Planning of forest plantation investments with the aid of linear programming: a case study of Sao Hill Forest, Tanzania

Amsterdam

1993

S. 51-72

1 Abb., 10 Tab., 38 Lit. Ang.

Bandaufführung

10588S

161793

Tanzania has adopted central planning. Since the realisation of the development strategy is essentially propelled by micro-level decisions, quantitative micro-planning is imperative. The feasibility of designing a planning scenario for forest projects along this locus is illustrated by a case study of Sao Hill Forest Project—the largest state-owned industrial plantation with 45 000 ha planted by 1990 of pines and eucalypts, supporting both a sawmill and an integrated pulp and paper mill. Planting activities include both afforestation and reforestation. Land evaluation is effected as a combination of biophysiographic approach and social cost-benefit analysis. Constrained by resource availability, the optimal combination of planting activities in a given year is determined using linear programming. This planning scenario is technically feasible. The smallest land unit studied is called a ‘land element’ which is the simplest component of the landscape which for practical purposes is uniform in lithology, form, soil and vegetation. A stratum of similar elements is called a ‘land facet’. Since the profitability of planting at Sao Hill partly depends on the species grown, site productivity, land preparation involved, terrain types and the forest products to be produced, the land elements are redefined as a function of these factors. All the plantable sites or land elements available in year 1984/1985 were inventoried covering 37 310 ha grouped into 62 land facets. Each land facet was identified as an independent forest plantation investment project. The resource demand for each operation on each land facet was gathered from the project management including costings. Financial cash flow was generated followed by shadow pricing, essentially based on the procedure of Little and Mirrlees and its variants. Land expectation value (LEV) was applied in evaluating land facets at financial, economic and social prices. All land facets had positive LEVs, implying that it was worth planting each land facet. Constrained by several resources, it is infeasible to undertake all technically feasible and economically desirable planting activities within the first plan period. Linear programming was found to be useful in solving this decision problem. The solution to the Sao Hill planting problem is given in terms of the number of hectares scheduled for planting between 1984/1985 and 1988/1989 inclusive, embodying the value of the objective function and the shadow prices of the binding constraints. The information generated is very useful to decision-makers and project management.