Mean Value	Standard Deviation
MOR (Mpa)	58.70	6.77
MOE (Gpa)	7.94	1.80

 
The 'hardness' of timber is defined as its ability to resist indentation. Hardness is most commonly measured using a Janka hardness test. The test requires a steel ball with a diameter of 11.28mm to be pressed into a sample until it has penetrated to a depth equal to half its diameter. Hardness has traditionally been used as a means to compare species for suitability as a flooring material. Hardness of a species is also closely related to its capacity to resist abrasion, another important property in the selection of a species for flooring and similar materials. When comparing species hardness for wearing properties, it should also be considered that other factors such as the tendency to edge split, or wear unevenly may also be important in the selection of a species for such applications.

 
3.3.1 Summary of Results
 
Janka hardness values are frequently quoted as an average value of both tangential and radial surfaces.The average Janka hardness value for the test population is 3.3kN.

 
Individual test results can be viewed in Appendix 4. Table 3 shows the average hardness result for camphor laurel in comparison to some other species.

 
Table 3. Janka Hardness data.

Species	Trade Name	Janka Hardness (kN)
Cinnamomum camphora	camphor laurel	3.3
Paulownia spp. (Australia)	paulownia	1.3
Araucaria cunninghamii	hoop pine	3.4
Corymbia citriodora	spotted gum	11
Elaeocarpus grandis	silver quandong	2.8
Toona ciliata	red cedar	2.3

 

 
Basic density is a measurement of the actual 'wood' substance present and is calculated as the oven-dry mass of a specimen divided by its green (saturated) volume. It influences wood properties such as hardness, strength, pulping, workability, and seasoning. Basic density reflects the fibre wall thickness, and the number of fibres per unit mass, and is therefore a useful indicator of paper and pulping properties. Basic density data is also useful when calculating the mass of green timber (used when calculating freight load weights). A disc taken from each billet was cut into two wedges. These wedges were cut into segments separating the sapwood from the heartwood, and then splitting the heartwood into two (representing inner and outer heartwood). Basic density was determined by the gravimetric method in which the green sample volume is determined by water displacement before it is oven-dried to a constant weight. Basic density is calculated as the ratio of oven-dry weight (grams) to the weight (grams) of displaced water (volume) from the equation:

 
Basic Density (kg/m3) = (oven-dry weight/green volume)*1000.
 
A total of 28 samples (15 herbicide treated and 13 untreated) were used for this experiment.
 
3.4.1. Summary of Results

 
>

	Inner Heartwood	Outer Heartwood	Heartwood Sample	Sapwood Sample	Whole Sample
	B/D (kg/m3)	B/D (kg/m3)	B/D (kg/m3)	B/D (kg/m3)	B/D (kg/m3)
Mean	391	423	414	480	452
Max	448	493	473	549	513
Min	329	364	353	431	403
StDev	28.04	36.31	32.10	30.12	28.48

 
Individual test results can be viewed in Appendix 5 or in chart form in Figure 1. Table 4 shows the average whole sample basic density result for camphor laurel in comparison to some other species.

Click Here to view a larger picture.

Individual test results can be viewed in Appendix 10 or in chart form in Figure 2.
 
Figure 2.

 
Click Here to view a larger picture.
 

 
3.10.1 Test Method
 
Twenty beetles, chosen at random from the culture, were placed into a jar with a section of timber from 25 different camphor laurel test billets, 13 from treated billets and 12 from untreated billets. A control jar containing samples of black bean (Castanospermum australe) sapwood (of known Lyctus susceptibility) was also established to provide a gauge for the final assessment of the camphor laurel samples. This was necessary in the event that no adult beetles emerged from the test samples. Once beetles began to emerge from the control sample, one generation was deemed to have been completed, allowing for assessment of the test samples. In cases where emergence holes and live adults were clearly visible in the jar, the wood sample was deemed vulnerable to attack. Where this was not the case, a portion of the sample was dissected with a chisel and hammer and viewed under a microscope for evidence of beetle larvae and/or larval galleries, filled with powder-like frass. Where only larvae or larval galleries were evident the wood was also deemed to be vulnerable to attack. Where there was no internal or external evidence of an infestation the wood was labelled potentially not vulnerable. Those tests that show samples to be vulnerable can be labelled as legally susceptible. Those tests that provided a potentially not vulnerable result must still be treated as legally susceptible until additional intensive testing can be completed to prove that the species is non susceptible.

 
The jars were inspected at irregular intervals up until the 9th January 2001 when they were assessed for infestation and adult emergence. At this time adult beetles had emerged from the control sample.

 
3.10.2 Summary of Results
 
Of the 26 samples tested (including the control) only the control was found to be vulnerable to lyctid attack. This result indicates camphor laurel is potentially not vulnerable to attack by powder post beetles although there is some published literature suggesting that it is. This therefore means that legally (depending on state legislation) the sale or use of susceptible sapwood from camphor laurel must be avoided unless further follow up testing can prove it as non susceptible.

 
Go to the Top
Go to the NEXT Section