This essay is structured as a sequence of six steps that explore the evolving role of “trees”, or “plants” across different spatial and temporal contexts—from the era of colonial resource extraction to the present age of sustainable development, from tropical plantations in the Global South to temperate forests in Europe, and finally to its complex urban centers.
It begins with the works of Jane Hutton and Timothy Pwee, which examine ipe wood in Brazil and rubber in Singapore as products of environmental and labor exploitation under colonial systems.
These extractive practices laid the material foundations for many modern Western cities. Following this legacy of resource extraction, the next phase traces how trees have been transformed and redefined—from exploited resources to symbols of national identity and instruments of state planning, most notably in the technocratic model of Singapore, analyzed in A City in Blue and Green.
However, this transformation is not entirely new. It stems from long-standing tensions between humans and nature in the urban development of Europe. From the heavily industrialized northern forests (as explored in A Short History of Urban Forestry in Europe) to transitional landscapes like wooded meadows (Urban Forests and Trees), trees reveal conflicts between economic, ecological, and communal goals. The sequence concludes with Seeing Trees by Sonja Dümpelmann, where urban trees become central to political history, exemplified by the linden tree rows in Cold War Berlin. Trees are not only biological organisms but also symbols of memory, identity, and resistance.
Together, these six works construct a multilayered map of landscape transformation, where every forest, tree line, or park embodies histories of power, ethics, and cultural choice within the global urbanization process.
The starting point of this sequence is Reciprocal Landscapes: Stories of Material Movements (2020) by Jane Hutton, a landscape architect and faculty member at the School of Architecture, University of Waterloo, Canada. The book focuses on tracing the movement of five common landscape construction materials from their sites of extraction to iconic projects in New York City. These include guano fertilizer from Peru, granite from Maine, steel from Pittsburgh, trees planted by prisoners on Rikers Island, and tropical ipe wood from Pará, Brazil. Through these case studies, Hutton highlights the complex and often unequal relationships between sites of material supply and sites of consumption. Chapter 5, titled “Arresting Decay,” focuses on the journey of ipe wood—a tropical hardwood prized for its durability and aesthetic appeal—used in the High Line project, a landmark of post-industrial landscape architecture in New York City. Despite its clean and resilient appearance, ipe wood is the product of large-scale logging operations in the Amazon, which have caused significant harm to biodiversity and tropical forest ecosystems. Hutton not only provides a detailed account of the extraction and transportation processes but also offers a critical analysis of the ethical and social implications, particularly the global inequalities involved. She highlights how cheap labor and natural resources in South America are exploited to serve the image and needs of affluent cities in the Global North. Through the example of ipe wood, the work presents a critical perspective on urbanization and its reliance on global supply chains—specifically, the dependence of Northern cities on labor and
resources from tropical regions like Brazil. This case also serves as a foundation for connecting and comparing with the subsequent examples in the Six Degrees sequence, linking to plantation agriculture and colonial landscape transformations explored in the next step.
https://biblioasia.nlb.gov.sg/files/pdf/vol-17/issue-1/v17-issue1_GambierRubber.pdf
Similar to the ipe wood supply chain in Brazil, From Gambier to Rubber: Plantation Agriculture in Singapore, published in the annual journal of the National Library Board Singapore, explores the consequences of material supply chains through the history of tropical plantation development in Singapore. In this work, Timothy Pwee—a research librarian at the National Library of Singapore—traces how, in the 19th century, Singapore emerged as an island extensively exploited for plantation purposes. Crops such as gambier, pepper, and rubber dominated land use, leading to severe resource depletion and ecological degradation.
Later, as rubber became a strategic export commodity to European countries in the late 19th century, plantation models in Singapore underwent a significant transformation—from scattered, small-scale cultivation to large, systematically managed estates with clear mechanisms for capital, land, and labor control. This shift did not primarily serve Singapore’s development; rather, it was designed to maximize benefits for Western nations importing these raw materials.
As a result, this organized plantation model also left severe consequences for the colonized country. Beyond long-term ecological damage—such as deforestation, soil degradation, and species extinction—it produced lasting social impacts: widening wealth inequality, labor exploitation, and the concentration of land ownership in the hands of a few. Migrant laborers, particularly poor Chinese workers, were often subjected to harsh working hours, poor living conditions, and exclusion from mechanisms of asset accumulation, such as land ownership rights.
