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Old 14-09-2004, 12:44 PM
daniel
 
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Default leaves of a tree

Hello,

does anybody know how many leaves trees are supposed to have?
(in summer of course ;-) )

What is the maximum estimated number?

What about trees with needles? How many needles can they have?
Are there estimates about the leave "density" e.g.
how many leaves per cubic meter?
How does that differ between the different species?

Thanks, daniel
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Old 14-09-2004, 01:15 PM
Cereus-validus
 
Posts: n/a
Default

Do you have a bar bet running on the answer?

The instructions booklet is provided by the maker.


"daniel" wrote in message
om...
Hello,

does anybody know how many leaves trees are supposed to have?
(in summer of course ;-) )

What is the maximum estimated number?

What about trees with needles? How many needles can they have?
Are there estimates about the leave "density" e.g.
how many leaves per cubic meter?
How does that differ between the different species?

Thanks, daniel



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Old 14-09-2004, 03:07 PM
Iris Cohen
 
Posts: n/a
Default

does anybody know how many leaves trees are supposed to have?

I hope this isn't a troll question, but serious curiosity. There is no specific
number. It depends on species, location, and many other factors. The larger the
tree, the more leaves it will have. Generally, a tree with large leaves, like a
sycamore, will have fewer of them. The same species in shade will have fewer &
larger leaves than in sun.
At one extreme, Welwitschia mirabilis, a primitive conifer from Africa, has
only two leaves its entire life, which may be 2000 years. The same two leaves
keep growing from the base as they wear out on the end. At the other extreme,
there are trees that grow in the desert or the far north, both conifers and
flowering trees, like Junipers and Tamarisks, which have thousands of tiny
scale leaves or needles you couldn't begin to count. If a tree is healthy and
growing, you can assume it has as many leaves as it should.
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)
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Old 14-09-2004, 04:32 PM
Phred
 
Posts: n/a
Default

In article ,
(Iris Cohen) wrote:
does anybody know how many leaves trees are supposed to have?

I hope this isn't a troll question, but serious curiosity. There is no specific
number. It depends on species, location, and many other factors. The larger the
tree, the more leaves it will have. Generally, a tree with large leaves, like a


I presume by "larger" you mean "wider"? A mature rainforest tree
probably has much the same number of active leaves throughout its life
because its canopy is in competition with its neighbours. So its
trunk and main branches will get bigger (mostly thicker hence
heavier), but its canopy probably won't change much over decades.

sycamore, will have fewer of them. The same species in shade will have fewer &
larger leaves than in sun.
At one extreme, Welwitschia mirabilis, a primitive conifer from Africa, has
only two leaves its entire life, which may be 2000 years. The same two leaves
keep growing from the base as they wear out on the end. At the other extreme,
there are trees that grow in the desert or the far north, both conifers and
flowering trees, like Junipers and Tamarisks, which have thousands of tiny
scale leaves or needles you couldn't begin to count. If a tree is healthy and
growing, you can assume it has as many leaves as it should.


Going back nearly 50 years we learnt about "leaf area index (LAI)" as
applied to herbage species (specifically, natural and sown pasture
plants). I seem to recall that there was an approximate limit to this
beyond which shading causes death of leaves at lower levels once
respiration exceeded photosynthesis. (Note: this limit will vary
somewhat depending on the typical attitude of the leaves on individual
species; but it can be made more consistent if the projected leaf
surface is used rather than one sided leaf area as such.)

Assuming such a "limit" it should be possible to work out the
approximate number of leaves by measuring the projected area of the
canopy of a mature tree and determining the average size of the
leaves. For example, if the maximum LAI is 4, the projected area is
30 square metres, and the average leaf single surface area is 20
square centimetres, then the estimated limit for leaf number would be
around 60,000. [Of course a "specimen tree" growing in the open would
be quite different because it's "canopy area" would effectively be
closer to a hemisphere -- at least here in the tropics. ]

Definition: LAI defines an important structural property of a plant
canopy as the one sided leaf area per unit ground area.
http://edcdaac.usgs.gov/modis/mod15a2.asp

Daffynition: Leaf Area Index A type of information worked out by
calculating the volume of the upper surface of leaves in relation to
the volume of ground that is directly below the plant.
http://www.biology-online.org/dictio...20Area%20Index

Ain't the World Wide Web marvellous! A "dictionary" no less. Sigh...

Cheers, Phred.

--
LID

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Old 14-09-2004, 10:37 PM
Sean Houtman
 
Posts: n/a
Default

"Cereus-validus" wrote in
:


"daniel" wrote in message
om...
Hello,

does anybody know how many leaves trees are supposed to have?
(in summer of course ;-) )

What is the maximum estimated number?

What about trees with needles? How many needles can they have?
Are there estimates about the leave "density" e.g.
how many leaves per cubic meter?
How does that differ between the different species?

Thanks, daniel




Do you have a bar bet running on the answer?

The instructions booklet is provided by the maker.

(top posting corrected)

It actually looks more like a homework question.

