Conservation and Creation of Urban Woodlands
Many cities especially compact ones are deprived of natural elements. High-quality pre-urbanization natural ecosystems such as forests are often obliterated in the course of city growth. Surveys of the key ecological and environmental benefits of urban wo
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Conservation and Creation of Urban Woodlands Chi Yung Jim
Abstract Many cities especially compact ones are deprived of natural elements. High-quality pre-urbanization natural ecosystems such as forests are often obliterated in the course of city growth. Surveys of the key ecological and environmental benefits of urban woodlands provide the basis to advocate conservation and creation. Urban woodlands tend to be isolated or fragmented remnant pockets enveloped by built-up areas. They are threatened by urban sprawl, and degraded by pollutant penetration, recreational impacts, inappropriate management, detachment from propagule sources, declining regeneration capacity, exotic invasion, and native-species pauperization. Sustainable management should be based firmly on ecological principles, to restore natural factors and processes, introduce minimum inputs, guard against intrusions, and foster spontaneous rehabilitation of degraded sites. Conservation strategy can aim at preserving large woodland patches, enlarging existing patches, fusing or connecting small woodlots with habitat corridors, and merging with adjacent natural areas. New woodlands can be proactively created at suitable green, brown and grey (rooftop) fields. Spontaneous colonization could trigger and sustain woodland succession to deliver urban woodlands on green and brown fields without human help. Afforestation with ameliorative treatments could be applied to harsh sites especially with poor substrate properties and scanty seed arrivals. On intractable sites, innovative techniques such as assisted relay floristics using an initial exotic nurse crop and direct plantation of grey fields could pump-prime woodland establishment. As a hybrid urban green space amalgamating nature and human influences in the novel urban setting, urban woodland conservation and management demand innovative and fusion solutions.
Keywords Urban woodland conservation Urban woodland creation Woodland ecology Natural colonization Urban afforestation Re-naturalization
C.Y. Jim (&) University of Hong Kong, Pokfulam, Hong Kong e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2017 P.Y. Tan and C.Y. Jim (eds.), Greening Cities: Forms and Functions, Advances in 21st Century Human Settlements, DOI 10.1007/978-981-10-4113-6_14
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Introduction
Urbanization can proceed at different intensities, bringing differential ratios of natural to impervious artificial coverage. Some cities have managed to keep extensive stretches of natural areas, whereas others may have eliminated them. The compact development mode can bring massive obliteration or drastic modification of nature. To compensate for the loss of nature, cities often create new urban green spaces (UGS) as surrogates of nature. Some UGS adopt the naturalistic or ecological design to create vegetated areas with a high degree of naturalness that can emulate the organization and functions of natural ecosystems. More often than not, most UGS follow the routine and non-descript parkland design ref
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