data collection

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data collection

Post by jaygee »

salut i-trees.
I am proposing an I-trees eco programme for the Ville de Cannes here in France. It is the first time such a study will have been undertaken. We are proposing a 250 plot stratified based study. The area of Cannes is 27klm squared, a third of the commun being woodland and two thirds being concrete etc. If we do 80 plots woodland trees and 170 town trees will I-trees recognise the stratification as different areas. Also if a plot lands in the middle of a tennis court/parking lot (treeless) , do you mark anything in the plot number as "no data" or do you move to the edges of the parking/tennis court and measure a few trees to augment the eventual findings?
I have used the trees eco here a few times and it is a great tool and I am hoping to establish here in France and see what we get. Many thanks for your response.

Jonathan G
i-Tree Team
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Joined: Fri Dec 21, 2012 7:45 am

Re: data collection

Post by Jason.Henning »

Hi Jonathan,
You can set up a stratified project and assign your plots to strata ahead of time. It is very important that you accurately enter the area of each strata otherwise any population level extrapolations will be incorrect. The stratification will be taken into account when population level statistics are calculated and many results are reported by stratum. You can check out the "Pr-Stratification" guide available under the "Support" tab in Eco for more details.
If a plot lands in the middle of tennis court or parking lot it must still be recorded. There are ways to mark the there is 0% tree cover on that plot and the ground cover can still be recorded. If you do not assess those plots or move them you will be biasing your sample and over estimating the numbers of trees in your city. it is important to remember the 0 trees is still a measurement.
If you check out our example plot projects you will see that there are many plots with 0 trees. For example if you take a look at the Gran Rapids project available under the "File" menu in Eco plot 2 is on an industrial and has 0 trees. You can note which variables were still assessed and that the plot is marked 100% complete.
A member of the i-Tree Team
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