What do Architects need to know about Trees? Video 1 of Designing Around Trees Series

Trees are beautiful aesthetic features, but they’re also vital components of our cities and communities. And we need to design carefully around them, so that they’ll be around for many years to come.

As an arboricultural consultant (and former landscape designer) I understand the value of trees and how we can design around them. This series of videos intends to help designers to work with trees so that they’ll live a long healthy life when the project is over. And along with each video, I’ll be providing free resources to help you do just that – check the links below to get your hands on those.

So what’s the deal with trees?

What do they need? How do they work? And what’s design got to do with it?

tree assessment consultation program

The three main components of a tree are the foliage, the stem and branches, and the roots. So in this example, the tree has a 400mm DBH (“diameter at breast height” – breast height being 1.4m) and we can calculate the Tree Protection Zone (TPZ) and Structural Root Zone (SRZ) using this measurement (although the SRZ is calculated on the trunk diameter above the root buttress which is often between 10-35% larger than the DBH).

Roots absorb water, air and nutrients, and provide structural support
Foliage (leaves) photosynthesise to feed the tree
Trunk and branches transport the water, nutrients and sugars and provide the tree’s structure

Want to download the New Leaf Tree Dimensions Cheatsheet?

The Tree Protection Zone

The TPZ is the area of roots that the tree needs to survive – to take in water, oxygen and nutrients to sustain itself and grow. The fibrous or feeder roots are located within this area (and beyond) and this is the zone we need to start with when we’re designing, so that the tree can continue to live into the future. And be aware that tree roots generally exist in the top 0.5-1m of soil and often right at the surface.
[pic of tree with TPZ & SRZ shown]

Arboricultural services

The Structural Root Zone

So what are structural roots? They’re the parts of the tree responsible for holding the tree upright and stable – kind of like a footing for a building. But trees are living things, and they need all of their roots, not just the structural roots, to survive. The really important thing to remember is that structural roots don’t grow back. They are the original network of roots starting from the trunk that the tree began its life with, and have grown in response to the tree’s physical and environmental needs for structural stability. The effects of cutting or damaging tree roots may not be apparent until the next storm event, or in many cases, until decay has formed within the root system which weakens the tree’s anchorage. So while trees failing in storms seems like an unpredictable event, it’s often evident that some root damage has happened which contributed to the tree’s instability.

Terms in Tree Management and Arboriculture in Australia

  • Tree Protection Zone and Structural Root Zone (NOT Critical Root Zone or Primary Root Zone – these are from the British Standard which has been superceded by our own Australian Standard AS4970)
  • Tree Removal (not demolition)
  • Tree Retention / Trees to be retained
  • Pruning is not the same as lopping

List of Actions & Works that Can Impact Trees [link]

If you want to work with me directly on your next project, there is a simple quote request form on the New Leaf website. Or contact New Leaf now.

Download the List of Actions & Works that can Impact Trees

Collab with New Leaf

If you want to work with me directly on your next project, there is a simple quote request form on the New Leaf website. Or contact New Leaf now.

Previous Post
What is a Consulting Arborist?
Next Post
Applying the Scientific Method to Tree Assessment

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