This chapter describes the laying out of the roadline from the initial paper plan, through field validation, to the final layout, ready for construction.
Planning is a critical component of any successful road construction programme, and is part of the broader harvest planning process. In commercial forests, the primary purpose of forest roads is to provide suitable access for forestry operations. A good planner intimately knows the area they are working in, has a broad skill set, and uses a suite of available tools to assist in decision-making.
Planning infrastructure for harvesting involves linking roads to the best extraction sites or ‘landings’ (see Chapter 4 for more detail). In harvest planning, locating landings are a priority because their position is critical in ensuring efficient harvesting operations.
While building roads is expensive, the road building cost per unit volume harvested is typically much less than the harvesting costs. However, it is not always possible to get a road to the optimum landing site. For example, there may be safety, environmental or economic constraints. The outcome is a trade-off where the landing position is changed, or an alternative harvesting system is used, for example, two-staging.
The figure in the next section sets out the typical planning steps for locating, designing and field layout of the roadline. For roads on relatively flat or rolling terrain, with good soil working conditions, an experienced road construction crew and a clear set of road standards, a flagged grade line might be all that is required for construction to proceed. However, roads on steep terrain needing extensive earthworks, or those having to cross waterways, will benefit from (or require) a more detailed plan, referred to as a full road design. Each step in this planning process is described in more detail in this chapter.