## How does Eco calculate tree Structural Value?

Section for FAQs regarding i-Tree Eco (UFORE)

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azelaya
i-Tree Team
Posts: 365
Joined: Fri Jun 27, 2008 10:50 am

### How does Eco calculate tree Structural Value?

The Eco structural values methods are best explained in the following journal A Ground Based Method for Assessing Urban Forest Structure and Function which can be accessed here for further Eco/UFORE methods http://www.itreetools.org/eco/resources/08%20UFORE.pdf The relevant text is below.

The structural value of the trees (Nowak et al. 2002a) is based on methods from the Council of Tree and Landscape Appraisers (CTLA 1992). Compensatory value is based on four tree/site characteristics: trunk area (cross-sectional area at dbh), species, condition, and location. Trunk area and species are used to determine the basic value, which is then multiplied by condition and location ratings (0 to 1) to determine the final tree compensatory value. Local species factors, average replacement cost, and transplantable size and replacement prices are obtained from ISA publications. If no species data are available for the state, data from the nearest state are used. Condition factors are based on percent crown dieback. Available data required using location factors based on land use type (International Society of Arboriculture 1988): golf course 0.8; commercial/industrial, cemetery, and institutional 0.75; parks and residential 0.6; transportation and forest 0.5; agriculture 0.4; vacant 0.2; wetland 0.1

It is also important to keep in mind that the estimates produced by Eco and Streets are meant to provide an understanding of structural value or replacement value of trees but are not intended to replace the process of performing an actual onsite detailed CTLA evaluation of a specific tree by a certified arborist.
A member of the i-Tree Team
Jason.Henning
i-Tree Team
Posts: 204
Joined: Fri Dec 21, 2012 7:45 am

### Re: How does Eco calculate tree Structural Value?

Additional land uses have been added to i-Tree Eco to increase completeness and flexibility. The additional land uses and their associated location factors are: multifamily residential 0.6, other 0.5, and utility 0.4.
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