leaf area measurements

Uelo.Niinemets at bitoek.uni-bayreuth.de Uelo.Niinemets at bitoek.uni-bayreuth.de
Fri Apr 19 12:46:14 EST 1996


Leaf area measurement in conifers is a rather complex task, and how 
to accomplish that really depends on what the measurements are needed for. 
There are many commercially available instruments to measure shoot (or 
branch) projected area. I have up to now used DIAS from Delta T (Cambridge, 
U.K.).However, these measurement systems are rather expensive. What one 
really needsis a video camera and a multimedia card for PC. As already 
pointed out, there exists some shareware for analysing bitmaps or one may 
like to develop the own software - one needs only to count the black pixels.
With moderate effort it is possible to reduce the cost at least by factor 10. 

BUT, it is very IMPORTANT to calibrate the system properly: the number 
ofpixels you get considered 'black' strongly depends on resolution, 
contrast etc. With commercially available devices there is ususally some way
to play around with 'threshold', and it is also explained in manual, how 
calculated area should perform to consider 'threshold' "correct". However, 
it does not work!! With conifer shoots you will always have some half-shade 
(i.e. penumbra)) and semihalf-shade there, which is also likely to be 
different for different shoots.Thus, I have always calibrated the 
measurement system with objects of known sizeand corrected the estimates of 
DIAS from these.

Another question is, if it is possible to calculate total needle area 
ofshoot from the measurements of shoot projected area. Unfortunately, the
answer is NO. The number of needles, and accordingly their total area, per 
unit stem length depends on ligh conditions the shoot was exposed to during 
its formation. You may want to check:

  Niinemets,U; Kull,O (1995): Effects of light availability and tree size on
  the architecture of assimilative surface in the canopy of Picea 
  abies: variation in shoot structure. Tree Physiol. 15(12), 791-798.

  Sprugel,DG; Brooks,JR; Hinckley,TM (1996): Effects of light on 
  shoot geometry  and needle morphology in Abies amabilis. Tree Physiol. 
  16(1/2), 91-98.

Now, for a more physiologically oriented work it is sometimes necessary to 
express the physiological quantities on either projected or total needle 
surface area.

IT IS NOT THE SAME! 

Again, how much total needle area would respect to a certain amount of 
projected needle area depends on long-time light conditions the needles were
exposed to:
 
 Niinemets,U; Kull,O (1995): Effects of light availability and tree size 
 on the architecture of assimilative surface in the canopy of Picea abies: 
 variation in needle morphology. Tree Physiol. 15(5), 307-315.

 Sprugel,DG; Brooks,JR; Hinckley,TM (1996): Effects of light on shoot 
 geometry and needle morphology in Abies amabilis. Tree Physiol. 16(1/2), 
 91-98.

Also, projected needle area as measured by DIAS is sensitive to needle 
structure as affected by light conditions (refs. above). I should therefore 
recommend touse direct morphological measurements on needles to derive 
their total and projected surface areas rather than to use some video or 
electronic-optiacal device.

Best,

Uelo.Niinemets at bitoek.uni.bayreuth.de, ylo at ut.ee, ylo at zbi.park.tartu.ee,
ylo at madli.ut.ee

PS. There has already been an extensive discussion on leaf area measurement 
on conifers already in Canopy list. I guess I do not waste bandwidth when I 
add this one tohere:


Extracted from Canopy list:
_______________________________________________________________________________
From:   MX%"clementj at elwha.evergreen.edu" 17-FEB-1995 21:52:35.52
CC:     
Subj:   branch tip surface area

How would YOU measure the surface area of a Douglas-fir branch tip? 
Assume the base diameter of about 1 cm, length of about .75m, and 
approximately 50-60 primary and secondary twiglets with needles 
extending from the main twig axis. Am aware of Pike et al 
methods, i.e measuring area of many small cylinders (or cones) plus 
subset of needles, any other suggestions? 

This is for the purpose of determining available macrolichen substrate.

thanks!

Joel Clement
The Evergreen State College
_______________________________________________________________________________
From:   MX%"vieglaid at tursiops.ksc.nasa.gov" 17-FEB-1995 23:09:32.02
Subj:   Re: branch tip surface area

Joel Clement writes:

>How would YOU measure the surface area of a Douglas-fir branch tip? 
>Assume the base diameter of about 1 cm, length of about .75m, and 
>approximately 50-60 primary and secondary twiglets with needles 
>extending from the main twig axis. Am aware of Pike et al 
>methods, i.e measuring area of many small cylinders (or cones) plus 
>subset of needles, any other suggestions? 

I have heard of a technique where the branch is dunked in a container
of small glass beads, which are subsequently washed off and weighed.
Assuming a uniform single layer coating, it should be straight foward 
to determine the total area (calibrate the technique using more easily
measured surfaces).  This might have been in documentation from
Li-Cor.  Not sure if it could be used for macrolichen studies.

