How is a tree alive, dying or dead?

UFOs, lost socks, discuss whatever you like here.

Moderators: Master_Kale, TNM Team

Post Reply
Hashi
Silhouette
Posts: 517
Joined: Wed Apr 11, 2007 3:13 pm

How is a tree alive, dying or dead?

Post by Hashi »

Ok so this may be a silly question, but there are a few things I want to know

So a seed contains all of the information for the tree to grow, and assuming the right conditions, this is how the tree will grow. The leaves perform photosynthesis and the entire tree continues to grow. We say it is alive.

What is the definition of a tree that is dying?

And what about a dead one? And why can't we bring a tree back to life? What does a tree do that gives it life? And how is death irreversible?

Thank you in advance friends.
User avatar
kdawg88
MJ12
Posts: 322
Joined: Wed Mar 18, 2009 10:50 pm

Re: How is a tree alive, dying or dead?

Post by kdawg88 »

42.
User avatar
gamer0004
Illuminati
Posts: 1215
Joined: Sun Mar 09, 2008 4:53 pm

Re: How is a tree alive, dying or dead?

Post by gamer0004 »

DDL will prolly know the answer, but I guess it has to do with whether the cells of the tree reproduce/function.
bobby 55
Illuminati
Posts: 6354
Joined: Wed Jun 24, 2009 9:15 am
Location: Brisbane Australia

Re: How is a tree alive, dying or dead?

Post by bobby 55 »

gamer0004 wrote:DDL will prolly know the answer, but I guess it has to do with whether the cells of the tree reproduce/function.

Yeah, I think a tree is like other forms of life and once enough cells die through lack of nutrients, or fire and such then it's not able to sustain the "energy" it needs for whatever bio-mechanics keep it alive.

Once enough cells die there's no resuscitating them, no franken-trees if you will.
Growing old is inevitable.......Growing up is optional
Hashi
Silhouette
Posts: 517
Joined: Wed Apr 11, 2007 3:13 pm

Re: How is a tree alive, dying or dead?

Post by Hashi »

I guess I should have elaborated:

Are the cells on the tree the same as in all living things? Do the cells or seeds have instructions in them that cause them to die naturally (grow old as it were)? If so, what are the advantgaes of such instructions appearing in seeds in the first place? And what is the exact defition of a tree that is old, have the cells copied themselves too many times and can no longer sustain themselves as they once did?

How many cells in a tree need to die before the tree is officially dead? Can half of the tree be alive while the other half is dead? What does a tree do naturally that it can't do while it is in a dying state? It's easier for me to imagine death with animals as we have consciousnesses (however the word is spelt) that we lose when we die. Gone forever. But a tree doesn't have that. Can't new cells be simply injected into a dying tree and brought back to life? Or would introducing the new cells cause it to be a new tree that is coming to life?
User avatar
Kee715
Illuminati
Posts: 1047
Joined: Sat Nov 29, 2008 7:15 pm

Re: How is a tree alive, dying or dead?

Post by Kee715 »

Take all this with a grain of salt, as I'm no expert.
Hashi wrote:Are the cells on the tree the same as in all living things? Do the cells or seeds have instructions in them that cause them to die naturally (grow old as it were)?
Tree cells are more-or-less the same as other plant cells, I suppose, though I could be wrong. Anyway, I don't think that trees "age." After all, some have grown for hundreds or even thousands of years. I think that, if nothing stops them, they keep growing (thus, living) forever.
Hashi wrote:And what is the exact defition of a tree that is old, have the cells copied themselves too many times and can no longer sustain themselves as they once did?
And "old" tree is just one of great age. Redwood trees are old, but they're not dead or dying, methinks.
Hashi wrote:How many cells in a tree need to die before the tree is officially dead? Can half of the tree be alive while the other half is dead? What does a tree do naturally that it can't do while it is in a dying state?
1 - I suppose that once enough of its cells are dead that it can't continues its normal processes, it dies.

2 - No.

3 - Trees really only grow, which requires water, nutrients, CO2, and sunlight. If it's dying, something is interfering with its normal processes, which stops it from growing. So... it stops growing. Once it stops growing, it's "dead."
Hashi wrote:But a tree doesn't have that. Can't new cells be simply injected into a dying tree and brought back to life? Or would introducing the new cells cause it to be a new tree that is coming to life?
No. A dead tree doesn't carry out any of its life processes. It needs leaves to produce sugar and it needs its roots to gather water and nutrients from the soil. Once those processes stop, the whole tree dies from lack of food and water, including the parts that normally allow life to continue. One does not simply restart a tree's life. Once it's dead, it begins to wither, dry out, and rot and decay, and possibly petrify. Even if you could reanimate dead cells, there's a point of no return where the cells have no means of returning to life.

