Age Correlations and an Old Earth: Part II.

I have a question. The oldest bristlecone pine tree was 4,900 years old. How can we find out that the Earth is 8,000 years old minimum from this fact? Do we have trees that have been dead for thousands of years, and we can match up events such as forest fires and droughts recorded in their rings with the events recorded in living trees?I'm not saying the world is only a few thousand years old by any means, I'd just like this clarified.Also, I'd like to add that layers of mud in lakes in the Eastern US record which species of trees were present at various locations, up to 15,000 years. The pollen is stored in layers, and through analysis of the pollen grains the relative distribution of each species could be determined. So that can be added to the list.

quote:

---

I have a question. The oldest bristlecone pine tree was 4,900 years old. How can we find out that the Earth is 8,000 years old minimum from this fact? Do we have trees that have been dead for thousands of years, and we can match up events such as forest fires and droughts recorded in their rings with the events recorded in living trees?

---

That's exactly it. The amount of rainfall is directly related to the thickness of the annual ring. By matching a pattern of thicknesses between older and newer trees a complete chronology can be established.

quote:

---

Also, I'd like to add that layers of mud in lakes in the Eastern US record which species of trees were present at various locations, up to 15,000 years. The pollen is stored in layers, and through analysis of the pollen grains the relative distribution of each species could be determined. So that can be added to the list.

---

I have read about that as well, mapping shifting ecological habitats using pollen grains and trace fossils. This is a great way to illustrate the theory of superposition, but these layers are not annual and are hard to date unlike the lake varves. This topic is centered around verifying the accuracy of radiometric dating with non-radiometric dating techniques such as annual deposition of algae, ice, tree rings, coral layers, and calcite deposits.

Yes is the answer.http://web.utk.edu/~grissino/databases.htmdown here
http://web.utk.edu/~grissino/principles.htm#1
near the bottom where it says The Principle of Crossdating is where it talks about this in a theoretical sense.

Can someone, with knowledge of the subject preferably, explain the answer to this question to me in layman's terms?

I have knowledge (how much is the question since I'm not a dendochronogist)Let's do this is steps:
The facts:
1) Tree rings are not uniform. They have patterns in them.
2) In recent, measurable, times the we see that the growing conditions have a clear effect on the tree ring patterns. This makes sense when we know how trees grow the rings.
3) There are some historical events (eruptions ) that can have rather drastic effect on the global climate.
4) Some of these events can be matched up with tree rings.If we have two sets of tree rings that, it happens, did not live at exactly the same time but did both live and grow for awhile at the same time (that is, they overlap) we can match up the overlapping part of the pattern.If we start with a living tree we can overlap that trees rings with other, perhaps older living trees and with ring patterns from trees that are no longer living. This can be done in steps and take ring counting back beyond the life of any one tree.
(incidently, sometimes the rings are taken from timbers that we can get a rough idea of when they were cut to build a building and this offers a check on the counting).This process can be performed on different species of trees in the same area that are affected by the same local climate changes. It can be done with different trees from widely separated parts of the world by using the global markers to line them up.It can be done not with just a a tree here and an over lapping tree there but with many, many trees. The ring counting and pattern matching can be done with rigorous methods.In the case of the bristle cone pines there are, apparently some material preserved from trees that died a long time ago but overlap with living trees. Bristle cones are, I understand, useful because of their great age but hard because their slow, tortured growth makes ring counting harder. Other species don't live as long but their rings are easier to deal with and then you just use lots of short lived overlapping trees.If you use both you get more confidence in the end result. If you tie it to independent events you get still more confidence.

Thank you for your help NosyNed.I will do a little research on my own and with the information you gave me.

See also Are tree-ring chronologies reliable? (by a creationist who was once affiliated with the ICR) and INTRODUCTION ABOUT DENDROCHRONOLOGY.

There are studies both in Germany and Finnland that use exactly the methods Ned mentioned on logs preserved in bogs and pond bottoms. Each used hundreds upon hundreds of trees, and each goes back to about 11,000 years ago. The Grissino link given a few posts back references these and other studies, but I've never found the primary stuff on the 'net. A paper in German I could interpret ein bisschen, but Finnish, in which I think the original Finnland paper is, wouldn't speak to me very clearly.

From the University of Arizona website: Can someone please explain to me how the these phenomena are dealt with when dating a tree?If possible, can someone address how these issues were dealt with concerning the dating of the 4900 year old bristlecone pine tree referenced in Message 16?

I have to go off-line now but I will be back later on or tomorrow.Thanks to all for your help!

I'm starting to reach outside my expertise. However, just think about it and read the sites that have been referenced already.These effects are local and species dependent (even individual tree dependent, I think). That is why you don't use one tree, one species or one location. The correlations between entire different series of tree rings are used to cross check.Additionally, the counting and dating is not perfect. They do have error bars on the results. The external checking is used to be sure that this is not a very wide reaching affect and to be sure that the dates are not very far off.This message has been edited by NosyNed, 12-09-2004 10:40 PM

hmmm errrr aaahhhcareful, that is awfully close to a "bare links" post ...

No the links supported the word "yes"
Which was the only answer needed to the question.

some species are more prone to having the kinds of recording "errors" mentioned in your post, and this makes them harder to use for dendrochronology. usually more than one sample is taken from a tree to prevent samples taken that have local errors (say a forest fire burned one side which was covered by later growth) and more than one tree (some are individually more susceptable to environmental changes).the major defense from problems like this is multiple samples from multiple trees from multiple sites. usually this means there is noticeable variation between the samples but the overall pattern emerges.this also means that there may be errors, usually expressed as +/-X years per 100 years or something similar.If you follow the links in the original post there is some discussion of this methodology.

---

we are limited in our ability to understand
by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}

heh. just razzin ya