Environmental Benefits Analysis of Trees for Greenmount Cemetery in Springfield, Ohio

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1 Environmental Benefits Analysis of Trees for Greenmount Cemetery in Springfield, Ohio T. Davis Sydnor and Sakthi Subburayalu School of Environment and Natural Resources and Pamela J. Bennett Ohio State University Extension April 18, 2011

2 An Analysis of Tree Benefits for Greenmount Cemetery EXECUTIVE SUMMARY An inventory of public trees in Greenmount Cemetery in the City of Springfield, Ohio was conducted by Pamela J. Bennett, Ohio State University Extension, State Master Gardener Volunteer Coordinator, and its Master Gardener volunteers in A total of 196 trees were inventoried during this period. A common bid price for this service is $4.00 per tree and thus the inventory represents a value of $800. Most importantly, however, is that the community now has a tree inventory in a form that can be used to better manage the tree resources of the cemetery. Benefits mentioned above do not include the value of the subsequent analysis and report by The Ohio State University s School of Environment and Natural Resources which would conservatively add another $11,500. Analysis of the inventory data was done using itree, a software suite by the USDA Forest Service. The specific program in the itree suite used to identify benefits was istreets. This program allows community leaders interested in making informed decisions about Springfield s green infrastructure or to explore many aspects including biodiversity, values of environmental services to reduce costs and the carbon footprint of Springfield. A long standing rule of thumb for taxonomic biodiversity is the guideline which suggests that no more than 10 percent of trees should be from the same species, no more than 20 percent should be from the same genera, and no more than 30 percent should be from the same family. In the cemetery, only black locust exceeds guidelines (Table 1). Ash plantings represent 8 individuals or 4 % of the cemetery trees and 3.8% of the canopy (Table 3). This represents a minor loss of canopy if emerald ash borer (EAB) should destroy all American ash as predicted. Ash removal for the city will likely be much higher and/or treatment costs will need to be addressed by informed community leaders. Based on the inventory and an earlier study, Removal costs for the eight Greenmount trees are likely to cost $9,600. However, costs for the City of Springfield including park, and public trees would be expected to exceed 2 million dollars for tree and stump removal plus replacement costs combined. Ohio State University Extension can assist in developing plans including costs and probabilities of treatment vs. no treatment. There is no single, simple answer for communities facing concerns with EAB. Larger growing deciduous trees constituting 1% or less of the cemetery s canopy cover that could be used to replace the ash include the Ky. coffeetree; various oaks; sycamore, buckeye, basswood, dawn redwood, and elms. Under ideal conditions tree numbers among various size classes should be stable and then decline as trees reach their mature size and older trees die. Cemetery trees inventoried are concentrated in mature to over-mature sizes (Tables 2 and 3). Smaller trees were absent in the area inventoried. Consider some larger growing trees that live longer and mature at larger sizes such as preferred in a resident preference survey in Toledo, OH. Of course, this should be consistent with the design intent for the cemetery and/or other public space. Trees are relatively uniform in size at present with 70% of the trees in the inch diameter size classes. Importance values and canopy cover percentages as detailed in (Table 4) are similar. Oaks are interesting in that there are 9 small and 14 larger trees. In most communities oaks generate more canopy cover and greater environmental benefits than their numbers suggest. In contrast the larger number of smaller black locusts is unlikely to deliver increased benefits as they are over-mature at present. This demonstrates the community s need for planting trees such as oaks that are larger and longer lived at maturity whenever possible as the importance value is a measure of the overall contribution of the species to the sum of environmental benefits delivered. 1

