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General References

• LEED Certification, US Green Industry Council - Leadership in Energy and Environmental Design (LEED) - http://www.usgbc.org/
• Delaware Valley Green Buildings Council - http://www.dvgbc.org/
• Sustainable Sites Initiative (SSI) - http://www.sustainablesites.org/
• Sustainable Sites Initiative Guidelines and Performance Benchmarks 2009 - www.sustainablesites.org
• Octoraro Native Plant Nursery - see "Related Links" from the homepage for many additional websites www.octoraro.com
• North Creek Nurseries - see "Resources" - from the homepage for many additional websites - http://www.northcreeknurseries.com/
• Pennsylvania Landscape & Nursery Association download PLNA's "White Paper on Green Infrastructure" - http://www.plna.com/?Page+About_Industry
• PLANET, Green Industry ECOnomics, Crystal Ball Report #29 - www.landcarenetwork.org

• Society for Ecological Restoration - http://www.ser.org/ 
• No Child Left Inside - http://www.learningbytheyard.com/
• Sustainable Sites Initiative (SSI) - http://www.sustainablesites.org/
• Meadow establishment & Maintenance - see North Creek Nurseries "Resources" page

• PA Envirothon - http://www.envirothonpa.org/ - see also your local County Conservation District Office (refer below)
• PA Center for Environmental Education - http://www.pcee.org/
• No Child Left Inside - http://www.learningbytheyard.com/
• Stroud Water Research Center - http://www.stroudcenter.org/

• PA Assoc. of Conservation Districts - http://pacd.org/
• USDA / Natural Resources Conservation Services ¡V http://www.nrcs.usda.gov/programs
• USDA Farm Services Agency (FSA) - http://www.fsa.usda.gov/FSA/webapp?area=home&subject=copr&topic=landing
• NRCS Conservation Technical Field Specifications -http://www.nrcs.usda.gov/technical/efotg/
• PA DEP ¡V Stormwater Best Management Practices (BMP) Manual ¡V http://www.depweb.state.pa.us/watershedmgmt/

• "Green Roof Plants - A Resource and Planting Guide" - Ed Snodgrass; available from Timber Press - http://www.timberpress.com/books/
• Green Roofs Association - http://www.greenroofs.org/
• Green Grid Roofing Systems - http://www.greengridroofs.com/
• Live Roof - http://www.liveroof.com/
• PSU Green Roof Research - http://horticulture.psu.edu/cms/greenroofcenter/

• See Government links above for conservation programs for your nursery/farm
• See Native Plants Journal below
• Hurst Biomass Boilers - http://www.hurstboiler.com/biomass_boiler_systems/
• Native Plant Societies - Google or Octoraro Related Links page
• Bayscapes program - http://www.fws.gov/chesapeakebay/bayscapes.htm
• National Wildlife Federation - Garden for Wildlife - http://www.nwf.org/gardenforwildlife/
• American Beauty Native Plants - see Steve Castorani @ North Creek Nurseries - http://www.abnativeplants.com/
• "Plants for Livable Delaware" - http://ag.udel.edu/EXTENSION/horticulture/pdf/PLD.pdf

• Federal Highways (FHWA) - Roadside use of native plants manual http://www.fhwa.dot.gov/environment/handbook.htm
• Enhancing Delaware Highways ¡V Roadside Vegetation & Management http://www.deldot.gov/information/pubs_forms/manuals/edh/index.shtml
• Maryland Reforestation Law - http://www.dnr.state.md.us/forests/programapps/newreforest.asp

• Wild Ones - http://www.for-wild.org/
• Ecological Landscape Contractors Assoc. - http://www.ecolandscaping.org/
• See above PA Stormwater Management Symposium
• Bayscapes program ¡V http://www.fws.gov/chesapeakebay/bayscapes.htm
• Chesapeake Conservation Landscaping Council (CCLC) - http://www.chesapeakelandscape.org/
• Mid-Atlantic Ecological Landscapes Partnership - http://www.maescapes.org/

• Watershed Organizations - PA Organization of Watersheds and Rivers (POWR) - http://pawatersheds.org/
• See links from Octoraro website "Related Links" page

• Native Plants Journal and Annual Resource Guide - http://nativeplants.for.uidaho.edu/
• Brooklyn Botanic Garden Handbooks - http://www.bbg.org/gar2/handbooks/

• "The Rain Garden Planner" Terry Wallace available thru Schiffer Books http://www.schifferbooks.com/newschiffer/book_template.php?isbn=9780764331169
• New Jersey Rain Garden Reference Guide - http://www.npsnj.org/rain_garden_home.htm
• Rain Gardens Templates - http://www.lowimpactdevelopment.org/raingarden_design/index.htm

