Species

Basically all timbers are "tonewoods" to some extent - if it makes a sound then it's tonal. But when we talk about "tonewoods" we are usually talking about timbers with exceptional acoustic qualities. This might be that they have greater sustain, a greater velocity of sound, reduced dampening, produce favourable overtones or simply give a certain tone. This selection will depend on many things but is most closely associated with the component of the instrument.

The different components of an instrument can loosely be associated with timber density. A soundboard is traditionally light yet stiff and has high sound radiation. The bridge and fingerboard need to be hard and stable to resist wear and movement. The back and sides are usually somewhere in the middle. This range is from about 370kg/m3 for soundboards up to a heavy 1300kg/m3 for fingerboards. The fine tuning of the piece is primarily in relation to its stiffness and mass (density x volume) and requires careful selection of the type of timber, and the subsequent skilled craftsmanship of the luthier, in order to achieve this.

Each species will have a range of stiffness and density that it naturally produces and as such is usually only used for certain components; Spruce for soundboards, Ebony for fingerboards, Mahogany for neck, back and sides.

The three types of timber that we supply are Blackwood, Satinwood and Mountain Ash

Blackwood

Satinwood

Mountain Ash

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Blackwood (Acacia melanoxylon)

Blackwood has been been given a few different trade names which can make it a bit confusing when trying to identify what timber you actually have. Acacia melanoxylon is called Australian Blackwood; as not to be confused with African Blackwood which is in the Rosewood Genus - Dablergia. Tasmanian Blackwood and Victorian Blackwood are also Australian Blackwood, the differing names refer to the areas, in this case Australian States, where the Blackwood is sourced from. This species has a distribution that extends from Tasmania, South Australia, Victoria, New South Wales and up into Queensland too. So unless you can be sure where the timber was harvested it should be just called Australian Blackwood. Australian Blackwood also grows in other countries but is still referred to as Australian Blackwood. Since Blackwood tree size reaches its full potential in moist gullies in tall mountain forests, most of the supply comes from Tasmania with a small amount from Victoria. Few other states besides Victoria and Tasmania produce Blackwood of commercial quantities.

Otway Blackwood (AKA Victorian Blackwood) comes from the Otway Ranges in Victoria. The Otway climate receives more rainfall and rain days than almost 1/2 of Tasmania, with Tasmania's capital city Hobart having an average rainfall of just 626mm, making it Australia's second driest capital city. Tasmanian Blackwood comes from Tasmania and can come from wetter or drier regions of the state but most of the supply comes from the wetter North-West of the state.

If the product you have is Otway Blackwood then it has most likely been harvested sustainably and with low-impact, since clear fell harvesting in the Otway Ranges ceased in 2008. There is also tight prescriptions around protecting rainforest in Victoria that are not associated with Blackwood sourced from other states. This is due to the differing environmental legislation in each state.

There is a common perception that faster grown trees are lighter in colour compared to slow grown trees (Morrow 2007), but a number of studies suggest that there is no relationship between these two traits (Nicholas et al. 2007, Bradbury 2005, Bradbury 2011a) or between colour and different sites (Machado 2013). However there appears to be both genetic and environmental influences that affect between-tree and within-tree heartwood colour (Bradbury 2011b). The density of Blackwood also varies considerably from 430kg/m3 to over 800kg/m3 and studies have also shown that this is not related to site (Machado 2013) or growth rate (Bradbury 2011b) but is strongly influenced by genetic (Nicholas et al. 1994) and genetic x environmental (Bradbury 2011b) interactions. Further research on the relationships between colour, density, growth and form from Australian provenances including environmental effects will help to identify superior strains for plantations.

In general there is more variation in timber properties between trees in the same provenance than what there is across trees from different parts of Australia. So because of the variability in Blackwood, the colour, density and stiffness will be unique to that piece more than it will be relevant to the state or provenance from where it came.

Properties

Average Dry Weight: 640 kg/m3

Elastic Modulus: 14.82 Gpa

JANKA hardness: 5180 N

Radial Shrinkage: 1.5%

Tangential Shrinkage: 4%

IUCN status: Not Listed

Blackwood has an average stiffness to density ratio of 23 Mpa/kg/m3, putting it up above that of Koa, Mahogany and some Rosewoods. It has good bending properties and has low shrinkage when drying. It is easy to work but figured pieces tend to be difficult to avoid tear-out, particularly on bladed machines. Blade angles should be increased and kept razor sharp to reduce tear-out. Careful bending of sides is required on figured pieces. The sawdust can cause breath and sinus irritation for some people and the use of dust mask is recommended. Wood colours range from Red Cedar to Walnut, having dark reds and browns to golden brown, orange and yellow, with occasional dark coloured streaks.

