Environmental Benefits Analysis of Public Trees for Chillicothe, Ohio

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1 Environmental Benefits Analysis of Public Trees for Chillicothe, Ohio T. Davis Sydnor and Sakthi Subburayalu School of Environment and Natural Resources And Ann Bonner ODNR Urban Forestry December 4, 2012

2 An Analysis of Tree Benefits for Chillicothe, Ohio Street Trees EXECUTIVE SUMMARY A sample inventory of street trees in the City of Chillicothe, Ohio was conducted by Ohio State University Extension and the Ohio Division of Natural Resources Urban Forestry. A 25% survey yielded 197 trees or an estimated total of 788 municipal trees along the streets were inventoried in the 2011 growing season. A common bid price for this service is $4.00 per inventoried tree and thus the inventory represents a value of $788. 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 Chillicothe. 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 distributed by the USDA Forest Service. The specific program in the itree suite used to identify tree benefits was istreets. This program allows community leaders the ability to make informed decisions about Chillicothe s green infrastructure or to explore many aspects including biodiversity and values of environmental services such that environmental benefits can be managed or enhanced to reduce costs and the community s carbon footprint. A long standing rule of thumb for taxonomic biodiversity in the urban forest is the 10:20:30 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 Chillicothe, maple trees exceed genus and family guidelines (Table 1). While pears do not exceed biodiversity guideline they are seriously invasive. We recommend against any further plantings of maples or pears to retain diversity and protect against invasive exotic pests. Ash are a separate issue due to emerald ash borer (EAB) and represent an estimated 3 time 4 or 12 individuals or 1.5 % of the public trees and 1.4 of the canopy (Table 4). This represents a minor loss of Chillicothe s canopy if EAB should destroy all American ashes as predicted. Based on the inventory and estimates, ash removal costs in Chillicothe would likely exceed $14,000. Replacement costs add another $3,780 more for a grand total of $17,480. Ash removal and/or treatment costs will need to be addressed by informed community leaders. Ohio State University Extension or Ohio s Division of Forestry can assist in developing informed plans including costs and probabilities of various treatment options vs. no treatment. There is no single answer for communities facing this problem but informed decisions are needed. Larger growing deciduous trees now constitute more than75% or less of Chillicothe s tree canopy and should be used to replace the ashes. Native suggestions might include Kentucky coffeetree; Shumard, swamp white, and chinquapin oaks; American sycamore; buckeye; basswood; catalpa; and sweetgum. Introduced species can be used as well if desired. Under ideal situations tree numbers among various size classes should be similar and then decline as trees reach their mature size and older trees die. Maples represent nearly 58% of the inventory (Tables 2 and 3). Maples are generally mature to over mature and will likely begin to decline if that has not already begun. The limited numbers of smaller trees suggest the need for an ongoing planting program to replace declining trees in a managed fashion. Canopy cover percentages are consistent with their importance value (Table 4). Smaller growing crabapples and cherries (plums) generally produce fewer benefits per tree than their larger growing counterparts. This reinforces the need for planting larger statured trees such as preferred in a Toledo, OH resident preference survey. 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 Ohio communities. Columbus, OH is embarking on a multi-billion dollar sewer and storm water upgrade for the community. Putting that into a local context, 25% of Chillicothe public trees intercept more than 500,000 2

