Abstract:
A problem of interest to forest managers is the optimum arrangement of truck roads and landings for economical logging operations.
This problem becomes more complex if,a combined yarding and swinging
operation is considered. I,t is possible to formulate a mathematical
model to express the cost per unit volume for a particular configuration
of truck roads, landings, and swing roads arranged to accommodate
this type of harvest operation. Then, any of several
numerical methods may be employed to assess the sought-for optimum
configuration. The parameters of interest are the truck road spacing,
landing spacing, and swing road length that produce the smallest
logging cost. This paper critically examines several assumptions
made in formulation of the problem, including yarding cost computation,
tractor movement patterns, and average yarding distance.
This paper uses a numerical method not frequently employed with
constrained objective functions: Newton Multivariate Gradient
Iteration. A computer program was developed to implement the
iteration procedure, using a Hewlett-Packard 9830A Desktop Computer.
The solution procedure reduced iterations required for convergence
from several thousand experienced with exhaustive enumeration techniques
to less than thirteen. The use of this gradient method,
observations on its behavior, and insights into the analytical
approach to a complex problem are the subjects of this paper.