• Stroud Water Research Center - http://www.stroudcenter.org/
• Conservation Reserve Enhancement Program (CREP) - http://www.fsa.usda.gov/FSA/webapp?area=home&subject=lown&topic=cep
• See TreeVitalize (above)
• Wye Research & Education fact sheets - http://www.riparianbuffers.umd.edu/
• Riparian Buffer Model Ordinances -http://www.epa.gov/nps/ordinance/buffers.htm

• Sustainable Business Network - Philadelphia - http://www.sbnphiladelphia.org/
• Sustainable Philadelphia - http://www.sustainablephiladelphia.com/
• The Natural Step - http://www.naturalstep.org/
• Sustainable Landscapes - University of Delaware - http://ag.udel.edu/udbg/sl/
• Low Impact Development - http://www.lowimpactdevelopment.org /

• Delaware Center for Horticulture - http://www.dehort.org/
• TreeVitalize - http://www.treevitalize.net/
• PA Horticultural Society - Philadelphia Green http://www.pennsylvaniahorticulturalsociety.org/phlgreen/index.html
• Tree-Mendous MD - http://www.dnr.state.md.us/forests/treemendous/
• Carbon Offsets - http://carbonfund.org

Similarly, a study of office conditions by the U.S. Army Corps of Engineers found that productivity, employee attitudes and perceptions were positively correlated with the amount of plants in the work place. The most negative employee response was found in an office setting with no plants, an improved employee response was found in a setting with a moderate number of plants, and the highest positive response was in an office with many plants. (Larson et al., 1998).

View with Plants Boosts Satisfaction

A European study of employee satisfaction looked at three variables connected with windows: The general illumination levels, sunlight penetration and the view through the window. The study found that sunlight penetration and a view of natural elements (trees, vegetation, plants and foliage) had a positive impact on employee job satisfaction and morale. The general illumination level provided by the window was found to have no impact (Leather, Pyrgas, Beale, & Lawrence, 1998).

Plants Reduce Illness and Fatique

As Kaplan and Kaplan found in their study of employees, Fjeld, Veiersted, Sandvik, Riise, and Levy (1998) from the University of Norway horticulture department found that plants in the workplace actually reduced reported symptoms of illness and fatigue 23 percent to 30 percent in a controlled study of office environments with and without plants.

Plants Reduce Absenteeism

Researcher Roger Ulrich (1984) found positive changes in medical outcomes resulting directly from people being able to see plants. Ulrich compared the hospital records of patients recovering from gall bladder surgery in a suburban Philadelphia hospital and found those with a view of a group of trees spent less time in the hospital than those looking out at a brick wall (7.96 days vs. 8.70 days). Equally important: the patients required fewer and less potent drugs to remain comfortable.

Translating that into economic terms, a University Of Michigan study found that average cost of the last day of stay for a hospital patient was $432 (Taheri et al, 2000) Assuming that the average reduction in hospital stays could be reduced by 0.74 days as in the Ulrich study and the annual number of hospital discharges was 34.9 million in the U.S. in 2006 (DeFrances, et al, 2008), that would equate to a potential savings of over $11 billion over a year to the U.S. healthcare system, insurers and individuals.

Breast Cancer Recovery Improved

A study of breast cancer patients used walks and other exposure to the natural environment for 120 minutes per week before and after breast cancer surgery to help women maintain and regain their mental and emotional strength (Cimprich & Ronis, 2003). The study found that the group having the exposure to the natural environment was significantly better than the control group, which had no such exposure, even after controlling for other variables such as age, education and other health problems.

Higher Bone Density

A University of Arkansas study found that women age 50 and older who gardened at least once a week had higher bone density than those who jogged, walked, swam or did aerobics. Lori Turner, assistant professor of health sciences at the university, says weight-bearing exercise is known to help women maintain healthy bones. According to Turner (2001), "being outside also gives bones an extra boost from the Vitamin D derived from sunlight.”

Healthier Hearts

The American Heart Association (AHA) recommends 30–60 minutes of aerobic exercise three to four times per week to promote cardiovascular fitness. The National Institute of Health (NIH) recommends that adults accumulate at least 30 minutes of moderate activity most days of the week. Moderate activities include pleasure walking, climbing stairs, gardening, yard work, moderate to heavy housework, dancing and home exercise. Regular physical activity reduces the risk of dying prematurely from cardiovascular disease. Gallup Polls put gardening as the No. 1 adult leisure-time activity.

