Go Back   Science Forums Biology Forum Molecular Biology Forum Physics Chemistry Forum > Molecular Research Topics Forum > Animal and Molecular Model Systems > Botany Forum
Register Search Today's Posts Mark Forums Read

Botany Forum Botany Forum


leaves of a tree

leaves of a tree - Botany Forum

leaves of a tree - Botany Forum


Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 09-14-2004, 10:44 AM
daniel
Guest
 
Posts: n/a
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
Reply With Quote
  #2  
Old 09-14-2004, 11:15 AM
Cereus-validus
Guest
 
Posts: n/a
Default leaves of a tree

Do you have a bar bet running on the answer?

The instructions booklet is provided by the maker.


"daniel" <[Only registered users see links. ]> wrote in message
news:b385c098.0409140244.5ece2744@posting.google.c om...


Reply With Quote
  #3  
Old 09-14-2004, 01:07 PM
Iris Cohen
Guest
 
Posts: n/a
Default leaves of a tree

<< 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)
Reply With Quote
  #4  
Old 09-14-2004, 02:32 PM
Phred
Guest
 
Posts: n/a
Default leaves of a tree

In article <[Only registered users see links. ].com>,
[Only registered users see links. ] (Iris Cohen) wrote:

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.


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.
[Only registered users see links. ]

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.
[Only registered users see links. ]

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

Cheers, Phred.

--
[Only registered users see links. ]LID

Reply With Quote
  #5  
Old 09-14-2004, 08:37 PM
Sean Houtman
Guest
 
Posts: n/a
Default leaves of a tree

"Cereus-validus" <[Only registered users see links. ]> wrote in
news:wpA1d.383$[Only registered users see links. ].prodigy.com:


(top posting corrected)

It actually looks more like a homework question.

Sean

Reply With Quote
  #6  
Old 09-14-2004, 08:49 PM
Sean Houtman
Guest
 
Posts: n/a
Default leaves of a tree

[Only registered users see links. ] (Iris Cohen) wrote in
news:[Only registered users see links. ].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.

Sean

Reply With Quote
  #7  
Old 09-14-2004, 09:33 PM
Cereus-validus
Guest
 
Posts: n/a
Default leaves of a tree - Welwitschia

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" <[Only registered users see links. ]> wrote in message
news:1095194978.hNTEkItUsoX/iqppnCe+QA@teranews...


Reply With Quote
  #8  
Old 09-15-2004, 05:15 PM
daniel
Guest
 
Posts: n/a
Default leaves of a tree

> An important factor in counting the number of leaves on a tree is

Thanks for the flowers.


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
Reply With Quote
  #9  
Old 09-20-2004, 04:49 AM
Sean Houtman
Guest
 
Posts: n/a
Default leaves of a tree - Welwitschia

"Cereus-validus" <[Only registered users see links. ]> wrote in
news:RsJ1d.16846$[Only registered users see links. ].prodigy. com:



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

Reply With Quote
  #10  
Old 09-20-2004, 04:54 AM
Sean Houtman
Guest
 
Posts: n/a
Default leaves of a tree

[Only registered users see links. ] (daniel) wrote in
news:b385c098.0409150915.655e43ac@posting.google.c om:


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


Reply With Quote
Reply

Tags
leaves , tree


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Everything you wanted to know about kokum (Garcinia family) Frederick Noronha \(FN\) Botany Forum 0 03-03-2005 10:09 PM
Compound leaves: primitive? or why? Archimedes Plutonium Botany Forum 32 10-25-2004 08:25 AM
Breakthrough in Cosmology Kazmer Ujvarosy Botany Forum 0 05-21-2004 06:50 AM
Breakthrough in Cosmology Kazmer Ujvarosy Forum Biologie 0 05-21-2004 06:32 AM
"exotic" trees for North America? Darren Garrison Botany Forum 6 01-31-2004 07:24 AM


All times are GMT. The time now is 08:45 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright 2005 - 2012 Molecular Station | All Rights Reserved
Page generated in 0.18471 seconds with 16 queries