Ecological Network: “a coherent system of natural and/or semi-natural landscape elements that is configured and managed with the objective of maintaining or restoring ecological functions as a means to conserve biodiversity while also providing appropriate opportunities for the sustainable use of natural resources.”
~International Union for the Conservation of Nature, 2001
My Illinois home
|Chicago has been described as "a flood waiting to happen"|
Prior to European incursion and settlement, few people, if anyone, lived on the swampy, marshy, waterlogged, muddy ground that is the natural terrain on which our gleaming towers, our great cultural institutions, our parks, our middle class neighborhoods and our slums are built. In those times, people sensibly gathered on higher ground in large summer camps along rivers such as the Illinois and Des Plaines, dispersing in winter family bands for hunting. Each family needed approximately five or six square miles to provide enough meat through the long, cold winters. The lake and connecting waterways made the place a good trading nexus through which goods and people flowed, not only by canoe, but also along trails that hugged the natural low ridges left by the glaciers and thousands of years of fluctuating lake levels.
The beaver trade and resulting wars among the French, British, and nations and tribes such as the Iroquois, Potawatomi, Illini, Sauk, and Fox brought turmoil to the region from the 17th century onward; the city was not fully established until the Americans took over and in the 19th century commenced completely altering the terrain to their liking, a process that continues to this day. Chicago owes its continued existence to some of the largest, most audacious engineering projects for water management in history. It continues to be a transportation and trade hub.
As in many US cities, it is possible to reside here and, other than snow in winter and heat and humidity in summer, never know what ecosystem you’re in, that the lake is nearby, what the landscape was, or that wolves, bears and cougars were at one time a presence. Yet despite all, Cook County remains one of the most biodiverse in the US, thanks in part to early establishment of 68,000 acres of forest preserves, shoreline restoration efforts, parks, community gardens and backyard gardens. However, much more could be done. Hedgerows, for example.
Cities are the perfect place for miles of post-modern hedgerows
While hedgerows in rural and exurban landscapes have a long history, cities and suburbs are another question entirely. When people think about hedgerows, windbreaks, fencerows and other forms of “linear forests,” as permaculturalist Peter Bane calls them--if they think about them at all--they mostly associate them with bucolic settings, perhaps as in an aerial view of England or Ireland: small green fields bordered by a network of beautiful green hedges, forming what is called “ancient countryside” in the UK.
Why don’t urban areas don’t boast complex networks as well? Hedgerows are linear, natural boundaries, and when siting them it’s good to look for natural edges and linear elements in the landscape that could benefit from hedgerow augmentation. Cities and towns are nothing if not linear, full of boundaries and borders, large and small. And many neighborhoods already contain single-species hedges of one sort or another; wherever sad ranks of privet, box, barberry, or yew stand in an over-pruned row, with little more effort a biodiverse, native shrub hedgerow (aka mixed shrub border) could thrive. You’d think you could walk the streets of an average residential neighborhood and see green infrastructure galore, including raingardens and bioswales, not to mention hedgerows. But no.
Won’t public greenways and natural areas suffice?
Since the late 20th century quite a few examples of large-scale greenways and wildlife corridors have been developed, often on a regional or even continental scale.
Chicago’s forest preserves that form riparian corridors along the Chicago and Des Plaines Rivers are a good, early 20th century example of this kind of thinking, planning and implementation, as is the restoration of Montrose point on Lake Michigan where natural shoreline along with its attendant vegetation has been restored, including its “Magic Hedge,” to the benefit of multiple species of birds as well as people. Other examples include the North-South corridors that will ultimately connect national parks along the Rocky Mountains, and the new Hackmatack Nature reserve that will cross the Illinois-Wisconsin border. In California the Sonoma Valley Wildlife Corridorallow cougars and other wildlife to move across an otherwise built-up landscape and even the Highline Park in New York City features green space created on old elevated line. Other large scale regional planning includes greenway projects along rivers or incorporated into new development.
|Hackmatack Nature Reserve: corridors connect natural areas|
To effectively plan and implement large-scale greenways and wildlife corridors takes the cooperation of multiple governmental entities (federal, state and municipal), citizens’ groups, public institutions, planning agencies, landscape architects and ecologists. They are well worth doing, though they can take years to accomplish. They have the potential to and in many cases actually either have helped landscapes retain some ecological integrity, or have altered over-built landscapes for the better. They are of vast importance for providing wildlife habitat and enabling wildlife species to move across an often unfriendly matrix and they can help preserve natural areas by helping focus new development to less sensitive zones so the natural terrain can maintain its coherence.
