Climate Action and Sustainability Plan June 2021 | Page 111

In 2020 , trees in Mount Auburn Cemetery Sample Plots emitted an estimated 444.1 pounds of volatile organic compounds ( VOCs ) ( 324.9 pounds of isoprene and 119.2 pounds of monoterpenes ). Emissions vary among species based on species characteristics ( e . g . some genera such as oaks are high isoprene emitters ) and amount of leaf biomass . Thirty- nine percent of the urban forest ' s VOC emissions were from Northern red oak and White oak . These VOCs are precursor chemicals to ozone formation .³

General recommendations for improving air quality with trees are given in Appendix VIII .

³ Some economic studies have estimated VOC emission costs . These costs are not included here as there is a tendency to add positive dollar estimates of ozone removal effects with negative dollar values of VOC emission effects to determine whether tree effects are positive or negative in relation to ozone . This combining of dollar values to determine tree effects should not be done , rather estimates of VOC effects on ozone formation ( e . g ., via photochemical models ) should be conducted and directly contrasted with ozone removal by trees ( i . e ., ozone effects should be directly compared , not dollar estimates ). In addition , air temperature reductions by trees have been shown to significantly reduce ozone concentrations ( Cardelino and Chameides 1990 ; Nowak et al 2000 ), but are not considered in this analysis . Photochemical modeling that integrates tree effects on air temperature , pollution removal , VOC emissions , and emissions from power plants can be used to determine the overall effect of trees on ozone concentrations .

I-Tree Report of Ecosystem Analysis at Mount Auburn Cemetery Insert to the Climate Action and Sustainability Plan

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