3 gallons of storm water annually at a savings to the community of more than $13,500 dollars per year. This could be could be increased with strategic planting of larger-statured trees in areas with adequate space to grow. Carbon sequestration, as reported here, represents the carbon removed from the air and stored in the trees over time (Table 6). Nearly 1.9 million pounds or 950 tons of carbon have been stored by the 197 trees sampled over time. In aggregate, Chillicothe s trees are estimated to sequester and avoid nearly 700,000 pounds of CO 2 annually (Table 8) and would represent carbon credits worth $5 thousand per year if a carbon trading system were in place. These are net gain figures and include deductions for tree losses and maintenance. Annual CO 2 benefits vary by species and size but average $6.64 per tree per year while larger silver maples and basswoods remove approximately $14 per tree per year. Strategic plantings could increase this over time and become a significant tool in reducing Chillicothe s carbon footprint if desired. 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). Twenty-five percent of Chillicothe trees save the community $3,300 in electricity and $5,800 in natural gas for a total savings of $9,100. This averages more than $46 per tree per year. Retaining larger trees, where possible, will enhance energy savings at the community level in time. Annual air quality savings (reduced ozone, nitrous and sulfur oxides as well as particulate matter) for the 25% of the trees sampled is nearly $1,550 (Table 9). This includes both direct savings ($400) and avoided pollution which is much greater at $1,300. Avoided pollution is pollution not generated at a power source because energy was not required (avoided) by the community. The total annual air quality benefits are discounted by $168 for the volatile emissions (BVOC) generated by the trees themselves. Aesthetic and miscellaneous benefits from 25% of Chillicothe s trees contribute $10,300 annually in the form of increased recreational opportunities, increased property values, and enhanced community identity 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 in such an environment. When all annual benefits are included the 197 trees that were sampled contribute an average of 182 per tree annually to the community (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 Chillicothe s trees. The Chillicothe budget for trees maintenance was estimated to be $174,000 based on the budget of $2.00 per capita required for Tree City USA status by the National Arbor Day Foundation and Chillicothe s population of 21,797 people. Thus the sampled (197 trees) require relatively little care per year they deliver $35,900 in annual benefits from storm water abatement, carbon sequestration, energy savings, air quality enhancement, aesthetic benefits, and the like. Thus the estimated 788 trees in Chillicothe would deliver a total of more than $143,500 in annual benefits. This is an 83% return on investment. Returns appear low relative to other communities of similar size as Ohio communities studied routinely discover returns on their tree maintenance dollars of 2-300% and Toledo had a 436% annual return with one of the larger tree maintenance budgets in Ohio. This could be dramatically increased if a planting program was initiated as Chillicothe has less than 1 tree per 20 residents while Dublin and Westerville have between 0.5 to 1 trees per resident. Further, unlike most community infrastructure, annual tree benefits per tree continue to increase over a tree s lifetime as younger trees increase in size over time. 3

4 Table 1. Distribution of the Most Common Trees in Chillicothe, Ohio Arranged from Most to Least Commonly Seen Percent Sugar maple Silver maple Freeman maple 6.09 Tulip tree 5.08 Flowering plum 4.06 Flowering crabapple 3.55 Plum 3.55 Callery pear 3.05 Black maple 2.03 Norway maple 2.03 OTHER SPECIES

5 Table 2. Relative Age Distribution of the 10 Most Commonly Planted Trees in Chillicothe, Ohio as a Percentage (%) of each Tree by Common Names DBH class (in) >42 Sugar maple Silver maple Freeman maple Tulip tree Flowering plum Flowering crabapple Plum Callery pear Black maple Norway maple Citywide total

6 Table 3. Population of Chillicothe Public Trees by Common Name, Tree Type and Size (DBH) Class. DBH Class (in) >42 Broadleaf Deciduous Large (BDL) Sugar maple Silver maple Freeman maple Tulip tree Black maple American basswood American elm Red maple Tree of heaven Black walnut London planetree Maple White ash Sweetgum Cottonwood Shumard oak Broadleaf Deciduous Medium (BDM) Callery pear Norway maple Goldenraintree Ash White mulberry Siberian elm Broadleaf Deciduous Small (BDS) Flowering plum Flowering crabapple Plum Flowering dogwood Amur maple European smoketree Eastern hophornbeam

