What is the Tree Protection Zone (TPZ)?
As we all know, there is far more to a tree that the aesthetically pleasing part above ground. A tree’s root system is critical both in terms of nourishing the tree and stability; as such, they need to be protected.
This is where the Tree Protection Zone comes in; the Tree Protection Zone is a specific area set aside surrounding a tree which is in place to protect the roots and crown and to give the tree a fighting chance against any nearby developments.
Roots often cannot be seen and crowns rather grow in an even manner, so the TPZ is often an approximation or best guess; the only way to truly identify where a tree’s roots are is by hydro or air excavation which must be carefully carried out by a qualified arborist.
When do you need to calculate the Tree Protection Zone?
There are certain times when calculating the TPZ is an absolute must; they are:
- Before carrying out excavation or fills close to a tree
- Before submitting an application to complete a development
It’s essential that no proposed development encroaches on the Tree Protection Zone of any tree on or adjacent to the proposed site. If it does, it is likely that your plans will need to be amended or they may just be rejected outright depending on the significance or the tree(s) or the number of trees that are affected.
What is the Structural Root Zone (SRZ)?
The Structural Root Zone focuses primarily on the stability of the tree; understanding the Structural Root Zone helps you to understand more about the tree’s structural stability, how you may respond to having to work around it and what measures you can safely take or avoid altogether.
The Structural Root Zone is essential when it comes to stability; if the tree experiences loss of any roots in the Structural Root Zone its overall stability will be compromised and it can become unstable to the point of collapse which nobody wants to see.
When should you calculate the Structural Root Zone?
It’s important that the Structural Root Zone is calculated if any major disturbance to the Tree Protection Zone is planned; safeguarding the trees in the area should be of paramount importance.
How to calculate the Structural Root Zone
The calculation itself is a very simplistic one; you use the diameter of the trunk taken from directly above the root flare.
For more information on any of the above information please don’t hesitate to get in touch