Do Trees ever die of Old age

[Bretts]

We often hear of the life expectancy of trees (or woody plants). Obviously this is an important factor to consider in bonsai and with many of our natives on the list of short lived woody plants I think it would be a good idea to get a better understanding of what really happens.

Lets start with two premises

Theoretically all woody plant Bonsai can live forever.

Some trees are shorter lived than others and have a limited life span as bonsai.

For a bit of fun lets make that a poll.

After a quick search I found these facts/opinions

http://bonsainurseryman.typepad.com/bon ... die_o.html

http://www.straightdope.com/columns/rea ... of-old-age

http://au.answers.yahoo.com/question/in ... 147AA85xmy

Does bonsai culture limit or extend the life of a tree. If you know the answer to this and why then you would know more than is explained in any of those articles/opinions

[Pup]

A lot depends on who the growers is

[nealweb]

Haha Pup, very true! I can attest to that.

Hmm forever is a very long time. Philosophically everything that is born has to die, so all physical forms come and go. Some trees in nature live a very long time, so do some bonsai. I do remember reading somewhere that trees don't die of old age they die because they get too big and the distance between roots and shoots becomes too great to sustain the movement of water and sugars. Bonsai being kept small and being pruned and so regenerated and caused to grow new tissues every year can live 'forever'. But thats just something I read, can't remember where

[Bretts]

Hmm forever is a very long time. Philosophically everything that is born has to die, so all physical forms come and go.

Lets take forever as meaning until the universe collapses in on itself again

That's a great start Neal and is also my understanding. This is the reason that a mature tree will be more ramified towards the top and outer reaches as the tree struggles to continue to put on growth higher and higher the internodes get shorter and shorter.
But there is still something missing in the equation that I think is important. Why would the tree not just send out new shoots lower down if the top died off?

Then if this is the case how does this relate to our shorter lived natives?

[bodhidharma]

Thanks for the PM Bretts. Yes, a good topic for sure.

Hmm forever is a very long time. Philosophically everything that is born has to die, so all physical forms come and go

I have to agree with neal here. Everything dies, it is just a matter of when. But our universe is a great recycler and the tree would rot down and produce mulch for the next generation. When in Japan i viewed a tree reputed to be a thousand years old. If we look at our humble Wattle, its sole purpose is to replenish the soil with nitrogen and has a short life term. In my opinion a tree will eventually die but All species are genetically imprinted to die after a certain life span We just look at it in terms of our own short life span and i guess we will be recycled too. I think the next question should be.. what is the purpose of the tree, and when has it outlived its purpose.

[Bretts]

Thanks Bodi I didn't think you would mind us dissecting this issue

At least one of the articles states that we should not look at trees having a certain life span but certain trees do have a tendency to live longer than others. As you say a good indication is the faster a tree grows the shorter lived it is. This works well with mother nature as it is a way for landscapes to regenerate.

Ok I guess I better give my full understanding of the process of a tree dieing from what we call old age.

As Neal has stated a tree will grow to a certain height where it now progressively has trouble getting the sugars from the tip of it's roots to the tip of it's shoots. This gradually weakens the tree over a period of time. The first explanation I read of this finished with stating this killed the tree.
As I said this left me wondering why the tree just didn't shoot out branches lower down as I imagined just the top of the tree would die off.
I finally came across the explanation to this that I think completes the theory.
As explained in the articles, through a trees life if comes in contact with many pathogens. Some may enter through wounds in the tree or the wounds themselves may weaken the tree? In either fact the tree is able to compartmentalize these areas or pathogens but this takes a certain amount of energy.
Eventually when the tree is weakened by becoming too big for itself it is no longer able to conjure the energy to keep these pathogens compartmentalized and the tree succumbs to these pathogens (or maybe even a new one?). The tree is not engineered to dispose of the top of the tree and continues to waste alot of energy keeping the highest parts alive as well as fighting the disease or whatever is afflicting the tree.
I find this theory very complete as it explains many things such as why the longest living trees are those that have suckered to create one large forest. This understanding is also used in our fruit orchards. As a fruit tree gets too big for itself it becomes weak and will not produce as much fruit. A solution to this can be to dig the trees up trimming the roots as well as the branches and then replanting. This is not often done as it is thought to be more economical to just plant new trees (maybe newer varieties as well) But some will chop the fuit tree back to it's base and graft a new variety to it instead of replacing the whole tree.

