Could tree rings skip a beat?

Rucking_Fetard

http://arstechnica.com/science/2014/06/could-tree-rings-skip-a-beat-astronomical-event-tests-tree-ring-dating/

Last year, we wrote about a real climate science debate taking place between researchers who look at tree ring records of past climate. Penn State climate scientist Michael Mann, well-known for his work on the “hockey stick” climate reconstructions, published a paper arguing that some trees may have failed to grow for a year following major volcanic eruptions. “Skipping” a ring could shift the whole record from that tree by a year, introducing subtle errors into the compilations that are used to reconstruct past climate.


In support of that possibility, the paper analyzed mismatches between the cooling following eruptions in tree ring compilations and climate model simulations of the predicted cooling. The cooling in the tree ring records was often less, and they found that the difference could be caused by ring-skipping.


Some researchers in the tree ring community were less than enthused with the suggestion that they had failed to catch an issue like this, given the care taken to reliably compile these tree-ring histories. They criticized the earlier paper by Mann, Jose Fuentes, and Scott Rutherford, arguing that there was little positive evidence for the rings going missing during eruptions. Now, a group of researchers has published some new data in the journal Nature Climate Change that they think defends the integrity of tree ring records....

Oldtree

An interesting point put forward there but I find it difficult to believe that a ring persay was not laid down, even a tiny one. By its very nature the tree grows by its functioning, so if it did not function it would have died over the period of a year I would have thought. Perhaps a microscopic analysis of ancient woods would not show very tiny "rings" as they have not been preserved, the cambium is only after all a single layer of cells. I look forward to further studies into this.

blue5000

Slightly off topic, I went to a lecture on dendrochonology (excuse spelling) I think it's called a few years back. They were saying that sometime around 900AD there may have been a meteorite off the North coast, and around this time tree rings were very small. I suppose depending on what time of the year such an event happened, eg. early summer there might not be a ring for that year.

Oldtree

I have been pondering this all day and could a tree survive a very long winter, Winter (1), summer (winter (2)), and winter (3), without dying. If anybody knows of trees in cold storage for more than a year then we have out answer, of this being very possible in the wild.

Reindeer

The only major volcanic eruptions that took place that could have darkened the skies for a full year or more were millions of years ago - and these would have lead to mass extinctions in many cases. The likes of Pompei et al were relatively miniscule. In such a case, the trees could have been a completely different genus, let alone family, than what we have today to judge by. I can see that maybe some trees were able to simply not come out of hibernation until the earth warmed and the sun hit them.

periodictable

Yes they can.
Competition from other trees, fire, severe insect attack, extreme crown loss or extreme climatic conditions can prevent the tree photosynthesizing enough to lay down an annual ring, or only part of the ring i.e. either early wood or late wood.
It's been noted in Pinus rigida-Pitch pine- in the eastern US which is heavily dependent on fire in its ecosystem.

Oldtree

periodictable wrote: »

Yes they can.
Competition from other trees, fire, severe insect attack, extreme crown loss or extreme climatic conditions can prevent the tree photosynthesizing enough to lay down an annual ring, or only part of the ring i.e. either early wood or late wood.
It's been noted in Pinus rigida-Pitch pine- in the eastern US which is heavily dependent on fire in its ecosystem.

have you a link please?

I remember being told in college that a holly seedling could wait up to 40 years to get a shot, but have no link.

periodictable

Oldtree wrote: »

have you a link please?

I remember being told in college that a holly seedling could wait up to 40 years to get a shot, but have no link.

No link. Had come across it in N. American forestry books and in something written by Mike Baillie QUB.

Oldtree

so would the resulting ring made up from 2 or 3 years with the bad year in the middle, be bigger than normal in the cases you mentioned?

periodictable

That I don't know- just that there would be some sort of abnormal appearance in the ring pattern which if the influencing factor were climatic would appear right across a range of rings from a large sample of trees in the affected area, and if fire would be an aberration within the ring profile of a stand of trees.
This link explains how dendrochronology works

http://ltrr.arizona.edu/about/treerings

Oldtree

periodictable wrote: »

can prevent the tree photosynthesizing enough to lay down an annual ring,

Do you specifically remember if there was no outward growth in a tree/ring/wood at all, is what I am trying to get at?

periodictable

yes-enough photosynthate produced to keep the tree ticking over only-no increment

Oldtree

The tree functioned for a year on its old wood (so to speak) and the cambium did not make any progress, I have a need to find out more about this specific point

Mike Baillie QUB what does QUB stand for? My manual of NA forestry is from 1925.

periodictable

Baillie is head of the dendrochronology unit in Queens Belfast

have2flushtwice

question:
when the ring is formed, is it added to the centre of the tree, or to the outer layer of the tree?
eg does the ring in the middle stay in the middle?


would be a good one for a table quiz !!

Oldtree

The ring is laid down (by the cambium) on top of the previous ring, growing outwards in effect, layer upon layer.