Clearly, these necessary projects can positively impact the ecosystems and ecology of whole regions, leading to great benefits for human and non-human residents. However, from a different angle they could be seen as another way of keeping nature corralled and in its place, as it were--still another iteration of the old American model of “nature over there, humans here.” Even within a context of urban green corridors, on a more granular scale neighborhoods, parks and individual properties may be completely “non-natural.” There may be no vegetation at all, or if there is, it is either weedy, as in abandoned properties, where as soon as the asphalt cracks, pioneer plants start growing, or fiercely controlled. Who has not experienced “green space” featuring the few species of non-native trees and shrubs tightly corseted by mulch and chemically controlled turf grass that constitutes much landscape design at every scale from corporate campus to the building owner who buys a few shrubs, species unknown, from the big box store to dress up the property? Admittedly I’m painting with a broad brush. There are plenty of more enlightened municipalities and homeowners, plenty of neighborhoods where pollinators, birds and other animals do well, but from a broad perspective, say, that of Google earth, or a migrating bird, this is how it often looks.
According to the authors of Designing Greenways, the four “indispensable patterns for ecosystem functioning” in anthropocentric landscapes include: ”a few large patches of natural vegetation; connectivity between the patches; vegetated corridors along major streams; and ‘bits of nature’ scattered through the less ecologically suitable matrix.” As in Chicago’s case, many urban areas have “large patches” in the form of nature reserves of one kind or another, and they may have “vegetated stream corridors,” both of which might be planned and managed by large agencies and/or citizens groups. Managed “connectivity” might appear in the form of other greenways, roadside plantings, and parkway trees.
However, nationwide, there is a crying need for vastly more “bits of nature” in the form of all kinds of gardens, large and small, utilizing native plants and natural, ecological gardening practices, and even more of a need for vastly increased “connectivity” in the guise of hundreds if not thousands of miles of hedgerows of one sort or another, bordering properties, acting as living fences, and sheltering gardens. Right now, most examples reside in my own imagination. As I walk or ride around neighborhoods in the Chicago area, if I’m not scouting out existing or potential pollinator habitat, I’m often taking mental notes of potential hedgerow sites. And of course, the two overlap. Out in the leafier suburbs, there are plenty of examples of beautiful mixed shrub borders, but there too, the questions remain: Are they largely native species? What kind of connectivity they help provide? Do they include a full compliment of understory and ground layer plants? If individual ecologically managed properties are surrounded by zones where overly restrictive homeowners’ associations hold sway, or where one individual’s property is bounded by a road and other properties governed by neat and tidy, non-native landscaping, they function as islands in what are basically biological deserts.
In short, the time is ripe for an urban revolution of sorts, a post-modern American urban hedgerow movement. The vexed question of what we do on our own private properties is of deep importance to our cities’ future resilience. Urban hedgerows have a potentially large part to play in a climate changing present and future by adding biodiversity and connectivity, providing habitat, managing water and storing carbon. And for humans at a time of economic uncertainty, when we need to develop sustainable, resilient livelihoods in cities just as in the country, managed hedgerows can provide fuel, food and materials. They can be considered a form of meliorative restoration, or rewilding that benefits humans as well as other species.
A few suggestions for urban hedgerow design and practice
Once upon a time long ago, I attempted to plant and grow an English perennial border in the continental climate of northern Illinois, using plants recommended in books purporting to be all-purpose gardening manuals. It failed of course and I began the long journey towards better understanding of the biogeographical place where I actually live. That and other failures (and successes) lead me to make the following suggestions, particularly for those just starting out. The first is most crucial and of inestimable importance for a host of reasons that extend well beyond garden design.
