Tree canopy i-TreeEco

Section for FAQs regarding i-Tree Eco (UFORE)

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cjusto
Posts: 2
Joined: Thu Apr 30, 2020 3:05 pm

Tree canopy i-TreeEco

Post by cjusto » Tue May 12, 2020 10:23 am

How i-Tree Eco calculate the percentage of tree canopy ?
Jason.Henning
i-Tree Team
Posts: 203
Joined: Fri Dec 21, 2012 7:45 am

Re: Tree canopy i-TreeEco

Post by Jason.Henning » Wed May 13, 2020 1:12 pm

Tree canopy cover percentage is calculated differently for plot-based i-Tree Eco projects versus complete inventories.
For plot-based projects users must choose to record the percent canopy cover on each plot. The canopy cover percentage for a project is then the average of the cover across all plots for an unstratified project. In the case of a stratified project, the software calculates the average canopy cover across all plots within a stratum then takes the area weighted average of the stratum estimates to create a population level estimate. These methods are following the common summary statistics for simple random samples or stratified random samples, respectively.
For complete inventories i-Tree Eco calculates the area covered by each tree using the crown widths and the formula for the area of an oval, A=PI*(CW1*CW2)/4. Where A=area covered and CW1 and CW2 are the two crown width measurements. The estimate assumes that the crowns don't overlap which may not be accurate in all cases.
We recommend using i-Tree Canopy when you are interested in the most accurate estimates of tree canopy cover. The i-Tree Eco methods create valid estimates but they are much less precise than what can be obtained by using aerial imagery.
Thanks for your question.
-Jason
A member of the i-Tree Team
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