Trees age and die.

[rthmjohn]

As silly as it may sound, I had always thought that trees never die for some reason. Maybe it's because I would always hear about how many hundreds of years old the trees in the redwood forest are. My bio teacher told me that they do age, however, and that they do die eventually, even though it can take hundreds of years. Do trees also succumb to free radicals? Or is there some other cause? What gives them such an extensive lifespan?

[silkworm]

What gives them such an extensive lifespan?

 

Diet and exercise.

 

I find this interesting that you have articulated this and I'm delighted about how accessible it is. I mean, the fact that trees age and die is no shock to me. No biological organism is immortal. And everything gets broken down by the weathering. I couldn't tell you how a tree dies of old age, I've never performed an autopsy on a tree but you have gotten me curious as well.

 

But I also find this post interesting because 1) I enjoy the fact that you've recently discovered this and are delighted by it and 2) this can be used as a tool to explain how things that take longer than our lifetimes don't appear to be happening at all if you're not looking for it, because I'm sure other people have had similar thoughts. But you can use someone who can't imagine deep time in geology or that evolution doesn't happen because you don't witness speciation every time you turn on the boob tube, maybe this will help them gain a little more of a perspective.

[ecoli]

I've actually heard that, given perfect living conditions, a tree will never die. Suggesting that the only thing that can kill off a tree is a pathogen or harsh climate. I saw thing on a documentary about a tree that's over 2,000 years old. But, of course we know that documenteries are made to make life seem more interesting then it is, I don't know how much stock I should put into it.

[starbug1]

I've actually heard that, given perfect living conditions, a tree will never die.

 

could you explain this a little further?

[ecoli]

could you explain this a little further?

 

sure... the optimal conditions depend on the species. If a tree gets the right amount of sunlight, water, access to nutrients, correct temperature, not too much bad weather to be stressful... etc.

[Nevermore]

The tree you are thinking of, ecoli, is Methuselah. A bristlecone pine in the middle of nowhere. Methuselah is 4,767 years old, going on 4,768. Scientist have, however, if Nova is to be believed, found an older tree, however for the tree's safty, they won't tell the general public where it is.

Trees die of the same things humans do; free redicals, murder and diseases such as the well known dutch elm disease, (which is an arboreal version of T.B, seeing as it attackes the leaves, (lungs) and is very contagious and deadly.).

[Glider]

True, and other trees have comparatively short lifespans. One variety of larch for example, has an average lifespan of between 50 and 70 years in the wild. However, as bonsai, they can live for a lot longer.

[rthmjohn]

So technically, if we were to create an ideal artificial environment with adequate sunlight, climate, nutrients, oxygen/carbon dioxide, and one free of harmful microbes, a particular species of a tree could live to be tens of thousands of years old (which, relative to the human lifespan, is pretty much like living forever)?

[Bluenoise]

Pretty much, but it might crack and fall over from it's own weight.

[ecoli]

The tree you are thinking of, ecoli, is Methuselah. A bristlecone pine in the middle of nowhere. Methuselah is 4,767 years old, going on 4,768. Scientist have, however, if Nova is to be believed, found an older tree, however for the tree's safty, they won't tell the general public where it is.

 

I think we saw the same documentery, then. I'm pretty sure it was Nova.

[Glider]

So technically, if we were to create an ideal artificial environment with adequate sunlight, climate, nutrients, oxygen/carbon dioxide, and one free of harmful microbes, a particular species of a tree could live to be tens of thousands of years old (which, relative to the human lifespan, is pretty much like living forever)?

Not really. Trees can outgrow themselves. Eventually, their roots get too long for the efficient transport of water and nutrients to the canopy. This is why bonsai tend to live longer than trees in nature. They are regularly root-pruned. The canopies are also pruned so most of the living areas of a bonsai are actually quite young.