Tonewood uses

Blackwood is recognised as a quality timber for instruments, having similar tonal properties to the more traditional tonewood, Acacia koa (Morrow 2007). It is suitable for: electric guitar bodies and necks; the neck, back and sides for acoustic guitars, ukuleles, violins, mandolins, cellos, double bass and weissenborns. Denser pieces can be used effectively for bridges and fingerboards. It also performs well in drums and stomp boxes. The aesthetic properties of figured pieces make it ideal for headstock veneers, bindings and inlays.

Tone

The tone produced by Blackwood is most similar to Koa and Mahogany in having a warm, prominent mid-range.

"Blackwood possesses a rich and powerful lower mid-range which contributes overall to a warm, dark tone. This contrasts with the drier, crisper tones that are realised if Queensland maple or Mahogany is used. As a tonewood, Blackwood sits somewhere between the fullness of Rosewood and the brightness of Mahogany. An unexpected bonus is the contribution Blackwood makes to tone when used as a neck. A Blackwood neck will consistently provide greater volume and clarity than either Queensland Maple or Mahogany" (Pat Evans - The Use of Blackwood in the Australian Guitar-Making Industry, Proceedings of a Blackwood Industry Group (BIG) Workshop, Victoria, 26-29 April 2006).

Traditional uses

Blackwood has had a long history of utilisation by indigenous peoples within Australia (Kean 1991). The seeds are high in protein and can be ground up to make flour and the timber has been used to make spears and boomerangs (Whitesell 1964; Daehler et al. 1999). It is easily workable and is a common material in furniture and kitchens.

Description

Blackwood is a wattle tree that can grow to 45m tall and have a diameter of 1.5m (Doran and Turnbull 1997). The bark is usually hard and fissured but occasionally may be flaky. Adult leaves are dark green with multi-veined phyllodes and juveniles have bi-pinnate compound leaves. Seeds have been known to germinate after 200 years in the soil (Tasmania) and after 10 years in sea water (Cambage 1915). Fire aids seed germination (Wilkinson and Jennings 1994) and it readily sprouts from damaged roots and stems. It is shade intolerant and relies on disturbance to recruit.

Blackwood trees can grow for over 150 years before they commonly rot out, are eaten by ants, blow over or are struck by lightning. The oldest known Blackwood was 210 from Smithton, Tasmania. Once a tree perishes it enables light to penetrate through the canopy - providing conditions suitable for seed germination. If the fire or disturbance frequency is 200 years or greater, the Blackwood component may disappear from the forest, leaving only ground-stored seed awaiting the next major disturbance (Forestry Tasmania 2005).

Distribution

The natural range of Blackwood extends from Northern Queensland along the east coast to far south-west Victoria and Tasmania, also naturally occurring in isolated pockets in South Australia. Blackwood is common in soils that exceed 600mm of rainfall but develops best on deep soils, especially in tall forests and ‘jungle’ pockets in mountain valleys (Costermans 1994). Blackwood is extremely resilient and is an invasive species in Brazil, South Africa and New Zealand.

Blackwood Distribution (Atlas of Living Australia 2020)

Similar Species

Acacia koa (Koa)

Dry Weight: 610 kg/m3

Elastic Modulus: 10.37 Gpa

JANKA hardness: 5180 N

Radial Shrinkage: 5.5%

Tangential Shrinkage: 6.2%

By far the most similar species to Blackwood in terms of timber, tonal properties and growth form, is the Hawaiian endemic Koa. Koa naturally occurs on the four largest of the Hawaiian Islands; Hawaii, Maui, Oahu and Kauai (Whitesell 1964). Growth form, inflorescence characters and timber properties are very similar with Blackwood, differing mainly in leaf and pod characters (Pedley 1975; Waner et al. 1990; Rock 1913; Kidman et al. 2008). The genetic sequence of one region (ETS) of DNA (Nuclear Ribosomal) showed only 6 base pair differences between Koa and Blackwood in an unaligned sequence length of 478 base pairs (Kidman et al. 2008). This study suggested that Blackwood and Koa have diverged relatively recently from a common ancestor. A further study by Le Roux et. al. 2014 estimated the maximum divergence of A. koa from Blackwood occurred less than 6Ma and the divergence of A. heterophylla (Reunion Island, Africa) from A. koa less than 1.4Ma.