3 A major benefit of urban trees is their ability to intercept rainfall and reduce storm water runoff (Table 5). Storm water runoff is a major cost for communities. Columbus, OH is embarking on a multi-billion dollar sewer and storm water upgrade for the community. One hundred and ninety-six trees, alone, intercept more than 436,600 gallons of storm water annually at a savings to the area of 11,800 dollars per year. Carbon sequestration, as reported here, represents the carbon removed from the air and stored in the trees (Table 6). More than 1.4 million pounds have been stored by the 196 trees over time. The cemetery trees currently sequester and avoid some 151,800 lbs of CO 2 yearly (Table 8) and would represent carbon credits worth nearly $1,140 per year if a carbon trading system were in place and if a system for accounting for them were available for those trees. These are net gain figures and include deductions for tree losses and maintenance. Annual CO 2 benefits vary by species and size but average $5.81 per tree per year while larger hickories average $8.72 per tree per year or 50% more. Strategic plantings of larger trees could increase this substantially. Annual air quality savings (reduced ozone, nitrous and sulfur oxides as well as particulate matter) for the cemetery trees is nearly $1,750 (Table 9). This includes both direct savings ($405) from cemetery trees and avoided pollution which is much greater at $1,462. Avoided pollution is pollution not generated at power source because energy was not required (avoided) by the community. The total annual air quality benefits are discounted by $121 for the volatile emissions from the trees themselves. Energy savings by trees are particularly important in view of the citizenry s increasing concern over the nation s energy dependency. Energy is saved by shading structures, evaporating water (evapotranspiration) and reducing wind speed around structures (Table 7). Greenmount Cemetery trees save the community $3,724 in electricity and $6,639 in natural gas for a total savings of $10,363 or an average of $53 per tree per year. Recent interest in strategic plantings of larger trees to enhance energy savings has tremendous potential for savings in Springfield. Aesthetic and miscellaneous benefits from trees contribute $8,207 annually to the cemetery in the form of more effective screening and enhanced sense of place among other things (Table 10). Research in public housing has shown that areas with trees facilitate interaction among residents and lead to reduced domestic violence and more sociable environments. Customer surveys suggest that customers prefer to spend their money and time in commercial streetscapes with trees and are willing to spend up to 11% more there. Perhaps an improved atmosphere in Springfield might translate into recruiting businesses into the area. When all benefits are included the 196 trees contribute an average of $75 per tree annually to Greenmount Cemetery and Springfield (Table 11). vary in their annual benefits but mature size, longevity, and maintenance costs are but some of the factors determining annual benefits. This would be well in excess of their maintenance and planting costs for trees. Springfield does not separate budgets for tree maintenance on individual cemeteries other public areas. Thus while the 196 trees inventoried require relatively little care per year, they deliver $33,289 in annual benefits from storm water abatement, carbon sequestration, energy savings, air quality, aesthetic benefits, and the like or $170 per tree. Ohio communities studied routinely discover returns on their tree maintenance dollars of 200 to 300% and Toledo had a 436% annual return on their urban forestry budget. Further, unlike most community infrastructure, annual tree benefits increase over time. 2

4 Table 1. Distribution of the Most Common Trees in Greenmount Cemetery Arranged from Most to Least Commonly Seen Percent Black locust Oak Maple Black walnut 8.67 Hickory 7.65 Black cherry 5.10 Sassafras 5.10 Ash 4.08 Hackberry 3.06 Honeylocust 3.06 OTHER SPECIES

5 Table 2. Relative Age Distribution of the 10 Most Commonly Inventoried Trees in Greenmount Cemetery as a Percentage (%) of each Tree Feet (DBH) class in inches Black locust Oak Maple Black walnut Hickory Black cherry Sassafras Ash Hackberry Honeylocust Class Percentage

6 Table 3. Population of Greenmount Cemetery Trees by Common Name, Tree Type and Size (DBH) Class. DBH Class (in) Broadleaf Deciduous Large (BDL) Oak Maple Black walnut Hickory Hackberry Buckeye, other Poplar Linden Horse chestnut Broadleaf Deciduous Medium (BDM) Black locust Black cherry Sassafras Ash Honeylocust Hardy rubber tree Callery pear Broadleaf Deciduous Small (BDS) Hawthorn Apple Flowering crabapple Conifer Evergreen Large (CEL) Dawn redwood Cemetery s