By the way, what prompted this inquiry?
AEmer
Illuminati
Posts: 1490
Joined: Fri Jan 26, 2007 12:04 am

Re: How is a tree alive, dying or dead?

Post by AEmer »

How is a river flowing, drying up, or exhausted?

That's probably a fruitful allegory.

A river exists because there is a drive for liquids to reach equilibrium, so they flow downwards. A river grows and flows because there is liquid to supply it. A tree grows because there is sunlight and nutrients to supply it.

The tree itself - the leaves, the trunk, the branches, is much like the landscape which supplies the river. While much more complicated, from our perspective, each part of the tree has a function that allows the tree to sustain itself when given the right condition. From an evolutionary perspective, we say that the various parts of the tree have a purpose: To make the tree sustain itself and reproduce.

But in simple terms, the leaves are simply there to absorb carbon and release oxygen as the sunlight hits the leaves. This is what they do. It is not what they wish to do, or even their "function", it is simply how they work. They function in this way, just like a solar panel, or a combustion engine, simply exists and does something if you treat it a certain way.

So far as we know, there is a minimal amount of in-plant communication that allows a tree to function as a cohesive whole in certain respects, but to even call it alive is probably tenuous.

But it does make sense to think about trees in terms of life and death. It is evolutionarily dead when it can no longer reproduce. It is alive when it either actively is or can in the future reproduce.

You can probably put forward other possible boundaries, but I'd argue that those are often the most relevant ones.
DDL
Traditional Evil Scientist
Traditional Evil Scientist
Posts: 3791
Joined: Mon Oct 17, 2005 10:03 am

Re: How is a tree alive, dying or dead?

Post by DDL »

Every cell in a tree has exactly the same general architecture as any other eukaryotic cell (nucleus full of DNA, mitochondria for oxidative energy production and metabolism, endoplasmic reticulum for biosynthetic purposes/solute storage, etc etc). With respect to the fact it's a plant, it also has chloroplasts (green organelles full of chlorophyll, that harvest energy from light and make sugar from CO2), a cell wall (layer upon layer of cellulose giving the cell external rigidity), and usually a vacuole (a big bag in the centre of the cell, for..storage stuff). Many of these other things are not unique to plants: photosynthetic protozoans have chloroplasts and yeast have vacuoles, but hey: a petrol engine is still a petrol engine even if one has a catalytic converter and nitrous injectors and the other doesn't. The overall cellular architecture is the same.

Trees are, you have to remember, pretty weird: the wood that makes up the bulk of the tree? That's dead tree. Trees are similar to coral, in that they grow as a layer upon the dead remains of themselves. The living tree is the roots, bark and the leaves, pretty much. The roots take up water (and dissolved nutrients), the bark conveys it up to the leaves, the leaves lose it through evaporation.

If you were to slice around a tree very very finely, cutting only the bark but leaving the underlying wood unaffected, then you have just killed the tree: you've stopped the flow of water from roots to leaves. The rest of the tree may carry on the appearance of living for quite some time, but it's now doomed. A dying tree would thus perhaps be one that is losing individual cells (through cell death) faster than it is adding new cells (through growing).
Aging happens more or less because there is zero pressure on organisms to not age: we still don't really know what causes aging, whether it's just accumulation of small errors, fraying of DNA telomere ends, a directed mechanism, or something else entirely. Or all of the above. As far as evolution is concerned, once you've successfully produced children your job is done: selection pressure only really applies to everything leading up to that. Since everything you do after breeding isn't going to pass on genetic information, what happens to an organism after reproduction is more or less ignored from a selection perspective.
It's like writing a computer program to perform a given operation a certain number of times. It might be possible to write one that can do the operation indefinitely, but if you only need it say...20 times, and that code is easier to write (and remember, this is evolution, so it's more like writing code by mashing keys at random: small simple programs that "JUST do the job" will be produced faster), then that's what you end up with. It may carry on cycling after it's done its required 20, but no effort has been made to make this an error-free process.

As to living/not living, you also have to remember, plants in generally are pretty weird if you consider them from a mammalian standpoint. Cuttings, for example: these work. Snip a branch off a tree, plant it in the correct conditions, and bam: new tree. Graft that branch onto the stump of a different tree? Bam: tree made from two trees (transplant rejection not so much a problem in trees). This, in fact, is vital to the apple industry: as apple trees do not generally breed true (a tree that makes great apples gives no guarantees that its progeny will also give great apples), orchards tend to be composed of one or two good trees grafted onto hundreds of rootstocks.