Regular gardening, like other moderate physical activities, offers a list of short- and long-term health benefits. A some of the more important benefits:

Gardening as Exercise.

Short-Term Benefits
More energy and stamina, stronger bones and muscles, cope more easily with daily stress, be less preoccupied with your weight, relax and sleep more soundly.

Long-Term Benefits
Reduced risk of: high blood pressure, heart disease, stroke, obesity, adult-onset diabetes, osteoporosis, depression, colon-cancer. Increased likelihood of continued independent living in later life

Dutch researchers (Maas, Verheij, Groenewegen, de Vries, & Spreeuwenberg,, 2006) found a strong tie between general public health in an area and the amount of green space in that environment. Not only was there a strong correlation between greenery and the health of residents in an area, but the more urbanized an area, the greater the impact green space had on the general health of the population in that area.Finally, in an article summarizing what we know about the interaction between human health and the natural world, a team of health scientists from Deakin University in Melbourne, Australia wrote:

Natural areas can be seen as one of our most vital health resources. In the context of the growing worldwide mental illness burden of disease, contact with nature may offer an affordable, accessible and equitable choice in tackling the imminent epidemic, within both preventative and restorative public health strategies. (Maller et al., 2005)

 A summary of evidence supporting the assertion that contact with nature promotes health and well-being.

Mayor Richard Daley of Chicago poured millions into making Chicago the "Greenest City in America.” But his claim is more than hype. For years, Daley has invested in the positive impact of planting trees in neighborhoods, putting perennial gardens in industrial areas and changing out the "color” in planters and street median plantings three times a season.

Why Chicago Invests in Plants

Several years ago, PLNA president Gregg Robertson was on a tour of Chicago with the then just retired director of the city’s Bureau of Forestry, Robert Benjamin. The Chicago Bureau of Forestry has responsibility for all things green in Chicago. After an impressive tour of an industrial district where street trees, parking-lot median plantings and street-side flower beds were in flower-show condition, Robertson asked him how the city justified spending so much on the city’s green initiatives.

His reply, "Because it lowers crime, the test scores of kids in these neighborhoods go up, and the neighbors take ownership of the streets. In the long run, the city saves money, is a better place to live and attracts business and tourists.”

Green Landscapes Reduce Crime

The data bears out Benjamin’s assertion. A study by University of Illinois, Urbana (Kuo, Bacaicoa, & Sullivan, 1998), found that residents in of Chicago’s Robert Taylor Homes felt safer if the grass was closely maintained and the tree density was increased. This was contrary to police opinions that increased tree density would provide hiding places for criminals and thus make residents feel less safe. In fact, improved landscaping made the residents feel safer.

In another Chicago study by Quo and Stanley (2001), there were dramatically fewer occurrences of crime against both people and property in apartment buildings surrounded by trees and greenery than in nearby identical apartments that were surrounded by barren land. In fact, compared with buildings that had little or no vegetation, buildings with high levels of greenery had 48 percent fewer property crimes and 56 percent fewer violent crimes. Even modest amounts of greenery were associated with lower crime rates. The greener the surroundings, the fewer the number of crimes that occurred.

Clues to Crimnals to Stay Out

Andrea Faber Tayor (2001) conducted a study of children with severe attention deficit disorder to see if the "greenness” of their play area affected their behavior while playing and after playing in that environment. Faber Taylor found that the ADD symptoms were worst in a room without windows, engendering extreme ADD behaviors that lasted for days. On the other hand, green play areas (i.e., those with grass, trees and landscaping) seemed to reduce the ADD behaviors, and the children were reported to be calmer and more focused the day after playing in the green area.

Contact with Nature Supports Healthy Child Development

In a review of the all the studies relating to the impact of nature and landscapes on children, Faber Taylor (2006) concluded that:

Curb appeal. That’s what it’s all about in residential real estate values. Does a home look good from the street and invite people in? If you can’t get prospects in the front door, you can’t sell the house.

And how do you generate curb appeal? Landscaping is one of the keys. Landscaping that is consistent with the tone of the neighborhood and that creates an aura of owner attention and care provides the best return on investment for the homeowner. Landscaping that is properly done can add 10%-15% to the value of a home (Niemiera 2007 and Behe 2005).

Return on Investment

The greatest return on landscaping investments are those features that increase the utility of the home to the homeowner as well as adding aesthetic appeal. Patios, decks and outdoor kitchens, for example, in scale with the home with a view toward the landscaped area of the yard typically offer a high return on dollars invested.

