Stone Wall Trees 2040: A Critical Discussion of their Alternative Futures

Honor Award


Hong Kong
Anson Ting Fung Wong, Student ASLA
Faculty Advisors: Montserrat Bonvehi Rosich; Paul Yuen King Chan
Harvard University Graduate School of Design

"This clever and informative public awareness campaign is designed to stimulate community discussion about the future of the Stone Wall Trees, a feature unique to Hong Kong, where 30 tree species, including banyan and mulberry, have taken root in the stone retaining walls that line the city’s steep roadways and paths. The project uses film, a website, exhibitions, extensive documentation, and publications to imagine alternative approaches and begin a dialogue among stakeholders. With the origins of these beloved examples of vertical urban forestry literally rooted in the Colonial past, and with issues of safety and aging tree populations getting increased attention, this public information project, infused with a spirit of optimism, is as much about preserving a distinctive history and culture as it is about these special trees."

- 2019 Awards Jury

Project Credits

  • Supports:
    • Penny White Project Fund 2018, Department of Landscape Architecture, Harvard University Graduate School of Design
    • Greening, Landscape and Tree Management Section, Development Bureau, Government of the Hong Kong Special Administrative Region
  • Advisors:
    • Montserrat Bonvehi Rosich, Lecturer in Landscape Architecture, Harvard Graduate School of Design
    • Paul Yuen King Chan, Part-time Lecturer, Faculty of Design and Environment, Technological and Higher, Education Institute of Hong Kong, HKILA, RLA
    • Alistair McIntosh, Lecturer in Landscape Architecture, Harvard Graduate School of Design
  • Interviewees:
    • Dr. Charlton Cheung, Member of Sai Wan Concern, Scholar on the study of Stone Wall Trees
    • Deborah Kuh, Former Head of Greening, Landscape and Tree Management Section, Development Bureau, Government of the Hong Kong Special Administrative Region
    • Gavin Coates, Senior Lecturer in Landscape Architecture, The University of Hong Kong
    • Katty Law, Convener of Central and Western Concern Group, Hong Kong
    • Kevin Eckert, Urban Arborist, Member of Urban Forestry Advisory Panel, Development Bureau
    • Dr. Kenneth Nicolson, Adjunct Associate Professor, Division of Architectural Conservation Programmes, The University of Hong Kong
    • Ken K.Y. So, Chief Executive, the Conservancy Association, Hong Kong
    • Yun-Cheung Chan, Former Head, Geotechnical Engineering Office, Civil Engineering and Development Department, Government of the Hong Kong Special Administrative Region

Project Statement

Stone Wall Tree is a collection of landscape artifact unique to Hong Kong's geomorphology, urban density and climate. It refers to a series of trees growing spontaneously on the vertical surface of masonry stone retaining walls since British Hong Kong. Currently, most studies on these trees are only around their impacts on retaining walls from an engineering perspective. Their cultural significance and ecological value to the local community is largely underestimated.

A controversial Stone Wall Tree removal in 2015 sparked public outrage, and every tree felling since then ends up becoming emotional disputes between tree huggers and tree fellers. Given that these hundred-year-old trees are predicted to face rapid decay in the next 2 decades, there is an urgency for a constructive discussion on their future treatment.

It is a critical moment for landscape architects to step in and provide a comprehensive reading on the current condition of Stone Wall Trees. Through multiple communication means, the project aims to set the table for a conversation among different stakeholders on the alternative futures of the trees.

Project Narrative

Purpose & Audience

The objective of the project is to expand general knowledge about Stone Wall Trees among the public audiences and suggest preliminary ideas of intervention for different practitioners to further develop on. It targets both general public and specialists, aiming to push forward new imaginations of the future urban landscape with Stone Wall Trees that are results of the collaborative discussion between both the public and the practitioners. The significance of the project is to bridge the current communication gap among these critical local stakeholders. In the long run, "Stone Wall Trees 2040" will serve as a local brand for continuing an active discussion and monitoring on the future development of these unique landscape artifacts.

Impact & effectiveness

The project is meant to be a continuous, accumulative effort through constant conversations with different stakeholders, including local landscape architect, arborist, geotechnical engineer, government management and community members. The project contains two major components:

1. Documentation and Archival Work

Documentation and Archival Work including interviews with practitioners and stakeholders, visual documentation of Stone Wall Trees aesthetics and controversies in multiple ways like still photos, drone shots and video documentary.

2. Preliminary Approach for Future Treatment

The alternative futures of Stone Wall Trees are explored in three approaches:

i. Farewell to the Urban Wonder - this approach assumes that more stone wall trees will be removed in the future and explore the treatment of tree ruins in relation to the preservation of historical retaining walls

ii. Home to Stone Wall Tree - this approach targets the building of communities around trees and community engagement. Understanding the Stone Wall Tree typologies is the first step towards reconsidering the design of the urban environment to truly embrace the existence of Stone Wall Trees in the neighborhood.

iii. Innovation for future Vertical Urban Forestry - this approach investigates on the structure of historical masonry stone walls and their upgrade in the 1980s, and re-imagine how new wall can be designed to accommodate trees as a new form of vertical urban forestry


The two major content components, Documentation and Archival Work and Preliminary Approach for Future Treatment, are presented to the audience through a wide range of communication means, including publication, video film, and online materials, to bring fruitful and multifaceted representations of the project that stimulate imaginations. The outcomes include:

  1. Timeline Info Pack (Publication & Digital) - A Publication with writing, graphical illustration and photo essay of the development timeline of Stone Wall Trees and their recent local controversies. It also includes the preliminary design approaches towards the future, where the management body, the community and other practitioners could take on any of them and further investigate on these approaches.
  2. Documentary Film - A video documentary including footage of a wall tree removal dispute in May 2018 and all different typologies of Stone Wall Trees within the urban context of Hong Kong.
  3. Exhibition - A public display to promote general knowledge on Stone Wall Trees, and connect people to the project. The "Stone Wall Tree Exhibition" was held in Harvard Graduate School of Design in April 2019, and will move to Hong Kong to reach out to local audience in the future.
  4. Website ( - An online platform as a living archive for Stone Wall Tree documentation and update. This website will become the major source of information distribution and platform for knowledge exchange, so as to encourage the constant discussion on Stone Wall Trees in the future