Trails and greenways advocates need to think more broadly and to look at the larger values of trails in the context of "green infrastructure."
The core of my job is fostering the systematic development of the Nation's national scenic and historic trails. The first two of these trails— the Appalachian and Pacific Crest National Scenic Trails— are known to most Americans. Since the National Trails System Act was passed in 1968, 21 more long-distance trails have been created. Today these 23 trail total almost 40,000 miles in combined lengths.
Hiking trails, like the Appalachian, were the original motivation for passage of the National Trails System Act. However, since 1983 there have been no more of these created— instead, popular and Congressional taste has turned to historic trails, such as the Oregon and Santa Fe, the Iditarod in Alaska and El Camino Real de Tierra Adentro in the Southwest. There are now 15 of these historic trails.
In my experience, most of the people who support a specific trail develop a fixation that "their trail" is a single-value resource— be it a hiking experience along the crests of the Appalachian Mountains or preservation of a set of historic ruts in the West where their ancestors trod. Passions do stay focused when everyone agrees on a single purpose. However, I am beginning to suspect that for these trails to survive through the 21st Century (and beyond) as linear corridors of protected resources, we are going to have to think more broadly.
Sometimes, the supporters of a trail lock in on one idea, one interpretation of their trail and its value. Let me suggest to you that for such trails to survive very far into the future they will need to become part of something bigger so that such places continue to offer value as our society's tastes, cultural standards, technology, attitudes towards the outdoors, and funding sources shift in the future.
At face value, trails seem simple enough: pathways through the landscape offering access to the scenic features of the backcountry, providing recreational opportunity and challenge, retracing the footsteps of history. In fact, from what I have seen, trails are too often complex and controversial, caught in the crossfire of property rights advocates, wildlife preservationists, new demands by trail user groups, and changing technologies. Seeking compromise or trying to remain unobtrusive, trail advocates often are too modest in "selling" the health and economic benefits of proposed or existing trails— as well as appreciating the complexity of their own trail enterprise.
To further complicate matters, trailways are often confused with the corridors through which they pass. The primary reason a recreation trail exists may actually be due to a sewer right-of-way or a pipeline easement. Green buffer lands, perhaps set aside to protect riparian habitats or reduce erosion, become corridors of opportunity for neighborhood-to-neighborhood bike paths.
In this age of heightened security and tough budget priority-setting, trails are only going to survive if they are part of larger ideas, multi-objective community-based infrastructure systems. Trails can no longer be just isolated nature trails or recreation paths, they should also help achieve health and fitness goals, perhaps shield rare and endangered species, link heritage sites, provide routes for alternative transportation, provide opportunities for volunteers and youth conservation corps, absorb surplus floodwaters. Ideally they should link together to form systems, rather than being stand-alone pathways.
Fourteen years ago American Trails issued Trails for America, a "national trails agenda." Much has changed since then, but the multi-objective values and benefits of trails and their rights-of-way that are outlined in that agenda still pertain to all of us today. These benefits include:
-- preserving open space and significant natural and cultural resources
-- fostering health and fitness
-- providing a natural respite in urban areas
-- fostering educational opportunities
-- increasing nearby land values
-- buffering wetlands and wildlife along waterways
-- linking historic sites and landmarks
-- providing opportunities for alternatives to car transportation.
Since 1990, a new term has emerged that captures some of this multi-dimensionality: "Green Infrastructure." Many communities, aided by sophisticated tools such as geographic information systems (GIS), can actually map, plan, and track the ever-changing components of their local green infrastructure: woodlands, streams, soils, floodplains, water tables, plant communities, recreation areas, playgrounds, etc. Trails become one of several arterial systems within such a community context.
What is "green infrastructure?" One definition is: " An interconnected network of green spaces that conserves natural ecosystem values and functions and provides associated benefits to human populations." This concept links conservation values with land development, growth management, and the built infrastructure.
"Seeking compromise or trying to remain unobtrusive, trail advocates often are too modest in "selling" the health and economic benefits of proposed or existing trails."
In most American urban areas, the early 20th Century impulse to save stream valleys as parks was a strong green infrastructure instinct— cited by planners then in much the same language that Smart Growth and Green Infrastructure advocates use today. Unfortunately, subsequent real estate development, vandalism, neglect, invasive species, urban runoff, highway construction, and dumping have often overwhelmed these stream valley systems and stressed them to points where many barely function in natural ways at all.
Green infrastructure, when it works, offers many benefits, closely parallel to the benefits of trails cited above:
-- supporting native species and habitats
-- fostering ecological processes and functions
-- sustaining air and water resources (providing the "lungs" of the community)
-- protecting and enhancing critical water resources
-- fostering human and community health and fitness through recreation
-- enhancing community appearance
-- linking neighborhoods to nature
-- increasing property values.
Therefore planning and management for green infrastructure— at whatever scale it occurs— needs to be inclusive, holistic, multi-disciplinary, and open ended. It must be sensitive to connections, linking people to programs. It must also respect good science and sound planning theory. It can be incorporated fully into methods of Smart Growth planning. Several national groups are strongly promoting these concepts, including the Conservation Fund and the Rails-to-Trails Conservancy.
And, of course, such holistic planning becomes more difficult as land use growth outpaces population growth. Without such multi-objective thinking, we are seeing in all our metro areas major losses of natural areas, loss of tree canopy, fragmentation of habitats, degraded water and air resources, increased flood losses, and an increasing inability of nature to heal itself for our benefit.
Bringing all this back to trails, let me suggest that one related technique my colleagues in rivers and wetlands use for creatively crossing disciplinary and political boundaries could be very helpful to enable trail work to act as an agent for broader green infrastructure thinking. It is called "multi-objective management planning." It is was used after the 1993 Mississippi River floods to look at all issues related to floodplain management and how it impacted specific communities. I believe a similar process could be used in developing or even rehabilitating a single trail or, better yet, an entire system of trails, linking to issues of transportation, safety and security, wildlife and vegetation management, education, runoff and erosion, community economics, community quality of life, heritage interpretation, and accessibility— in short, the list of issues we've discussed earlier.
In Alexandria, Virginia, near where I live, a shoreline esplanade along the Potomac River serves many purposes: tourist promenade, access to water and pleasure water craft, special event area, bike trail, neighborhood viewshed to the water, and shoreline utility access corridor. To plan for such multi-dimensional projects gets complicated quickly, and certainly relies of partnerships that may be hard to create and maintain. But, bottom line, to quote the 1996 handbook on multi-objective floodplain management, " By allying yourself with these other interests, you gain longer-lasting, broader support for your common concerns."
As the Conservation Fund's Ed MacMahon says. "If you think conserving green space is expensive, just imagine the future costs for clean air, clean water, and healthy natural systems if we don't invest in green infrastructure today."
Association of State Floodplain Managers, 1996, Using Multi-Objective Management to Reduce Flood Losses in Your Watershed, 58 pages + appendices.
Benedict, Mark A. and Edward T. McMahon, 2002, "Green Infrastructure: Smart Conservation for the 21st Century," in Renewable Resources Journal, Autumn, 2002.
McMahon, 2000, "Green Infrastructure," in Planning Commissioners Journal, No. 37, Winter 2000.
National Park Service, 1990, Trails for All Americans: The Report of the National Trails Agenda Project, 21 pages.
National Park Service and Federal Emergency Management Agency , 1994, A Multi-Objective Planning Process for Mitigating Natural Hazards, 47 pages.