1. Learn the terrain
I’m assuming that if you are reading this, you are interested in or already practicing some form of urban gardening, or are engaged with your landscape as landscape in some other way—as opposed to the New Yorker who once said that the outdoors was the space between the door to her building and the waiting cab. It’s possible to simply plant an assortment of (hopefully native) shrubs and companion plants along a fence. However, experiences such as my English garden disaster tell me that it is always wise to gain knowledge of the larger landscape in which one lives. Start to learn the terrain and read the landscape, not only of the neighborhood and larger urban surroundings, but of the region.
|Glacial kame at Bluff Spring Fen, |
Cook County Forest Preserves
If we are interested in knowing where it is we actually live and purposefully making room for wild nature, there’s so much more to learn. Why is your town hilly or flat? What is the climate? The underlying rocks? The hydrology? Are you near a river or lake? How does it affect the landscape? What are the native plants and animals? Are there any in your neighborhood? What is the human history of the place, and how did previous peoples interact with the land? What is the soil like on your property, neighborhood, and region? Where are the local nature reserves or other pockets of nature that may include parks, riverbanks, vacant lots, and railroad rights of way? Much of this you may already know, though perhaps organized differently in your brain. This kind of systems knowledge can be the deeply rewarding study of a lifetime.
A warning comes attached to this project. Often, as people proceed, the more they learn, the more they seek out nature, and the more understanding they gain of their place, the more the land works on them and the closer they come to an “indigenous” point of view, in the sense that identity begins to incorporate biogeographical place dependency. One's life, priorities, and ethics, that is, ideas about what’s important and how people should live, might change in surprising ways. In the ensuing years since my first disastrous project, I first learned enough to plant and maintain a pretty nice, if small, perennial border, and then progressed to a point where my yard has become a tiny, semi-natural ecosystem and learning lab that produces some food for my family and habitat for wildlife. I got deeply involved with restoring natural areas and teaching others about these kinds of subjects. My definition of beauty expanded. My spiritual life changed. Now, whenever I look at any piece of ground, I first wonder what the soil is like. Next I consider whether bees and other pollinators and beneficial insects would be happy there. (These little creatures are fine indicator species. If they can't thrive, little else will.) Then I wonder what it needs and how to help.
Naturally one does't have to know all this in such detail in order to get started on an urban hedgerow, especially if you are in contact with others who do have this knowledge and experience, but some kind of broad overview will help prevent failures. And finding mentors can help ease the learning curve.
2. Assess and understand your situation and purpose
Perhaps you are already doing some urban farming, or gardening, or perhaps you live in a suburb with a nice large lot. Perhaps you live in an apartment but have a park or community garden down the street that you already or would like to utilize. Wherever you live, odds are it’s anthropocentric to the extent that it’s unbalanced.
To me, urban gardening of any sort, whether ornamental landscaping, in parks and other urban green spaces, or for community or individual food production must address several questions: How will this garden and its plantings take its place in and benefit local ecological functioning and the wildlife that live in the area? How will it help create beauty? How will it help the people who live in this place and what will they use it for? Will it, overall, tend to sequester carbon, regenerate the soil and manage water? (Residents of rural areas could also profitably answer these questions, to be discussed in a future post). When planning an urban hedgerow, considerations also include what the property owners’ needs are, and how the hedgerow should function—as a living fence? As a source for human food and wood? As a privacy and sound screen? As wildlife corridor and habitat? Often, of course, the answer will be “all of the above,” and then the next challenge will be to fit the hedgerow to the space.
3. Design the hedgerow to suit the place
When I imagine a city full of hedgerows, I imagine them in many guises. The definition of a hedgerow is so elastic, and the styles and variations so various, that they could be designed for almost anywhere and tailored to almost any situation, large or small. Wherever a line of weedy species has grown up, wherever there is need for fencing or privacy, wherever there is a chain link or wrought-iron fence with a few Eurasian shrubs straggling alongside, urban hedgerows could be an answer. The important considerations are purpose, structure (including management) and species of plants used. These are important because not only are human needs being taken into account, but also the needs of wildlife, including insects, and issues such as water management and quality of life. Trees and shrubs would be chosen to fit the space, and hedgerow purpose and design. Plants would be largely native, because native plants really do better help support important beneficial insects and pollinators and when birds eat the berries, they will not later be spreading the seeds of invasive non-native shrubs. I am not recommending specific plant species, because where readers live determines what would be most appropriate. Management would be ecological. Leaf litter would remain on the ground, pruning would be selective, and if appropriate, understory plants and ground covers could be encouraged to grow.
City lots. OK, so you live in a townhouse, or your lot measures 25 or 30 feet by perhaps 125 or 150 feet and much of that is taken up by house and garage. While there’s no room for a full-on hedgerow,
|What not to do: |
boxwood, mulch, chemical turf
Suburban properties. Between two larger suburban properties the owner or collaborating neighbors could create a 15-20 foot wide, mixed shrub border that includes a few conifers, small flowering shrubs and even a small tree or two, planted fairly close together so gaps fill in. This would provide beauty, privacy, and help serve the area’s wildlife needs. The shrubs could be faced down with grasses and flowers for an American-style perennial garden. Herbs and vegetables could be mixed in. A neighborhood full of such properties would be a leafy green haven.
