Australian Timber Hardness Table |Which Is The Toughest?

Australian timber comes from a variety of trees and plants—the Ironbark, Jarrah, Messmate, and Tasmanian Oak to name a few. Every species of tree has a unique DNA sequence that defines everything about it, instructing the tree to grow a certain height and breadth, to grow leaves of a certain shape, and to grow wood that has a particular molecular structure.

The uniqueness of every tree species has resulted in various types of timber being available, and in this article, we’ll provide an Australian timber hardness table for the commonly available timbers in the country.

How is timber hardness rated?

Timber hardness is rated by something called the Janka hardness test, named after Austrian Gabriel Janka. Hardness is measured based on the wood’s resistance to denting and wear, and is carried out by embedding a small steel ball into the wood. The amount of force required to embed the ball provides the hardness rating, and is measured in kilonewtons¹.

Australian timber hardness table

Here is a full breakdown of Australian timber, sorted by hardness². While some of these trees aren’t native to Australia, the timber is all available across the country.

Tree or plant species	Janka rating (kN)
Brazilian Walnut	16.37
Bamboo (strand woven)	16.1
Grey Box	15
Ironbark	14
Red Mahogany	12
Turpentine	12
Spotted Gum	11
Brushbox	9.5
Blackbutt	9.1
Forest Reds	9.1
Sydney Blue Gum	9.01
Karri	9
Tallowwood	8.6
Merbau	8.56
Jarrah	8.5
Stringybark	8.1
Australian Beech	7.5
Flooded / Rose Gum	7.5
Northern Beech	7.5
Messmate	7.1
Bamboo (vertical)	6.58
Cypress Pine	6.1
New England Oak	6.1
Ribbon Gum	6.1
American Oak	6
Bamboo (horizontal)	5.87
Tasmanian Oak	5.5
Victorian Ash	4.49

What defines the hardness of timber?

The hardness of a material is based on its molecular structure. For example, the hardest material on earth is diamond, which has carbon atoms that share electrons with four other carbon atoms, creating an incredibly strong molecular structure that is difficult to break. The same applies to timber—the hardest types of timber have a molecular structure that creates a stronger bond than the weaker types, which defines its hardness.

Why is timber hardness important?

Timber hardness defines how easily the material will tear. The softer the timber, the easier it will be scratched, marked, and worn down over time, which makes harder timber more desirable.