Traditionally Koa was used by native Hawaiians to make canoes, spears and ukuleles amongst other things (Whitesell 1964). The timber is very aesthetically pleasing, with beautiful colours and figure that are also very similar to Blackwood (Rock 1913). More recently this species has become exploited and its availability for instrument making is becoming increasingly limited. As an instrument timber, this species is renowned for its rich warm tonal qualities.

Acacia implexa (Lightwood, Hickory Wattle)

Dry Weight: 800 kg/m3

Elastic Modulus: 15 Gpa

JANKA hardness: 8,300 N

Radial Shrinkage: 2%

Tangential Shrinkage: 4%

Lightwood is morphologically and genetically similar to Blackwood (Maslin 2001; Miller et al. 2011) and has a similar distribution but only grows to 15m tall. Its timber is of a similar colour to Blackwood but is much denser and rarely grows with a clean straight trunk. Recently it has been used as bridges and fingerboards for guitars in Australia (Morrow 2007).

Acacia heterophylla

Dry Weight: 600 kg/m3

Elastic Modulus: 11.18 Gpa

Chalais-Meudon side hardness: 2.2

JANKA Hardness: data unavailable

Radial Shrinkage: data unavailable

Tangential Shrinkage: data unavailable

Acacia heterophylla is native to Reunion Is. and Mauritius but has also become naturalised in Madagascar (Du Puy 2001). It is almost identical to Koa and its leaf shape and size, inflorescence characters and growth form is more similar to Koa than what Koa is to Blackwood (Rock 1913; Pedley 1975; Kidman et al. 2008). The study by Le Roux et. al. (2014) suggests that A. heterophylla is so close to A. koa that it could be considered the same species. It is likely to have been dispersed from the Hawaiian Islands less than 1.4Ma. This species has a very limited distribution but prospects of establishing plantations on Reuinion Island have potential.

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Satinwood (Nematolepis squamea)

Properties

Dry Weight: 995 kg/m3*

Elastic Modulus: 30.0 Gpa*

JANKA hardness: data unavailable

Radial Shrinkage: data unavailable

Tangential Shrinkage: data unavailable

IUCN listing: Not Listed

*one random sample only.

otway tonewoods satinwood satinbox instrument timber

Satinwood (syn. Satinbox) has a dry weight of 995 kg/m3 and a modulus of elasticity of 30.0 GPa (one random sample only). The stiffness to density ratio of this timber (30.2 Mpa/kg/m3) is higher than any timber listed in the online Wood Database. It is also higher than all species listed in Bootle 2010 (Wood in Australia: Types, properties and uses) apart from one; White ash (Eucalyptus fraxinoides) in NSW which had a ratio of 33.0 Mpa/kg/m3. This property enables it to be thinner (less volume) whilst providing the same stiffness and mass.

Satinwood is very difficult to dry but once dried remains very stable. It is easy to work with however figured pieces may cause some difficulty, particularly chip-out on bladed machines. Light can be seen through the timber when thinned to less than 3mm.

Uses

Historically the timber has been used for fence posts, telephone poles and firewood. Only recently has this timber been used for instruments. In 2003 Murray Kidman gave Maton some timber for a few prototypes that ended up in the hands of Xavior Rud and Lior. From there it has been picked up by many luthiers and musicians, proving to be an excellent tonewood for guitars, ukuleles, weissenborns and snare drums. Given the high stiffness to density ratio it can be thinned to maximise its acoustic qualities without compromising its structural integrity. It has a relatively high density and is also suitable for bridges and fingerboards. Cole Clarke adopted this species for fingerboards in 2017. It has also been used for guitar necks and is a perfect substitute for a maple electric guitar neck (one piece fretboard and neck).

Tone

"Satin box has the most pure balanced tonal response of any material i have used over the years. Crisp and definitive with depth and presence, a fingerpickers delight." - Phil Carson-Crickmore.