Outstanding remnants of nature in compact cities: patterns and preservation of heritage trees in Guangzhou city (China)

Abstract Heritage trees (HTs) play pertinent ecological-landscaping roles in cities, yet the few known studies are mainly descriptive or resource inventories. This paper explores the intertwined natural and cultural spatial associations between trees (species, dimensions and age) and city (landscape impact, urban fabric, district history and landuse), assessing the integrated city–tree complex at the macro-scale. The study area includes eight main built-up districts (covering 116 km 2 ) of Guangzhou, a compact and major city in South China. A survey of historical and inventory records identified 348 HTs which encompass the city’s officially recognized HTs. Principal component analysis (PCA), Jaccard Index of Similarity (JIS), and other statistical tests helped to unravel spatial associations. The 25 HT species, compared to 254 species in the city’s entire urban forest, are dominated by four common species. The number of HTs increases with district age of 25–2500 years. The more stressful and cramped roadside habitat accommodates more HTs, followed by spacious park, and intra-lot interstitial spaces in education, government-institution, and religious sites. The HTs are dominated by the 100–200-year age bracket, with few older trees, indicating a generation gap and the inability of old districts to preserve older trees. Park and religious sites accommodate more of the oldest and largest trees. Roadside contains more wide-crown trees mainly due to effective protection from motor vehicles by the inner bicycle lane. District is indicated by JIS as the major determinant of species variations, with landuse playing a secondary role. Large trees polarise into normal and degraded tree forms due to physical site constraints. Tall-wide and short-wide tree forms with high landscape impact contribution dominate landscape impacts. PCA extracted three factors that explained 71.9% of the variations, namely age–dimension, potential growth, and district history. Increasing compactness and the present management regime may fail to sustain the HT stock and deprive the city of HT precursors. The concept of ecological brinkmanship and transgenerational arboriculture are proposed to enhance HT conservation.

[1]  Chi Yung Jim,et al.  Comprehensive greenspace planning based on landscape ecology principles in compact Nanjing city, China , 2003 .

[2]  J. C. Stevens,et al.  Brooklyn's urban forest , 2002 .

[3]  C.Y. Jim.  Impacts of intensive urbanization on trees in Hong Kong , 1998, Environmental Conservation.

[4]  H. Clepper,et al.  Famous and Historic Trees , 1987 .

[5]  M. Philip,et al.  Measuring Trees and Forests , 1994 .

[6]  Katie Williams,et al.  Urban intensification policies in England: problems and contradictions , 1999 .

[7]  J. Bowers.  Policy instruments for the conservation of remnant vegetation on private land , 1999 .

[8]  C Y Jim,et al.  Managing Urban Trees and Their Soil Envelopes in a Contiguously Developed City Environment , 2001, Environmental management.

[9]  Chi Yung Jim,et al.  Planning strategies to overcome constraints on greenspace provision in urban Hong Kong , 2002 .

[10]  G. Hestmark.  Temptations of the tree , 2000, Nature.

[11]  F. E. Kuo,et al.  Environment and Crime in the Inner City , 2001 .

[12]  F. Langevelde,et al.  Two strategies for conservation planning in human-dominated landscapes , 2002 .

[13]  L. Jackson.  The relationship of urban design to human health and condition , 2003 .

[14]  D. Nowak.  Historical Vegetation Change in Oakland and Its Implications for Urban Forest Management , 1993, Arboriculture & Urban Forestry.

[15]  Henry W. Lawrence,et al.  Origins of the Tree-Lined Boulevard , 1988 .

[16]  Gary Moll,et al.  Growing Greener Cities: A Tree-Planting Handbook , 1992 .

[17]  H. Read.  Veteran Trees: A Guide to Good Management , 2000 .

[18]  D. H. Knight,et al.  Aims and Methods of Vegetation Ecology , 1974 .

[19]  Foo Tuan Seik.  Planning and design of Tampines, an award-winning high-rise, high-density township in Singapore , 2001 .

[20]  Catharine Ward Thompson,et al.  Urban open space in the 21st century , 2002 .

[21]  Thomas Pakenham.  Meetings with remarkable trees , 1996 .

[22]  R. A. Sanders.  Some determinants of urban forest structure , 1984 .

[23]  R. Miller,et al.  Planting Survival of Selected Street Tree Taxa , 1991, Arboriculture & Urban Forestry.

[24]  Chi Yung Jim,et al.  Species diversity of three major urban forest types in Guangzhou city, China , 2001 .

[25]  C.Y. Jim.  Tree canopy cover, land use and planning implications in urban Hong Kong , 1989 .

[26]  S. Godefroid.  Temporal analysis of the Brussels flora as indicator for changing environmental quality , 2001 .

[27]  Bill Ames,et al.  Working proactively with developers to preserve urban trees , 2003 .

[28]  R. Loeb.  Will a tree grow in Brooklyn? Developmental trends of the New York City street tree forest , 1992 .

[29]  O. Gilbert,et al.  Urban Vegetation: A Review and Chicago Case Study. , 1975 .

[30]  D. Nowak,et al.  Syracuse urban forest master plan: guiding the city's forest resource into the 21st century , 2001 .

[31]  D. May.  Big trees of the Midsouth Forest Survey , 1990 .

[32]  H. Lawrence.  The Neoclassical Origins of Modern Urban Forests , 1993, Forest and Conservation History.

[33]  J. Kuser.  Handbook of Urban and Community Forestry in the Northeast , 2000, Springer US.

[34]  L. Mumford.  The city in history : its origins, its transformations, and its prospects , 1961 .

[35]  J. Dwyer,et al.  Understanding the Benefits and Costs of Urban Forest Ecosystems , 2007 .

[36]  C.Y. Jim,et al.  Statutory measures for the protection and enhancement of the urban forest in Guangzhou City, China , 2000 .

[37]  A. F. Mitchell,et al.  Champion trees in the British Isles. , 1990 .

[38]  Gordon A. Bradley,et al.  Urban forest landscapes : integrating multidisciplinary perspectives , 1995 .