7 DBH Class (in) >42 Conifer Evergreen Large (CEL) Norway spruce Chillicothe Sample

8 Table 3A Estimated Expenses for Ash Removal and/or Replacement of Chillicothe Public Trees due to Emerald Ash Borer Based on a 25% Sample SIZE NUMBER REMOVAL COSTS PER TREE REMOVAL TOTALS REPLACEMENT COSTS REMOVAL WITH REPLACEMENT $100 $0 $200 $ $375 $0 $290 $ $375 $0 $290 $ $675 $5,400 $290 $7, $675 $0 $290 $ $1,290 $0 $290 $ $1,625 $0 $290 $ $2,150 $8,600 $290 $9,760 >42 0 $2,150 $0 $290 $0 TOTALS 12 REMOVAL ONLY COSTS $14,000 REMOVAL & REPLACEMENT $17,480 8

9 Table 4. Chillicothe, Ohio Public Trees Listed by Common Name from Greatest to Least Importance Value. Number of Trees % of Trees Leaf Area (ft2) % Leaf Area Canopy Cover (ft2) % Canopy Cover Importance Value Sugar maple Silver maple American elm American basswood Freeman maple Black maple Tulip tree Black walnut Flowering plum Siberian elm Red maple Norway maple Plum Callery pear Ash Flowering crabapple White mulberry Tree of heaven Goldenraintree London planetree Flowering dogwood OTHER TREES

10 Table 5. Annual Storm Water Benefits for 20% Sample of Chillicothe, Ohio Trees by Ordered by Decreasing Benefits/Tree. Rainfall Interception (Gal) % Tree Numbers % of $ Avg. $/tree Silver maple 152,239 $4, $ Siberian elm 9,134 $ $ American elm 18,203 $ $ American basswood 18,131 $ $ Sugar maple 235,117 $6, $95.11 Black walnut 8,721 $ $78.78 Black maple 11,467 $ $77.70 White mulberry 5,312 $ $71.98 Red maple 7,337 $ $66.29 Ash 6,582 $ $59.46 Norway maple 6,130 $ $41.53 Tree of heaven 4,191 $ $37.87 Callery pear 2,669 $ $12.06 Goldenraintree 1,251 $ $8.48 Flowering dogwood 529 $ $7.17 London planetree 709 $ $6.41 Freeman maple 2,395 $ $5.41 Plum 1,264 $ $4.89 Flowering plum 1,271 $ $4.31 Tulip tree 191 $ $0.52 Flowering crabapple 52 $ $0.20 OTHER STREET TREES 8,623 $ $25.97 SAMPLE TOTAL 501,519 $13, $

11 Table 6. Stored CO 2 Benefits in 25% of Public Trees in Chillicothe, OH by Ordered by Decreasing CO2 Stored stored CO2 (lbs.) % Tree Numbers % of $ Avg. $/tree American basswood 101,235 $ $ American elm 94,691 $ $ Siberian elm 39,456 $ $ Silver maple 586,934 $4, $ Sugar maple 895,738 $6, $ Black maple 31,781 $ $59.59 Black walnut 22,025 $ $55.06 Ash 21,528 $ $53.82 White mulberry 13,153 $ $49.32 Red maple 19,515 $ $48.79 Norway maple 18,092 $ $33.92 Tree of heaven 8,349 $ $20.87 Flowering dogwood 1,816 $ $6.81 Callery pear 4,840 $ $6.05 Plum 4,165 $ $4.46 Goldenraintree 2,093 $ $3.93 Flowering plum 4,179 $ $3.92 London planetree 1,398 $ $3.49 Freeman maple 1,815 $ $1.13 Tulip tree 299 $ $0.22 Flowering crabapple 96 $ $0.10 OTHER STREET TREES 9,566 $ $17.57 SAMPLE TOTAL 1,894,288 $14, $

