Silvicultural Methods Effects on the 82 Year Old Planted Pericopsis elata (Fabaceae) and Entandrophragma cylindricum (Meliaceae) Dendrometry in Yangambi Region, DR Congo

The effects of four silvicultural methods notably Layon, Blanc-Etoc (BE), Martineau and assisted natural regeneration (ANR) have been compared on the dendrometric traits of Pericopsis elata Harms and Entandrophragma cylindricum Sprague planted in 1938 in Yangambi for controlling anthropogenic activities (agricultural deforestation and forest degradation) threatening the species to extinction added to difficult natural regeneration. The sustainable pedosilvicultural system will preserve Yangambi biosphere reserve. In case of variance analysis significance; the non-parametric test of Kruskal Wallis and the test of Tukey Honest Significant Differences were applied to separate the traits means. Results have revealed that the three plantation methods were significantly different from ANR. BE, Martineau and Layon have determined the Gaussian shape for P. elata diametric structures while Layon, Martineau and ANR presented the inversed J shape for E. cylindricum. BE method convenes for plantations of the two species whose trait values were higher than those of other methods. The difference was significant between the widest average breast height diameter (DBH) of 44.49±10.63cm with the total height mean of 24.46±4.45m for P. elata and DBH of 29.63±11.59cm with the total height mean of 22.04±5.80m for E. cylindricum. The differences were also identified respectively for the two species regarding the basal areas with 25.54±5.6 against 9.474±1.67 m/ha, the aboveground biomasses with 318.81±77.2 against 94.315±11.59t/ha and the loose volumes with 45069.49±12219.30 against 14 471.348±3 645.692m/ha. The Layon method did not have significant effect on the E. cylindricum, but has influenced the DBH, AGB and basal area of P. elata. The least productive method ANR has expressed a convenient natural regeneration inversed J shape for the two species, as related to Yangambi reserve preservation.