How does i-Tree Canopy estimate carbon and pollution removal

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

How does i-Tree Canopy estimate carbon and pollution removal

Post by azelaya » Fri Apr 21, 2017 7:20 am

General description Info below is derived from the older Canopy application "Help" text. Refer to Understanding i-Tree - NOV2020 (See section on Canopy on pg56) for more details and links to references. https://www.itreetools.org/documents/65 ... nrs200.pdf

Canopy Air Pollution -The i-Tree Canopy default values (the multipliers) of air pollutant removal rates (g/m²/yr) and monetary values ($/m²/yr) for a unit tree cover were derived from i-Tree Eco analyses in the conterminous United States in 2010 (Nowak et al. accepted for publication). Three analyses were conducted for rural and urban areas in all counties and then aggregated into the county-level; 1) derivation of the total tree cover, evergreen percentage and leaf area index, 2) estimation of air pollutant removals and concentration changes, and 3) valuation of air pollutant removals. For more detailed information on Canopy pollution removal, see the following document https://www.itreetools.org/documents/56 ... ptions.pdf

Carbon Sequestration and Storage - The i-Tree Canopy default values of carbon dioxide storage rates (g/m²) and carbon dioxide sequestration rates (g/m²/yr) are derived from the following Nowak et al. (2013) document https://www.itreetools.org/documents/55 ... ration.pdf . Removal rates are originally defined as grams of carbon removed per meter squared of tree canopy but are converted to carbon dioxide by multiplying by 44/12. The default value of carbon dioxide storage rate is a national value for the U.S. Default values for the monetary value ($/m²/yr) of carbon dioxide removal are based on the Social Cost of Carbon for Regulatory Impact Analysis, https://www.itreetools.org/documents/65 ... update.pdf , for 2015 (in 2007 dollar values) with a 3% discount rate adjusted to 2014 dollar values using GDP implicit price deflator (108.289) from the National Income and Product Accounts Tables, http://www.bea.gov/iTable/index_nipa.cfm, Table 1.1.9 (i.e., $40 per metric ton of CO2 for 2015).

Hydrology Effects in U.S. -added in Canopy v7.x
Estimates of avoided runoff, transpiration, and rainfall interception are based on the area of tree cover and local weather data. A local standardized removal rate (e.g., m3 water/m2 of tree cover) is multiplied by local tree cover (m2) from i-Tree Canopy to estimate a local total effect from the trees (m3). For hydrologic estimates, i-Tree Eco used weather data to estimate average effects per unit of tree cover (m3/m2 or $/m2 of tree cover) for each U.S. county. Detailed methods regarding this process are given in Hirabayashi (2015) i-Tree Eco United States county-based hydrologic estimates - https://www.itreetools.org/documents/11 ... imates.pdf.
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