Studies on gum arabic in Tanzania were conducted in eleven districts aiming at
estimating the country's potential and current production, assessing its utilization and contribution to the local and national economies and its marketing channels. For the gum yield studies, 1,106 trees represented in four diameter classes were sampled and tapped by de-barking a portion of the stem at breast height. The tree parameters assessed were dbh, height and number of branches. Gum from the trees was collected four times at an interval of three weeks, and weighed using a sensitive electronic weight scale. A total number of 518 circular 0.1 ha plots each were selected using a systematic random
sampling method for the inventory of Acacia senegal and other associated woody species. The plot characteristics assessed were elevation, climate, soils, terrain type and disturbance by bush fires whose intensity levels were recognised as 1, 2 and 3. For the studies on actual gum arabic production, economic potentials and marketing data were collected using social survey methods from 630 gum collectors as well as 630 non collectors living in gum producing areas, in 64 villages, eight gum middlemen and three final gum buyers and exporters. The quality of gum was assessed using 90 samples from
each district. Secondary data were collected from district and regional forest and natural resources offices in which gum arabic is collected and several other public offices. Data analyses were carried out using the Microsoft Excel package of Microsoft Office 98 and 2000 and SPSS employing descriptive statistics, one-way statistical analysis of variance and regression analyses.
Results indicated that the overall mean gum arabic yield per tree is 246±333 g, greatly influenced positively by tree size particularly diameter, up to an optimum size, temperature, fire intensity and stem crowdedness. The overall mean population density of Acacia senegal was estimated as 225 stems ha^-1, marginally influenced negatively by altitude and positively by temperature. The actual mean annual gum arabic production was 4,030 ± 15 metric tonnes composed mainly of gum from A. drepanolobium (65 %), therefore not qualifying for the name gum arabic rather than gum talha. There is a serious lack of a clear definition of gum arabic from the exporters to the collectors, leading to its
haphazard collection and trading without processing and grading. All gum is collected from trees in natural stands and not by tapping, by mainly women (44%), children (30.5%) and male livestock herders (25.5%). The gum is important to the subsistence economy of many rural people, using it for food, medicine and glue. The gum is also economically important to the collectors, the middlemen, the final buyers and exporters and local and central governments. The business is however, purely a private enterprise, highly disorganised and controlled by the final buyers and exporters in which the bulk of the gum (75 %) is traded unrecorded. The gum collectors are therefore, the most disadvantaged group receiving the minimum payment in the whole chain. Managing Acacia senegal plantations for gum is economically viable with LEV of TShs 814,529,
NPV of TShs 469,089 and IRR of 63 % at rotation age of 9 years and interest rate of 10%. Among the recommendations given by these studies include tapping Acacia senegal trees, gum processing and grading, improvement of the existing A. senegal resources and closer monitoring of the trade by the local and central governments.