Availability of machinery

In many cases the type of machinery that is available locally will be critical in determining what options are realistic for extraction. There is more information on extraction systems here.

Costs

You should have some idea of the total cost of operations including:

• Capital costs:
  The direct purchase or lease/hire cost of machinery. This is affected by whether the equipment is already available, the expected level of use (generally higher usage results in a lower hourly cost), and the expected life of the equipment.
• Operating costs:
  This includes the costs of maintenance, fuel and spares, insurance and operator(s)

Note: you will need to evaluate costs in relation to expected revenues. In many cases the woodfuel products will only have a low value, and higher value products generated as part of the same harvesting operation will raise a much higher income. It is also possible, especially in the case of very small scale operations, that cooperating with other local woodland owners/managers allows work to be more cost effective.

Terrain

Some sites factors will limit the choice of extraction machinery. The Forestry Commission operates a terrain classification system based on:

• Ground bearing capacity, in relation to the weight of machinery.
• Terrain roughness, in relation with machine terrain capability.
• Slope, in relation to machine stability.

Weather conditions, particularly rain, can change sites much more vulnerable to damage and modify the conditions in which machines can operate safely. The Forestry Commission has produced a document on terrain classification (TDB Technical Note 16/95), which can be obtained from Technical Development Services.

Site impact

Small woodlands can be particularly vulnerable to environmental damage; to reduce potential impact, at the planning stage it is useful to consider:

• Type of machines that are usable on site (for instance skidding is not advised on sensitive soils).
• Brash mat requirements for machine movement in relation to soil type, machinery and species.
• Timing of operations in relation to wet weather, especially on soils type such as clays and brown earths. (Adverse weather conditions might require harvesting to be rescheduled, or alternative systems to be selected).
• Use of skilled labour.
• Implementation of good environmental working practices, e.g. when working in the vicinity of water courses to minimise the risk of water pollution.

The impact on growing trees

Extraction systems and routes should be planned to minimise tree damage; for example, avoid skidding long poles against standing trees, or activities that may cause ground compaction as this could damage root systems.

Access

Site access must be available for machinery to get to the site and for the produce from harvesting to be transported away. When hard roading (a forest road or adequate track) is not available then you may need to construct a suitable track.

In wood access: bear in mind that ground conditions within the wood may not be adequate to cope with all the machinery travel needed, and it might sometimes be necessary (for example key route or extraction route convergence at forest roads) to construct hard tracks. Such requirements will depend upon the total area to be harvested, extraction distances, load sizes and volumes to be extracted.

Extraction distance to the nearest road has a significant impact on machinery choice and cost.

Other operational considerations

• Provisions need to be made for roadside conversion and stacking space. If available space is limited, additional area clearing and/or additional hard road access might be required.
• Greater yields of produce will require more in-wood travel for extraction purposes, and might require larger extraction machinery or higher extraction route specification.
• Different product types may affect the choice of extraction machinery or system, for example long poles or whole trees cannot be extracted by some forwarders.
• If the product specifications are varied, extraction of mixed loads might not be possible, and in the case of low yields per hectare, this can result in small loads being extracted with a detrimental effect on outputs and costs.