Alternatively, such a border could be a linear forest garden, either on one person’s property or serving as a sort of commons between two properties. Fruiting trees and bushes would naturally be a part of this, as would bushes that respond well to coppicing. In sub-developments where rows of properties back up to one another, hedgerows could extend a long way if owners decided to work together.
|A young hedgerow and herbaceous understory plants |
add beauty and usefulness for humans and other species
Community gardens and urban farms. Many urban areas boast wonderfully fertile and well functioning community gardens. Since these are agricultural production sites, often slotted in between buildings and can range in size from a single city lot to several acres, it makes sense that many could well use the addition of a small mixed hedgerow full of native flowering shrubs along a back fence. Laid or pleached hedgerows along building walls or perimeter fences could add needed biotic functionality and beauty to the site by offering shelter to (insect-eating) birds and beneficial predatory insects and nectar and pollen for pollinators. The understory, full of leaf litter, perhaps some logs left to decay naturally (and inoculated to grow edible mushrooms?), and low native plants such as wild strawberry and native ginger would provide habitat for predaceous ground beetles and potential overwintering habitat for other beneficial insects.
|Hedgerows would add good ecological function and help optimize crops|
In a multi-lot space, hedgerows could be wider, and managed for berries, coppiced for a supply of usefully sized wood such as bean poles, or even basket-making materials. A small rock pile could be constructed for small critters, or “beetle bumps,” small areas of raised earth planted with native perennial grasses to serve as habitat for predatory beetles could be put in place. Flowers such as milkweed could be included. Here again, learning your landscape and learning the plants and beneficial insects native to the ecosystem is crucial. I have never understood why I’ve met so many food gardeners, including urban permaculturalists, who, though often brilliant horticulturalists and designers, have so little real understanding of the suite of native plants and animals of the Chicago region or how to incorporate native plants into and exclude overly invasive plants from their gardening and permaculture schemes. A row of native serviceberries are a blessing in early June when the sweet deep blue berries ripen, Aronia’s somewhat tart berries make good jam, and native wild roses produce good hips for tea.
|This park needs a hedgerow|
|The whole park would be improved|
constructed that, while not especially wide or tall, would add beauty, habitat, and, if composed of thorny species, a measure of security to a space usually dominated by shade trees, grass and play equipment. If not laid, less thorny species could be woven together or pleached to good effect. One obstacle to this is that park districts often have restrictions regarding shrubs for security reasons. Yet smaller shrubs along a fence would not really compromise security, particularly if composed of deciduous species.
|Soccer, baseball--and hedgerows?|
|Crabapple trees need companionship|
Shielding natural areas. I know of several small natural areas such as savannas and pocket prairies where the stewards have left a strip of woody growth between the restored area and road. Often these are full of buckthorn, Eurasian honeysuckle and other weedy species. What if other native shrubs and small trees such as American hawthorn, wild plum, elderberry and even Osage orange were planted in these strips as the buckthorn and honeysuckle are removed? These could be managed as semi-wild shelterbelts full of native savanna plants. Since the wider a corridor is, the better it is for wildlife, here, as in athletic fields, the potential for greater width could be an immense benefit.
It seems clear that how we treat the land within cities could make a difference on multiple scales for multiple species, including us. If individuals and groups consciously bring more nature into the city by creating small semi-natural areas using native plants, practicing ecological gardening and adding connectivity with hedgerows and fencerows composed of diverse native species, cramped urban areas and over-manicured suburbs would dramatically transform. Our urban areas would become more resilient, ecological networks incorporating all four essential landscape patterns. This is already happening in some places, but so much more could be done. The potential benefits are so abundant, by so many measures, that it seems as though the transformation should already have taken place.
Note: Thanks to readers Thomas Rainsborough and Jason Heppenstall for information and suggestions regarding hedgerows in the UK. Also thanks to Resilience.org editors Luanne and Bart for their useful comments.
In Praise of Native Shrubs
Where Do We Find Beauty in a Landscape?
Just What is a Hedgerow: A Few Notes on History, Form and Function
Flowering Plants that Native Bees Love
"Farming with Native Beneficial Insects" Means Solving for Pattern