| Abstract
| - Roads influence the cost of every phase of forestry, but before roads are built in the forest it must be shown that they will pay. The problem is best faced at the start of the life of the forest when planting is being planned since early determination then will ensure that routes built for access and management are on alignments which will later form part of the extraction network. Later, at the beginning of the thinning stage, management may have to decide whether the small mileage already constructed for access is sufficient or whether to add to it to form a full extraction network, i.e. a system of motorable roads close enough spaced to reduce the length and therefore the cost of the very expensive off-the-road haul to a reasonable figure. Three tables are given. The first shows the limiting figure for profitable expenditure on a road network for a range of conditions based on the reduction of the length of off-the-road haul from ½ mile to 150 yards. The second shows the effect of the provision of roads on the investment yield. The third shows roadwork costs per mile and per acre. Using these tables, two typical examples are worked out: one from the point when thinning begins; the other for the entire life of the forest.
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