General formulas

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General formulas

Post by umberto » Fri Dec 06, 2019 9:54 am

I would need general formulas to calculate the average absorption of pollutants (co2, no2, o3, so2, PM10 / 2.5), water runoff, oxygen production and temperature difference starting from the dimensions at maturity of the plants having only height and width at maturity as in a nursery catalog.
I thought of using the average LAI values ​​for the plant type (shrubs, trees, conifers, etc.) by multiplying them by the area of ​​the ground foliage projection calculated from the maturity width.
I know there are a lot of location's factors like the climate, the precipitations, the concentration of pollutants, etc, and many parameters concerning the health and the size of the plant but I'm trying to stimulate the average values ​​for the species.

thanks for future answers
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Re: General formulas

Post by Jason.Henning » Mon Dec 09, 2019 9:28 am

Unfortunately we don't have general equations for average benefits by species. To see more about how the underlying models in i-Tree Eco work please see these documents, ... ptions.pdf and ... risons.pdf for air pollution and precipitation respectively. At this time we don't have a model for temperature difference. We can't estimate air pollution removal or runoff benefits without some knowledge of local precipitation or pollution. If there is no precipitation or no pollution there will be no benefits.
You do have a few alternatives:
1. You could use the carbon and air pollution removal multipliers that are embedded in i-Tree Canopy. You can access those for every county in the US during Canopy project set-up. They are are applied to the area of canopy cover and rely on county level data about species composition and air pollution.
2. You could use i-Tree Eco and select a location that may be representative of your area. The benefits will changes based on the location you select but they will allow you to compare among species.
3. You could use i-Tree Eco and ignore the ecosystem services but rely on the leaf surface area estimated for each tree for comparison and analysis. Many of the benefits you are interested in are driven by leaf surface area so leaf surface area may be a better way to compare them.

If you use i-Tree Eco you need to provide a minimum of tree species and dbh. If you have additional data on trees you should provide. However, you cannot provide partial crown data. If you want to use crown height and width data you will also need to provide the height of the crown-base and the percent crown missing. If you do not have those variables you may want to model them or assume some default values. For example you could assume an average of 13% crown missing and a crown base height that is 15% of the total height (these are example assumptions not based on research or data). The accuracy of estimates you obtain from i-Tree Eco will be largely dependent on how accurately your data represents real world conditions. This is why we encourage users to collect field data from their population of interest or they risk creating projects based on inaccurate data that may lead to incorrect conclusions.

Thanks for your interest in i-Tree.
A member of the i-Tree Team
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