Residential Energy Savings

But beyond resale value, landscaping, particularly trees, provides other economic benefits as well. Properly placed deciduous trees can reduce the summer heat load on a house by 10% to 30%, cutting air-conditioning costs. Additionally, well-placed evergreens can reduce winter heating requirements by a similar percentage, acting as a break against cold winter winds. And as the trees grow and mature, so do the savings.

Economic Value of Trees

And mature trees have intrinsic economic value. While the appraised value of a tree depends on many variables, the Council of Tree & Landscape Appraisers (CTLA) estimates that a mature tree in a residential landscape can have a value of from $1,000 to $10,000.

To a certain extent, some of the same principals that apply to residential landscapes also apply to commercial landscapes in terms the value of the real estate itself. The landscape is a reflection of the owner’s level of care for his property and a proxy for how he maintains his buildings. This not only translates in to increased value at the time of sale, but also produces higher rents and lower vacancy rates over the period of ownership.

Higher Occupancy Rates

According to a study by Professor Joel Goldsteen, at the University of Texas, Arlington, landscape amenities had the highest correlation with occupancies of any other architectural and urban design variables evaluated. His conclusion was "landscaping amenities pay back the developer as evidenced by the higher occupancies (and rents) clearly justifying the investment.” A shopping center in San Diego cites landscaping as the reason for high occupancy and the ability to charge rental rates that are double those of other shopping plazas. The carefully designed project uses landscaping to create a refuge in the midst of a busy shopping area. A Chicago developer points to unique interior landscaping in glass-roofed atriums as a major selling point and reason the building occupancy rates are 21% above the national level.

Shoppers Spend More

But in addition to the real estate value impact, there is also a growing body of research that shows that a well-maintained commercial landscape can have a positive influence on consumer buying behavior in retail shopping areas. In a Wall Street Journal article by Lucinda Harper, entitled "Landscapers Help Spruce Up Main Street,” several revitalization efforts around the nation were cited where landscape was key to creating a sense of community and bolstering the local economy. The city of Valdosta, Georgia, according to Harper, had tried everything from incentives to restoring the facades of buildings only to find that $9 million in landscaping brought shoppers to the district who spend longer periods of time, which in turn, brought more shops.

Most areas adjacent to highways are not now designed with an eye toward increasing biodiversity. As the plant palette that we use in landscapes adjacent to highways narrows, we unwittingly also determine the fate of many species of butterflies and birds that have relied on the native plant communities for their survival. Tallamy has compiled the research that connects plant selection with the wildlife communities that rely on these plants.

Highway development has reduced habitat for many species, but by careful attention to plant selection in the design of adjacent landscapes, we can restore the ecological balance that once existed in these places. The result can be highway landscapes that provide aesthetic value to the traveler as well as environmental value to the butterflies and birds.

Better Use of Adjacent Land

We can achieve the environmental benefits outlined above by more creative and thoughtful use of highway rights-of-way, including road sides, interchange infields and median strips. The land that is a part of our highways is a public resource that is greatly underutilized to provide cleaner air, cleaner water and to reduce net carbon emissions. In the United States, we have an estimated 4 million miles of roads with 60 million acres of right of way, which now is largely managed by mowing and spraying with herbicides as an afterthought and nuisance (Thompson, 2006). Federal transportation policy should incorporate a component that incorporates better use of this resource in new projects and converts existing rights-of-way to improve the ecological services they provide.

In urban areas and along corridors where the right-of–way does not permit development of robust ecological services, projects can be planned in the adjoining neighborhoods, parks and other public spaces to accomplish similar objectives.

Delaware Leads In Green Highway Design

Green roofs, building roofs that actually use living plants as the exposed surface, are very prevalent in Europe, but are just now catching on in the Untied States. Literally any building can be designed with a green roof. The advantages to a green roof are that it can reduce energy use by moderating temperature on the roof and surrounding areas. It also can dramatically reduce storm runoff volume and peak flow rate by holding and releasing stormwater slowly. A green roof can also restore the ecological and aesthetic value of urban open space by replacing a stark conventional roof with a green, softer roof line. Last, a green roof will protect conventional roofing systems, typically doubling the service life of the underlying waterproofing membrane.

As a matter of public policy PLNA recommends that any new public building be designed with an energy-saving, stormwater managing green roof.

