A trial load of green sawn 150-200mm wide X 50mm thick regrowth Douglas fir was dried in Gen 4 kilns in Melbourne recently. Sourced from WFP and MacKenzie Lumber- Chermainus BC, this material is generally regarded as difficult to dry.


  • Dried in 7 days to 12-15% using less than 0.5 gj/ M3 of heat energy
  • Free solar heat contributed 93% of the normal heat energy consumed by conventional kilns
  • Electrical energy consumed was less than 25% of that used by conventional technology.
  • Quality outcome was high with notable absence of reject “wets” and absence of knot checking and fall-out.
  • Total cost of drying was less than $AU15/ M3.
  • Vancouver, Canada’s best solar drying months are equal to Melbourne