NUS Prof Veera Sekaran and NTU's Dr Shawn Lum on code of practice for pruning tropical trees

Key Concepts

• Code of practice for pruning tropical trees in urban environments
• Tree management in Singapore
• National standards for tree care
• Urban forestry
• Climate change resilience
• Tree inspection and maintenance
• Technology in tree management
• Native vs. ornamental trees
• Tree failure prevention
• Regenerative tropical microforest systems

Main Topics and Key Points

Introduction of New Code of Practice

• The National Parks Board (NParks) and the Landscape Industry Association Singapore (LIAS) are developing the first code of practice for pruning tropical trees in urban environments.
• Existing guidelines, based on temperate region practices, are inadequate for tropical trees.
• The new guidelines aim to improve tree health and reduce susceptibility to pests and diseases.
• A work group will gather opinions from stakeholders, with a first draft expected by mid-2026.
• The goal is to establish national standards through consensus, ensuring a higher level of tree care and preventing incorrect pruning practices that lead to disease, decay, and failure.
• The code will provide clear guidelines and service standards for tree owners, practitioners, and training providers.
• NParks is also exploring standards for tree inspection and maintenance.

Current Industry Best Practices and the Need for Nationwide Standards

• Early tree management practices in Singapore relied on standards from the International Society of Arboriculture, primarily from temperate regions (America and Europe).
• While techniques like tree cutting and climbing were useful, many practices were not suitable for tropical trees, which behave differently.
• Singapore's vegetation is evolving towards more native trees, necessitating a reevaluation of existing standards.
• Practices from the last 20-30 years need to be updated to reflect the changing vegetation types.
• NParks is engaging with the industry to identify practices more suitable for tropical trees.

Preventing Tree Failures

• Singapore has significantly reduced tree failures, from over 3,000 cases in 2001 to around 400 per year.
• New standards will focus on understanding tree growth and pruning them proactively to prevent problems.
• The right tree should be planted in the right place, considering the specific conditions.
• Tree management should then address any remaining issues.

Warning Signs of Hazardous Trees

• Traditional arborists can recognize signs of stress, rot, or subtle tilts in trees.
• Technology is needed to detect unseen issues early.
• Managing trees to prevent fungal infections and other problems is crucial.

Content of the New Guidelines

• Technology will play a significant role in tree management.
• NParks has GIS systems with information on most trees planted in Singapore.
• Other agencies like SLA, HDB, and JTC, which also manage land and trees, need to be involved.
• The goal is to have a unified standard across all agencies in Singapore.
• Collaboration with universities and IHLs is needed to develop technologies for detecting decay and tilt in trees.
• Sensors can provide data on ground movement and tree angles, helping to mitigate potential hazards.

Application to Natural Landscapes

• Management strategies are needed for natural forests.
• Patches of old-growth forest (200-300 years old) are resilient but slow to expand.
• Efforts are needed to restore and buffer the rest of the forest, connecting populations to improve survival chances.
• Standards can be applied to forests to a certain extent, but trees in forests grow differently than in open areas.
• The forest edge, which experiences drier and windier conditions, may require protection.

Challenges in Applying National Standards to Natural Forests

• Vegetation types are changing, with increased use of native species in both urban and natural environments.
• Landscapes are evolving towards regenerative tropical microforest systems.
• Different standards are needed for these new types of landscapes.
• This initiative provides a roadmap for evolving as a "city in nature."
• Ornamental trees may not survive future climate change conditions, necessitating a shift in tree species.

Weatherproofing Trees Against Climate Change

• Planting schemes are evolving to include more resilient species.
• Education is needed to ensure that the industry and clients appreciate these changes.
• Selecting the right trees now can "future-proof" streetscapes and urban forests.
• Trees are living things with unique characteristics, requiring a holistic approach to their care.

Important Examples, Case Studies, or Real-World Applications Discussed

• Mention of the International Society of Arboriculture (ISA) and its standards from temperate regions.
• Reference to the reduction of tree failure cases in Singapore from 3,000 in 2001 to 400 per year.
• Example of mature forests in MacRitchie Reservoir.
• Discussion of the shift from ornamental trees to native species in urban landscapes.

Step-by-Step Processes, Methodologies, or Frameworks Explained

• The process of developing the code of practice: NParks and LIAS collaboration, stakeholder consultation, draft publication.
• The approach to reducing tree failures: understanding tree growth, proactive pruning, right tree in the right place.
• The strategy for forest management: restoring and buffering forests, connecting populations.

Key Arguments or Perspectives Presented, with Their Supporting Evidence

• Argument: Existing tree management guidelines are inadequate for Singapore's tropical environment.
  • Evidence: Current guidelines are based on temperate region practices, which do not account for the unique characteristics of tropical trees.
• Argument: Technology is crucial for improving tree management.
  • Evidence: NParks uses GIS systems to track tree information, and sensors can detect early signs of decay and instability.
• Argument: Climate change necessitates a shift towards more resilient tree species.
  • Evidence: Ornamental trees may not survive future climate conditions, requiring a transition to native species.

Notable Quotes or Significant Statements with Proper Attribution

• "...incorrect pruning practices that can result in pass disease decay and eventually potential failure" - Speaker from NParks/LIAS
• "We've been remarkably successful over the past 20 years" - Dr. Shawn Lum
• "...green our hearts too" - Dr. Shawn Lum

Technical Terms, Concepts, or Specialized Vocabulary with Brief Explanations

• Arboriculture: The cultivation and management of trees.
• GIS (Geographic Information System): A system for capturing, storing, analyzing, and managing data linked to location.
• IHLs (Institutions of Higher Learning): Universities and other tertiary education institutions.
• Regenerative Tropical Microforest Systems: Landscaping approach that mimics natural forest ecosystems to promote biodiversity and ecological resilience.
• Native Trees: Tree species that naturally occur in a specific region.
• Ornamental Trees: Trees planted for their aesthetic value.

Logical Connections Between Different Sections and Ideas

• The need for new pruning guidelines stems from the inadequacy of existing temperate-based practices for tropical trees.
• Preventing tree failures is linked to understanding tree growth, proactive pruning, and planting the right tree in the right place.
• Technology is presented as a key tool for early detection of tree problems, complementing traditional arboricultural knowledge.
• The discussion of urban tree management naturally extends to the management of natural forests, highlighting the need for similar principles and strategies.
• The impact of climate change on tree survival leads to the discussion of selecting more resilient tree species and adapting planting schemes.

Data, Research Findings, or Statistics Mentioned

• Reduction of tree failure cases in Singapore from over 3,000 in 2001 to around 400 per year.

Brief Synthesis/Conclusion of the Main Takeaways

Singapore is proactively updating its tree management practices to better suit its tropical environment and address the challenges of climate change. The development of a new code of practice for pruning tropical trees, the integration of technology, and the shift towards native species are all key components of this effort. Collaboration between government agencies, industry professionals, and research institutions is essential for ensuring the long-term health and resilience of Singapore's urban and natural forests.