The Tree Course: Science, Design, and Sustainability

This course examines the scientific, economic, and aesthetic benefits of trees, the science of healthy and mature trees, trees as design elements, trees and site requirements, trees that outlive designs, and threats to trees.

The curriculum addresses the critical concept of "Deforestation by Design," exploring how well-intentioned projects often fail due to a fundamental misunderstanding of tree biology—specifically regarding root systems and soil requirements. Participants will dive deep into the inherent conflict between engineering specifications for soil compaction and the biological needs of tree roots, learning how to reconcile these opposing forces through modern solutions like structural soils, soil profile rebuilding, and suspended pavement systems.

Key topics covered in this course include:

• Tree Benefits and Value: An analysis of the quantifiable economic, environmental, and social health benefits of the urban canopy, including stormwater mitigation, heat island reduction, and impacts on human mental health.
• Tree Biology and Myths: Debunking common misconceptions about taproots and root depth, understanding phototropism, and the critical role of sunlight and photosynthesis.
• Soil Science for Design: A deep dive into soil texture, structure, and density, including the impact of construction compaction on root survival and hydrology.
• Nursery Stock Quality: How to identify and reject poor nursery stock, specifically looking for circling roots, buried root flares, and structural defects that lead to premature failure.
• Installation and Maintenance Standards: Best practices based on ANSI A300 standards, including proper planting depth, mulching techniques, and the dangers of "volcano mulching."
• Tree Biomechanics: Understanding how trees physically respond to wind loads and gravity, and why "lion-tailing" and improper pruning weaken tree structure.
• Sustainable Design Solutions: Practical strategies for creating adequate soil volume in paved environments, protecting trees during construction, and selecting the right tree for the right place.

By the end of this course, professionals will possess the diagnostic skills to evaluate site conditions, the vocabulary to communicate effectively across disciplines, and the technical knowledge to design landscapes where trees do not just survive, but appreciate in value as sustainable infrastructure.