[Mokele]

So, if it's structural/physical constraints that are the problem, could a rhizome-based plant live forever, given ideal conditions? I'm specifically thinking of my pitcher plants, who grow from a horizontal rhizome which lengthens and branches as they grow (and dies behind them). Since such growth is more or less one-dimensional, they wouldn't run into any major structural issues.

 

Mokele

[Bluenoise]

I don't know much about pitcher plants. But take many crawling vines for example. Many tropical ones just keep on sendiing out new roots along their length. the original part can die but it keeps on growing. The are even some speices of plants that are loosing the ability to produce viable seeds, they just grow from parts the fall off and grow new roots.

 

actually I'm pretty sure that's the case with seedless oranges. Since the trees can't produce natural offspring they're propagated from cuttings. They're all clones really.

[Glider]

So, if it's structural/physical constraints that are the problem, could a rhizome-based plant live forever, given ideal conditions?

As far as I know that's the case, yes. It's also the case for other plants that can multiply asexually, although I suppose you could get bogged down in semantics.

 

Each new 'generation' is simply a shoot from the plant, and so is simply an extension of the same plant. Take Clorophytum (spiderplant) for example. It produces long stems with new shoots at the end. These grow, pulling the stem down. Eventually they touch the ground and the shoots throw out roots and begin to take nourishment from the soil. They remain attached to the central rosette though and remain structurally a part of it. Eventually, the spread of new plants will crowd out the central rosette and it dies off, but the surrounding rosettes are, genetically, the same plant, just more spread out. However, they don't need to touch the ground. If they fail to reach the ground (say, growing on the edge of a cliff), these shoots will continue to grow, and in time will produce more shoots. This can go on and on. It's all the same plant. Eventually, one cascade will reach the ground and put out roots.

 

There are many trees that can propogate in the same or similar ways. The crack willow is particularly good at it. It grows next to rivers and has evolved to be particularly brittle (hence the name). In moderate wind, twigs and branches snap off, float down the river and eventually stick in the bank at a bend where they root (regardless of which end sticks in). The new trees could be seen as new trees, but in reality, they are the same tree 'spreading out' to increase its chances of survival.

 

Rhizome based plants work to the same principle. They're not strictly speaking producing new plants, it that the original plant is spreading out to take advantage of a particularly favourable patch of ground and to defend against being overwhelmed by other plants. There is (as far as I know) no constraint on how long they can live, as long as external condition remain favourable.

[rthmjohn]

Interesting, I remember studying propogated growth in bio, but I never knew there were so many species that could do it. I think I read that there's a forest somewhere in the world that consists entirely of clones of the same tree or something to that effect.

[Bluenoise]

Actually it's possible with virtually all plants. Just some need to be coaxed with some special care and rooting hormones.

[Nezumi]

If I understand right, the genetics for the growth of humans and their set biological system is within their DNA.

 

I'm sure that the DNA of trees would also establish their biological clock, molecular biology, and not to forget biophysics.

 

The key item here would have to be the biophysical limitations the plant has to withstand inside of an environment which makes me question how the genetics in a tree could be altered to live longer in an environment.

 

Perhaps a stronger bark? Better ability to bring in nutrients? Better root structure? Transplanting the best gene of a tree that has excellent physical conditions in the roots in one tree with terrible roots could enhance it's biophysical limitations.

[sunspot]

One of the interesting things about some trees is that they have to pump water to great heights. The tree does not pump water in the centrifugal pump sense but every 30 ft is 13 PSI. Eventually, the tree just cannot pump enough water and the back pressure at the stump and roots takes it toll on the tree. Some trees adjust by going laterally.

[mantrid]

physical factors are the main cause of death for plants (not annuals etc)

weather

extreme winters

very hot summers

earth movements

changes in the habitat (bog drying out with your pitcher)

earthquakes

etc

 

disease

humans

 

and eventually (with tall trees anyway)

they get too big and the laws of physics stops them

they become too heavy and fail structurally, disease gets in and quickens their demise

[kok3000]

some plants their next generation's body is connect with them,so it hard to say they died because their next generation is still alive