Connecting to the previous step, the relationship between dominant centers and exploited margins—where value is drawn from tropical regions to fuel Western industrialization—is a recurring feature in both contexts: Brazil and Singapore. Beyond similarities in extractive practices, these two cases reflect a broader asymmetrical global structure, in which modern industrial cities are built upon the losses and sacrifices of regions at the edges of global power.
At the height of production and export activity, international merchants leveraged the vast financial resources of colonial powers to transform agricultural land into commercial agricultural assets, establishing a highly systematic model of plantation agriculture. These structured approaches to
agricultural planning and estate management had a lasting influence on later models of land governance and spatial planning in Singapore.
Link to the previous book: Direct link (offers a parallel example situated in a different spatial and temporal context)
Secondary references :
- Cameron, J. (1865). Our tropical possessions in Malayan India: Being a descriptive account
of Singapore, Penang, Province Wellesley, and Malacca; Their peoples, products, commerce, and
government.
- Gia Lim Tan (2018). An introduction to the culture and history of the Teochews in Singapore
https://link.springer.com/book/10.1007/978-981-13-9597-0
The formation of Singapore’s governance model and planning orientation in the 20th century, as introduced in the previous step, is further clarified in A City in Blue and Green. Authors Peter Rowe (Professor of Architecture and Urban Design, Harvard Graduate School of Design) and Limin Hee (School of Design and Environment, National University of Singapore) argue that the transformation of the landscape—from extraction to planning—in the 19th century laid the groundwork for Singapore’s model of “environmental governance” and its post-1965 urbanization strategy. This is clearly illustrated in the chapters “Early Days” and “Visions of Clean and Green”, where tree planting is no longer merely about restoring ecological balance—it becomes a component of national identity, a strategic image of the nation, and a political and social project rooted in Singapore’s unique historical trajectory.
In Chapter 2, the authors trace Singapore’s environmental transformation back to the colonial period. In the 19th century, agriculture primarily served subsistence needs and the expansion of plantation economies, with little concern for aesthetics or sustainability. The first efforts at plant management came from Stamford Raffles, and the 1822 “Town Belt” plan by Lieutenant Philip Jackson—one of the earliest urban plans—was focused solely on clearing land, production, trade, and labor organization. This utilitarian approach had severe consequences: approximately 90% of native ecosystems were destroyed.
A key turning point came in the late 19th century, when the McNair Report (1879) and the Cantley Report (1883) criticized widespread deforestation and proposed conservation-oriented planning. The establishment of the Forestry Department in 1884, along with the spatial division of land into town, coastal, and inland reserves, marked the beginning of an “environmental governance”
mindset. Driven by the need to control the damage caused by resource extraction, Singapore gradually developed a planning and resource management approach, laying the groundwork for its later technocratic development strategy.
Continuing from the previous chapter, Chapter 3 clarifies that Singapore’s model of environmental governance was the result of a long process of learning and adaptation, evolving from colonial practices to the post-independence era. After 1965, Prime Minister Lee Kuan Yew not only inherited the colonial planning mindset but also elevated it into a comprehensive national development strategy. The "Garden City" vision, initiated by Lee, was a political–economic strategy aimed at reshaping Singapore’s image in the aftermath of independence.
This new direction was clear: greenery was not just for beauty, but for livability, promoting efficiency, sustainability, resilience, and investment appeal. In the face of pressing economic, social, and infrastructural challenges, building a clean, well-organized, and livable national image became a strategic step to attract foreign investment and boost public morale. During this period, large-scale tree planting, streetscape greening, and the development of parks and residential green spaces were vigorously implemented. However, nature primarily served an aesthetic role—as a decorative green layer—and remained largely separate from the city’s operational systems. Greening efforts were more symbolic than ecologically functional.
Since the early 21st century, Singapore has shifted toward the “City in Nature” model—a significant advancement in planning philosophy that adopts a holistic and integrated ecological approach. In this model, nature is no longer merely decorative but becomes an essential part of urban infrastructure: regulating microclimates, managing stormwater, mitigating floods, preserving biodiversity, and improving quality of life. Initiatives such as ABC Waters, Eco-Link, Nature Ways, the Park Connector Network, and Skyrise Greenery have created a multidimensional green–blue network that spans not only horizontally across the city but also vertically through buildings and structures. Unlike the “Garden City,” which incorporated greenery as a form of visual enhancement, the “City in Nature” seeks to embed urban life within natural ecosystems, encouraging citizens to live in harmony with, engage in, and take responsibility for their environments. Notably, the role of the state has been institutionalized through the Urban Redevelopment Authority (URA), which oversees the implementation of this integrated planning model. These policies ensure not only effective urban management but also ecological resilience, forming a prototype of technocratic environmental governance.