Most plants are also totipotent: every cell can potentially give rise to the entire plant again. In theory, given the correct conditions, I believe you could take a single cell from a dying tree and grow a whole new tree from it. It would in effect be the same tree, since it'd have the same DNA etc etc. Technically it's a clone, but with totipotent organisms this is a fuzzy line anyway. See apple trees, above. And quite a few plants actually grow this way: strawberries spread across the ground, making new strawberry plants every so often..but they're all technically the same plant. How you define a "new plant" is actually a fairly challenging question.

So I think a central flaw in your question is phrasing it in more..animal terms.
Hashi
Silhouette
Posts: 517
Joined: Wed Apr 11, 2007 3:13 pm

Re: How is a tree alive, dying or dead?

Post by Hashi »

Thank you for the responses friends, obviously kdawg88's response being the most useful.

@kee715 This is just a number of things I'll be asking as there are still many things I don't fully understand but want to
ggrotz
X-51
Posts: 780
Joined: Tue Nov 10, 2009 12:55 am

Re: How is a tree alive, dying or dead?

Post by ggrotz »

DDL wrote: Trees are, you have to remember, pretty weird: the wood that makes up the bulk of the tree? That's dead tree. Trees are similar to coral, in that they grow as a layer upon the dead remains of themselves. The living tree is the roots, bark and the leaves, pretty much. The roots take up water (and dissolved nutrients), the bark conveys it up to the leaves, the leaves lose it through evaporation.
On this note, it's weird to see trees grow after they were destroyed naturally. They indeed do sprout branches around the outside. While it makes for one weird looking tree, it really is how trees work if they're destroyed and yet still viable.
bobby 55
Illuminati
Posts: 6354
Joined: Wed Jun 24, 2009 9:15 am
Location: Brisbane Australia

Re: How is a tree alive, dying or dead?

Post by bobby 55 »

ggrotz wrote:
DDL wrote: Trees are, you have to remember, pretty weird: the wood that makes up the bulk of the tree? That's dead tree. Trees are similar to coral, in that they grow as a layer upon the dead remains of themselves. The living tree is the roots, bark and the leaves, pretty much. The roots take up water (and dissolved nutrients), the bark conveys it up to the leaves, the leaves lose it through evaporation.
On this note, it's weird to see trees grow after they were destroyed naturally. They indeed do sprout branches around the outside. While it makes for one weird looking tree, it really is how trees work if they're destroyed and yet still viable.
There are some trees here that need a bushfire so that the seed casings pop open and the species can continue....amazing stuff nature.
Growing old is inevitable.......Growing up is optional
ggrotz
X-51
Posts: 780
Joined: Tue Nov 10, 2009 12:55 am

Re: How is a tree alive, dying or dead?

Post by ggrotz »

ggrotz wrote: On this note, it's weird to see trees grow after they were destroyed naturally. They indeed do sprout branches around the outside. While it makes for one weird looking tree, it really is how trees work if they're destroyed and yet still viable.
This actually leads me to a question I think I know the answer to, but I'm not sure. If this were a 6 meter tree that was destroyed and did this, I would presume given enough time (say 20-50 years) the tree would regenerate itself and look like before (bulk into the inside)? Or would it look more like a bush and could never regain its former appearance?
DDL
Traditional Evil Scientist
Traditional Evil Scientist
Posts: 3791
Joined: Mon Oct 17, 2005 10:03 am

Re: How is a tree alive, dying or dead?

Post by DDL »

I suspect it depends on the tree.

If you sliced the top off a tree, so it was more or less "5 feet of stump", then provided it has some stored sugar/a few leaves, and was the right kind of tree (I would guess some are vastly more robust than others), you'd get a series of offshoot branches around the periphery of the stump, that over time would grow and thicken and you'd end up with a tree that goes straight up for 5 feet and then just splinters off into fucktons of directions. It'd never really grow back "up top" on the stump, though. It might eventually swallow it, so looking at it years later you'd have no explanation for why the tree suddenly splurges out, but it won't 'regenerate' the original shape to any real extent.
AEmer
Illuminati
Posts: 1490
Joined: Fri Jan 26, 2007 12:04 am

Re: How is a tree alive, dying or dead?

Post by AEmer »

This is actually how you make apple trees.

You generally want them to be low enough that you'll be able to pick them while you stand on the grond, so you chop off the main branch heading upwards a couple of times and it'll generally spread out.
AEmer
Illuminati
Posts: 1490
Joined: Fri Jan 26, 2007 12:04 am

Re: How is a tree alive, dying or dead?

Post by AEmer »

Post Reply