Estimation of volume, biomass, and carbon of coarse woody debris in native forests in São Paulo State, Brazil

Abstract

With the objective of increasing knowledge on carbon stocks, and thus improving the accuracy of published estimates, the present study explored wood density and carbon concentration of coarse woody debris by decay class in a Seasonal Semi-deciduous Forest (SSF) area in the Atlantic Rain Forest and in a Cerrado sensu-stricto (CSS) area. For this research, only large elements (diameter geq 10 cm), known as coarse woody debris (CWD), were considered. Data were collected according to the line intersect sampling (LIS) method. Two strata were chosen in each area, and in each stratum ten sampling units were installed according to a systematic sampling protocol. Each unit included: one 200 m transect line in the North-South direction, one 200 m transect line in the East-West direction (crossing the center point of the N-S transect), a 150 m line crossing the N-S line in the East-West direction at 25 m south of the center point, and a 50 m East-West line crossing the N-S line at 50 m south of the center point (for a total of 650 m of transect length per sampling unit). For each element, the diameter, length, and perpendicular width were recorded at the transect intersection point; each element was also classified into a decay class, and when possible the species was identified. Furthermore, disc samples were also taken from each element, from which cylinder samples were extracted then oven dried to determine density. These cylinders were milled and analyzed using a LECO-C632 to determine carbon content (as a mass percentage). The volume of each element was calculated by taking the difference between the cross-sectional area and the hollowed area, then multiplying by the element's length. Biomass was calculated by multiplying an element's volume by its density, and carbon stocks were calculated by multiplying biomass values by carbon factor computed via lab analysis. Data from the 650m line intersect sampling units were used to calculate wood density and carbon concentration averages across the areas. Cross shaped transects (with 150 m segments for the CSS, and 200 m segments for the SSF) were used to calculate estimators of biomass and carbon stock. In both areas, as the decay class increased (from least to most rotten material), wood density decreased, which follows the same pattern as other literature. The present study concludes that carbon concentration barely changes within each decay class. Biomass was estimated at 6.7 and 1.3 Mg/ha for the SSF and the CSS, respectively. Carbon stock concentrations reported from laboratory analyses were 3.3 and 0.7 MgC/ha for the SSF and the CSS, respectively. Using a conversion constant of 50% similar results were obtained, though other studies using the conversion constants found that they had overestimated carbon stock values. Due to this result, we strongly recommend the evaluation of wood density and carbon concentration for CWD at the site-level using decay classes.

Wood density and carbon concentration of coarse woody debris in native forests, Brazil

“…A 50 m tape measure was used to lay out the transects, with corrections for slope when necessary. Additional details about the field protocols can be found in Moreira (2017) and Moreira et al (2019).…”

Biodiversity of Rhizobia from a Wide Range of Forest Leguminosae Species in Brazil

“…Probably the VSG strains belong to B. liaoningense, which must be confirmed. Other phenotypic (SDS-PAGE protein profiles) and genotypic (multilocus enzyme electrophoresis/MEE, RAPD fingerprints) analyses on part of these SG and VSG alkanisers confirm their taxonomic position in the genera Bradyrhizobium (Moreira et al, 1993;Moreira et al, 1995;Coutinho et al, 1995). This result is conflicting with previous reports that Bradyrhizobium japonicum was introduced in Brazil as bacterial inoculants for soybeans (Martinez Romero and Caballero-Mellado, 1996).…”