In short, in A City in Blue and Green, planting becomes a national narrative, rooted in colonial history and grown into a cultural symbol. Though not developed around existing natural forests, Singapore’s model still reflects the same values of urban forestry traditions, where trees and wooded spaces carry ecological, civic, and symbolic weight. This dual lens helps us see that greenery in cities is never just about ecology—it’s also about memory, identity, and power.
Link to the previous book: Direct link (showing how the 19th-century plantations in Singapore described in the previous step impacted the country’s political and cultural foundations from the 20th century onward)
Secondary references:
- Kip Lin Lee (1984). Emerald Hill, the Story of a Street in Words and Pictures. Singapore.
- Brooke, G.E. (1921). Botanic gardens and economic notes (p. 71). In W. Makepeace, G.E.
Brooke & R.St.J. Braddell (Eds.), One hundred years of Singapore (Vol. II; pp. 63–78). London:
John Murray
https://www.researchgate.net/publication/40203927_A_Short_History_of_Urban_Forestry_in_Euro pe
If we trace the origin of Singapore’s Garden City and City in Nature models even further back, we find that many of their foundational ideas were rooted in Europe centuries earlier, where cities developed a deep and complex relationship with forests and urban green spaces. These models in Singapore—symbolic versions of greenery where forests are planned and managed by the state—emerged in the post-colonial period, but were strongly shaped by British colonial planning traditions from the 19th century.
This historical perspective is explored in depth by Cecil Konijnendijk, a leading scholar and practitioner in the field of urban forestry at the University of British Columbia, in his essay A Short History of Urban Forestry in Europe. As Cecil Konijnendijk explores in his essay, many of the foundational principles of modern green urbanism—public access to forests, integration of nature in city life, and the balancing of ecological and social priorities—can be traced back to medieval and early modern European cities:
In Europe, many European cities had forested areas near them for generations, which helped shape modern concepts of urban green planning and the idea of forests as shared civic assets. These urban forests are seen as unique because of how closely they’re tied to public use, recreation, and local policy-making.
However, historically, many of these forests date back to the Middle Ages, when forests surrounded growing cities across Europe. Back then, most urban forests were owned by feudal lords or the church, used mainly for hunting or resource control. Over time, as power shifted toward the bourgeoisie and local governments, ownership and access to these green areas also began to change.
By the 19th century, during the rise of urbanization and industrialization, cities became more crowded and unhealthy, and people started demanding open, green spaces for leisure and well-being. This turned urban forests into important social assets.
These transformations parallel Singapore’s own post-colonial pivot: from seeing land as an economic asset to valuing green infrastructure as public commons and a means of urban resilience. This transition shaped the Garden City model, which used greenery for image and order, and the City in Nature model, which fully integrates nature into urban life and public responsibility.
Researching further, the document also shows that urban forests were places of conflict. As cities expanded and land became more valuable, tensions grew between the state’s economic goals (like timber production) and the public’s desire for recreation and nature conservation.
Konijnendijk discusses cases like the famous cases of Oslomarka near Oslo, which show how people fought to protect these forests from overdevelopment or destruction. Oslomarka represents a vast forested region that surrounds the capital and has long been cherished as a public commons. In the post-war decades, local communities and activists successfully advocated for legal protections against urban encroachment, culminating in the 1950 Oslo Marka Act, which secured the area for public access and conservation.
Similarly, in Berlin, the Grunewald forest—one of the city’s largest green areas—became a focal point in the early 20th century when local citizens and environmental groups opposed plans for intensive urban expansion and infrastructure projects within the forest. Their resistance helped preserve Grunewald as a vital recreational and ecological space for the city.
These Scandinavian examples highlight how forests in the Nordic region have long been seen not only as economic resources but as shared landscapes with cultural, ecological, and civic meaning. These conflicts also eventually helped shape today’s urban forestry policies in Europe, ones that aim to balance ecological, recreational, and social needs. These historical conflicts laid the groundwork for the modern policies that define urban forestry in Europe today—policies that seek to balance ecology, recreation, public access, and cultural identity.
