The Oldest Trees and the Age of the Earth

Trees in the Bristlecone Pine Forest on White Mountain, California. Some of these trees are the oldest known (non-clonal) trees.

I forgot about this argument. I watched the Ken Ham/Bill Nye debate when it happened back in 2014. I forgot about Bill Nye’s rebuttal to a young Earth by stating that there were trees older than 6,000 years. I ran across the argument recently, and I had to take a moment to look into it. See, growing up in a Christian and creationist household, I had been taught that old trees were consistent with a 6,000 year age of the Earth; that there are no trees older than the time of the Flood. So which is it? Do ancient trees refute the creationist model or do they support the creationist model? The answer to this question is going to be more complex than it may seem like it should.

To set the stage, we all know how to determine the age of a tree, right? You count its tree rings. This can be done when the tree has been cut down or it can be done while the tree is still alive. The latter requires a borer to cut out a narrow cylinder (a core) from the trunk of the tree. Then the layers can be counted in the core.

Counting tree rings presumes that a single ring grew each year. As a tree grows, the wood is not replaced. Instead, new wood is added on the outside of the existing wood.[1] This means that all of the wood in a tree has been accumulated since the tree began growing. Why does the wood grow in rings? Because of differing rates of growth. During spring, new growth occurs. Wood is laid down rapidly as the ideal temperature and sufficient moisture allows for quick growth. This rapidly growing wood is spacious with lots of holes within it. As the year wanes into summer and fall, the growth of the tree slows down. As growth slows, new wood continues to be laid down, but now, it is denser and there is less of it. When winter comes, growth can stop altogether. That pattern, of rapid growth in the spring slowing down and eventually stopping by winter, creates a single, visible ring. The same thing happens the next year creating a new ring, and the year after that, and you have annual tree rings.

Based on the description given above, dating a tree seems like a simple task. If all we wanted to know was how old the oldest tree was, all we would have to do is sample a number of old trees, count their rings, and determine which is the oldest. It is a simple method that, unlike radioisotope dating, doesn’t require any faulty assumptions, right?

Well…

We now come to our first speed bump. When talking about ancient trees, have to distinguish between non-clonal and clonal trees. See, when we think of a tree, we think of a single trunk with a set of branches with an array of leaves and a single root system. However, plants can be weird when compared to human and animal biology. Many plants, including some trees, can reproduce vegetatively. That is, in addition to producing seeds, which are produced by sexual reproduction, they can produce a new plant using a different part of the body. A new tree begins growing off of the root of an existing tree. A new strawberry plant begins growing off of a stolon from the original plant (the stolon is a horizontal stem that looks a bit like a vine running on the ground). In these cases, the “daughter” plant is genetically identical to the parent plant, since the daughter is a clone of the parent (the daughter was produced asexually).

There are some stands of trees that represent a whole colony of clones. The original tree has died away but the current living trees are all its clones. Depending on how we want to define a tree, such a colony can be considered to be a single tree, since they are all genetically identical to one another. A non-clonal tree would be what we think of as a typical tree: a single trunk with its branches and leaves. Interestingly, clonal trees can give much older ages than non-clonal trees. In fact, one of the trees that Nye cited, with an age of 9550 years,[2] is a clonal tree.

As you may have guessed, clonal trees are not dated by counting tree rings. After all, if the original tree is dead and long gone, how can we count rings from one tree to another? If they aren’t dated using tree rings, how are clonal trees dated? First, it needs to be established that a grove of trees is a colony of clones. This includes not only all of the living trees, but also any dead trees in the area. Genetic testing can determine if the trees are clones. After it has been established that the trees are all clones, the age of the oldest surviving wood can be determined by carbon dating.[3] That’s right, the age of the oldest tree was determined by radioisotope dating, not from counting tree rings. The problem there is pretty simple: creationists already doubt radioisotope dating. Citing a tree’s age as a challenge to creationism, yet basing that age on radioisotope dating is just a convoluted way of saying that radioisotope dating contradicts creationism. Creationists are already prepared to debate radioisotope dating, and citing the age of clonal trees doesn’t add anything new. Nothing is gained by bringing the trees into it.

What about non-clonal trees? These are often cited by creationists as evidence for creationism, as the age of the oldest known (non-clonal) trees actually fit pretty well with a young Earth.[4] The oldest known non-clonal trees are bristlecone pines found in the White Mountains of California. The oldest living bristlecone pine is named Methuselah, and it is dated to be 4,842 years old in 2010, making it 4,854 years old years old today.[5] Now, Methuselah is the oldest living tree, but there was another bristlecone pine cut down in 1964 that has been dated to be even older, believed to have begun growing in 2936 BC.[6] This older bristlecone pine, named Prometheus, would have been 4,958 years old today if it had not been cut down.