12 Table 7. Annual Energy Benefits of Chillicothe Public Trees by Common Name and Decreasing Energy Benefits per Tree Electricity (MWh) Electricity Natural Gas (Therms) Natural Gas % Tree Numbers % of $ Avg. $/tree American elm 1.9 $ $247 $ $98.30 Siberian elm 0.8 $ $104 $ $82.09 American basswood 1.4 $ $196 $ $75.16 Silver maple 10.4 $ $1,323 $2, $70.47 Sugar maple 20.4 $1, $2,710 $4, $63.50 Black walnut 0.9 $ $120 $ $62.98 Black maple 1.1 $ $156 $ $60.68 Red maple 0.8 $ $108 $ $56.77 Ash 0.8 $ $104 $ $54.80 White mulberry 0.5 $ $66 $ $52.11 Norway maple 0.7 $ $111 $ $41.58 Tree of heaven 0.6 $ $67 $ $37.33 Callery pear 0.5 $ $78 $ $19.31 Flowering dogwood 0.1 $ $25 $ $18.19 Plum 0.4 $ $61 $ $12.71 Flowering plum 0.4 $ $62 $ $11.23 London planetree 0.1 $ $22 $ $11.20 Goldenraintree 0.2 $ $28 $ $10.65 Freeman maple 0.3 $ $45 $ $5.79 Tulip tree 0.1 $4 9.1 $9 $ $1.29 Flowering crabapple 0.0 $2 4.4 $4 $ $0.87 OTHER STREET TREES 1.2 $ $147 $ $26.18 SAMPLE TOTAL 43.6 $3, $5,795 $9, $

13 Table 8. Annual Carbon Dioxide Benefits of Chillicothe, Ohio Trees by Common Name and Ordered by Decreasing Benefits per Tree Sequestered (lb) Sequestered Decomp Release(lb) Maint Release (lb) Release Avoided (lb) Avoided Net (lb) % of Tree Numbers Silver maple $ $ $ $ $14.45 American basswood 5481 $ $ $ $ $13.67 Siberian elm 1593 $ $ $ $ $10.20 American elm 2389 $ $ $ $ $9.64 Sugar maple $ $ $ $ $8.54 Red maple 1407 $ $ $ $ $6.73 Black walnut 1018 $ $ $ $ $6.09 Tree of heaven 1322 $ $ $ $ $5.65 Ash 772 $ $ $ $ $4.97 Norway maple 1388 $ $ $ $ $4.73 White mulberry 201 $ $ $ $ $3.65 Black maple 0 $ $ $ $ $3.27 Callery pear 1087 $ $ $ $ $2.36 Flowering dogwood 228 $ $ $ $ $1.74 Goldenraintree 423 $ $ $ $ $1.38 Plum 569 $ $ $ $ $1.23 Flowering plum 578 $ $ $ $ $1.09 London planetree 187 $ $ $ $ $1.06 Freeman maple 662 $ $ $ $ $0.74 Tulip tree 65 $ $ $ $ $0.11 Flowering crabapple 61 $ $ $ $ $0.10 OTHER STREET TREES 1325 $ $ $ $ $2.64 SAMPLE TOTAL $ $ $ $1, $6.64 % of $ Avg. $/tree

14 Table 9. Annual Air Quality Benefits of Chillicothe, Ohio Trees by Common Names and Ordered by Decreasing Air Pollution Benefits per Public Tree Deposition O3 (lb) Deposition NO2 (lb) Deposition PM10 (lb) Deposition SO2 (lb) Deposition Avoided NO2 (lb) Avoided PM10 (lb) Avoided VOC (lb) Avoided SO2 (lb) Avoided BVOC Emissions (lb) BVOC Emissions (lb) % Tree Numbers Avg. $/tree American elm $ $ $ $ $20.45 Siberian elm $ $ $ $ $16.11 Silver maple $ $ $ $ $13.25 American basswood $ $ $ $ $11.88 Black maple $ $ $ $ $11.54 Red maple $ $ $ $ $10.61 Black walnut $ $ $ $ $10.59 Sugar maple $ $ $ $ $10.18 Ash $ $ $ $ $9.81 White mulberry $ $ $ $ $8.58 Norway maple $ $ $ $ $6.81 Tree of heaven $ $ $ $ $5.93 Callery pear $ $ $ $ $2.72 Flowering dogwood $ $ $ $ $2.55 Plum $ $ $ $ $1.76 Flowering plum $ $ $ $ $1.55 Goldenraintree $ $ $ $ $1.54 London planetree $ $ $ $ $1.49 Freeman maple $ $ $ $ $0.77 Tulip tree $ $ $ $ $0.16 Flowering crabapple $ $ $ $ $0.11 OTHER STREET TREES $ $ $ $ $4.19 SAMPLE TOTAL $ $1, $ $1, $