Cheers,
Dave Vieglais

--------------------------------------------------------------------------------
From:   MX%"angoulet at rsvs.ulaval.ca" 18-FEB-1995 00:19:21.26
Subj:   Leaf area density

Hello everyone,

I am trying to gather some informations about leaf area density
(expressed in square metres of leaves per cubic metres). A graphical
way to show it is with the height (non-dimensional if possible) along
the Y axis and the density along the X axis (1/m). If you have any kind
of relevant informations about it please forward it to:

angoulet at rsvs.ulaval.ca

Thank's!

Andre

--------------------------------------------------------------------------------
From: Anna Schoettle <schoettl at lamar.colostate.edu>
_____________________________________________________________________________
From:   WINS%"angoulet at rsvs.ulaval.ca" 21-FEB-1995 16:19:05.03
Subj:   RE: Leaf area density

>Dear Andre,
>Please be more specific. Many people, and I among them have measured 1,
>2 and 3-D distributions of leaf area density. What species do you need,
>broad leafed plants or conifers? What do you need the data for? There
>is much published information for a wide variety of plants.
>Shabtai Cohen
>Volcani Center
>Israel

Dear M.Cohen,

What we need are data of leaf area density (1/m) in function of
tree height (dimensionless or not). We need data concerning 
North American tree species if possible. They are needed 
as an input to a simulation model. The model is simulating 
wind patterns, pressures, drag forces, etc. in and surrounding 
a forest clearcut (Miller et al. 1991).

If you need some more informations, please contact me again.
Thank you,

Andre Goulet

Andre Goulet 
room 2153 
Pavillon Marchand
Universite Laval
Ste-Foy, PQ, Canada
G1K 7P4
Tel.:(418) 656-7902
FAX:(418) 656-7493
Email: angoulet at rsvs.ulaval.ca
--------------------------------------------------------------------------------
From:   MX%"angoulet at rsvs.ulaval.ca" 28-FEB-1995 22:31:03.84
Subj:   leaf area index

Hello everyone,

A few days ago I requested data about leaf area density
(expressed in square metres of foliage per cubic metre of canopy) 
of North American trees. I received many replies and I wish to thank 
everyone for this.
For many poeple the term "leaf area density" was unfamiliar;
they were asking for the difference between LAI (index) and
LAD (density). Leaf area density may be seen as many measurements
of leaf area index taken at constant intervals along the tree 
(say each meter H) minus the leaf area index measured at height below 
(H-1 meters). Thus, this gives:

square meter (H) - square meter (H-1) = square meter per cubic meter

= Leaf area density between H and (H-1)

It is therefore possible to deduct LAD from many measurements of 
LAI made along the canopy. My new request (a more specific one) is
to gather some informations about LAI recorded at different heights
and for North American trees (deciduous and coniferous). I thank you...

Andre Goulet

EMAIL:angoulet at rsvs.ulaval.ca
Andre Goulet 
room 2153 
Pavillon Marchand
Universite Laval
Ste-Foy, PQ, Canada
G1K 7P4
Tel.:(418) 656-7902
FAX:(418) 656-7493
Email: angoulet at rsvs.ulaval.ca
--------------------------------------------------------------------------------
17-NOV-1994 02:31:50.39
Subj:   Image for leaf area (fwd)
From:   NAME: Nalini Nadkarni

To canopy 'netters: This message came to me from Truman Young, who has
worked on many aspects of plant ecology.


From:TYOUNG at MURRAY.FORDHAM.EDU Subject: Image for
leaf area

At the recent Canopy conference in Sarasota, there
was discussion about how to measure leaf area lost to
herbivory.  NIH Image was mentioned.  I have used
Image as a leaf area meter (and am working on it as a
particle counter: seeds, ovules, insects).  It is very easy
to use and it is free!  It works with color too, so you can
look at smut infections, leaf miners, etc.  It is only
available for Macintosh computers, so DOS-jocks
need not apply.  Here is the scoop from the user manual:

IMAGE:  Updated Versions and Bug Reports

Updates to Image are available to Internet users via
anonymous ftp from zippy.nimh.nih.gov. Those without
Internet access can get updates from many Macintosh
bulletin boards and user group libraries. A reasonably
current version, including Pascal source code and
example images, is available from any of the
following sources:

1) From a friend. The Image program, including
source code and documentation, is public domain
and may be freely copied, distributed and modified.
However, if you modify Image, please update the about
box before distributing your version of the program.

2) Via anonymous FTP from
zippy.nimh.nih.gov[128.231.98.32]. Enter "anonymous"
as the user name and your e-mail address as the password.
The /pub/nih-image directory contains the latest version
of Image (nih image154_fpu.hqx or
nih-image154_nonfpu.hqx), documentation in
Word format (nih-image154_docs.hqx), and complete
Think Pascal source code (nih image154_source.hqx).
The directory /pub/image/images contains sample TIFF
and PICT images. The directory /pub/image/image_spinoffs
contains versions of Image extended to do FFTs
(ImageFFT), fractal analysis (ImageFractal), and
to support quantitative evaluation of cerebral blood
flow, glucose metabolism, and protein synthesis
(Image/MG). There is a README file (0README.txt)
with information on the file formats used.

