Australian hardwoods, why so different?
Tough trees evolved from a tough environment
A land of frequent fire
The majority of Australian ecosystems have adapted to frequent fire. Fossil pollen records show the Eucalypts became dominant approximately 40,000 years ago assumably due to increased fire frequency judging by increase in carbon in the same fossil layers.
Fire causes gum veins and other marks in the timber.
A dry country
Australia is the driest continent in the world. Low rainfalls mean the trees grow slower and harder and denser. In semi arid areas the growth rings are often caused by rain events rather than the seasons.
In high rainfall areas (such as rainforest) we do find 'regular' density trees but most of these are now protected due to the high levels of harvesting with first settlement as these 'normal' timbers were far easiter to process and use than the denser 'hardwoods'.
A land of voracious insects
Everything fights for survival, including the insects. Trees produce chemicals (called extractives) to deter insects and to preserve the timber from decay. These extractives can give beautiful rich colours. These extractives also affect glue adhesion and drying and stability during use.
Borer holes of various sizes and scribble marks are often found in timber to the extent where Australia has specific grading requirements for the timbers.
