benefits of urban trees

8/11/2019 Benefits of Urban Trees

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Urban andCommunity

Forestry: Improving Our QualityOf Life

Urban andCommunity

Forestry: Improving Our QualityOf Life

United StatesDepartment ofAgricultureSouthern Region



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I thinkthat I shall

never see

a poem

lovely as a tree.These words by American poet Joyce Kilmer capture thelove most people share for trees. This sentiment may be

especially appropriate in urban areas where trees are particularlynoticeable and play critical roles in the quality of life.

Trees are also major capital assets in our cities and towns –as much an integral part of the scene as streets, sidewalks,and buildings -- they represent a major component of the

"green infrastructure."



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Trees are not only beautiful inthemselves but add beauty totheir surroundings. Trees addcolor to the urban scene, softenthe harsh lines of buildings,screen unsightly views,provide privacy and a sense of solitude and security, whilecontributing to the generalcharacter and sense of place incommunities.

Beyond aesthetics andemotional well-being, treesperform important functionsthat protect and enhance citydwellers’ health and property.Trees literally clean the air byabsorbing air pollutants andreleasing oxygen. They reducestormwater runoff and ero-sion; they temper climate; theycan save energy; they createwildlife habitat; they canimprove health, serve asscreens, and strengthencommunity. They can evenhelp contribute to a communi-ty’s economy and way of life.

What Trees DoWHAT TREES D O

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Air pollution is the bane of most cities and many towns.At its worst, it can be seen andsmelled and even felt. Sincethe emission of many air pol-lutants increases with highertemperatures, trees canimprove air quality by lower-ing air temperatures. Trees fur-ther their cleansing work byabsorbing gaseous pollutantsinto their leaves and trappingand filtering particulates onand through their leaves,

stems, and twigs. Trees havethe potential to impact pollu-tants emitted from powerplants by shading buildingsand lowering air temperaturesin the summer and blockingwinds in the winter, whichreduces the use of energy forair conditioning and heating. If trees shade a parking lot, theycan also reduce pollutantsemitted from vehicles.

TREES IMPROVE AIR Q UALITY

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Trees influence the flow of water in several ways. Theirleafy canopy catches precipita-tion before it reaches theground, allowing some of it togently drip and the rest toevaporate. This interceptionlessens the force of storms andreduces runoff and erosion.Research indicates that 100mature trees intercept about100,000 gallons of rainfall peryear in their crowns, reducingrunoff and providing cleaner

water. Tree roots also hold soilin place. Decaying leaves forman organic layer on the groundthat allows water to percolateinto the soil, which alsoreduces runoff and soil ero-sion. All of this helps reduceflooding in the streets andsedimentation in streams.

TREES REDUCESTORMWATER RUNOFF AND EROSION

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Trees modify local climate,chiefly by lowering air temper-ature and increasing humidity;they can also influence windspeed and reduce glare. Innercities are commonly known as"heat islands" because the buildings and pavementabsorb solar energy andradiate it back. Trees liningstreets or near buildingsprovide shade that can reducethe heat-island effect, lesseningthe amount of air conditioning

needed. Evaporation of waterfrom trees through thetranspiration process also hasa cooling effect, especially inhot climates or seasons.

TREES TEMPER LOCAL CLIMATE

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Daytime thermal temperatures inAtlanta, Georgia (Central Business

District) in 1997 (courtesy of NationalAeronautics and Space

Administration)



In addition to reducing theheat island effect, communitytrees can conserve energy withtheir shading and evapotran-spiration effect. For example,three or more large treesstrategically placed on sunnysides of a house shade it fromthe hot summer sun, thusreducing the air-conditioningcost as much as 30 percent.Deciduous trees are best forthis use because they lose theirleaves in winter, exposing the

house to the warming wintersun, which lowers the energyneeded to heat the house.Coniferous trees, because theyretain their needles year-round, make fine screens andserve well as windbreakswhen placed in the path of theprevailing winds, usually thenorth and northwest sides.These trees can also reduceenergy use in a house byshielding it from the mostsevere cold.

These energy savings, spread

over many houses and manyneighborhoods, can reduce thedemand for power production by utility plants, which in turn

reduces the air pollutantsproduced by these plants.

