biomass adjustment factor

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Waldschrat_0815
Posts: 8
Joined: Tue Jun 06, 2017 7:42 am

biomass adjustment factor

Post by Waldschrat_0815 » Mon Oct 16, 2017 4:47 am

Dear iTree Team,

In https://www.itreetools.org/eco/resource ... 102016.pdf you have explained how you estimated the amount of carbon stored.
You mentioned a field land use related biomass adustment factor. Unfortunately I couldn´t find any detailed backgrlund information about that.

It would be great, if you could give me a short explanation (or a link to information I overlooked) about what characteristics of land use are influencing the biomass adjustment factor.

Thank you very much in advance and

best regards
Jason.Henning
i-Tree Team
Posts: 153
Joined: Fri Dec 21, 2012 7:45 am

Re: biomass adjustment factor

Post by Jason.Henning » Mon Oct 16, 2017 9:20 am

Hello,
The relevant text can be found in this publication, http://www.itreetools.org/eco/resources/08%20UFORE.pdf.
Essentially, if the field land use is anything besides "Vacant" or "Wetland" a 0.8 multiplier is applied to reduce biomass estimates. For this reason we recommend using the "Vacant" land use for closed canopy "natural" forests as described in the Eco Field Manual (http://www.itreetools.org/resources/man ... Manual.pdf).

Here is the relevant text from that document:
"Open-grown, maintained trees tend to have less above ground
biomass than predicted by forest-derived biomass equations for
trees of the same dbh (Nowak 1994c). To adjust for this differ-
ence, biomass results for urban trees are multiplied by a factor of
0.8 (Nowak 1994c). No adjustment is made for trees found in
more natural stand conditions (e.g., on vacant lands or in forest
preserves). Because deciduous trees drop their leaves annually,
only carbon stored in wood biomass is calculated for these trees.
Total tree dry weight biomass is converted to total stored carbon
by multiplying by 0.5 (Forest Products Laboratory 1952; Chow
and Rolfe 1989)."

Thanks for your question.
-Jason
Waldschrat_0815
Posts: 8
Joined: Tue Jun 06, 2017 7:42 am

Re: biomass adjustment factor

Post by Waldschrat_0815 » Mon Oct 16, 2017 10:25 am

Dear Jason,

thank you very much for you explanation and the links to the helpfull documents!
Just to make sure I understand right: There is not an different adjustment factor for every Land-use-type?
There is only a differentiation between urban trees, more or less natural stands and deciduos trees in gerneral.
Did I get it right?

best regards
Jason.Henning
i-Tree Team
Posts: 153
Joined: Fri Dec 21, 2012 7:45 am

Re: biomass adjustment factor

Post by Jason.Henning » Mon Oct 16, 2017 1:20 pm

I think that's just about right. For the "Vacant" and "Wetland" field land uses there is no adjustment. For all other land uses the adjustment of 0.8 is applied to the carbon storage (i.e. biomass) estimates to account for the restricted growing space and explicit pruning of urban trees.
Thanks,
Jason
Waldschrat_0815
Posts: 8
Joined: Tue Jun 06, 2017 7:42 am

Re: biomass adjustment factor

Post by Waldschrat_0815 » Tue Oct 17, 2017 2:19 am

Great!

Thank you very much for your help!
Jason.Henning
i-Tree Team
Posts: 153
Joined: Fri Dec 21, 2012 7:45 am

UPDATED METHODS!!! Re: biomass adjustment factor

Post by Jason.Henning » Fri Feb 08, 2019 10:14 am

The i-Tree Eco biomass adjustment factor methods have been updated. The biomass adjustment factor (BAF) is a 0.8 multiplier that gets applied to tree biomass and subsequent carbon storage estimates. The BAF is meant to account for the fact that i-Tree biomass equations are largely from natural forests but trees in urban areas are impacted by human activities such as man-made structures and pruning that reduce their biomass relative to their natural forest counterparts. In the past the BAF was applied only to trees occurring on land uses likely to have an urban character.
The new methodology no longer relies on land use but now uses CLE (crown light exposure) to determine if the BAF should be applied. Trees with a CLE of 4 or 5 will have the 0.8 multiplier applied to their biomass and carbon storage estimates. All other trees will have their biomass and carbon storage estimated without the reduction of the 0.8 multiplier. Land use no longer impacts tree biomass or carbon storage.
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