Link to the previous book: Direct link (This part connects to the previous section by tracing back the concept of Singapore’s “Garden City” and “City in Nature” to their original form of Urban Forestry concepts from Europe. Meanwhile, this shows conflicts between protecting nature and growing cities, and how communities fight to keep green areas.)
Secondary references:
- Aalde, H. 1992. A small case study on the forest areas surrounding Oslo, pp. 43-47. In
Hummel, J.A.and M.P.E. Parren (eds.). Forests, a growing concern.
- Beckley, Th.M. and D. Korber. 1995. Potential to improve forest management and inform
forest policy. Forestry Chron. 71(6):712-719.
https://www.researchgate.net/publication/237589510_The_history_and_transformation_of_a_Scan dinavian_boreal_forest_landscape_since_the_19th_century
The conflicts discussed in the previous step, with even deeper layers of tension that extend beyond city boundaries, are further explored in the next work: a 1997 study titled The History and Transformation of a Scandinavian Boreal Forest Landscape Since the 19th Century by Östlund, Zackrisson, and Axelsson.
Through a case study of a large forested area in northern Sweden, the research shows how the shift from traditional, semi-natural forest systems to modern industrial forestry has led to new types of conflict. These are similar to those seen in the previous step's case of Berlin’s Grunewald and Oslo’s Oslomarka. In this research, the most striking tensions concern fire:
In the past, forest fires were a natural phenomenon playing a vital ecological role in boreal forest ecosystems. Fire helped recycle nutrients, created openings for young trees to grow, and supported the diversity of species that depended on periodic disturbances. In this sense, fire was not a “disaster” but an essential part of the biological rhythm of the northern forest.
However, by the early 20th century, forestry policies in Sweden and across much of Northern Europe shifted toward the complete suppression of forest fires. The goal was no longer to maintain ecological balance, but to protect economic interests, particularly large-scale timber production. Within the technocratic management system, fire was viewed as a threat to the "order of the forest" and thus had to be eliminated entirely. This shift marked a growing disconnect between the natural rhythms of the forest and the industrial logic of production.
The consequences of this policy extended beyond the disappearance of fire itself—it led to the collapse of entire ecosystems that had evolved to depend on fire. Plant species, microorganisms, and animals adapted to fire gradually declined. The ecosystem became less diverse and more impoverished, while its natural capacity for regeneration weakened. This reflects a fundamental and persistent conflict between ecological integrity and industrial efficiency—a tension also observed by Konijnendijk (in the previous step) within European cities, where forestry has often been driven by economic development priorities at the expense of environmental and cultural forest values.
Furthermore, there is one more layer. The paper challenges us to think about what we mean when we say “natural forest.” If fire is removed, if native species are replaced, if age diversity disappears—can we still call it natural? When conservationists look to protect or restore forests, what kind of baseline are they using?
Link to the previous book: Direct link (Showing conflicts in the previous step are even more intense by going deeper with a specific example of wildfire management in Northern Europe)
Secondary references:
- Östlund, L. 1995. Logging the virgin forest: Northern Sweden in the early-nineteenth
century. For. Conserv. Hist. 39(4): 160–171.
- Haila, Y. 1994. Preserving ecological diversity in boreal forests: ecological background,
research and management.
https://www.researchgate.net/profile/Alan-Simson-2/publication/278714131_Design_of_Urban_For ests/links/5e84862392851c2f52713a90/Design-of-Urban-Forests.pdf
The open question of how to mitigate the tensions discussed in the previous step is addressed in Chapter 13 of Urban Forests and Trees by Kjell Nilsson, Thomas B. Randrup, Jasper Schipperijn, and Cecil C. Konijnendijk. In this chapter, the authors suggest that one way to reduce such conflicts is to “rediscover” traditional landscape types, such as open woodlands, tree-dotted meadows, and forest-agriculture mosaics. These landscapes, rooted in long-standing human–nature interactions, are being studied for their potential to inform and inspire the restoration of modern green spaces. A central example discussed is the wooded meadow landscape.
