Processing eucalypts

Eucalypts can produce timber of the highest quality, but they can be challenging to process. This is mainly due to unpredictable levels of growth strain. Experienced eucalypt sawmillers use well-proven cutting strategies to release growth strain during sawing to produce straight lumber. Care is also needed during the drying process. 

Small-scale sawmilling

Portable sawmills, or small-scale fixed equipment, are of interest to durable eucalypt growers and wood users because it is this scale of sawmill that is most likely to be used, in the short term at least, for milling New Zealand grown durable eucalypts.

A report produced in 2020:  Portable sawmilling of locally grown alternative timber species - A report on the potential for a sustainable small-scale industry in the Hawke's Bay Region' provides a comprehensive review of the sector.

A factsheet on portable sawmilling is available on Te Uru Rākau's  Canopy website.

Stickered and stacked eucalypt timber after sawmilling, Specialty Timber Solutions.

The challenge of growth strain

Eucalypt logs can display unpredictable levels of growth-strain, reducing sawing yields and increasing processing costs. Growth strain causes log splitting, warp, and brittle heart.  Logs with high levels of growth strain will distort immediately upon sawing if they are not sawn correctly. Well-proven cutting strategies are necessary to release the strain during sawing to produce straight lumber.

One of NZDFI's earliest research activities was to better understand growth strain, and devlop a methodology to assess growth strain in young trees.

Australian examples

In Australia, native eucalypt forests have been sustainably harvested to supply logs to a wide range of medium and large-scale sawmills. These processing operations have developed cutting and drying strategies to maximise the recovery of sawn and well-seasoned hardwood products that are sold to both domestic and international markets.

An example is Hurford’s Hardwood located in far north coast region of NSW. Their supply chain is based on five processing hubs supplied with native eucalypt logs. They deliver product into their global sales and distribution chain that includes an Auckland showroom, supported by a warehouse in Tauranga offering ‘a full range of quality Cladding, both Engineered and Solid Flooring, Decking, Timber Wall Lining and much more’.