Fine Root Production and Turnover Estimation by Ingrowth Core Method in Two Tropical Forests of Congo Basin

Abstract

In the context of global warming and its escalating consequences, forests have proven to be crucial for mitigating the impact of climate change. Therefore, we conducted a study on the impact of ingrowth core’s method on carbon transfer into the soil in two tropical forests in the Republic of Congo, the Patte d’oie forest in Brazzaville and the forest of Lésio-Louna reserve in Batéké Plateau. Forest plots were installed in these areas, and fine root biomass and productivity were determined by sampling soil cores over the course of one year at two horizons: H₁= 0–15 cm; H₂= 15–30 cm. Moreover, three classes of root diameter were considered for quantifying standing fine root biomass: class I =[0-2 mm] (fine roots); class II = ] 2-4 mm] (medium roots); and class III = ] 4-10 mm] (large roots). For fine root productivity and root turnover studies, only class I was considered. We recorded the following fine root turnover values for horizons H₁ and H₂: 1.66 y^-1 and 1.77 y^-1, respectively, at Lésio-Louna, and 1.19 and 1.56, respectively, at Patte d’oie forest. Concerning the root turnover value, we obtain in H₁ a root turnover of 1.66 yr^-1 in the Lésio-Louna forest against 1.19 yr^-1 in the Patte d’oie forest; in H₂, the turnover is 1.77 yr^-1 in the Lésio-Louna forest against 1.56 yr^-1 in the Patte d’oie forest. Furthermore, the forests are structurally different, which can influence fine root biomass and production but not the differences in root life between both forests. Finally, our results helped to conclude that these two forests did not transfer the same amount of carbon to the soil compartment.