Sean



  #6   Report Post  
Old 14-09-2004, 10:49 PM
Sean Houtman
 
Posts: n/a
Default

(Iris Cohen) wrote in
:

does anybody know how many leaves trees are supposed to have?


I hope this isn't a troll question, but serious curiosity. There
is no specific number. It depends on species, location, and many
other factors. The larger the tree, the more leaves it will have.
Generally, a tree with large leaves, like a sycamore, will have
fewer of them. The same species in shade will have fewer & larger
leaves than in sun. At one extreme, Welwitschia mirabilis, a
primitive conifer from Africa, has only two leaves its entire
life, which may be 2000 years. The same two leaves keep growing
from the base as they wear out on the end. At the other extreme,
there are trees that grow in the desert or the far north, both
conifers and flowering trees, like Junipers and Tamarisks, which
have thousands of tiny scale leaves or needles you couldn't begin
to count. If a tree is healthy and growing, you can assume it has
as many leaves as it should. 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)


Welwitschia isn't a tree, but...

An important factor in counting the number of leaves on a tree is
time of year. Since Daniel is posting in fairly decent English, he
is likely in a north temperate area. If he would wait till some time
in December, the easy answer to his question would often be 'none'.
However, a quick scan and guess of the 25 year old mulberry tree
outside my window looks like perhaps about 50 thousand leaves. I
would expect that a large Giant redwood would have several million
leaves.

Sean

  #7   Report Post  
Old 14-09-2004, 11:33 PM
Cereus-validus
 
Posts: n/a
Default

Actually, by definition, Welwitschia is a tree because it has a single
unbranched woody trunk!!!! That it has only two leaves is besides the point.


"Sean Houtman" wrote in message
news:1095194978.hNTEkItUsoX/iqppnCe+QA@teranews...
(Iris Cohen) wrote in
:

does anybody know how many leaves trees are supposed to have?


I hope this isn't a troll question, but serious curiosity. There
is no specific number. It depends on species, location, and many
other factors. The larger the tree, the more leaves it will have.
Generally, a tree with large leaves, like a sycamore, will have
fewer of them. The same species in shade will have fewer & larger
leaves than in sun. At one extreme, Welwitschia mirabilis, a
primitive conifer from Africa, has only two leaves its entire
life, which may be 2000 years. The same two leaves keep growing
from the base as they wear out on the end. At the other extreme,
there are trees that grow in the desert or the far north, both
conifers and flowering trees, like Junipers and Tamarisks, which
have thousands of tiny scale leaves or needles you couldn't begin
to count. If a tree is healthy and growing, you can assume it has
as many leaves as it should. 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)


Welwitschia isn't a tree, but...

An important factor in counting the number of leaves on a tree is
time of year. Since Daniel is posting in fairly decent English, he
is likely in a north temperate area. If he would wait till some time
in December, the easy answer to his question would often be 'none'.
However, a quick scan and guess of the 25 year old mulberry tree
outside my window looks like perhaps about 50 thousand leaves. I
would expect that a large Giant redwood would have several million
leaves.

Sean



  #8   Report Post  
Old 15-09-2004, 07:15 PM
daniel
 
Posts: n/a
Default

An important factor in counting the number of leaves on a tree is
time of year. Since Daniel is posting in fairly decent English, he


Thanks for the flowers.

is likely in a north temperate area. If he would wait till some time
in December, the easy answer to his question would often be 'none'.
However, a quick scan and guess of the 25 year old mulberry tree
outside my window looks like perhaps about 50 thousand leaves. I
would expect that a large Giant redwood would have several million
leaves.


I thought about giving the background of my question when opening the
thread but I decided not to do it, due to the fact that I wanted more
biological oriented answers.

Beside the fact that I was simply curious if there exist reasonable
estimates about the maximum amount of leaves/needles of trees my focus
was on realistic graphical representation of trees. Most tress I have
seen in computergraphics are among the poorest objects.
A good representation could aim to draw at least one triangle per
leave and let them swing in the wind.

I am pretty sure that nobody ever "counted" the leaves of large trees,
but there should be reasonable estimates for their amount.
e.g. collect all the leaves in autumn for a standalone tree and weigh
them. Maybe some inside bilogical knowhow as described in one of the
threads could help. Up to now I have seen some guesses. Isn't there
some scientific work
about this topic?
How is the amount of the oxygen/carbon dioxid turnover estimated?
Wouldn't it make sense to have some O_2 capacity estimate for leaves
of
different trees?

thanks for your posts, daniel
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Old 20-09-2004, 06:49 AM
Sean Houtman
 
Posts: n/a
Default

"Cereus-validus" wrote in
. com:



Welwitschia isn't a tree, but...

An important factor in counting the number of leaves on a tree is
time of year. Since Daniel is posting in fairly decent English,
he is likely in a north temperate area. If he would wait till
some time in December, the easy answer to his question would
often be 'none'. However, a quick scan and guess of the 25 year
old mulberry tree outside my window looks like perhaps about 50
thousand leaves. I would expect that a large Giant redwood would
have several million leaves.


