Tree Transplanting Metrics

Department: Landscape Architecture
Active Dates: 2010 – 2016

Principal Investigator: Matthew PRYOR (PI), Gary WATSON (Co-I),  Wei LI (Co-I)
Funding body: GRF


This original research study has investigated the science behind the transplantation of mature trees, a previously un-researched area of arboricultural practice, but one that is becoming increasingly common as an environmental mitigation measure in high density cities. As controlled experiments on such trees are not feasible, we developed a research methodology comprising detailed literature review of scientific papers relating to the arboricultural responses of nursery stock trees to transplantation, scaling that up via known morphological and physiological differences between nursery stock and very mature trees, and then testing the predicted responses against detailed analysis of more than 1000 actual transplanting operations in the field.


The study aims to establish the physical and operational limits of mature tree transplanting as a potential environmental mitigation measure within high density urban settings, and generate reliability based technical guidelines for future operations.


The study has generated a wide range of unique data on different tree transplanting techniques in Hong Kong and the factors that contribute most to successful transplanting operations.


Academic publications

  • Pryor, M. and Watson, G. Mature Tree Transplanting: Science Supports Best Management Practice. Arboricultural Journal. DOI: 10.1080/03071375.2016.1157401.
  • Pryor, M. and Li, W. (2015). Aerial roots of Ficus microcarpa. Yuan Lin, Journal of the Hong Kong Institute of Landscape Architects.
  • Pryor, M. (2014). Extreme Arboriculture: Lessons from moving big trees. In proceedings of Trees People and the Built Environment II conference p196-209. Institute of Chartered Foresters. Birmingham UK. (April 2015).
  • Pryor, M. (2014) The challenge of planting trees on slopes in Hong Kong. 7th Annual International Arboriculture Summit – Hong Kong. (November 2014).
  • Pryor, M. Demystifying Tree Transplanting. In proceedings of IASHK Seminar Hong Kong, (November 2012).
  • Pryor, M. Transplanting mature trees. Technical Seminar, University of Hong Kong. (17 October 2015).
  • Pryor, M. Urban Tree Transplanting in Hong Kong. Chinese University of Hong Kong Seminar on Urban Greenery in Hong Kong. (12 July 2014).
    Conference papers / other outputs
  • Pryor, M. Model Specification for tree transplanting and related works in Hong Kong. (2015) Open source publication on research website.
  • Invited technical expert for the following high profile tree protection projects. All work was peer-reviewed by professional and academic experts:
    • MTRC Express Rail Link (XRL) – Tree transplanting Contract 801. (2010-17).
    • Widening of Castle Peak Road: Castle Peak Bay
    • CE17/2013(HY). (2014).
    • Wanchai Bypass, PhII – Victoria Park Tree Transplanting, HY/2009/19. (2013).
    • HKILA & HKIE Joint Task Force on Wall-Tree Management (2015 – 2016).

Anticipated Outputs

  • Pryor, M. and Sarkar, C. Responses to transplanting of three species of street trees. (Under revision for Forestry: An International Journal of Forest Research).
  • Tree transplanting research website.

Anticipated Impact

The results of the study have particular application in Hong Kong, where the value of tree transplantation as an environmental remediation measure has been widely debated by practitioners, but are relevant to arboriculturists in tropical environments across the world. The study has also identified Hong Kong as an emerging area of arboricultural research, and the findings were recognised in a 2014 HKILA Research prize.

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