Greening Marrickville

Marrickville is one of the most densely populated areas of Sydney.

Great native shrubbery at O'Dea Reserve Camperdown

Great native shrubbery at O’Dea Reserve Camperdown

It has only a small amount of public open space and lacks a substantial tree canopy.

The Greens have a vision of a greener Marrickville, literally.  We want to increase the number of trees, or tree canopy in our area.

Our policy goals area:

  • Increase the number of street trees planted
  • Ensure street trees speicies are of a good size and preferably native
  • Protect existing street trees from removal by council or by Electricity Australia
  • Increase the number of plantings in street treatments such as curb blisters and round-a-bouts
  • Encourage residents to plant their verges with native ground covers and shrubs instead of grass
  • Increase the number of ‘bush pockets’ in disused open areas
  • Increase the number of trees in some of our parks, such as Sydenham Green

Trees serve important purposes because they:

  • provide oxygen and absorb carbon dioxide
  • provide shade and reduce the ‘urban heat island’ effect
  • reduce run off from storms
  • promote rainfall through respiration
  • provide habitat for birds and animals
  • beautify the environment
  • increase property values
Good nature stip planting at the corner of Lincoln St & Railway Ave Stanmore

Good nature strip planting at the corner of Lincoln St & Railway Ave Stanmore

On council we are working to green the Inner West.  We have started two online galleries:

1) Good street treatments – examples of good street treatments.

2) Areas that need trees – streets in the Marrickville local government area that need trees planted.

If you would like to send us your photographs of good street treatments, or an area you think needs a tree email: phillips.max@gmail.com (include the location of the photo).

HOW TO MEASURE HOW MUCH CO2 TREES STORE

How to calculate the amount of CO2 sequestered in a tree per year
We at Trees for the Future estimate that our agroforestry trees, planted in tropical
climates, will sequester atmospheric carbon dioxide at an average of 50 pounds of carbon
dioxide per tree per year.
The rate of carbon sequestration depends on the growth characteristics of the tree species,
the conditions for growth where the tree is planted, and the density of the tree’s wood. It
is greatest in the younger stages of tree growth, between 20 to 50 years.1 Further
complicating the issue is the fact that far less research has been done on tropical tree
species as compared to temperate tree species.
Nevertheless, we can roughly estimate the amount of CO2 sequestered in a given tree,
and if we divide by the tree’s age, get a yearly sequestration rate.
We got this process from two educational websites who had conceived it as a learning
activity for their students. 2 This is the process:
1. Determine the total (green) weight of the tree.
2. Determine the dry weight of the tree.
3. Determine the weight of carbon in the tree.
4. Determine the weight of carbon dioxide sequestered in the tree
5. Determine the weight of CO2 sequestered in the tree per year

Determine the total (green) weight of the tree
Based on tree species in the Southeast United States, the algorithm to calculate the weight
of a tree is: 3
W = Above-ground weight of the tree in pounds
D = Diameter of the trunk in inches
H = Height of the tree in feet
For trees with D < 11:
W = 0.25D2H
For trees with D >= 11:
W = 0.15D2H
Depending on the species, the coefficient (e.g. 0.25) could change, and the variables D2
and H could be raised to exponents just above or below 1. However, these two equations
could be seen as an “average” of all the species’ equations.
The root system weighs about 20% as much as the above-ground weight of the tree.
Therefore, to determine the total green weight of the tree, multiply the above-ground
weight of the tree by 120%.

Determine the dry weight of the tree
This is based on an extension publication from the University of Nebraska.4 This
publication has a table with average weights for one cord of wood for different temperate
tree species. Taking all species in the table into account, the average tree is 72.5% dry
matter and 27.5% moisture.
Therefore, to determine the dry weight of the tree, multiply the weight of the tree by
72.5%.
Determine the weight of carbon in the tree
The average carbon content is generally 50% of the tree’s total volume.5 Therefore, to
determine the weight of carbon in the tree, multiply the dry weight of the tree by 50%.
Determine the weight of carbon dioxide sequestered in the tree
CO2 is composed of one molecule of Carbon and 2 molecules of Oxygen.
The atomic weight of Carbon is 12.001115.
The atomic weight of Oxygen is 15.9994.
The weight of CO2 is C+2*O=43.999915.
The ratio of CO2 to C is 43.999915/12.001115=3.6663.
Therefore, to determine the weight of carbon dioxide sequestered in the tree, multiply the
weight of carbon in the tree by 3.6663.6