7 Table 4. Greenmount Cemetery Trees Listed by Common Name from Greatest to Least Importance Value. Number of Trees % of Trees Leaf Area (ft2) % of Leaf Area Canopy Cover (ft2) % of Canopy Cover Importance Value Black locust Oak Maple Black walnut Hickory Black cherry Sassafras Ash Hackberry Honeylocust Buckeye, other Poplar Hardy rubber tree Dawn redwood Linden OTHER TREES Cemetery s

8 Table 5. Annual Storm Water Benefits of Greenmount Cemetery Trees by Ordered by Decreasing Benefits/Tree Rainfall Interception (Gal) ($) % of Tree Numbers % of $ Avg. $/tree Hickory $1, $88.78 Hackberry $ $83.03 Black walnut $1, $81.58 Honeylocust $ $70.45 Poplar $ $70.21 Black cherry $ $66.70 Ash $ $66.58 Oak $1, $66.06 Black locust $3, $53.37 Maple $1, $51.47 Linden 3321 $ $45.01 Sassafras $ $38.94 Buckeye 5747 $ $38.94 Hardy rubber tree 2519 $ $34.14 Dawn redwood 2377 $ $32.21 OTHER TREES 3237 $ $17.55 CEMETERY TOTAL $11, $

9 Table 6. Stored CO 2 Benefits in the Trees in Greenmount Cemetery by Ordered by Decreasing Benefits per Tree stored CO2 (lbs) ($) % Tree Numbers % of $ Avg. $/tree Hickory $1, $94.58 Oak $1, $85.98 Poplar $ $63.43 Ash $ $62.89 Black cherry $ $62.23 Black walnut $1, $59.52 Hackberry $ $55.51 Honeylocust $ $45.80 Black locust $2, $45.04 Linden $ $44.30 Sassafras $ $36.72 Maple $ $35.69 Buckeye, other $ $30.55 Hardy rubber tree 7190 $ $26.96 Dawn redwood 7190 $ $26.96 OTHER TREES 5846 $ $19.33 CEMETERY TOTAL $10, $

10 Table 7. Annual Energy Benefits Greenmount Cemetery Trees by Common Name and Decreasing Dollars/Tree Electricity (MWh) Electricity ($) Natural Gas (Therms) Natural Gas ($) ($) % Tree Numbers % of $ Avg. $/tree Hackberry 1.9 $ $ $ $68.05 Black walnut 5.2 $ $ $1, $65.65 Hickory 4.4 $ $ $ $63.20 Honeylocust 1.8 $ $ $ $60.61 Poplar 1.1 $ $ $ $57.32 Black cherry 2.6 $ $ $ $56.53 Ash 2.1 $ $ $ $55.99 Black locust 15.4 $1, $2, $3, $52.42 Maple 4.9 $ $ $ $49.40 Oak 5.3 $ $ $1, $48.79 Linden 0.5 $ $61.19 $ $47.91 Dawn redwood 0.4 $ $51.06 $ $41.84 Buckeye 0.8 $ $ $ $41.52 Hardy rubber tree 0.4 $ $46.92 $ $38.70 Sassafras 1.7 $ $ $ $35.32 OTHER TREES 0.7 $ $98.77 $ $29.83 CEMETERY TOTAL 49.1 $3, $6, $10, $

11 Table 8. Annual Carbon Dioxide Benefits of Greenmount Cemetery Trees by Common Name and Ordered by Decreasing Benefits per Tree Sequestered (lb) Sequestered ($) Decomposition Release(lb) Maintenance Release (lb) Release ($) Avoided (lb) Avoided ($) Net (lb) ($) % of Tree Numbers Hickory $ $ $ $ Poplar 2639 $ $ $ $ Maple 9945 $ $ $ $ Hackberry 2312 $ $ $ $ Black walnut 6143 $ $ $ $ Hardy rubber tree 1029 $ $ $ $ Linden 913 $ $ $ $ Honeylocust 1897 $ $ $ $ Black locust $ $ $ $ Ash 2676 $ $ $ $ Black cherry 3246 $ $ $ $ Sassafras 4068 $ $ $ $ Dawn redwood 632 $ $ $ $ Buckeye, other 1310 $ $ $ $ Oak 2767 $ $ $ $ OTHER TREES 1233 $ $ $ $ CEMETERY TOTAL $ $ $ $1, % of $ Avg. $/tree

