typical pioneer tree species (Holz et al 2009), with low WD (Wittmann et al 2008). In addition to H, WD is another important predictor that can improve biomass estimation (Chave et al 2006).…”