Wooded meadows are a transitional landscape type between grasslands and forests, where scattered trees grow among areas of short grass or rich herbaceous vegetation. Unlike dense forests with continuous canopies, these ecosystems feature a diverse mix of tall trees and low-growing plants, creating an open space that still retains key forest-like characteristics. In the book, wooded meadows are described as traditional landscapes that were once widespread across many parts of Europe but have gradually disappeared or been replaced due to land-use changes, modern agriculture, and rural abandonment. These meadows were typically maintained through traditional practices such as periodic mowing, which supported high biodiversity and the continued presence of characteristic plant, insect, and bird species. As such, wooded meadows represent a unique biodiversity model situated between forest and grassland, offering both ecological value and deep historical–cultural significance.
The historical dimension of wooded meadows is clearly emphasized in the book, which notes that many of these landscapes were traditionally managed and used by farmers or local communities for hundreds of years. However, with the transformation of agricultural systems and the spread of modern urbanization, such landscapes have been erased or forgotten. The disappearance of wooded meadows not only represents a loss of ecological value but also makes it more difficult to imagine and design future landscapes with scattered tree structures.
Through historical examples, the book also highlights the importance of old photographs—such as vintage postcards—as visual records and evidence of landscape change. In this way, wooded meadows are not merely an ecological concept but also a vital historical trace, reflecting the long-standing interactions between humans and nature in the history of land use.
Another key point emphasized in the book is the use of wooded meadows as reference models in “landscape laboratories” in Sweden and Denmark. These are experimental sites where researchers test and manage diverse landscapes to better understand the design and development of mixed tree–grass environments. The landscape laboratories provide opportunities for hands-on research into how traditional models like wooded meadows function, while also enabling the development of sustainable management practices suited to future needs. Through this approach, wooded meadows become symbols of the fusion between historical knowledge and modern technologies, aimed at restoring and preserving ecologically rich and culturally meaningful landscapes. This also underscores the importance of engaging deeply with historical contexts and traditional practices in order to create more sustainable urban and rural environments in the future.
The concept of wooded meadows is closely tied to the tensions within forest conservation, particularly in landscapes that have been shaped by long-term human intervention. As transitional areas between forest and grassland, wooded meadows have historically been maintained through traditional farming practices, yet are now rapidly disappearing due to urbanization and changes in modern land management. The conflict arises when one side seeks to preserve the ecological and cultural value of wooded meadows, while the other prioritizes economic development and urban expansion. This reflects a broader and ongoing debate in the conservation of urban and peri-urban forests, where ecological integrity often comes into tension with development pressures.
Thus, the concept of wooded meadows is not merely an ecological model, but a reflection of deeper debates about how humans understand and protect “forests” within landscapes that have been long shaped and managed by human activity. It represents a point of convergence where social, political, and cultural conflicts over nature conservation are softened, offering a space where the role of trees shifts to mediate and balance competing interests.
Link to the previous book: Direct link (Answering how to mitigate the tensions discussed in the previous step by an example of the wooded meadows concept)
Secondary references:
- Zackrisson, O. 1977. Influence of forest fires on the northern Swedish boreal forest. Oikos, 29: 22–32
- Wikars, L.O. 1992. Forest fires and insects. Entomol. Tidskr. 113: 1–11
In Seeing Trees by Sonja Dümpelmann (a German landscape historian, currently a professor at Ludwig-Maximilians University Munich), the shifting and evolving roles of urban trees are further explored—this time within the complex fabric of the city itself. While in the previous two steps, trees were often associated with productive landscapes or transitional spaces like wooded meadows, where nature and human activity intersect, in Berlin, trees are redefined not only as ecological elements but as integral components of social, political, and cultural life. A central example is the linden trees lining Unter den Linden, the symbolic boulevard at the heart of Germany’s capital. Their significance is clearly demonstrated in the chapters focusing on Berlin (Chapters 5 through 8), where trees are shown to carry meanings that extend far beyond their biological function, becoming emblems of memory, identity, and public life. Originally, the boulevard was established in the 17th century as a royal axis, with linden trees planted to provide shade and enhance the landscape. However, their role quickly extended beyond conventional ecological functions. As Dümpelmann notes, lindens “have long served not only ecological and aesthetic functions but also symbolic and political ones.” These trees have been present throughout key moments in German history—from the monarchy, through the Third Reich, to socialist East Germany and the era of reunified Berlin. One of the moments that most clearly illustrates the political significance of the linden trees came after World War II. When most of the trees were destroyed or cut down for fuel during the war, their replanting carried deep symbolic meaning. The East German government actively undertook the restoration of the boulevard—not merely to repair the landscape, but to “reclaim the image of a civilized, orderly nation connected to its traditions.” Though the new trees were no longer the original specimens, they served as a “channel of memory”, carrying the past into the present and reinforcing a sense of continuity amid historical rupture. Dümpelmann also analyzes the role of the linden trees during the reunification of Germany after 1989. In the context of East–West division, the lindens along Unter den Linden were not merely “green symbols,” but became active agents in reconstructing shared memory and national identity. As she poignantly writes: “The trees were not neutral elements of the urban landscape; they carried political and emotional meanings for different populations.” In this sense, the trees served as living
witnesses and mediators in a period of profound transition, embodying both continuity and contested memory in the reshaping of a unified Germany.