12 Table 9. Annual Air Quality Benefits of Greenmount Cemetery Trees by Common Names and Ordered by Decreasing Air Pollution Benefits per Tree Deposit O3 (lb) Deposit NO2 (lb) Deposit PM10 (lb) Deposit SO2 (lb) Deposit ($) Avoided NO2 (lb) Avoided PM10 (lb) Hackberry $ $ $ $ $12.12 Hickory $ $ $ $ $10.90 Black walnut $ $ $ $ $10.84 Honeylocust $ $ $ $ $10.23 Black cherry $ $ $ $ $10.07 Ash $ $ $ $ $10.05 Poplar $ $ $ $ $9.34 Black locust $ $ $ $ $9.06 Maple $ $ $ $ $8.96 Linden $ $ $ $ $7.12 Oak $ $ $ $ $6.82 Dawn redwood $ $ $ $ $6.46 Buckeye $ $ $ $ $6.43 Hardy rubbertree $ $ $ $ $6.42 Sassafras $ $ $ $ $5.83 OTHER TREES $ $ $ $ $4.81 CEMETERY TOTAL $ $1, $ $1, $8.91 Avoided VOC (lb) Avoided SO2 (lb) Avoided ($) BVOC Emissions (lb) BVOC Emissions ($) (lb) ($) % Tree Number Avg. $/tree 11

13 Table 10. Annual Aesthetic or Other Benefits of Trees by in Greenmount Cemetery. ($) % Tree Numbers % of $ Avg. $/tree Honeylocust $ $68.47 Maple $1, $64.69 Hickory $ $59.73 Poplar $ $57.69 Hardy rubber tree $ $55.09 Hackberry $ $53.24 Black walnut $ $53.12 Sassafras $ $45.12 Buckeye, other $ $39.75 Black locust $2, $39.06 Linden $ $38.12 Ash $ $31.70 Black cherry $ $30.82 Dawn redwood $ $28.70 Oak $ $9.48 OTHER TREES $ $19.64 CEMETERY TOTAL $8, $

14 Table 11. Annual Benefits and Annual Benefits per Tree by Common Name for Greenmount Cemetery Trees Energy CO2 Air Quality Stormwater Aesthetic /Other Hickory $63.20 $8.72 $10.90 $88.78 $59.73 $ Hackberry $68.05 $6.59 $12.12 $83.03 $53.24 $ Black walnut $65.65 $6.24 $10.84 $81.58 $53.12 $ Honeylocust $60.61 $6.00 $10.23 $70.45 $68.47 $ Poplar $57.32 $7.93 $9.34 $70.21 $57.69 $ Maple $49.40 $6.62 $8.96 $51.47 $64.69 $ Ash $55.99 $5.43 $10.05 $66.58 $31.70 $ Black cherry $56.53 $5.37 $10.07 $66.70 $30.82 $ Black locust $52.42 $5.92 $9.06 $53.37 $39.06 $ Hardy rubber tree $38.70 $6.24 $6.42 $34.14 $55.09 $ Oak $48.79 $3.35 $6.82 $66.06 $9.48 $ Buckeye, other $41.52 $4.90 $6.43 $38.94 $39.75 $ Sassafras $35.32 $4.99 $5.83 $38.94 $45.12 $ Dawn redwood $41.84 $4.93 $6.46 $32.21 $28.70 $ Linden $47.91 $6.06 $7.12 $45.01 $38.12 $ OTHER TREES $29.83 $3.42 $4.81 $17.55 $19.64 $

15 Table 12 Environmental Benefits from Five Benefit Categories for Greenmount Cemetery Trees Benefits ($) $/tree Stormwater $11,833 $60.37 Energy $10,364 $52.88 Aesthetic/Other $8,207 $41.87 Air Quality $1,746 $8.91 CO2 $1,139 $5.81 Benefits $33,289 $