From what I understand (to save time let's agree that this qualification applies
to all of what follows), there are certain plants that have a finite lifespan
built into them: they go to seed and then they die. (Incidental question: does
such a lifespan always coincide with a single solar year?) Then there are
animals, who have decrepitude built into them instead: it can't be put off
indefinitely, and once it starts, it continues until the animal is too feeble to
survive.

Please comment on anything that's incorrect so far.

My main question is: What about trees? I can't recall ever hearing of a tree
that died of old age. They continue growing throughout their lives, but is there
anything about perpetual growth that necessarily leads to death? (Incidental
question: How does a tree's growth rate change over the course of its life?)
Obviously something will get them eventually, just because life is a gamble and
every lucky streak has to end. But, in principle, could a tree live forever?

Any help greatly appreciated.

Peace

In article Aui9d.19220$a41.9801@pd7tw2no, Elaine Jackson
writes
From what I understand (to save time let's agree that this qualification applies
to all of what follows), there are certain plants that have a finite lifespan
built into them: they go to seed and then they die. (Incidental question: does
such a lifespan always coincide with a single solar year?) Then there are
animals, who have decrepitude built into them instead: it can't be put off
indefinitely, and once it starts, it continues until the animal is too feeble to
survive.

The lifespan from germination to death is rarely a year; there are
emphemerals in which it is a few weeks or months, annuals in which it is
about 6 months, winter annuals in which it is around 9 months, biennials
in which is 12 to 18 months and monocarpic perennials in which it is
several years. If you include the whole lifecycle, including seed
dormancy it's still not always a single year, as seeds can remain
dormant for many years.

Please comment on anything that's incorrect so far.

My main question is: What about trees? I can't recall ever hearing of a tree
that died of old age. They continue growing throughout their lives, but is there
anything about perpetual growth that necessarily leads to death? (Incidental
question: How does a tree's growth rate change over the course of its life?)
Obviously something will get them eventually, just because life is a gamble and
every lucky streak has to end. But, in principle, could a tree live forever?

Trees do die of old age. The life span of a tree varies, IIRC, from
about 50 years (birches, rowans) to hundreds of years (oaks) to
thousands of years (redwoods, yews, gingkos, bristlecone pines).
--
Stewart Robert Hinsley

It is does seem feasible that some trees could live forever unless
killed by disease, pests or environmental factors such as drought,
climate change, wildfire or catastrophic weather events such as floods
and hurricances. The same trunk would not survive because it would
eventually decay. However, some tree species are very good at
sprouting from their base or suckering and would be good candidates
for immortality. Quaking aspen is often considered "theoretically
immortal"

http://www.treesforlife.org.uk/tfl.aspen_boreal.html

I posted the following before in sci.bio.botany:

A single quaking aspen (Populus tremuloides) clone can spread via root
suckers to cover 100 acres or more. One quaking aspen clone in Utah
named 'Pando' has been estimated to be 80,000 years old.
http://www.nps.gov/brca/quaking_aspen.html

Mitton and Grant (1996) stated that a quaking aspen clone can exceed a
million years in age. 'Pando' has been considered the most massive
living organism. It might be the oldest plant as well.

Reference

Mitton, J.B. and Grant, M.C. 1996. Genetic variation and natural
history of quaking aspen. BioScience 46:25-31.

David R. Hershey


"Elaine Jackson" wrote in message news:Aui9d.19220$a41.9801@pd7tw2no...
From what I understand (to save time let's agree that this qualification applies
to all of what follows), there are certain plants that have a finite lifespan
built into them: they go to seed and then they die. (Incidental question: does
such a lifespan always coincide with a single solar year?) Then there are
animals, who have decrepitude built into them instead: it can't be put off
indefinitely, and once it starts, it continues until the animal is too feeble to
survive.

Please comment on anything that's incorrect so far.

My main question is: What about trees? I can't recall ever hearing of a tree
that died of old age. They continue growing throughout their lives, but is there
anything about perpetual growth that necessarily leads to death? (Incidental
question: How does a tree's growth rate change over the course of its life?)
Obviously something will get them eventually, just because life is a gamble and
every lucky streak has to end. But, in principle, could a tree live forever?

