To compare the forest and the city as an ecosystem is quite challenging. And to find possible analogies is even more exciting. Both are complex systems. Why a city as a metaphor and not a region or a country?

For citizens, the city mostly has an association with their personal well-being. It is natural and existing: you are born, marry, raise your children and die in a city. The mayor of your city signs your passport. It is the nearest and most tangible governmental system, the closest to people’s self-identification (“Where are you from?”). 

The public canvas of the city, where components, interests, roles, relations, factors, processes, and cycles meet, is the most dynamic in cities. The fabric of society is woven within the boundary of the town. The term politics has been derived from the Greek: πολιτικά, politiká, meaning “affairs of the cities”. 

So there is some logic to starting the journey for exploration on the city level. It is this entity where at the end, all things meet. The American politician O’Neill et al. (1994) stated once:  

“All politics, after all, is local.” 

The city is not a closed but a lively and open ecosystem. It is interconnected as part of a region, metropolitan area, province and state. Downwards it consists of subsystems such as districts, sites, neighbourhoods, streets, houses/families and individuals. The city overall, in general, has that organic image from an eagle-view perspective, like on this map of Genua.

The organic appearance of the city, City map (1836) of Genua.

Like the forest, the city is influenced by biotic factors (a result of the activities of human beings, groups and all kinds of organisations) and abiotic factors (the non-living components such as terrain, climate and availability of energy, water and nutrients). Those factors influence the city and its inhabitants. The elements combined form the habitats of the city. These are the places where citizens live. This analogy is elaborated, comparisons explored, and new light is shared on the governance of cities. A city, after all, is a living thing.

Ecology was the starting point for this discovery because it can offer ways to enter the city from a holistic point of view and surf its levels. Naturalist, explorer and geographer Alexander Von Humboldt (1856) concluded that zooming out leads to more overview and allows interconnecting things (and even sciences). Von Humboldt gave guidance on the relationship between ecosystems and abiotic factors. At the beginning of the 19th century, he came to a fascinating, revolutionary conclusion. 

“Physical geography…, elevated to a higher point of view… embraces the sphere of organic life…”

The connection between sciences is necessary to find accurate answers. Oldeman et al. (1990) underlined the need for a holistic approach to diagnosis in cross-border studies of forests. He always encouraged me, within the fragmented landscape of sciences, to try to cross the individual university so heavily guarded boundaries. He stated:

“The group that was responsible for the forest components theme decided to accelerate the process by starting an ambitious project, the writing of a common book. There is no way in which cooperation can be stimulated better, but this way has to be learned and practised too. The result is now before you. The book is not yet ideal, in our opinion, because it still contains too many traces of the old University tradition of researchers working, each apart, on such narrow subjects as they know best. 

This way of executing the course research is necessary to reach sufficient depth. But it carries the risk of loss of vision of the whole system, parts of which are studied. Still a little bit unbalanced, but on its way to improving along lines that are more clear now, this presentation in a pluridisciplinary way is a first step, however, to overcome both the limits of individual researchers and the shallowness of groups. We trust, however, that it is exactly this wrestling with integration of broad views versus the deepening of restricted views that may be as interesting to the reader as the facts, figures, conclusions and hypotheses on forests and their components which are presented in the following pages.”

Von Humboldt and Oldeman are inspiring in this cross-scientific discovery. What an exciting journey for an ecologist to discover the public domain.


Humboldt, A. von (1856) Cosmos: A Sketch of a Physical Description of the Universe [Volume 1]. New York: Harper & Brothers Publishers. 406 pp.

O’Neill, T. and Hymel, G. (1994) All Politics Is Local: And Other Rules of the Game. Canada: Bob Adams, Inc. 

Oldeman, R., Schmidt, P. and Arnolds, E. (1990) Forest components. Wageningen: Agricultural University, 111 pp

This article is part of the Chapter Foreword of Ecosystem City: Lessons from the Forest.