So in bonsai the theory of them living forever is that they will never get so big as to become weakened by this height issue.

So if the premise is that some trees reach this height restriction sooner and lower than others but succumb in the same fashion. Then it would seem fair to conclude that they should be able to have their life expectancy increased in bonsai culture maybe even indefinitely as well

[Paulneill]

I read the same thing as Neil .A trees roots that support it are only A few weeks old . So they are contionusly growing longer and becoming less efficient the longer they get until they become so long the tree starts to use more enegery that it revives and starts to die . Some junipers are 4000 years old .

[rowan]

I did two botany courses as well as forestry courses (I live in a high forestry dependant area) and here is my take. Of course there are heaps of variables but the main thing that kills trees is that they get too wide. Here is a very basic explanation:

You know that a young tree has a lot of sapwood (Xylem) and only a bit of heartwood. The Xylem contains half the tubes that flow water and 'food' up the tree to the leaves and the Phloem (on the outer side of the Xylem, under the bark) has the other tubes that run the water and energy down to the roots.
As the tree grows the inner cells of the Xylem turn into heardwood and stop transporting water. The number of Xylem cells do keep multiplying but not enough to keep the same thickness which is why a tree gets more heartwood and the phloem gets thinner as the tree ages and the trunk grows thicker. You can easily see this in a trunk cross section.

Eventually the Xylem gets so thin that it cannot transport enough water to the whole tree. It just doesn't have enough tubes.

The reason some trees in cold and harsh environments can live so long is that they grow so slowly and cells divide so slowly that the Xylem does not thin as fast. This is also the reason that bonsai should in theory live longer than trees in the natural environment - also with better care and past control thrown in.

No trees can live forever because cells eventually deteriorate after dividing a certain number of times. Sort of like when you take a photocopy of a photocopy of a photocopy - each one is just a tiny bit more degraded than the one before. Every division damages the DNA just a tiny bit so it is un-noticable but still there.

I don't have good communication skills but I hope I made this understandable.

[bodhidharma]

I would also imagine that the reason that they grow up is to reach the greatest energy source in our universe which, of course, is our sun. when they reach the height that it cannot sustain itself anymore the death process begins. That does not answer the question of a Bonsai though as they are kept short and root pruned and can sustain themselves (with our help) but,as stated before, they die also. As Pup stated, through the hand of man, some die quicker than others but i guess it keeps going back to the same question..how long. Guess the answer is akin to a puppy chasing its tail. Ahh.. the answer is, there is no answer.

[Dario]

Good thread Bretts and great timing too. I recently revisited this question after reading that Bodhi's acacia died and he suspected the reason was that it had run it's course. Although that is only one documented example, I am sure he knows what he is doing and has the experience with that particular bonsai to assess the reason for it perishing...he said "one week it was healthy, next week it was no longer"...or words to that affect.
This got me thinking as I had also read a fair bit about the actively growing part of the tree always being/remaining young. So if the tree is looked after and has optimal growing conditions and is controlled so that it doesn't meet/exceed its ultimate height determined by its genetics, it theoretically should keep going indefinetely.
However I am still on the fence as I also subscribe to the belief that all things that live, must die.
I know, I haven't been any help and I don't have the experience to make a statement either way, but it certainly gets me thinking and is a topic that I am very interested in and would love to read more about and see results from documented examples etc.
Thanks for posting, and I will enjoy the members contribution to this topic.
Cheers, Dario.

[astroboy76]

"Each wound in a tree is compartmentalized.......not healed.....but rather isolated by chemical barrier walls within the plant to contain disease development or spread. New wood grows over the wound and we say "healed" but the wound is always there. This comparmentalization takes energy to maintain 24/7/365. The more wounds, the more compartments, the more energy drain on the plant. "

The quote above i find quite interesting. The fact that trees may not actually heal, even though new wood may cover a wound, but the wound itself needs constant energy to stay compartmentalized is quite an important fact when it comes to bonsai.