TREESCONSERVE ENERGY

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Community trees providesubtle but real economic benefits. The value of houseson lots with trees is usuallyhigher than those of compara- ble houses on lots withouttrees. Studies have shown thatshoppers linger longer along ashaded avenue than on one barren of trees. Shadedthoroughfares are not onlymore physically comfortable but also psychologically moreattractive. And an abundance

of trees "says something"about a community thatmakes it more appealing tonewcomers as well asresidents. In addition toenhancing the home and

business environment in anurban area, recreation areassuch as parks, greenways, andriver corridors that are wellstocked with trees tend to keeprecreation seekers "at home"rather than driving manymiles to find suitable places toplay. Here again, less fuel isused and less pollution creat-ed. It would be difficult to puta dollar value on such urbanplaygrounds, but if each visitwere valued at only one dollar,

the total for the typical citywould be in the thousands of dollars per year.

TREES AREGOOD FOR THE ECONOMY

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Wherever trees are established,

wildlife and other plants aresure to follow. Trees and asso-ciated plants provide shelterand food for a variety of birdsand small animals. The pres-ence of trees creates an envi-ronment that allows thegrowth of plants that other-wise would not be there,enhancing the diversity. Again,the monetary value of suchdiversity is incalculable, but itis well known that residents of and visitors to a communityappreciate and enjoy it. Simplyput, the presence of trees cre-ates an environment that ismuch more pleasant for living,working, and playing.

TREES CREATEHABITAT FOR PLANTS AND ANIMALS

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Densely planted rows of treesaround homes and buildingsand along streets and roadscan serve as screens to pre-

serve privacy and shut outunwanted or unsightly views.Wide belts of such plantingscan also help to muffle sound.

TREES IMPROVE H EALTH

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The health benefits of cleanerair and water are self-evident.But it is also known that greenenvironments reduce stress inpeople, making them moreproductive at work and happi-er at home. Trees and their

associated vegetation have arelaxing effect on humans, giv-ing them a general feeling of calmness and well-being.

Among those who benefit fromthe proximity of trees are hos-

pital patients. Studies showthat patients with a windowview of greenery recover fasterand suffer fewer complicationsand medications that thosewithout such views. Further,children with Attention DeficitDisorder (ADD) were foundto have better behavior ingreen environments. Thepresence of trees and othervegetation seems to have asoothing effect that tempersexcessive behavior.

TREES SERVE AS SCREENS



A stronger sense of communi-ty, an empowerment of inner-city residents to improveneighborhood conditions, andthe promotion of environmen-tal responsibility and ethicscan be attributed to involve-ment in urban forestry efforts.Active involvement in tree-planting programs enhances acommunity’s sense of socialidentity, self-esteem, and own-ership; it teaches residents thatthey can work together to

choose and control the condi-tion of their environment.Planting programs also projecta visible sign of change andprovide the impetus for othercommunity renewal andaction programs. Several stud-ies show that participation intree-planting programs influ-ences individuals’ perceptionsof their community.Conversely, a loss of treeswithin a community can havesignificant psychological effecton residents.

TREES PROMOTE COMMUNITY

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Cities and towns make harshenvironments for trees, so wemust give them special careand protection. Establishingand maintaining communitytrees and forests can be chal-lenging and costly, but the benefits described here arewell worth the time, trouble,and money spent. Trees inurban settings often need to beprotected, planted (or trans-

planted), and tended. This is both an individual and com-munity responsibility.

In addition to looking after thetrees where you live, you canlearn about and become

involved in the managementof the trees along your city’sstreets, parks and recreationareas. The wrong species orplacement of trees, whetheraround a private home orcommercial building or onpublic land, can mean wastedmoney and effort as well asdefeating the purpose of theplanting. Citizen input intosuch decisions is important.You can get involved at thelocal level in a range of activi-ties. Organizations that canhelp you get started are listedon the next few pages. Also,visit this web site for a list of organizations and resources inthe State where you live:http://www.treelink.org/docs/states.phtml.

