Logs and firewood

The simplest, and most traditional form of woodfuel is firewood logs.  The only processing required is drying and cutting to a size that conveniently fits in your stove or boiler.

Firewood logs have the big advantage as a fuel that they can be sourced from one's own woodland or trees with minimal specialist equipment other than a chainsaw and appropriate protective equipment.  Owing to the physical size of the pieces it is critical that it is dried thoroughly, usually down to 20-25% moisture content (wet basis), which typically requires seasoning for two years.

See the Equipment section for information on suitable stoves and boilers for burning logs.

Cutting, stacking and drying

Small round wood (SRW) may simply be cut into logs.  This may be done in the forest for ease of extraction and handling and to assist drying, and involve delimbing and cutting into logs of typically 2-3 m in length. 

These may be stacked at the roadside for convenience of subsequent collection, which may follow a period of drying.  On average 1 m3 of roundwood requires 1 linear metre of roadside space.

If well stacked, a pile of round and split logs can show a bulk density 70% of that of the solid wood, though if loose this can drop to only 40% or less.

Scoring or partial removal of bark may help to accelerate drying.  For logs over 15 cm diameter splitting is recommended to assist drying.

Optimum size for firewood

Logs may also be sold directly to domestic consumers as fire wood logs to be burned in an open fire or log burner.  For this they need to be around 15-50 cm long (for many domestic users 25-30 cm is the optimum) and typically split if greater than 10 cm diameter. 

What's of interest

Domestic heating with logs

General information about heating your home with logs (PDF - 1MB)

Wood as fuel

Information about using conventional firewood logs for domestic heating in both traditional log stoves and boilers, and modern, high efficiency batch type log boilers (PDF - 1.7 MB)

Wood as fuel - Technical supplement for fuel suppliers

A technical supplement to Wood as Fuel aimed at log suppliers and individuals processing logs for their own use (PDF - 968kB)

Biomass Heating: a guide to small log and wood pellet systems

First in a series of three technical design guides from the Biomass Energy Centre.  This guide covers small scale systems suitable for a domestic house or similar sized projects (PDF - 4.0 MB)