3) Library 9 (Graphics Tools) of the MACAPP
forum on CompuServe. Source code is in Library 6
of the MACDEV forum.

4) Twilight Clone BBS in Silver Spring, MD.
The Clone has 16 lines on sequential rollover, starting
with 301-946-8677. To guarantee a V.32 connection,
call 946-5034. Image is cul1ently available at no
charge from the Twilight Clone.

5) Subscribe to the NIH Im~lge mailing list by
sending a message containing the line
"subscribe nih-image <your name>" to
listserv at soils.umn.edu. Next obtain a list of the
available NIH Image archive files by sending an
"index nih image" command to listserv at soils.umn.edu.
These files can then be retrieved by means of a
"get nih-image filename" command. The files are
Binhexed and broken into chunks less than 32K in size.
The NIH mailing is maintained by the Soil Science
Department at the University of Minnesota.

6) NTIS (National Technical Information Service),
5285 Port Royal Road, Springfield, VA 22161,
phone 703-487-4650, order number PB93-504868
($100 check, VISA, or Mastercard). Both the
zippy.nimh.nih.gov FTP site and the Twilight Clone
BBS are likely to have newer versions of Image than NTIS.

Bug reports and suggestions are welcome, as are
connections or additions to this manual. The author
(Wayne Rasband) can be reached at the following
electronic mail addresses:

Internet:      wayne at helix.nih.gov
AppleLink: wayne @ helix.nih.gov @ internet#
CompuServe: >INTERNET: wayne at helix.nih.gov


Truman Young
________________________________________________________________________________
From:   MX%"darwyn at unbc.edu" 22-FEB-1995 19:15:16.29
Subj:   Re: branch tip surface area


I have used the technique of a surface bead coating on several occasions
to obtain surface area determinations of macrolichens and bryophytes.  I 
have found that chromatography beads (eg. Poropak R) have a much higher 
surface adhesion and produce a much better monolayer (which is critical 
to the success of this technique (eg. Can. J. Bot. 67:167-176).  This 
technique produces some very interesting data on the surface area of 
non-vascular plants in canopies, eg. in tropical montane forest (Can. J. Bot 
69:2122-2129) and is described by Larson and Kershaw (1976) Can. J. Bot. 
65:182-191. Cheers, Darwyn Coxson, University of Northern British Columbia

> Joel Clement writes:
> >How would YOU measure the surface area of a Douglas-fir branch tip? 

> I have heard of a technique where the branch is dunked in a container
> of small glass beads, which are subsequently washed off and weighed.
> 
> Cheers,
> Dave Vieglais
--------------------------------------------------------------------------------
From:   MX%"rdial at tardaddy.wr.usgs.gov" 22-FEB-1995 23:30:59.00

On the subject of measuring surface areas of branch tips ... I've been
thinking about a similar topic: the fractal surface of a branch. It seems
that if you use these beads, then the area you get may depend on the size
of your beads. This would be very interesting (to me!). The protocol
being plot the log of the surface area of the branch tips as a function 
of the log of the bead size. Intuitively this would match up with one of
Mandlebrot's (sic?) methods of estimating the fractal dimension of a surface.
Wouldn't it? Any comments?

As as aside, if you could asign a dimension (fractal or otherwise) to open 
space what would you assign? and what of a flat planer, simple leaf 
surface? Andhow about the airspace within a crown? Is that simply 
3-dimensional? Is it moreor is it less?

Back to my first paragraph and direct measuring of fractal dimension, this
bead method would appea to have significant advantages over the 1985 Nature 
paperby Morse, someone else, and Lawton about arthropod body sizes and the 
fractal dimension of vegetation.

Roman Dial
--------------------------------------------------------------------------------
From:   MX%"vieglaid at tursiops.ksc.nasa.gov" 22-FEB-1995 23:59:21.14
Subj:   branch fract dim

Roman Dial writes:

....
>thinking about a similar topic: the fractal surface of a branch. It seems
>that if you use these beads, then the area you get may depend on the size
>of your beads. This would be very interesting (to me!). The protocol
>being plot the log of the surface area of the branch tips as a function 
>of the log of the bead size. ...

Why not try it with glass beads for the smallest then using something
like "styrafoam" beads when you get up to a few mm?  Seems like the 
method should work, the only problem being a mechanical one of getting
beads made of a suitable material.  Could be a pretty straightforward
technique.

Good luck,
Dave Vieglais :-)
--------------------------------------------------------------------------------
From:   MX%"nphillip at acpub.duke.edu" 23-FEB-1995 20:05:33.77
Subj:   Re: branch fract dim

Hi, folks,

        Speaking of fractal measures of vegetation, there is a USDA/USFS 
publication called "The Fractal Forest: Fractal Geometry and Applications 
in Forest Science" that has recently been published.  You can call 
612-649-5000 to order this free publication.  The code for the publication is
GTR-NC-170

Good luck,

Nathan Phillips
School of the Environment
Duke University




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