Deliberate and less intentional urban forests

AbstractThe term ‘urban forest’ is an oxymoron and continues to provoke a staggering set of questions. The default practice of transplanting cloned saplings from nurseries into the city holds little promise of adding up to more than the sum of its destressed trees. In contrast, there is growing recognition of the unsanctioned emergent forest vegetation of urban fallows. While the fields of cultural geography and urban ecology recognize such unintentional urban forests for their layered sociocultural, ecological and health benefits, city administrators, the general public and even landscape architects have been slower to embrace them. However, consequences of global warming and the subsequent rise of urban ecology mandates an update regarding current challenges and potentials in managing urban forests. Park projects can expand the normative canon by embracing recent urban ecology concepts concerning spontaneous vegetation on fallow urban land, such as ‘ruderal’ and ‘fourth nature’. This paper critically reviews traditional notions of urban forestry and refutes the single tree planting approach. It questions standardized connotations and nativist biases towards invasive species and argues that spontaneous vegetation is well equipped to provide and expand critical networks to more resilient and enduring urban forest patches. It explores cases in Germany, in general, and Berlin, in particular, to ground the relevance for emergent vegetation. It considers the acknowledgment and utilization of recent developments in forestry science regarding microbial ecology, including the mycorrhizal and symbiotic macro/micro networks, important for landscape architecture and necessary to propose more resilient and healthy forested urban environments.Keywords: urban ecologymyceliumwood-wide-webmicrobiomeholobiont AcknowledgmentsI would like to thank professor Kelly Shannon for her invaluable contribution in the editing process. My special thanks go to Dr Jake M. Robinson, microbial ecologist, for his work as consultant and studio co-advisor, and my research assistants Flora Kießling and Florian Opitz at the Norwegian University of Life Sciences. The work was funded through the Norwegian Research Council, project “spaces for resilience”.Notes1 Sonja Dümpelmann, Seeing Trees: A History of Street Trees in New York City and Berlin (New Haven: Yale University Press, 2019), 21–42.2 Berlin’s rapid increase in housing along with the growth of industrialization was structured by British engineer James Hobrecht, who introduced the layout of the sewer network as the armature for urban form.3 Dümpelmann, Seeing Trees, op. cit. (note 1), 2.4 Joanna Dean, ‘Seeing Trees, Thinking Forests: Urban Forestry at the University of Toronto in the 1960s’, in: Alan Mac-Eachern and William J. 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Gellie et al., ‘Revegetation Rewilds the Soil Bacterial Microbiome of an Old Field’, Molecular Ecology 26/11 (2017), 2895–2904.39 Zdravko Baruch, et al., ‘Increased Plant Species Richness Associates with Greater Soil Bacterial Diversity in Urban Green Spaces’, Environmental Research 196 (2021).40 Ehrenfried Pfeifer (1899–1961), German scientist, soil scientist, leading advocate of biodynamic agriculture, anthroposophist and student of Rudolf Steiner.41 Benjamin M. Ford et al., Paper Chromatography: An Inconsistent Tool for Assessing Soil Health’, Geoderma 383 (2021).42 Maria Olga Kokornaczyk et al., ‘Analysis of Soils by Means of Pfeiffer’s Circular Chromatography Test and Comparison to Chemical Analysis Results’, Biological Agriculture & Horticulture 33/3 (2017), 143–157.43 Graham Huggan, Colonialism, Culture, Whale: The Cetacean Quartet (London: Bloomsbury, 2018).Additional informationNotes on contributorsJorg SiewekeJorg Sieweke, licensed landscape architect and urban designer, directs his practice ParadoXcity in Berlin. He is an associate professor at the Norwegian University of Life Sciences. He obtained his PhD from the TU Berlin in 2015; fellowships in Hamburg (DAAD, 2014) and Rome (Villa Massimo, 2015). He held academic appointments at the University of Virginia, the RWTH Aachen, the HCU Hamburg, the TU Berlin and the TU Dresden as well as at various Art Academies (ABK Stuttgart, UDK Berlin and Berlin-Weissensee).