Any help greatly appreciated.

Peace

On Thu, 07 Oct 2004 21:24:48 GMT, "Elaine Jackson"
wrote:

From what I understand (to save time let's agree that this qualification applies
to all of what follows), there are certain plants that have a finite lifespan
built into them: they go to seed and then they die. (Incidental question: does
such a lifespan always coincide with a single solar year?) Then there are
animals, who have decrepitude built into them instead: it can't be put off
indefinitely, and once it starts, it continues until the animal is too feeble to
survive.

Please comment on anything that's incorrect so far.

My main question is: What about trees? I can't recall ever hearing of a tree
that died of old age. They continue growing throughout their lives, but is there
anything about perpetual growth that necessarily leads to death? (Incidental
question: How does a tree's growth rate change over the course of its life?)
Obviously something will get them eventually, just because life is a gamble and
every lucky streak has to end. But, in principle, could a tree live forever?

Any help greatly appreciated.

Peace



The Story they tell at Sequoia National Park is that the sequoia trees
die when they get too big and can't support their own weight. They
(the trees) fall down.
--

- Charles
-
-does not play well with others

Far out!! Thanks very much for telling me about this! I would like to find out
what's known and/or speculated about an evolutionary explanation for the fact
that most organisms have a finite lifespan even (presumably) under ideal
conditions. Can you point me toward any references?

Thanks again for the thought-provoking information you've already provided.

Peace


"David Hershey" wrote in message
om...
| It is does seem feasible that some trees could live forever unless
| killed by disease, pests or environmental factors such as drought,
| climate change, wildfire or catastrophic weather events such as floods
| and hurricances. The same trunk would not survive because it would
| eventually decay. However, some tree species are very good at
| sprouting from their base or suckering and would be good candidates
| for immortality. Quaking aspen is often considered "theoretically
| immortal"
|
| http://www.treesforlife.org.uk/tfl.aspen_boreal.html
|
| I posted the following before in sci.bio.botany:
|
| A single quaking aspen (Populus tremuloides) clone can spread via root
| suckers to cover 100 acres or more. One quaking aspen clone in Utah
| named 'Pando' has been estimated to be 80,000 years old.
| http://www.nps.gov/brca/quaking_aspen.html
|
| Mitton and Grant (1996) stated that a quaking aspen clone can exceed a
| million years in age. 'Pando' has been considered the most massive
| living organism. It might be the oldest plant as well.
|
| Reference
|
| Mitton, J.B. and Grant, M.C. 1996. Genetic variation and natural
| history of quaking aspen. BioScience 46:25-31.
|
| David R. Hershey
|
|
| "Elaine Jackson" wrote in message
news:Aui9d.19220$a41.9801@pd7tw2no...
| From what I understand (to save time let's agree that this qualification
applies
| to all of what follows), there are certain plants that have a finite
lifespan
| built into them: they go to seed and then they die. (Incidental question:
does
| such a lifespan always coincide with a single solar year?) Then there are
| animals, who have decrepitude built into them instead: it can't be put off
| indefinitely, and once it starts, it continues until the animal is too
feeble to
| survive.
|
| Please comment on anything that's incorrect so far.
|
| My main question is: What about trees? I can't recall ever hearing of a tree
| that died of old age. They continue growing throughout their lives, but is
there
| anything about perpetual growth that necessarily leads to death? (Incidental
| question: How does a tree's growth rate change over the course of its life?)
| Obviously something will get them eventually, just because life is a gamble
and
| every lucky streak has to end. But, in principle, could a tree live forever?
|
| Any help greatly appreciated.
|
| Peace

Elaine Jackson writes
From what I understand (to save time let's agree that this qualification
applies to all of what follows), there are certain plants that have a finite
lifespan built into them: they go to seed and then they die.

***
This is called monocarpic (Greek 'monos' = "single"; 'carpos' = "fruit").
***

My main question is: What about trees? I can't recall ever hearing of a
tree that died of old age.

