Growth Performance and Carbon Sequestration potential of Planted Albizia versicolor and Albizia harveyi in Morogoro, Tanzania

This study assessed the growth performance and Carbon sequestration potential of 21-year-old Albizia versicolor Welw ex. Oliver. (Av) and Albizia harveyi Fourn (Ah) planted in 2003 at Maseyu village, Morogoro, Tanzania. These species are among the species preferred for wood fuel in Tanzania and other countries within African savanna ecosystems. Seedlings of the two species were planted at a spacing of 2 x 2 m with 25 trees per plot (8 x 8 m) using a completely randomized block design with three replications. In 2024, measurements were taken for diameter at breast height (Dbh) and height. Data was analyzed to get means for Dbh, height, volume, annual increment (MAI), above-ground biomass (AGB) and above-ground Carbon stock (AGC). An independent t-test was used to analyze differences in species parameters using R-studio. Results showed significant differences in stocking density (p < 0.001), Dbh (p < 0.001) and height (p < 0.001) between species, with Albizia versicolor exhibiting larger mean Dbh (8.82 ± 1.36 cm) and height (7.46 ± 1.47 m) but relatively lower stocking density (1,188 ± 407 stems/ha) compared to Albizia harveyi (7.33 ± 1.16 cm,6.63 ± 2.28 m and 2,230 ± 1046 stems/ha respectively). However, no significant differences were found in volume, AGB, and AGC. Volume increments were 2.41 m³/ha/yr for Albizia versicolor and 2.58 m³/ha/yr for Albizia harveyi, while AGB increments were 1.23 and 1.17 t/ha/year for Albizia versicolor and Albizia harveyi respectively. Above-ground Carbon (AGC) stock increments (0.58 and 0.62 tC ha⁻¹ year⁻¹) for Albizia versicolor and Albizia harveyi respectively under monoculture were consistent with studies on mature Miombo woodlands. These findings suggest that both Albizia species perform well in monoculture growth, demonstrating their potential for sustainable Miombo woodland management and Carbon sequestration, despite lower biomass accumulation rates compared to natural Miombo ecosystems.