A species of casuarina tops the world's hardest woods

(writing in progress)

https://web.archive.org/web/20120426064548/http://www.morlanwoodgifts.com/MM011.ASP?pageno=207
 
The data for wood density (tonnes/cubic metre when air-dry) and hardness (according to Janka scale) shows some surprises. The most relevant surprise, for me at the moment, is that a species of Allocasuarina widespread in eastern Australia ranks as the very hardest wood in the world, despite not being the densest wood.
 
Combretum imberbe in southern Africa, which is called ‘leadwood’ on account of its heavy wood, contains an unusual amount of calcium. This impressive wood is certainly remarkably dense (1.21 where it only takes >1.0 to sink in water), but its Janka hardness is not particularly remarkable at 3570.
 
Mulga (Acacia aneura) is well-known to have hard wood (with aboriginal knocking-sticks that sound more like metal than wood when played musically) and it certainly has dense wood (1.20). However, its Janka hardness is only 3820, much the same as C. imberbe.
 
Eucalyptus wandoo is well-known for its dense wood (1.10), but once again its Janka hardness is not exceptional (3370). This species of eucalypt is similar to ebony (Diospyros ebenum) in these parameters, the latter species scoring 1.12 and 3220.
 
Several species of ‘acacia’ score higher in both density and hardness, the top species being the Australian Acacia peuce at 1.372 and 4630. This really is dense and hard wood.
 
I have long known that casuarinas have dense wood. So the value for density in the case of Allocasuarina luehmannii (1.11) comes as no surprise. However, what does surprise me is that the Janka hardness of this species, at 5060, is considerably greater than that of any other tree familiar to me in this data-set.
 
So the wood of at least one common species of casuarina is the very hardest known in the world, easily exceeding other famously hard woods including ebonies, eucalypts, acacias, dalbergias and combretums. And at least one other casuarina (Casuarina cristata, 1.15, 4500) is also noteworthy, with Janka hardness being about fifth in the world.
  
(writing in progress)

Publicado el julio 30, 2022 10:57 TARDE por milewski