Title : Aboveground biomass of the tree species used for fuel in tree-based systems within the agricultural landscape of Rwanda
Abstract:
Tree-based systems (TBS) in the agricultural landscape of Rwanda do supply considerable amounts of fuelwood to the local communities. However, there needs to be more information on the available stocking, aboveground biomass (AGB), and productivity of the trees used for fuelwood. We assessed the occurrence, distribution, AGB, and productivity of the trees used for fuel within five TBS, namely home garden, mixed cropping, boundary planting, live fence, and woodlot. The study used a systematic sampling design, establishing 130 band transects, each measuring 2 km x 5 m. The transects were systematically distributed across the Bugesera and Musanze Districts, representing low and high-altitude regions. In Bugesera District, the common tree species for fuelwood use were Grevillea robusta, Eucalyptus spp, Senna spectabilis, and Markamia lutea. The results indicated that the mean stem density and AGB of Eucalyptus spp and Senna spectabilis were substantially higher than other species. Across all TBS categories, trees covered an average stem density of 50 stems/ha and an AGB of 2.07t/ha. The stem density and AGB were substantially higher in boundary plantings and mixed cropping than in other TBS. Most trees in all TBS categories had a diameter ranging from 1-5 cm, except for the woodlot, where trees had a diameter ranging between 5.1-10 cm. In Musanze District, the common tree species for fuelwood use were Grevillea robusta, Eucalyptus spp, Alnus acuminata, and Markamia lutea. The mean stem density, standing AGB, and productivity of Eucalyptus spp were substantially higher than those of the other species. Across all TBS, trees covered an average stem density of 109 stems/ha and AGB of 5.38t/ha. The number of stems and AGB were substantially higher in boundary plantings and woodlots than in mixed cropping, live fences, and home gardens. Furthermore, the results on fuelwood supply indicated that Senna spectabilis in Bugesera and Eucalyptus spp in Musanze have a higher potential to produce higher biomass in short rotation.
Keywords: agroforestry; fuelwood;, cooking, stem density, biomass