15 Table 10. Annual Aesthetic or Other Benefits of Public Trees by in Chillicothe, Ohio % of Tree Numbers % of $ Avg. $/tree Silver maple $3, $ American basswood $ $92.62 American elm $ $77.00 Sugar maple $4, $71.84 Red maple $ $58.32 Black walnut $ $50.72 Siberian elm $ $50.67 Tree of heaven $ $49.42 Norway maple $ $34.64 Ash $ $26.11 Callery pear $ $21.78 Freeman maple $ $18.53 Goldenraintree $ $16.91 White mulberry $ $15.74 London planetree $ $7.23 Flowering dogwood $ $6.40 Plum $ $4.54 Flowering plum $ $3.98 Tulip tree $ $2.03 Flowering crabapple $ $0.03 Black maple $ $0.00 OTHER STREET TREES $ $15.66 CITYWIDE TOTAL $10, $52.43

16 Table 11. Annual Benefits per Sector and Annual Benefits per Tree by Decreasing Benefits for Chillicothe Public Trees Energy CO2 Air Quality Stormwater Aesthetic/Other Silver maple $70.47 $14.45 $13.25 $ $ $ American elm $98.30 $9.64 $20.45 $ $77.00 $ American basswood $75.16 $13.67 $11.88 $ $92.62 $ Siberian elm $82.09 $10.20 $16.11 $ $50.67 $ Sugar maple $63.50 $8.54 $10.18 $95.11 $71.84 $ Black walnut $62.98 $6.09 $10.59 $78.78 $50.72 $ Red maple $56.77 $6.73 $10.61 $66.29 $58.32 $ Ash $54.80 $4.97 $9.81 $59.46 $26.11 $ Black maple $60.68 $3.27 $11.54 $77.70 $0.00 $ White mulberry $52.11 $3.65 $8.58 $71.98 $15.74 $ Tree of heaven $37.33 $5.65 $5.93 $37.87 $49.42 $ Norway maple $41.58 $4.73 $6.81 $41.53 $34.64 $ Callery pear $19.31 $2.36 $2.72 $12.06 $21.78 $58.22 Goldenraintree $10.65 $1.38 $1.54 $8.48 $16.91 $38.95 Flowering dogwood $18.19 $1.74 $2.55 $7.17 $6.40 $36.05 Freeman maple $5.79 $0.74 $0.77 $5.41 $18.53 $31.23 London planetree $11.20 $1.06 $1.49 $6.41 $7.23 $27.39 Plum $12.71 $1.23 $1.76 $4.89 $4.54 $25.14 Flowering plum $11.23 $1.09 $1.55 $4.31 $3.98 $22.16 Tulip tree $1.29 $0.11 $0.16 $0.52 $2.03 $4.11 Flowering crabapple $0.87 $0.10 $0.11 $0.20 $0.03 $1.31 OTHER STREET TREES $26.18 $2.64 $4.19 $25.97 $15.66 $

17 Table 12 Environmental Benefits from Five Categories for Chillicothe Trees Adjusted to Estimated Benefits $/tree Stormwater $13,592 $68.99 Aesthetic/Other $10,330 $52.44 Energy $9,106 $46.22 Air Quality $1,548 $7.86 CO2 $1,307 $6.63 Benefits $35,883 $