How was Crown Light Exposure (CLE) and Land Use modified in Eco v6 in the iTree2019 release?

Section for FAQs regarding i-Tree Eco (UFORE)

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azelaya
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How was Crown Light Exposure (CLE) and Land Use modified in Eco v6 in the iTree2019 release?

Post by azelaya » Sun Feb 17, 2019 9:29 pm

The crown light exposure (CLE) entry is now used as the determining factor to apply a biomass adjustment factor (BAF). 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. Potential changes in Eco v6 estimates include: carbon , precipitation and pollution estimates due to potential changes in growth and subsequent leaf area.

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. Land use no longer impacts tree biomass or carbon storage and will only affect structural values. Additional documentation regarding this methods change is not available at this time and will be posted when available.

Similar historical topic discussion can be accessed at the following link viewtopic.php?f=9&t=1368
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Inkeri Salo
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Joined: Tue Oct 08, 2019 4:24 am

Re: How was Crown Light Exposure (CLE) and Land Use modified in Eco v6 in the iTree2019 release?

Post by Inkeri Salo » Sun Nov 17, 2019 6:07 pm

Hi,
Relating to CLE question: Does i-Tree have default value for CLE, when it is not given?
Thanks
Inkeri
azelaya
i-Tree Team
Posts: 355
Joined: Fri Jun 27, 2008 10:50 am

Re: How was Crown Light Exposure (CLE) and Land Use modified in Eco v6 in the iTree2019 release?

Post by azelaya » Mon Nov 18, 2019 8:12 pm

The Crown Light Exposure default is 2-3 when not entered by the user.

The default values used for Eco when data is not provided are listed in the Data Limitations guide http://www.itreetools.org/resources/man ... ations.pdf

A section is copied below from that guide.

The limitation of not collecting those highly recommended variables is that, without the actual data for each tree, the Eco model will use various approaches to fill in the missing variables. Some of these approaches use a default value, meaning all trees will be assigned the same value. Where defaults are not used, the model will use regression equations to fill in the other missing values. The following is a brief synopsis of how the additional recommended variables are estimated and used by the model if they are not collected in the field:

The letters in parentheses after each description below indicate the ecosystem service or model function affected by the data. Each of these components, excluding energy effects and wildlife suitability, will be calculated using estimated or default data variables if any or all of the highly recommended fields are not collected. Energy effects (E) and avian habitat suitability (H) are extra model components that require additional data and cannot be estimated if you do not collect distance and direction of the tree to buildings for energy or ground cover composition and percent shrub cover for wildlife (see the User’s Manual for more information).

A = air pollution removal; C.Stor. = carbon storage; C.Seq. = carbon sequestration; E = energy effects; F = Forecast, R = avoided runoff; S = structural or compensatory value; V = volatile organic compound emissions; H = avian habitat suitability
• Land use – defaults to residential (C.Seq., S, H)
• Total tree height – predicted from a regression equation (A, C.Stor., C.Seq., E, F, R, V, H)
• Height to live top – assumed to be the same as total height
• Height to crown base – predicted from a regression equation (A, R, V)
• Crown width – predicted from a regression equation (A, R, V)
• Percent crown missing – assumed to be 13% crown missing (A, E, R, V)
• Crown health – assumed to be 13% dieback (87% condition) (C.Seq., F, S, H)
• Crown light exposure – defaults to class 2-3 (C.Seq., F)
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