Princeton University
OP-9: Landscape Management

The footprint of impervious land is 210 acres.

We have two zones of inspections: the main campus is inspected in-house and the east and west sides by Bartlett Trees Experts. Our objective is to use cultural practices, good plants selection and soil remediation to have healthier plant material and therefore plants that can tolerate pests. Aspects of the plan include using the least toxic chemical pesticides; minimum use of chemicals; use of chemicals only in targeted locations and only for targeted species; and biological control through the release of beneficial insects (e.g. ladybugs) and larvae (e.g. greenlacewig larvae)

Princeton embraces the opportunity to integrate the campus more fully into the local natural landscape through restoration efforts and natural plantings. Robust natural landscapes provide pervious surfaces, thereby improving groundwater recharge, preventing soil and stream bank erosion, and protecting nearby surface waters. Since the first Sustainability Plan in 2008, the University has undergone a series of design improvements, such as strategic woodland plantings in degraded areas and stream restoration. Historically, Princeton has irrigated minimally on campus, instead relying on robust plantings that require little maintenance, chemical input, and watering. This approach is a historically sustainable one, requiring far less fossil fuel input than extensive annual or sensitive specialty plantings. While limited specialty plantings are an integral part of the campus character, Princeton will maintain its traditional approach to general landscaping. Princeton emphasizes: preserving native soils, increasing pervious surfaces, installing plantings adapted to the local climate and soil types that require minimal maintenance, favoring organic approaches, and irrigating as an exception rather than a rule.

All University plantings are selected for their appropriateness in Princeton, New Jersey's hardiness zone, as defined by the U.S. Department of Agriculture. Additionally, the University chooses plantings by considering soil and watering requirements, as well as its proven ability to flourish in this campus environment. When possible, Princeton protects and uses existing vegetation on campus and in its natural areas. When possible, the University uses natural methods to control weeds, insects and fungi. An example of this is the University's integrated pest management program: periodically the University releases a variety of beneficial insects and larvae.

Princeton’s Stormwater Management Plan comprises of a two pronged approach. First, campus-wide strategies include enhancing existing systems, constructing new local systems, and implementing landscape-based restoration projects. Additionally, since 2008, Princeton has implemented sustainable design principles to minimize adverse effects in new development projects. Sites selected for new development projects have respected the environment by protecting sensitive natural resources, buffer zones, forests, and other ecologically sensitive areas. Whenever possible, new projects have been built on sites that are already developed and make them “greener” by creating new green space. All projects have demonstrated innovative site design techniques, such as integrating stormwater within the landscape for treatment, and promoting infiltration and rainwater reuse. Overall, since the adoption of the Stormwater Plan in 2006, Princeton has reduced annual stormwater runoff by 23 million gallons by implementing the following strategies on more than 100 acres of Princeton’s campus: stream restoration (1,400 linear feet) along Washington Road, green roofs (63,000-plus square feet), porous pavement (63,000-plus square feet), subsurface infiltration facilities (450,000 cubic feet), infiltrating turf fields (580,000 square feet), and 24,000 gallons of rainwater harvesting systems at Frick Chemistry and the Andlinger Center.

Nearly 100 percent of the leaves and landscape trimmings collected on campus are composted. During fiscal year 2017, almost 7,000 cubic yards of "green waste" were composted. Beginning in 2018, the University will pilot a food waste composting system developed by FOR Solutions. The in-vessel aerobic digester will convert a portion of campus food waste into a soil amendment for University grounds, while serving as a living laboratory for multi-disciplinary investigations into all aspects of food waste conversion.

Several campus buildings include green roofs which support wildlife habitat, minimize stormwater run-off, and reduce building heating and cooling costs through lower maximum and higher minimum roof membrane temperatures.

Whenever possible, Grounds staff uses natural fertilizers on the University's campus, such as compost tea and mulch. Synthetic chemical use is also reduced by incorporating natural materials such as sand and clay into fertilizers. However, weather conditions sometimes require the use of synthetic fertilizers. The University completes pre-storm treatment on campus to better prepare the campus before snow. Additionally, the University uses environmentally safer chemicals such as calcium magnesium acetate to remove snow.

Additional Links: Princeton University’s food waste demonstration project: https://biodigester.princeton.edu/