There are a number of elements which you will need to consider specifically when producing woodfuel. These elements are in addition to generic forestry considerations.

Timing of operations

The cheapest way to dry timber is passive air drying (more on drying), however depending on initial and target moisture content this will typically take 12 to 24 months. This means you need to plan ahead when either harvesting or buying in green timber. Some species will naturally contain more water by weight than others when felled (for instance typical moisture wet basis for fresh Ash: 32%, Oak: 47%, Poplar:64%, European Larch: 50%, Sitka Spruce: 61%, Norway Spruce: 65%) and this need to be factored into the expected drying time. There is more information on calorific values and drying in our information note Wood as Fuel.

Products specification

Bear in mind that the methodology you use when harvesting will have an impact on the whole supply chain and not just the harvesting phase. For instance studies have shown that cutting random length poles can improve felling and chipping outputs, however this practice can have a detrimental effect on the outputs of forwarder extraction as it becomes difficult to optimise loads. Similarly if the product cut at the harvesting stage at 2.4 m length and the firewood to be later processed in 0.5 m lengths, this will lead to unnecessary costs at the transport and processing stage.

Transport and storage of products

Presentation of the products in a way that will allow easy handling and loading will bear an impact on the subsequent transport costs. In most cases products will be removed from the felling site as rapidly as possible and taken to a storage site (roadside or depot) to allow the drying process to start as early as possible. It is important to ensure well ahead of the harvesting taking place that sufficient storage is available for the expected volumes, ideally within short transportation distance of the harvesting and/or processing sites. The extraction method, and to a lesser extent, subsequent storage, will also have an impact on the contamination of material.