Now we encounter our second speed bump. You may guess that the age of Prometheus was determined by counting its tree rings. It was not. Instead, Prometheus’s age was determined by crossdating it with reference chronologies.[7] 

Crossdating is a key practice within dendrochronology.[8] Dendrochronology is the science of using tree rings to date artifacts. At first, dendrochronology may seem inapplicable to artifacts. How can you date an artifact by looking at the rings of a tree? How do you know when the artifact was made based on rings in a living tree? By looking at wood, such as timbers, used in buildings. If enough of the timber is preserved, it will have tree rings. If you can compare those tree rings to a tree living in the area, you may be able to find a similar pattern of rings. The “pattern of rings” can be a variety of things, but for our example, we will use tree ring width as a way to determine patterns. See, tree rings will not all be the exact same width. In a good growing season, the tree ring will be wide because the tree did a lot of growing. If the growing season was poor, the tree will produce a small ring. All of the trees in a single area will have experienced the same growing conditions over the years, so if a specific pattern can be found in multiple trees, say seven very narrow rings in a row, that pattern is presumed to be from the same event, and the age of the trees can be correlated with one another. If one of those trees is a timber in a building, you can use the correlation to determine the age of the tree when it was cut down, see how many more years trees in the area have been growing, and use that to figure out how long ago the tree was cut down. Moreover, you can correlate across multiple trees, both dead and alive, extending your chronology back as far as possible. Think of crossdating as giving a pattern of growth over the years, a pattern of growth correlated to tree ring widths, and as long as you can match a pattern in your wood sample to the crossdating chronology, you can work out how long ago that piece of wood was alive.

An example of cross dating. Tree rings from a living tree (right), a dead tree (middle), and timbers (left) can be correlated based on distinct patterns of ring spacing. Image from Nash, Stephen (2002) “Archaeological Tree-Ring Dating at the Millennium” Journal of Archaeological Research 10(3): 243-275

Now, crossdating has another benefit. It can help identify missing rings and double rings.[9] If there is an especially bad growing year, a tree may have no new growth. In that case, there is a missing ring for the year. If a growing season starts out good, and then suddenly gets bad but returns to normal growing conditions later in the same year, a tree can actually grow two rings in a single year. By comparing rings across several trees, these missing rings and double rings can sometimes be identified.

Hence, Prometheus was not aged based on his rings alone: his age was determined by comparing his rings to the rings of other bristlecone pines in the White Mountains of California, to create a complete tree ring chronology, hopefully devoid of any missing rings or double rings.

Now, I want to say a word about this practice of crossdating. From what I can tell, there is nothing wrong with it in theory or in practice. It makes sense. In fact, dendrochronology has been used to calibrate radiocarbon dating.[10] In other words, long agers consider dendrochronology to be a good enough practice that they are willing to correct radioisotope dating using dendrochronology as a standard. Granted, the only radioisotope dating that can be calibrated with dendrochronology is carbon dating, since it is the only commonly used radioisotope dating method that can be used to date recent history. Nevertheless, I still think that it is a testament to how well dendrochronology works that radioisotope dating, the gold standard of old age dating, is calibrated by dendrochronology. Nevertheless, we should never forget that dendrochronology can still get dates wrong because of the presence of missing rings and double rings.

Now that we have established that dendrochronology is a pretty secure dating method, let us compare the age of Prometheus to the date of the Flood as given from the Bible. As a reminder, according to recent calibrations of its age, Prometheus began growing in 2936 BC. According to James Ussher, the Flood ended in 2348 BC,[11] meaning that the Flood ended 4,370 years ago. You may notice that Prometheus is actually older than the date of the Flood by 588 years.

And now comes the last speed bump. Is there a problem with the Biblical chronology because trees like Prometheus are too old?[12] First of all, I want to remind us about the double rings. Is it possible that there are enough overlooked double rings in the bristlecone pine reference chronology that the age of Prometheus could be corrected to match the date of the Flood? I do not know. I do not know dendrochronology well enough to know what kind of error it produces. Nevertheless, it should be remembered that dendrochronology can, in theory, be off a few years because of the double rings and missing rings.