Stewart Robert Hinsley schreef
Trees do die of old age. The life span of a tree varies, IIRC, from
about 50 years (birches, rowans) to hundreds of years (oaks) to
thousands of years (redwoods, yews, gingkos, bristlecone pines).

***
Probably there are trees with lifespans shorter than 50 years. Some tropical
trees are harvested within ten years.

Also, I recall that trees can be monocarpic also (dying after setting seed).
It is quite rare and IIRC it concerns fairly long-lived trees..
PvR

there are certain plants that have a finite lifespan built into them: they
go to seed and then they die. (Incidental question: does such a lifespan always
coincide with a single solar year?)

Not always. With some plants, like bromeliads, when they reach blooming size,
they bloom & set seed, then the parent plant dies, but first it produces
several baby plants around its edges.

What about trees? I can't recall ever hearing of a tree that died of old
age. They continue growing throughout their lives, but is there anything about
perpetual growth that necessarily leads to death?

With people, the obituary rarely reads that the person died of old age; he died
of cancer, pneumonia, heart-failure, or whatever other problem old people die
of.
The same with trees. They have various expected lifespans, from 15 years for a
poplar to 2000 for a bristlecone pine, but they rarely die of "old age." They
become weak & succumb to fungus or some other problem. What you are thinking of
has more to do with size. A large tree, like a redwood, can only pump water up
to a certain height. I don't know if this limit eventually leads to the plant's
demise.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)

In article nzo9d.22131$a41.19778@pd7tw2no,
Elaine Jackson wrote:
Far out!! Thanks very much for telling me about this! I would like to find out
what's known and/or speculated about an evolutionary explanation for the fact
that most organisms have a finite lifespan even (presumably) under ideal
conditions. Can you point me toward any references?

A multicellular organism is a complicated system, and a lot can go
wrong. The longer it lives, the more likely something is to go wrong.
The repair mechanisms aren't perfect, and they too can fail. A sick or
deteriorating organism can't compete with healthy ones for resources,
and will produce fewer offspring.

Evolutionarily, a handwave is to say that the old models have to give
way to the new ones, or what's sexual reproduction for? More
carefully, we can say that there's a tradeoff between investing
resources in self-maintenance and in reproduction, so there's a point
at which improved self-maintenance is unfavorable. Other than top
predators, few animals live long enough to deteriorate with age in
nature, so there's not much selection for traits that deal with conditions
that arise long after almost every individual has been eaten by a
predator, long after an individual has produced most of its offspring.

When we say an organism is "immortal", or potentially so, it's usually
an organism that propagates clonally. That 80,000 year old aspen clone
is genetically the same individual, but it's not the same tree.
Similarly, single celled organisms that reproduce by fission could be
said to be immortal, but each individual can die before it fissions.

Note that parthenogenesis has arisen numerous times in several families
of lizards. Some of these all-female "species" are extremely
successful - some geckos, for example, are now pan-tropical. There may
be many millions of individuals in each "immortal" clone, but each
lizard meets its doom eventually.

You might ask, so what good is sex? (Or even, who needs men? ;-))
Genetic diversity is the raw material of selection, and conditions
eventually change. Asexual propagation is a win in the short term --
it lets you really multiply your genotype -- but when conditions
change, you could lose all in the Darwinian sweepstakes. Those poplar
clones may form the entire poplar population of a substantial piece of
ground, those geckos may be the main gecko fauna in their area, but
when some new disease or competitor comes around all members of the
clone are equally vulnerable. In the long term it's a better bet to go
for the diversity possible with sexual reproduction, but selection has
no way of considering the long term, so we have these unusual cases,
"immortality" through natural cloning.

Elaine Jackson wrote:

From what I understand (to save time let's agree that this qualification
applies to all of what follows), there are certain plants that have a
finite lifespan built into them: they go to seed and then they die.
(Incidental question: does such a lifespan always coincide with a single
solar year?)

Because these sorts of plants are seed oriented.
all they aim to do is produce a crop of viable seed.
Not all coincide with one year, annuals do, biannuals
will go two years, produce seed and die



Then there are animals, who have decrepitude built into them
instead: it can't be put off indefinitely, and once it starts, it
continues until the animal is too feeble to survive.

