Negative values for Net Carbon Sequestration?

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lovebergquist
Posts: 1
Joined: Fri Dec 01, 2017 7:04 am

Negative values for Net Carbon Sequestration?

Post by lovebergquist » Fri Dec 01, 2017 7:11 am

Looking at the data for Torbay, 2010, I found the English elm having a reported Net Carbon Sequestration value of -356,82 (negative 356,82) ton/yr.
What does the negative value signify?
Jason.Henning
i-Tree Team
Posts: 120
Joined: Fri Dec 21, 2012 7:45 am

Re: Negative values for Net Carbon Sequestration?

Post by Jason.Henning » Fri Dec 08, 2017 9:47 am

It is possible to get negative net sequestration values for larger and older trees. Trees release carbon to the atmosphere through respiration and decay while they take up and sequester carbon by adding new woody material. Mature trees will eventually reach a point where they are adding new wood very slowly while expelling much more carbon through maintenance respiration and essentially decaying in place. I couldn't find a summary for the English Elm in the Torbay report we have on the i-Tree website but it is very likely that species groups is comprised of large mature trees that are releasing more carbon than they are sequestering. For more information on the carbon methodology in i-Tree Eco please see this document, http://www.itreetools.org/eco/resources ... ak_001.pdf
Thanks for your question.
-Jason
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