What about the Biblical chronologies? First, we should assume that the chronologies as given in Genesis 5 (Adam to Noah) and Genesis 11 (Noah to Abraham) are correct. After all, they come from the Word of God. However, there are two things that can allow a bit of a “fudge factor” when it comes to the Biblical chronologies. The first is that we are not told the exact birthday of anyone in the chronology. We are simply told the age, in years, of the father when the son was born. Suppose a son was born the day before his father’s birthday. The age given for the father would essentially be off by a year. Conceivably, there could be as much as a year’s difference between each father/son pair given in the Genesis geneologies. The second thing to consider is that while I have been calling it the Biblical chronology, the fact is, at some point, we have to switch from the geneologies given in the Bible to secular geneologies. For example, we have a complete geneology from Adam to Abraham. Now, to move that geneology over to an actual chronology, we need to know what calendar year Abraham was born. That would require comparing the events of Abraham’s life (recorded in the Bible) with historical events we can recreate from archaeology and written history (human investigations). Which means that some errors can be introduced in the Biblical chronologies when we connect it with human chronologies.

It is because of these “fudge factors” that I would caution being dogmatic about the age of the Earth. I am certain that the genealogies in Genesis 5 and 11 are correct: they are in the Word of God, after all. However, a precise date of 2348 BC for the Flood may be wrong. That is why I tell people that the Earth is around 6,000 years old, to give myself a little leeway in case there were any errors correlating the Biblical genealogies with historical chronologies. Taking the possibility of slight adjustments to both the Biblical chronologies and to dendrochronology, a difference of 588 years is notable but not insurmountable.[13] In fact, I would go so far as to say that Prometheus’s age actually fits well with the Biblical account.

If we take everything into account, clonal versus non-clonal trees, the practice of cross-dating, missing rings and double rings, and correlating the Genesis genealogies to human recorded history, there is nothing that stands in opposition to creationism. Quite the opposite. While there is a 588 year difference between Prometheus and the date of the Flood, the ages match fairly well. Thus, ancient trees are not anywhere near the challenge to creationism that Bill Nye thinks that they are.

Thoughts from Steven

P.S. I just want to say it: the idea that there are trees alive today that began sprouting shortly after the Flood ended is amazing! While Prometheus may be dead, Methuselah (the tree) is still alive, and it is quite possible that it began sprouting a matter of years after the Flood. That is an awesome lifespan.


[1]If you want to get really technical, what we call wood is made up of xylem, one of the two types of tissue in plants that transports nutrients. Xylem builds up each year and old xylem is not removed.

[2]Seidensticker, Bob (2014) “Evolution is Crazy, Says Man Who Thinks the Earth Was Created 6000 Years Ago, All the Animals Were Saved on a Boat Built by a 600-yo Noah, and our Loving Creator Drowned Everyone” Patheos.com, retrieved from https://www.patheos.com/blogs/crossexamined/2014/02/evolution-creationism-ken-ham-bill-nye-debate/ on April 30, 2022 (By the way, wonderful title there, isn’t it?)

[3]Umea University (2008) “World’s Oldest Living Tree — 9550 years old — Discovered in Sweden” Science Daily, retrieved from https://www.sciencedaily.com/releases/2008/080416104320.html on March 8, 2022

[4]homas, Brian (2010) “Why Aren’t Earth’s Oldest Trees Older?” ICR.com, retrieved from https://www.icr.org/article/why-arent-earths-oldest-trees-older/ on April 30, 2022 

[5]Ibid.

[6]Salzer, Matthew and Christopher Baisan (2013) “Dendrochronology of the ‘Currey Tree'” Ameridendro, May 13-17, Tuscon

[7]Ibid.

[8]Nash, Stephen (2002) “Archaeological Tree-Ring Dating at the Millennium” Journal of Archaeological Research 10(3): 243-275

[9]Ibid.

[10]Ibid.

[11]Ussher, James (2003) The Annals of the World, Master Books, Green Forest, Arkansas, pg. 21

[12]https://christianity.stackexchange.com/questions/15394/how-do-bible-literalists-deal-with-trees-older-than-the-flood retrieved on April 30, 2022

[13]By the way, in case anyone may suggest that Prometheus began growing before the Flood and survived through the Flood, I will point out that the purpose of the Flood was to destroy life on the Earth. With a year long Flood, I seriously doubt any tree from the pre-Flood world could have survived, so I will presume that Prometheus, and any other tree alive today, must have begun sprouting after the Flood.