The image of the linden tree was even incorporated into media campaigns, tourism promotions, and efforts to redefine Berlin’s identity. Replanting the boulevard was not a return to some “pristine nature,” but rather a form of “historical design”—carefully planned to maintain a symbolic continuity between past and present, between former regimes and the newly unified state. The trees thus became more than landscape elements; they were strategic instruments in shaping collective memory and urban identity.
This case clearly illustrates that urban trees are not merely ecological resources, but constitute a form of symbolic infrastructure—a political and cultural institution shaped over time. In this context, trees live not only as biological organisms, but also as symbols: embedded in collective memory, urban strategy, identity politics, and the consciousness of the community.
Link to the previous book: Direct link (Continuously deepening the shifting and evolving roles of urban trees within the complex fabric of the city)
This essay has shown how trees, across six case studies, shift from natural resources to powerful symbols embedded in histories of exploitation, governance, and identity. From colonial plantations to post-industrial cities, trees serve not only ecological functions but also political, cultural, and symbolic roles. They reflect global inequalities, mediate human–nature conflicts, and shape collective memory. Recognizing these layered meanings and understanding trees as both living infrastructure and cultural artifacts is essential to imagining more resilient and just landscapes, where ecology, history, and social meaning are deeply intertwined.
- Cameron, J. (1865). Our tropical possessions in Malayan India: Being a descriptive account of Singapore, Penang, Province Wellesley, and Malacca; Their peoples, products, commerce, and government.
- Low, S.C. (1955). Gambier-and-pepper planting in Singapore, 1819–1860 (p. 36). University of Malaya, Singapore; thesis
- Gia Lim Tan (2018). An introduction to the culture and history of the Teochews in Singapore
- Kip Lin Lee (1984). Emerald Hill, the Story of a Street in Words and Pictures. Singapore
- Brooke, G.E. (1921). Botanic gardens and economic notes (p. 71). In W. Makepeace, G.E. Brooke & R.St.J. Braddell (Eds.), One hundred years of Singapore (Vol. II; pp. 63–78). London: John Murray
- Corlett, R.T. (1992, July). The ecological transformation of Singapore. Journal of Biogeography, 19 (4), 411–420.
- Aalde, H. (1992). A small case study on the forest areas surrounding Oslo, pp. 43-47. In Hummel, J.A.and M.P.E. Parren (eds.). Forests, a growing concern.
- Beckley, Th.M. and D. Korber. (1995). Potential to improve forest management and inform forest policy. Forestry Chron. 71(6):712-719.
- Östlund, L. (1995). Logging the virgin forest: Northern Sweden in the early-nineteenth century. For. Conserv. Hist. 39(4): 160–171.
- Haila, Y. (1994). Preserving ecological diversity in boreal forests: ecological background, research and management.
- Zackrisson, O. (1977). Influence of forest fires on the northern Swedish boreal forest. Oikos, 29: 22–32
- Wikars, L.O. (1992). Forest fires and insects. Entomol. Tidskr. 113: 1–11
- Kuusela,K. (1990). The dynamics of boreal coniferous forests. Sitra, Helsinki.
- Muona, J., and Rutanen, I. (1994). The short-term impact of fire on the beetle fauna in boreal coniferous forest. Ann. Zool. Fenn.
- Lok, M. and H. Mars. (1989). The relationship between forestry and urbanization: the term urbanforestry as a conceptual framework. UnpublishedM.Sc.-thesis. Departments of Forestry and Physical Planning, Agricultural University, Wageningen.