Determine the weight of CO2 sequestered in the tree per year
Divide the weight of carbon dioxide sequestered in the tree by the age of the tree. Et
voila!
EXAMPLES
Estimated growth rates and sizes of agroforestry trees were taken from the World
Agroforestry Centre’s “Agroforestree Database”7:
Let’s see how much a Calliandra calothyrsus might sequester in a year. A 10-year-old
Calliandra would probably grow about 15 feet tall with a trunk about 8 inches in
diameter. Therefore:
W = 0.25D2H = 0.25(82)(15) = 240 lbs. green weight above ground.
240 lbs. * 120% = 288 lbs. green weight (roots included)
288 lbs. * 72.5% = 208.8 lbs. dry weight
208.8 lbs. * 50% = 104.4 lbs. carbon
104.4 lbs * 3.6663 = 382.8 lbs. CO2 sequestered
382.8 lbs / 10 years = 38.3 lbs. CO2 sequestered per year
Or consider a 10-year-old Grevillia robusta, 45 feet tall with a trunk 6 inches in diameter.
Using the same calculations as above, the amount of CO2 sequestered would be 64.6 lbs.
per year.
Or a newly-planted Acacia angustissima, 2.5 years old, 15 feet tall with a trunk 3 inches
in diameter: 21.5 lbs. of CO2 sequestered per year.
Or an Albizzia lebbek, 15 years old, 30 feet tall, with a 12 inch trunk: 68.9 lbs. of CO2
sequestered per year.

Other methods
Another way to estimate the amount of CO2 sequestered by a tree in a year is to estimate
the amount sequestered in a hectare per year, and divide that amount by the number of
trees per hectare. Scanning around on the Internet, it seems that the number of trees per
hectare (in agroforestry and/or industrial plantations) ranges from under 500 to over
2,000.
According to Myers and Goreau, tropical tree plantations of pine and eucalyptus can
sequester an average of 10 tons of carbon per hectare per year. 8 Therefore, the
plantation can sequester an average of 20,000 lbs * 3.6663 = 73,326 lbs CO2/ha/year, or,
taking an average of 1,000 trees per hectare, 73.326 lbs CO2/tree/year.
Of course, we heavily discourage the planting of pine and/or eucalyptus in our
agroforestry systems. Our trees may not grow as fast or as straight as eucalyptus, but
they are not invasive, and they do not destroy the water table and the soil!
Disclaimer
This research and methodology is based on research papers, university publications, and
other information freely available on the Internet. As we stated before, it is difficult to
calculate the amount of carbon dioxide sequestered per tree per year due to the
complexity of the variables involved, as well as the lack of research on tropical tree
species. If you have any information that could further refine or enhance our
calculations, please let us know at info@treesftf.org. Thanks and happy tree planting!

1 http://www.rcfa-cfan.org/english/issues.13.html
2 The National Computational Science Leadership Program
http://www.ncsec.org/cadre2/team18_2/students/purpose.html and
The Shodor Education Foundation
http://www.shodor.org/succeedhi/succeedhi/weightree/teacher/activities.html
3 “Total-Tree Weight, Stem Weight, and Volume Tables for Hardwood Species in the Southeast,”
Alexander Clark III, Joseph R. Saucier, and W. Henry McNab, Research Division, Georgia Forestry
Commission, January 1986.
http://www.forestdisturbance.net/publications/GF%20RP60-Clark.pdf
4 “Heating With Wood: Producing, Harvesting and Processing Firewood,” Scott DeWald, Scott Josiah, and
Becky Erdkamp, University of Nebraska – Lincoln Extension, Institute of Agriculture and Natural
Resources, March 2005.
http://www.ianrpubs.unl.edu/epublic/live/g1554/build/g1554.pdf
5 “Carbon Storage and Accumulation in United States Forest Ecosystems, General Technical Report W0-
59,” Richard A. Birdsey, United States Department of Agriculture Forest Service, Northeastern Forest
Experiment Station, Radnor, PA, August 1992.
http://www.ilea.org/birdsey/fcarbon_index.html#toc
6 http://www.ncsec.org/cadre2/team18_2/students/helpCalcCO2.htm
7 http://www.worldagroforestrycentre.org/Sites/TreeDBS/aft.asp
8 “Tropical Forests and the Greenhouse Effect: A Management Response,” Norman Myers and Thomas J.
Goreau, Discovery Bay Marine Laboratory, University of the West Indies, Discovery Bay, Jamaica, 1991.
http://www.ciesin.columbia.edu/docs/002-163/002-163.html

One comment

  • The take-up of solar and the increasing move towards utilising backyards for growing food is in direct conflict with large trees. I would like to see tree removal/replacement policies amended to take these shifts in trends into account. Shadowing has a detrimental effect on the output of solar panels and also limits the use of backyards.

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