WHAT YOU CAN D O

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Other Sources of AssistanceUSDA Forest Service,Urban & CommunityForestry Centers

Southern Center for Urban ForestryResearch and Information

USDA Forest Service – SouthernResearch Station and Southern Region320 Green StreetAthens, GA 30602-2044Phone 706-559-4236Fax 706-559-4266Web www.urbanforestrysouth.usda.gov

Southern Center forWildland-Urban InterfaceUSDA Forest Service – Southern

Research Station and Southern RegionSeagle Building408 West University Ave., Suite 306Gainesville, FL 32601Phone 352-376-3213Fax 352-376-4536Web www.interfacesouth.usda.gov

Center for Urban Forest ResearchUSDA Forest ServicePSW Research Stationc/o Department of EnvironmentalHorticultureOne Shields AvenueDavis, CA 95616-8587Phone 530-752-7636Fax 530-752-6634Web wcufre.ucdavis.edu

Mid-Atlantic Center for Urban andCommunity ForestryUSDA Forest Service, Northeastern AreaKeystone CollegePO Box 1466La Plume, PA 18440-1099Phone 570-945-8095Fax 570-945-8096Web www.fs.fed.us/na/morgantown/macucf/index.htm

Midwest Center for Urban andCommunity ForestryUSDA Forest Service, Northeastern Area1992 Folwell AvenueSt. Paul, MN 55108Phone 651-649-5253

Fax 651-649-5238Web www.na.fs.fed.us/spfo/urban-forestry/ucf.htm

National Agroforestry CenterUSDA Forest Service – NACEast Campus UNLLincoln, NE 68583-0822Phone 402-437-5178 ext 24Fax 402-437-5712

Web www.unl.edu/nac/

FOR ADDITIONAL INFORMATION

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Contact the office listed below:



Northeast Center for Urban ForestryUSDA Forest Service, Northeastern AreaHoldsworth Natural Resources CenterUniversity of MassachusettsAmherst, MA 01003-4201Phone 413-545-3755Fax 413-545-4358Web www.umass.edu/urbantree/

USDA Forest Service,Urban and CommunityForestry Research WorkUnits

Center for Urban Forest ResearchUSDA Forest ServicePSW Research Stationc/o Department of EnvironmentalHorticulture

One Shields AvenueDavis, CA 95616-8587Phone 530-752-7636Fax 530-752-6634Web wcufre.ucdavis.edu/

Effects of Urban Forests and TheirManagement on Human Health andEnvironmental QualityUSDA Forest Service, NortheasternResearch Stationc/o SUNY-ESF, 5 Moon LibrarySyracuse, NY 13210-2778Phone 315-448-3200Web www.fs.fed.us/ne/syracuse

Managing Forest Environments forUrban PopulationsUSDA Forest Service, North CentralResearch StationForestry Sciences Laboratory1033 University Place, Suite 360Evanston, IL 60201Phone 847-866-9311Fax 847-866-9506Web www.ncrs.fs.fed.us/4902/

Recreation, Wilderness, Urban Forest,and Demographic Trends ResearchUSDA Forest Service,Southern Research Station320 Green StreetAthens, GA 30602Phone 706-559-4264Fax 706-559-4266Web www.srs.fs.fed.us/trends/

Southern Regional ExtensionForestry

Southern Regional ExtensionForestryThe University of Georgia4-433 Forest Resources

Building

Athens, GA 30602Phone 706-542-7813Fax 706-542-3342Web www.soforext.netWeb www.forestryindex.net

Southern Group of State Foresters

Southern Group of State

ForestersP.O. Box 930Winder, GA 30680

Phone 770-868-0337Fax 770-920-1661Web www.southernforests.org/

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Never doubt that a small group

of thoughtful, committed

citizens

can change the world.

Indeed,it is the only thing

that ever has.- Margaret Mead

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The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activ-ities on the basis of race, color, national origin, sex, religion, age, disability, political beliefs, sexualorientation, and marital or family status. (Not all prohibited bases apply to all programs.) Personswith disabilities who require alternative means for communication of program information(Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600(voice and TDD).To file a complaint of discrimination write USDA, Director, Office of Civil Rights, Room 326-W,Whitten Building, 14th and Independence Avenue, SW, Washington, DC 20250-9410 or call (202)720-5964 (voice or TDD). USDA is an equal opportunity provider and employer.

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