Costing and Estimation ofWorks - Afforestation, Reforestation and Forest Restoration in Arid and Semi-arid Tropics - page 121

Chapter 7
Costing and Estimation of Works

Abstract Estimates of work quantities and their costing is an important element
in planning of afforestation and reforestation programmes. Cost estimates can be
prepared in two stages. First, the quantities of work (e.g. volumes of excavation,
numbers of polypots to fill) are worked out. Thereafter, unit costs are developed and
multiplied by the quantities of work to arrive at the final cost estimates. An approach
is also provided with examples of model cost estimates of plantations which can be
used in planning of afforestation projects and programmes.

7.1 Schedule of Labour Rates

Afforestation works in arid and semi-arid tropics are likely to involve a high propor-
tion of labour inputs as level of mechanization is low. The schedule of labour rates
is therefore an important part of the cost estimation process. The schedule of rates
also serves as a means to standardisation of the specifications of work items. Each
item is described in the schedule with full specifications, so that quality may be both
prescribed and measured.
Table 7.1 presents an example of a basic schedule of labour rates. The rates
presented are an average indication of likely costs. Labour rates have been expressed
in terms of man-days per unit quantity of work. The actual output of workers in a
given setting will depend upon many factors like physique and health of the workers,
climatic conditions, and work culture. While the rates presented in the table are
good enough for design of projects—and to go by in execution where nothing else
is available—the locally available rates, based on actual work studies, should be
adopted for more accurate estimation of costs. Minimum wage legislation can also
regulate wage rates paid in local currency. Therefore, it is more useful to express
costs in terms of man-days, which will be usable not only across all changes in time
but also across different currencies.
Three kinds of man-days have been used: unskilled, semi-skilled, and skilled
(Table 7.2 ). A principle of equivalence among these man-days has been followed
in certain places where totalling of different kinds of man-days is required. This
equivalence assumes that 1 skilled man-day is equal to 1.5 semi-skilled man-days,
and to 3 unskilled man-days.
In all labour items, it is assumed that the skilled and semi-skilled workers will
carry their own tools, whereas the unskilled workers will be provided with tools