One of my favorite memories from my childhood was finding a box turtle living under a line of gnarly Osage orange (Maclura pomifera) trees in my suburban Chicago neighborhood. It was not until many years later that I realized that this row of rough trees, threading through backyards and along roadsides, was a remnant farm boundary—a 19th century hedgerow that had outgrown its purpose and yet, managed to persist into modern times. The sight of that turtle—a small, wild (by suburban standards) visitor—must have made an impression on me. For several years now, I have felt that it is high time to reconsider the role of hedgerows, to be redeployed, this time, as a tool in the service of biodiversity enhancement.
I have to admit that I have a bit of a sales job ahead of me. It seems that when most people (especially Americans) hear the word hedgerow, they look a little bit puzzled. It is not a familiar concept, but on occasion I will get nods of understanding from naturalists, hunters of pheasant or quail, and especially from anyone who has spent any time in the British Isles. Hedgerows are utilitarian agricultural features that were developed thousands of years ago to hold in livestock and to delineate property boundaries.
The modern transformation of the landscape and society has been nothing short of tremendous, as have many of the negative impacts to ecosystems and biodiversity. This rapid change from the natural to the rural to the urban is a global concern. The problems that are associated with this transition have led many on a search for pragmatic solutions in order to shift the balance towards more positive outcomes. Enter an old friend from the edges of farm country: the hedgerow.
Hedgerows seem to have become harbors of life by accident. Over time, as agricultural landscapes were being altered by the hand of mankind, the adjacent hedgerows and field margins often became havens for plants, insects, and animals seeking habitat. These thinnest of reservoirs began to gain greater appreciation in the mid 20th century. In one landmark study of British hedges conducted in the early 1960’s,1 focus on the ecological value of hedges was based on the recognition that wildlife—birds, in this particular study—had come to depend upon these elements in the landscape as habitats. Such efforts and understanding have helped lead to the development of laws that protect hedgerows. Practitioners in the British Isles continue to take a leading role in research to better understand and promote the biodiversity benefits that hedgerows can offer.
Several years ago, while conducting a tree survey in the suburbs of Chicago, I found myself assessing dozens of old Osage orange trees growing in two long rows. These trees were also leftover farm field boundaries that were now themselves bounded on all sides by an expressway, new housing, and encroaching commercial developments. What struck me was the evidence of wildlife (birds, small mammals, etc.) that were clearly making use of these old hedgerows as a way station in a setting that was changing before our eyes. The trees were removed by 2010 to make way for new development, and I wish now that I could have spent more time there making more careful observations of what animals were visiting.
It was at that time that I really made the connection that these old hedges growing in the greatly-altered Illinois landscape were analogous to the hedgerows that I had seen growing in the greatly-altered landscapes of England. I think there are lessons to be learned from older cultures to examine where they have been and to see where we may be headed. Since then, my thoughts turned to the idea of American hedgerows, and their potential for improving natural biodiversity in our own landscapes.
Such renewed interest in hedgerows has taken hold around the world. Recent studies, led by researchers such as Morandin and Kremen,2 have shown that the restoration and installation of new hedgerow materials have improved the populations of pollinators and native bees. In June 2014, President Obama announced the creation of a Pollinator Task Force. For advocates of hedgerows, this was almost too good to be true in promoting our cause.
Who cannot see the myriad possibilities offered by a new generation of hedgerows, linear assemblages of plants designed specifically for biodiversity, or for food, pollinators, or endangered species? We are missing opportunities, that are right in front of us, to create new niches for life. How many suitable spaces—urban and rural—do we pass every day that are otherwise going to waste? No amount of wire fencing has the potential to regenerate life in this way.
Despite these many possibilities, hedgerows continue to be removed. They are often seen as non-productive obstacles to getting full benefit from one’s land. The operative phrase to remember when discussing the hedgerows of the future is well-managed. One of the valid reasons for which hedgerows are disparaged is that they can become dominated by invasive species, becoming nothing but a nuisance. This is fair criticism, but the management of invasive species can be a problem in any restoration-type planting. Planting a hedgerow is like planting any other man-made installation.
The linear structure and nature that the hedgerow offers is well suited to many applications, but their ongoing management is a question to which willing designers and ecologists will have to speak. We are always tempted to promote beauty and utility at these moments, but in the projects upon which I have embarked, the land managers do not necessarily want to take on new landscape features that are difficult to maintain.
Once upon a time, our country put people to work creating windbreaks and shelterbelts in response to soil erosion and the Dust Bowl. Here in the early 21st century, an old friend—the hedgerow—is waiting to be re-deployed and re-employed on a new mission, or possibly, on more new missions in more new places than we can imagine. This is a good old friend to have, because I believe we live in a time where we will need to imagine quite a lot.
