Is there a difference between carbon stored and carbon seque

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rfotu
Posts: 4
Joined: Fri Jan 04, 2008 10:44 am

Is there a difference between carbon stored and carbon seque

Post by rfotu » Fri Jan 04, 2008 10:50 am

Hi,



I was looking at a study from Minneapolis’ urban forest (they used UFORE), and in the appendix there is a table showing carbon storage and carbon sequestered by the diameter of the tree.



I don’t understand how the carbon stored can be 3 or 4 x more than the amount sequestered per year?



Here is a sample of the table’s information.


1-3 Diameter
8 Carbon Storage (lbs)
2.4 Carbon Sequestered (lbs./year)

3-6 Diameter
44 Carbon Storage (lbs)
6.2 Carbon Sequestered (lbs./year)

6-9
124
12

9-12
268
18.7

12-15
483
24.5

15-18
721
30.3

18-21
1068
37.7

21-24
1303
40.7

24-27
1516
31.4

27-30
2883
75.3

30+
4338
91.2




It does not appear that a 1-3 diameter tree can jump from 8lbs. of carbon to 44lbs when it only sequesters 2.4 pounds of carbon per year. Even if the growth rate is 0.5 inches per year, it still would not add up to 44 lbs.



Can you give me an idea on what’s happening here? And which is the appropriate method to use for monitoring carbon taken out of the atmosphere?



Thanks in advance.
Jerry
Posts: 100
Joined: Wed Nov 28, 2007 8:11 pm

This has always given me trouble

Post by Jerry » Fri Jan 04, 2008 11:47 am

UFORE seems to use these terms--especially sequestration--in a particular way:
  • carbon sequestration refers in UFORE to the removal of carbon (in the form of carbon dioxide) from the atmosphere through the process of photosynthesis.
  • carbon storage refers to the amount of carbon bound up in woody material above and below ground
As the UFORE Methods paper available on the i-Tree website states, the difference in estimates of carbon storage between one year and the next is the gross amount of carbon sequestered annually. Since the woody parts of a tree represent the sum of years of annual sequestration, it is understandable why the storage number is greater than the sequestration one.

Carbon storage can be equated I think with the more generally used term net primary production. Outside UFORE, carbon sequestration usually refers to (and appears to be a synonym of) any long-term form of carbon storage, from woody plants to seawater.

Hope this helps.
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