Age of a tree

atula

Now I know that we can find out the age of a tree by counting the rings of the main trunk of the tree. But then for this method we will have to cut the tree down..
Isnt there any other way of finding out the approximate age of a tree just by looking at it or something????

mdvaden

Increment borers...

Increment Borers

If you go to REPLY #17 in this Treeworld thread, I posted a LINK to a page with video (video link) of me using one...

Historic Artifact: Catalpa in Jacksonville, Oregon

On the linked page, I estimated the tree's age based on the core extracted and a few other observations.

Again, that's Reply #17 where the link is.

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Ekka

Tree rings can be unreliable in tropical/semi tropical areas like where I live as there's more than one growing season and you can have many rings for 1 year.

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Sean Freeman

Erics correct tree rings are pretty useless to us in calculating the age of tropical trees, we have to base estimations on our knowledge of the growth rates of particular species in our area compared to specimens that the planting date is known and verified..certainly not a perfect method by any means.

Even in the temporate regions of the world tree rings become meaningless when it comes to many aging veteran trees that loose their heart wood to decay...then all you can count are the rings in the outer shell or the branches.

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Sean

Trees are poems that earth writes upon the sky,
We fell them down and turn them into paper,
That we may record our emptiness.
- Kahlil Gibran

mdvaden

Do they keep a record of cut trees for which ages are clearly known, as a gauge to compare with?

I was thinking about how how core samples have been taken out of very old European buildings for which the dates are known (the timbers), and how those can be used to verify the age of of antique musical instruments supposedly from the same era. I think Dr. Shigo mentioned it in his tree biology book, too.

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atula

I remember reading somewhere that the age of a tree can also be found out by measuring the girth. For a tree that is growing with other trees every 12 mm of growth is equal to one year and a tree that is growing all alone the ration is 25 mm to one year.

Ekka

Interesting concept but I wouldn't trust that too much as each location has variables and so do species.

It's tough but around here I'm pretty darn close at guessing tree ages ... but this is a new country as such and most vegetation is planted within last 200 years.

Old bush trees are harder to tell but you get bit of an idea.

Try to find the source of that info ... I always like to check the facts.

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TrevMcRev

A lot of the times in suburbia they're as old as the house.

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Sean Freeman

Lets face it even a poor declining tree is likely to outlast the newer houses being thrown up these days

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Sean

Trees are poems that earth writes upon the sky,
We fell them down and turn them into paper,
That we may record our emptiness.
- Kahlil Gibran

Tree Machine

I'm wondering how old this one is. The non-traditional stump cut doesn't allow a good counting of the rings,
but the stump grinder guy sure loves it.

Attached Images

big-trunk.jpg (139.1 KB, 69 views)

atula

Here Eric, I performed a google search and found this pretty interesting way to find the age of a tree,

Do tell me if this is a good way....

The link is
http://www.athensclarkecounty.com/do...nt/tcn_age.pdf

mdvaden

That's more of what we would call a "guess", but it can be far from correct with some trees.

What you read there, is similar to what I did for the Catalpa? Did you read the page in the link I posted?

But I had an advantage - I did a core sample as well, and most of the growth rings were approximately the same size from year to year. Also, I was able to take a core 14" deep, and only need to estimate for the remaining 3".

In Oregon, I volunteered at a demonstration forest Magnus Tree Farm for the World Forestry Center - my friend was the curator. He showed me a cross-cut piece of a Douglas fir tree. It would have been about 20" diameter while standing.

The inner (and older) 10" or so of diameter, had about 80 growth rings. And the rest, or younger 10" of diameter (outer) showed about 30 growth rings.

Why, is unknown. It could have been shaded for nearly a century, then surrounding trees were removed. The point is, without a core sample from a tree like that, measuring diameter is totally unreliable.

It can be more reliable for trees that have been growing alone out in the open, but if the trees are quite old, we may or may not know whether they were within dense forests centuries ago, etc..

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Ekka

Atula, what I thought, simply a mathematical calculation based on ave annual ring growth for species divided into trees radius.

Things change, often on cut trees you'll notice that the inner rings are wider than the outer, that's opposite to Mario's post (but Mario is corrrect too). The reason is if all things never change (environmentally/water/soil etc) as the tree gets older it has a larger surface area (mass) to grow another shell over. Also as the tree gets mature and consumes more of the resources around it ... it grows slower.

It's a theoretical method, an educated guess.

Recently at a job there was a HUGE FICUS tree, massive. The owner planted it and knew exactly how old it was. It was only 18 years old! I guessed 30 to 50 but what happened is he lives near the beach on sand and there's underground water only 8' down. This monster has tapped that and gone nuts. When you cut it latex runs out of it like a tap.

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ninikins

So the rings in a tree trunk thing is actually correct? I mean, you can averagely guess the age like that. I always thought it was false.

Ekka

The rings are created by a cycle of dormancy and growth ... thereby saying a ring is 1 year.

But in reality some places (semi tropical) dont have a genuine dormancy period and can experience more than one growing period a year resulting in multiple rings for a years growth.

It has been found by both anecdotal and scientific methods that some trees in tropical type regions grow according to available water resources.

Where I live in winter it is common to have 24C days. However winter traditionally is our dry season and summer our wet. Now if it does rain a lot in winter (unusual but can happen) the trees grow, sometimes a darn lot! So what happens through a calendar year is trees might have 3 or 4 rings for various growing conditions pertaining to rain.

Many times I can tell when cutting trees or even palms for that matter how wet years were in the past ... currently we are experiencing drought conditions and palms have small heads and tapers and in real wet years the head region will fatten up ... trees similar but with growth rings.

But lets say down is some place where it's cold in winter, deciduous trees that lose their foliage and sit there dead looking for months there will be definate rings that YOU CAN COUNT ON. In those rings you'll also see bad years and good years by the width of the ring.

Hope that helps.

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mdvaden

Some areas like where I live - basically - yes.


Try this article here, and the external links on it too...

Dendrochronology - Wikipedia, the free encyclopedia

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ninikins

Thanks, mdvaden! I guess I should've googled myself, hehe.