Thread: Timber ID please

1 & 2 - no idea.

3 - Kwilia / Merbau

species one - and even 2, look like spotted gum to me.

I think you’re right Bob, I just thought it’d be more dense?

Lemon scented gum Corymbia Citriodora. Very similar to Spotted Gum but not as dense. Leaves have strong lemon scent, the timber has none.

Dry Densities are pretty similar, average is 990 kg/m^3 for spotty and 950 for Lemon. In practice densities of individual bits of wood vary by +/- 10% so there’s well and truly overlap making it very difficult to determine which species a specific piece of wood was based on just density. There’s a bit of a larger difference in green densities but still tricky.

That's what it says in the book. On the ground things are often quite different. The way we could tell spotty from lemon was weight.

Hmmm, I think this is a debate that can't be resolved too easily.

Bob, I would say that densities in some species can vary by even more than 10% - you can get that much variation between the top & bottom of some individual trees, and there are always the extreme outliers that decide to be more than two standard deviations from the mean for that species! So as you imply, while it's a useful guide, density is a pretty loose guide to species!

To Rusty I would say, what was your gold standard? It's easy to lump wood into two piles based on weight & call one "X" & one "Y" - you'll never be wrong! Lemon scented gum has a very restricted natural range, it's exceedingly difficult for a non-botanist to tell from regular Spotty in all but that lovely perfume after a rain shower, in my experience. The botanists have been arguing & lumping the two together & pulling them apart again for yonks. I think the current status, based on genetic evidence is that they are the same species again. You may well have been correct with your id for a given range of each "species" but I have serious doubts that you could separate samples from all over the country so neatly by density alone ....
Cheers,
Ian

Identification was made in the forest - standing trees. You dont need rain to identify lemon scented - just crush a fresh leaf. Our logging was from the Qld boarder to the Vic boarder. Both species grew in select areas the full length of NSW. There are at least 5 different spotted gum variants, to my knowledge. Lemon scented is only one of them. Interestingly, it always weighed lighter than the others which could be verified by the hammer stamp on the butt. Personally, I have always found the book weights to be indicative only. You wouldn't want to use them to load a jinker and then drive through town.

Originally Posted by rustynail

.....I have always found the book weights to be indicative only. You wouldn't want to use them to load a jinker and then drive through town....

No indeed, "indicative" is a good description. The 'book' densities are a mean (one would hope of many samples, though not always), & as Bob said, densities vary by at least 10% each side of average.

I'll bow to your experience on this one, I reckon your sample size is big enough to draw some conclusions from! I've never been able to compare the woods, only the living trees. And yeah, I do know you can pick the lemon-scented by crushing a leaf, I had one growing in my backyard at one stage. There is one in a front yard just down the road from where I live now; it would be at least 45 feet tall & the leaves are well out of reach, but whenever I walk past after rain it tells me what it is...
Cheers,

The problem I am having with this and similar threads is the photography. If people would add a reference colour, like a coke can or something to give us an idea if the colour is distorted by the lighting. Just my two bobs worth.
Rgds,
Crocy.

Interestingly the CSIRO "Forest trees of Australia" book list the density range for LSG as 950 - 1010 kg/m^3, while for SG its 745 - 1080 kg/m^3 which places LSG inside the range for SG

I've milled loads of spotty but not much LSG, either way of those I have milled I've never been able to tell the difference based on density.

Bob, I wonder if it is an environmental thing? I have never had anything to do with WA timber, other than jarrah. Over here, LSG grows quicker than SG in the same soils. Grown naturally, the former prefers better soil, which would lend to a faster growth rate. As for the book weights, I'm sorry, it just doesn't stack up which, in my experience, is not unusual. Many is the log I have lifted or tried to lift with a scaled grapple which was well outside the constraints of the manuals.

Originally Posted by rustynail

Bob, I wonder if it is an environmental thing? I have never had anything to do with WA timber, other than jarrah. Over here, LSG grows quicker than SG in the same soils. Grown naturally, the former prefers better soil, which would lend to a faster growth rate. As for the book weights, I'm sorry, it just doesn't stack up which, in my experience, is not unusual. Many is the log I have lifted or tried to lift with a scaled grapple which was well outside the constraints of the manuals.

The problem with our own experiences is it's limited to just what we experience/observe. I would believe that in some areas that it is possible the LSG and SG have significantly different densities but it appears that is not a general rule.

The guys from CSIRO will have assessed and compiled densities from a wide range of sources from different states so they are seeing a bigger picture than any one of us can see as individuals.

I agree there's probably a significant amount of environmental effects.
In the CSIRO book on "Forest Tress of Australia", the Maps for where LSG and SG grow as natives are instructive LSG grows mainly in QLD - there is an LSG subspecies (Variegata) that grows from west of Maryborough to Coffs harbour in NSW. The Citriodora tends to grow further north and not as far south as the Variegata. SG is naturally distributed from Southern QLD to eastern Vic.

SG typically grows in rainfall areas from 680 to 1700 mm/yr. LSG has a wider range 600 - 2000 mm/yr

Where rainfall is low trees tend to grow denser and VV but its the SG that has the wider range of densities. It could be sampling error problem but I doubt it as the CSIRO blokes should take this account.

Then there are weed trees. SG yard trees, of which we see many at the tree loppers yard, benefit from often excess irrigation which sees them grow really fast. Over here in WA SG is a weed - In 1978 we planted 6 of the as 50c seedlings and in 1994 it cost us thousands to have then taken down for a house reno. The densities of these can range considerably.

Like I said I cannot tell the difference between LSG or SG just by looking or picking up a piece of each type of timber.

I get to know what things are because they get labelled when they come into the yard but not always. Jeff the tree lopper is a trained Arborist can tell by looking at a tree, so I often ask him what something is. He's shown me how to use the bark as an identifier but by the time I mill logs the bark has usually fallen off and I have not paid enough attention anyway.

I agree, they are hard to tell apart once the leaves and bark are gone. All our LSG came out of the Coffs area. Our SG was from the NSW south coast. I can't remember any common location logs. This may have been the reason for under weight LSG. As you say personal experiences may be limiting my knowledge here. One thing I do know - the scales don't read the manuals.