Hi,
How will STRATUM work if I import data for a single zone but the City Definitions will be for the entire city? The imported data will only involve a portion of the entire city.
STRATUM - Zones and City Definitions
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City Definitions
Sure.
In section 2.4.1 you need to define City and Costs. One of the requirements for the city is "Total Land Area (sq mi) - enter the total land area (in whole square miles) of your city to calculate the percentage of total land area covered by street tree canopy." There are also other city-wide parameters required by this same section.
Thx.
In section 2.4.1 you need to define City and Costs. One of the requirements for the city is "Total Land Area (sq mi) - enter the total land area (in whole square miles) of your city to calculate the percentage of total land area covered by street tree canopy." There are also other city-wide parameters required by this same section.
Thx.
The best approach would be to redefine the “City” data to reflect the specific zone or area the inventory represents. However, leaving these entries as citywide data will not cause reporting errors with STRATUM; how these reports will be interpreted is a different matter. Suppose for example, your project consisted of the following parameters:
--you entered a citywide human population of 65,000
--you entered annual citywide tree maintenance costs totaling 750,000
--you imported an inventory of 5,000 trees that represents approximately 1/5th of the total street tree population throughout the city
--STRATUM reports that, individually, these trees average $100 in annual benefits with total benefits equal to $500,000 ($100 x 5,000)
If you went on to run a summary Net Annual Benefits report, the net benefit value on a $/capita basis will be negative, equal to -$3.80. The $/capita benefits of $7.69 ($500,000/65,000) do not outweigh the management costs of $11.53 ($750,000/65,000), on a per person basis, because you did not account for the fact that the 5,000 project trees only represent a fraction of the costs. Now, if we assume that the number of people in your city and tree management costs were proportional by zone to the number of trees, your real benefit on a per capita basis would be positive, equal to $26.92 (($500,000 - (.20 x $750,000) / (.20 x 65,000)).
--you entered a citywide human population of 65,000
--you entered annual citywide tree maintenance costs totaling 750,000
--you imported an inventory of 5,000 trees that represents approximately 1/5th of the total street tree population throughout the city
--STRATUM reports that, individually, these trees average $100 in annual benefits with total benefits equal to $500,000 ($100 x 5,000)
If you went on to run a summary Net Annual Benefits report, the net benefit value on a $/capita basis will be negative, equal to -$3.80. The $/capita benefits of $7.69 ($500,000/65,000) do not outweigh the management costs of $11.53 ($750,000/65,000), on a per person basis, because you did not account for the fact that the 5,000 project trees only represent a fraction of the costs. Now, if we assume that the number of people in your city and tree management costs were proportional by zone to the number of trees, your real benefit on a per capita basis would be positive, equal to $26.92 (($500,000 - (.20 x $750,000) / (.20 x 65,000)).
a member of the i-Tree Team