This research article published by the Journal of Biodiversity and Environmental Sciences, Vol. 13, No. 6, 2021Deadwood (DW) is an important carbon component for conservation and management of biodiversity resources. They are ubiquitous in many semi-arid ecosystems although its estimation is still posing lots of challenges. At Chimwaga woodland in Dodoma Region of Central Tanzania, seasonal quantification of DW produced by two Acacia spp. was done to evaluate the influence of each tree species, Dbh and canopy area on DW biomass and to determine their ecological role in conservation of semi-arid ecosystem. Both purposive and random sampling techniques were used in the course of a completely randomized design (CRD). Thirty trees from each species of Acacia tortilis and Acacia nilotica were studied. Results portray that DW biomass was significantly higher (P < 0.05) in the dry season than in the rain season whereby A. tortilis produced 669.0 ± 135.90kg DM/ha (dry season) and only 74.3 ± 135.90kg DM/ha (rain season) while A. nilotica produced 426.1 ± 135.90kg DM/ha (dry season) and 36.5 ± 135.90kg DM/ha (rain season). DW biomass did not correlate significantly (P > 0.05) with Dbh and canopy area. Inter-specific interactions were encountered from experimental areas where DW was littered that facilitated ecosystem balance in semi-arid areas. This information is important for estimating amount of dead wood biomass required to be retained in the forest provided that, at the expense of ecology, they are refuge for arthropods, fungi, bryophytes and other important soil microbes representing primary components of Biodiversity in semi-arid ecosystems.