Actually, by definition, Welwitschia is a tree because it has a
single unbranched woody trunk!!!! That it has only two leaves is
besides the point.


Odd definition, most definitions of trees include some means of
distinguishing them from shrubs, generally height. Do you mean to
imply that if a woody plant has branches on the trunk, or more than
one trunk, that it must not be a tree? If so, there aren't very many
species that manage to be trees.

Sean

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Old 20-09-2004, 06:54 AM
Sean Houtman
 
Posts: n/a
Default

(daniel) wrote in
om:


I thought about giving the background of my question when opening
the thread but I decided not to do it, due to the fact that I
wanted more biological oriented answers.

Beside the fact that I was simply curious if there exist
reasonable estimates about the maximum amount of leaves/needles of
trees my focus was on realistic graphical representation of trees.
Most tress I have seen in computergraphics are among the poorest
objects. A good representation could aim to draw at least one
triangle per leave and let them swing in the wind.

I am pretty sure that nobody ever "counted" the leaves of large
trees, but there should be reasonable estimates for their amount.
e.g. collect all the leaves in autumn for a standalone tree and
weigh them. Maybe some inside bilogical knowhow as described in
one of the threads could help. Up to now I have seen some guesses.
Isn't there some scientific work
about this topic?
How is the amount of the oxygen/carbon dioxid turnover estimated?
Wouldn't it make sense to have some O_2 capacity estimate for
leaves of
different trees?

thanks for your posts, daniel


You would probably be surprised by the things done by scientists 2-
300 years ago. Rest assured that someone has counted leaves on trees
of various species.

Just don't ask me to tell you the names of the works that document
such, you would probably have to go to Europe and mug around in some
dusty stacks to find them.

Sean




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Old 20-09-2004, 11:19 AM
Zeitkind
 
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Default

Sean Houtman wrote:

generally height.


So.. all bonsai are shrubs?






Sorry.. couldn't resist..
  #12   Report Post  
Old 20-09-2004, 02:40 PM
Iris Cohen
 
Posts: n/a
Default

If you look at most pictures of Welwitschia, it doesn't look much like a tree.
It looks like the stuff you throw in the garbage after you made the salad.
However, Two thirds of the trunk of a Welwitschia is underground. The two
permanent leaves grow out of the top, and the cones appear between them. Since
it has a permanent woody trunk, I believe it fits the definition of a tree.
Look, it works. Some Welwitschias are 1500 to 2000 years old.
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)
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Old 20-09-2004, 03:33 PM
Cereus-validus
 
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Default

As Iris has already pointed out, the definition of what constitutes a tree
has absolutely nothing to do with height, number of leaves or number of
branches at all.

Most trees obviously do have branches arising from the trunk but not the
base.

Mulberries are actually trees not shrubs because they have a single main
woody trunk. They do not branch primarily from the base as do shrubs.

I suppose if you actually bothered to look up the definitions of the terms
in a botanical dictionary it would boggle your mind and incorrect
preconceived notions.

There are actually many more tree species found around the world than you
will see sitting behind your 'puter looking out your window. Try going out
into the real world. You might actually learn something on your own.


"Sean Houtman" wrote in message
news:1095655795.vHDg1ppMHVISnXQw36/VQw@teranews...
"Cereus-validus" wrote in
. com:



Welwitschia isn't a tree, but...

An important factor in counting the number of leaves on a tree is
time of year. Since Daniel is posting in fairly decent English,
he is likely in a north temperate area. If he would wait till
some time in December, the easy answer to his question would
often be 'none'. However, a quick scan and guess of the 25 year
old mulberry tree outside my window looks like perhaps about 50
thousand leaves. I would expect that a large Giant redwood would
have several million leaves.


Actually, by definition, Welwitschia is a tree because it has a
single unbranched woody trunk!!!! That it has only two leaves is
besides the point.


Odd definition, most definitions of trees include some means of
distinguishing them from shrubs, generally height. Do you mean to
imply that if a woody plant has branches on the trunk, or more than
one trunk, that it must not be a tree? If so, there aren't very many
species that manage to be trees.

Sean



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Old 20-09-2004, 03:38 PM
Cereus-validus
 
Posts: n/a
Default

Oh look, isn't that Sean out in the aviary stunting trees?

Are you done waxing the car already?

Remember: Right hand - wax on. Left hand - wacks off!!!


"Zeitkind" wrote in message
...
Sean Houtman wrote:

generally height.


So.. all bonsai are shrubs?






Sorry.. couldn't resist..



  #15   Report Post  
Old 20-09-2004, 04:07 PM
Iris Cohen
 
Posts: n/a
Default

most definitions of trees include some means of
distinguishing them from shrubs, generally height.


The one I am familiar with is that a shrub is a woody plant which is usually
under ten feet tall & has multiple stems. A tree is usually over ten feet tall
& usually has a single stem.
What about dwarf trees which are way under ten feet tall & might have multiple
trunks, like a dwarf birch? I would assume if the standard plant is a tree, the
dwarf form is also called a tree. Tsuga canadensis 'Minuta' is still a tree,
albeit 3" tall.

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)
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