Considering we inflict a fair bit of inury to our trees: pruning, branch removal, dead wood, jins and sharis...even wiring... can these things become too much for a tree over a long enough time span or do we balance them out with the forced rejuvination or leaves and roots (defoliation and root pruning) and does the constant care, fertilising, housing in the right environment, pest control etc balance out the inuries and stress we may cause our trees?

on second thought perhaps this quote is specific to disease...any thoughts?

[Bretts]

Thanks for the input Rowan that's an interesting take on the situation. It makes sense to me as when the tree gets too big for itself and weakens the rings would get smaller and I think this would be a significant factor.
But some other things don't seem to fit so well, for me anyway? Or maybe I misunderstand ?

The reason some trees in cold and harsh environments can live so long is that they grow so slowly and cells divide so slowly that the Xylem does not thin as fast.

My understanding is the slower growing a tree the thinner the rings. My understanding is this makes the tree tougher.

No trees can live forever because cells eventually deteriorate after dividing a certain number of times. Sort of like when you take a photocopy of a photocopy of a photocopy - each one is just a tiny bit more degraded than the one before. Every division damages the DNA just a tiny bit so it is un-noticable but still there.

From what I read my understanding is the opposite.

And some of the oldest trees on earth, the great bristlecone pines, don’t seem to age like we do. At 3,000-plus years, these trees continue to grow just as vigorously as their 100-year-old counterparts. Unlike animals, these pines don’t rack up genetic mutations in their cells as the years go by.

See here
http://www.wired.com/wiredscience/2010/ ... e-gallery/

[Bretts]

I would also imagine that the reason that they grow up is to reach the greatest energy source in our universe which, of course, is our sun. when they reach the height that it cannot sustain itself anymore the death process begins. That does not answer the question of a Bonsai though as they are kept short and root pruned and can sustain themselves (with our help) but,as stated before, they die also. As Pup stated, through the hand of man, some die quicker than others but i guess it keeps going back to the same question..how long. Guess the answer is akin to a puppy chasing its tail. Ahh.. the answer is, there is no answer.

At the moment I will have to disagree with ya some what Bodi. I have an amur maple that is said to be short lived. I hear of people saying that as bonsai they die after a number of years. Yet we can't believe everything we hear and from what I understand on the life of trees as bonsai, it leaves me with this question we are discussing.

As Pup stated, through the hand of man, some die quicker than others but i guess it keeps going back to the same question..how long. Guess the answer is akin to a puppy chasing its tail. Ahh.. the answer is, there is no answer.

Ye have little faith Logic will get you from A to B. Imagination will take you everywhere. Einstein

[rowan]

Hi Bretts, I wish I was better at explaining but here goes. Thin rings do indeed make the wood tougher but not necessarily the tree itself. The reason the rings are so thin is because they grow so slowly, this does not affect my argument. I'm not sure how to explain this better, maybe someone else can.

Genetics has been a lifelong interest of mine so I am not sure where you got your infomation on non-damaging cell division from but I would be interested in any source you have to read.

I'm certainly interested in the genetic make up of bristlecones but I don't doubt that some plants and animals would be resistant to a certain amount of genetic deterioration. I could be wrong but these pines grow so slow from an early age that the cell division rate might not be much different than other trees - it would have slowed down to such an extent that a 1000 year old bristlecone could be the same genetic age as a 80 year old other pine.

Just thinking - I am happy to be proved wrong on any points.

[Bretts]

Hey Astro
I think they are very good questions and something I have been contemplating myself. My first thought is that as long as the tree has plenty of strength it will continue to compartmentalize these areas. But I guess there is the possibility that if a tree gets too many of these areas/pathogens that any weakness in the tree could spell the end

Maybe we have something to learn from the Japanese that where sterile like gloves and sterilize their tools when working on trees. We only tend to see this on great specimens but maybe if we do want trees to live forever we need to be aware of this from the very start

But then we also need to contemplate that if we take a cutting from a 3000 year old tree everything we know is that cutting has every chance of living for another 3000 years so obviously there is alot to learn.