What tree is this?

[benb]

Hi,

I am trying to find out what tree this is I took a photo of on the track along to Pelion Gap. I can't tell whether it is Pencil Pine or King Billy Pine.
Hopefully someone on this forum will be able to enlighten a non Tasmanian on the species.
Thanks,

Ben

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[tasadam]

King Billy.
And a massive example at that.
It's about a third to half way from Pelion Hut to Pelion gap, on the right of the track as you head south, the track sort of swings round it.
It's one of the biggest King Billy pines I've seen and I remember it well.

Next time you're here, take a trip to the Walls, go down to Dixons Kingdom and take a look at (as you walk through) possibly the largest and oldest stand of Pencil Pines. Some are as much as 1000 years old.

[tomberli]

If it is the tree that I think it is then you might just be wrong Tasadam, sorry It looks like the tree roughly 2/3 of the way up the gap, just after a stretch of tall eucalypt forest, you come to a little crest and its one of the only short descents between pelion hut and the gap. You drop down into rainforest and the track goes over a little creek which actually forms a natural tunnel for about 5 to 7m through the roots and the rainforest soil. Does that sound like roughly the spot? You then climb out of the creekbed for and then follow a flat stretch through some of the most amazing king-billy rainforest before it starts climbing up again next to a huge fallen eucalypt...

You might not remember all the detail but if that is the spot - and i'm fairly sure it is, then it is in fact an Athrotaxis laxifolia - the hybrid between king billy and pencil pine - and as far as I know the biggest and oldest known in Tassie - 1300 years apparently. Most of the others near there are all king billies but the first and biggest one over the creek is a laxifolia. A stop my group every single time and talk about it. When you look at the leaves then it is quite obvious that they are different from king billy. There is a whole Botany PhD largely based on that tree.... You can find it in the science library at UTAS if you're keen...

[tasadam]

Look at the leaves? Crikey, you are tall!
Hey, I can handle being wrong on this one, I'm no expert on King Billy but I knew it wasn't a pencil pine.
Having a cross-breed species? Well that's just plain tricky...

It's not an easy tree to forget though, is it - truly magnificent.

[tomberli]

Well to be honest I would have never picked it myself that it was a hybrid rather than a king-billy because it does pretty much look exactly like one but if you pick up some of the branches that will be on the ground underneath it and then compare it to some others nearby you can clearly see the difference. It was pointed out to me by other guides howeverand I think it was originally identified by parks staff So I don't claim to be an authority, I just have been told before...

[Buddy]

Why not Athrotaxis X ? How can a hybrid be named a species? A walk up Mt Read will show forms of the hybrid from near pure selaginoides to near pure cupressoides. At what point does one decide to call it laxifolia?

[tasadam]

At what point does one decide to call it laxifolia?

I guess when one is an expert enough to know what that means AND how to pronounce it...
Beyond me on both counts, sorry.

Perhaps the answer lies in that PHD referred to?

[tomberli]

At what point does one decide to call it laxifolia?

Very good point and I have often wondered this myself. Being a biologist myself I would have to say that this is almost certainly wrong. I'm not fully aware of how the breeding system works but there is basically two options - either the hybrid between king billy and pencil pine produces fertile hybrids that can then themselves breed with either of the other to produce further offspring - in that case there would really only be one species with a few different morphs and we'd have to get rid off all three names - king billy, laxifolia and pencil pine...

Or it could be that the mixture is a sterile hybrid that cannot reproduce any further, in which case it doesnt deserve its own species name either. I believe this MAY be the case (having said that, I haven't read the PhD myself either). In either case, we have a taxonomical mess here and it appears that names may be incorrectly used. if you have a bit of biological training you realise that this is quite often the case but its is usually quite hard to convince people they should call something a different name all of a sudden (like there is technically not a Class for 'Birds' but simply a sub-group of reptiles)...

[tomberli]

Just done a bit of follow-up up research, maybe a bit scientific, so if you don't care about genetics or taxonomy, stop here...

There isn't much published on A. laxifolia, but what I did found was this paper in the Australian Journal of Botany 2000 48 (6). pp. 753-758 (you'll need institutional access if you don't want to pay). Some guys compared the DNA of King Billy, pencil pine and laxifolia to see how genetically related they are. They used a total of 45 trees from the Botanical gardens and Mount fields and compared 29 different DNA markers (sites on the genome) to show how related they are. It appears that there is not a 'spread from one extreme to the other but that there is 3 distinct groups and that the laxifolia sit right in between the other two. Therefore it seems that we do indeed have three distinct trees, rather than a spectrum. However, keep in mind that all the samples were collected from pretty much the same area. Interestingly they didn't know in the paper either whether or not A. laxifolia could indeed breed with any of the other two trees or itself - so really the most interesting factor of the whole story remains untested. Generally it seems that very little is known about this *&%$#! tree Time someone does some breeding experiments!

Just my observations makes me belief that there is a spectrum at least between laxifolia and king billy as you can get all sorts of variants in the leaves. So maybe laxifolia can breed with king billy but not with pencil... Who knows... I also can't help but notice that the specific laxifolia on this photos is much bigger and bulkier than all the king billies around it, so maybe it has something funky going on on a chromosomal level (as do many hybrid crops), which makes it grow fatter than a normal tree - but thats all just speculation. Someone please devote their life to plant genetics and look into this issue...

[kramster]

a.k.a. Intermediate Pine... I've got one growing in a pot at my house.
Quite a prickly little specimin (see below... NB: the Christmas decorations are not generally naturally occuring)

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[tomberli]

Hm, see thats what I mean. to me this looks much more like a king billy than a pencil pine - the leaves are still fairly large. So i'm not fully convinced its such an easy definition of the hybrid. The plant key from the school of botany also shows quite a clear difference between the laxifolia and the king billy. Generally a very useful reference by the way, you can key out just about anything Tasmanian there!

[Steve]

Next time you're here, take a trip to the Walls, go down to Dixons Kingdom and take a look at (as you walk through) possibly the largest and oldest stand of Pencil Pines. Some are as much as 1000 years old.

I visited Dixons Kingdom for the first time on Sunday, its a truly amazing place.

[nakedape]

Hi tomberli,

Great description of a complex issue. For my two-cents-worth I'd suggest that its entirely plausible to have a range of morphs (races if you will) among all three of these closely allied tree species. I research birds and occasionally reptiles - you would not believe to variation among individuals of the same species within the same area much less where there is a spacial separation. But I'm with you - will some one please dedicate there life to this issue

[benb]

King Billy.
And a massive example at that.
It's about a third to half way from Pelion Hut to Pelion gap, on the right of the track as you head south, the track sort of swings round it.
It's one of the biggest King Billy pines I've seen and I remember it well.

Next time you're here, take a trip to the Walls, go down to Dixons Kingdom and take a look at (as you walk through) possibly the largest and oldest stand of Pencil Pines. Some are as much as 1000 years old.

You're pretty much correct on it's location as far as I remember, the track passes within 1m of it and it is on the right of the track (going up). It is an amazing tree. I'll take it from the posts that if I label it as a King Billy Pine I would be safe, though it sounds like it is accurately it is the hybrid (laxifolia) from Tomberli's post.
Many thanks.

[jcr_au]

As an Engineer that knows next to nothing about biology I'm finding this thread very interesting

By coincidence I was listening to some podcsts whilst outand about today & this one on the definition of a species/breading was one of them, which might be of interest http://www.abc.net.au/rn/ockhamsrazor/s ... 682256.htm

John r