Please comment on anything that's incorrect so far.

My main question is: What about trees? I can't recall ever hearing of a
tree that died of old age.


Many do, Many trees are not that long lived, a
lot of trash trees are sold in nurseries for landscaping.
Trees that grow fast, but won't last. Arizona ash for instance.
Some trees do have long, but distinct life spans,
A few may life quite a long span, olives, bristlecone
pines, but only a relative few species will have such a long
life before them.



They continue growing throughout their lives,
but is there anything about perpetual growth that necessarily leads to
death? (Incidental question: How does a tree's growth rate change over the
course of its life?)


Depends on the species. Any number do have distinct
life cycles. They grow fast when young, slow down in middle age,
and may spread a bit in old age but don't grow noticably
taller. And many trees do have distinct lifespans,
some may go 100 - 150 years and decline. Some fast
growing pines may not get 50 years.




Obviously something will get them eventually, just
because life is a gamble and every lucky streak has to end. But, in
principle, could a tree live forever?

Bristlecone pines are known thousands of years old,
possibly they may go on forever until accident,
or change of their habitat ends their lives.










Any help greatly appreciated.

Peace

--
Dance, monkeys, dance!

Cheerful Charlie

"wcb" wrote in message
...
Elaine Jackson wrote:

From what I understand (to save time let's agree that this qualification
applies to all of what follows), there are certain plants that have a
finite lifespan built into them: they go to seed and then they die.
(Incidental question: does such a lifespan always coincide with a single
solar year?)

Because these sorts of plants are seed oriented.
all they aim to do is produce a crop of viable seed.
Not all coincide with one year, annuals do, biannuals
will go two years, produce seed and die



Then there are animals, who have decrepitude built into them
instead: it can't be put off indefinitely, and once it starts, it
continues until the animal is too feeble to survive.

Please comment on anything that's incorrect so far.

My main question is: What about trees? I can't recall ever hearing of a
tree that died of old age.


Many do, Many trees are not that long lived, a
lot of trash trees are sold in nurseries for landscaping.
Trees that grow fast, but won't last. Arizona ash for instance.
Some trees do have long, but distinct life spans,
A few may life quite a long span, olives, bristlecone
pines, but only a relative few species will have such a long
life before them.



They continue growing throughout their lives,
but is there anything about perpetual growth that necessarily leads to
death? (Incidental question: How does a tree's growth rate change over
the
course of its life?)


Depends on the species. Any number do have distinct
life cycles. They grow fast when young, slow down in middle age,
and may spread a bit in old age but don't grow noticably
taller. And many trees do have distinct lifespans,
some may go 100 - 150 years and decline. Some fast
growing pines may not get 50 years.




Obviously something will get them eventually, just
because life is a gamble and every lucky streak has to end. But, in
principle, could a tree live forever?

Bristlecone pines are known thousands of years old,
possibly they may go on forever until accident,
or change of their habitat ends their lives.










Any help greatly appreciated.

Peace

--
Dance, monkeys, dance!

Cheerful Charlie


If human beings could find the fountain of youth, then their lifespan would
be about 10000years average because some accident would take them out.
Maybe:
1/ Falling out of a tree.
2/ Falling off a cliff.
2a/ Falling off a horse.
3/ Overdosing on cascara.
4/ Run over by a train.
5/ Being hit by a meteor.
6/ Succumbing to some loathsome disease.
7/ etc ad nauseam.

From: wcb


Elaine Jackson wrote:

From what I understand (to save time let's agree that this qualification
applies to all of what follows), there are certain plants that have a
finite lifespan built into them: they go to seed and then they die.
(Incidental question: does such a lifespan always coincide with a single
solar year?)

Because these sorts of plants are seed oriented.
all they aim to do is produce a crop of viable seed.
Not all coincide with one year, annuals do, biannuals
will go two years, produce seed and die


Some ephemeral plants produce seed and die quickly enough that if conditions
are right, they may have several generations in a year. Some others are so long
lived that it may be more than 10 years before they flower and die, for example
Agaves.

Sean


--
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Last updated 03-16-04 with 42 pictures of Chaco Canyon.