Carbon Sequestration

Escalating global temperatures are an increasing concern among climatologists, economists and government officials. Even private sector companies are assessing their vulnerability to increasing temperatures, ocean levels and erratic weather. Two strategies for slowing the rising temperatures involve either reducing the production of green house gases, primarily CO² produced by burning fossil fuels (oil, coal, natural gas) or converting the CO² now in the air to solid or liquid carbon compounds.

The process of converting atmospheric CO² to solid or liquid compounds is called "carbon sequestration.” There are a variety of high tech solutions being explored for sequestering atmospheric CO², such as liquefying it and pumping it underground under high pressure. But probably the simplest, most effective and most efficient way to sequester atmospheric CO² is to let plants do that work for us.

Plants as Carbon Sequestration Machines

Plants are carbon sequestration machines. They take in carbon dioxide from the atmosphere and with energy gained from sunlight through photosynthesis convert the CO² to complex sugar compounds and pure oxygen. The complex sugar compounds are converted further by the plant into cellulose, energy and other molecules required by the plant. The oxygen is expelled as waste.

But some plants do carbon sequestration better than others. Annuals, for example do little carbon sequestration over their life cycle. Once an annual plant dies at the end of the season, its carbon is slowly released back into the atmosphere as natural decomposition processes take over. Perennial grasses, forbs and herbaceous plants do a better job, since their root systems persist in the ground and thereby sequester some carbon year to year, although their tops die back and annually decompose into simpler molecules, including carbon dioxide. In research being conducted in Kansas, deep-rooted prairie grasses, forbs and herbaceous perennials have been found to sequester as much as 1/3 of a ton of carbon per acre per year (Rice, 2002).

Young Trees Most Effective at Sequestering Carbon

One of the most efficient plant systems for sequestering carbon is a young tree. Young trees sequester carbon at a comparatively high rate, converting CO² into wood as they grow. A tree will be a net user of CO² for most of its life as it continues to grow. As a tree matures its will continue to sequester the carbon held in its wood, but its ability to convert CO² slows with its growth. Eventually, when a tree dies, it will release its carbon dioxide back into the atmosphere slowly, if it decays naturally, quickly, if it is burned as fuel, or for a much longer period if it is converted to lumber or furniture.

Highways as Carbon Producers

Highways produce carbon, first by the construction process, but more significantly over time with the carbon dioxide produced by combustion of petroleum-based fuels by the vehicles using the highways.

Table 1. Carbon dioxide emissions from building one lane-mile of urban highway over 50 years

• Construction, building materials, and maintenance: 3,500 tons
• Net congestion relief: -7,000 tons
• Additional vehicle travel on the facility: 90,000 tons
• Induced vehicle travel off the facility: 30,000–100,000 tons
  
  Total: 116,500-186,500 tons
  
  Source: http://www.sightline.org/wp-content/plugins/download-monitor/download.php?id=29   

A mile of highway produces from 2,330 - 3,730 tons per year of CO². Conversely, a healthy tree stores about 13 pounds of carbon annually -- or 2.6 tons per acre each year. An acre of trees absorbs enough CO² over one year to equal the amount produced by driving a car 26,000 miles (Nowak, 1993).

By including trees and meadows of deep-rooted perennial grasses and herbaceous plants as a part of highway design, either within or adjacent to the right-of-way or in areas removed from the project, at least a part of the carbon produced by a highway project can be offset.

Air Quality
 
Beyond the carbon sequestration issue, plants and trees have a positive impact on the air we breathe. As mentioned above, plants produce oxygen as a by-product of their existence in our environment. Its part of that wonderful symbiotic relationship that plants have with animals: plants give off oxygen as a waste product and we need oxygen to survive.

Urban Air Quality

Highways and vehicles produce a plethora of air pollutants. But we are learning that plants and especially trees have a much more positive impact on our air quality than we once realized. Studies (Coder, 1996) have shown the following air quality benefits of urban trees:

• A sixty percent reduction in street level particulates on tree-lined streets vs. streets with no trees;
• Reduction in nitrogen dioxide, sulfur dioxide, carbon monoxide, cadmium, chromium, nickel and lead levels;
• Reduction in noise by up to 50%;

Plants Reduce Energy Use

In addition, trees, plants and lawns have huge impacts on temperatures and energy use, especially in urban areas. A landscape lowers local air temperatures by transpiring water and shading surfaces. Because trees lower air temperatures, shade buildings in the summer, and block winter winds, they can reduce building energy use and cooling costs. The US Forest Service estimates that the evaporation cooling effect from one large tree is equivalent to the cooling produced by ten room-sized air conditioners! In a residential setting, well-placed trees can reduce energy use by 10-30% compared to a similar home on an open lot.