Soil Volume Simulator

Key Factors influencing suitable minimum soil rooting volumes for New Trees in Limited Spaces.

* Required

Minimum Soil Volume

Select from the dropdown lists below to work out the suitable simulated recommended minimum soil volume for your project.

How much of the surrounding soil (outside the tree pit) can be attributed to the total soil volume needed?


Shared Root Systems. Soil volumes can reduce when planting multiple trees in the same connected planting zone.

* Required

The Soil Volume Simulator. (SVS)

As part of the new Landscape Soils Handbook, Simon Leake and Elke Haege have developed the Soils Volume Simulator to assist their professions towards not just sustainable, but regenerative landscape environments.

The first part of the SVS allows tree planting scenarios to influence recommended soil volume through 5 selections.  Influencing factors on tree volume include:

  • – tree design size,
  • – climate,
  • – soil within the tree pit,
  • – maintenance including irrigation,
  • – design life (considering acceptability of tree stunting)


Our soil volume calculations are estimates from a combination of averages and ranges of scientific research results (as detailed in Leake and Haege, 2014, Appendix C) as well as published literature and combining soil testing experiments, observations, and experiences we have had and observed with different tree species.  We acknowledge that calculating soil volumes will always be a non-precise science based on the multitude of organic influencing factors.

We have all observed trees growing in available soil volumes that are much less in volume than the commonly recommended soil volumes from the literature, so by providing this SVS we hope it will encourage tree planting and not the opposite.

For the most part, trees will stunt according to the volume of soil (and hence water and nutrients) available to them and yet still provide adequate function as a street tree.
Rather than use measures such as crown spread height or diameter at breast height (DBH) of a fully mature naturally growing tree, we suggest the use of ‘design size at 15-20 years’ (in situ) to allow for the fact that a stunted tree might provide a perfectly adequate design response as intended.


The second part of the Soil Volume Simulator (SVS) incorporates the inclusion of surrounding soil to work out if and how much of the surrounding adjoining soil can contribute to the total soil volume.


The third part of the SVS is about ‘shared root zones’ which is the ability of trees of like species to share resources and have a shared network of root systems (and consequent reductions in overall volume can be made when this occurs).


We hope you find our Soil Volume Simulator (SVS) useful in planning for new trees in limited spaces or in formulating space requirements in all phases of regulation, planning, design and implementation.

Recently Simon Leake and Elke Haege presented on the Soil Volume Simulator for consulting arborists at The TREENET Symposium. You can see the presentation here.

Soils for Landscape Development

Elke, together with soil scientist Simon Leake, SESL Australia (www.sesl.com.au) have published 2 x award winning publication through CSIRO Publishing titled: “Soils for Landscape development: Selection, Specification and Validation”.

Click here for a link to CSIRO’s book sales site.


OLYMPUS DIGITAL CAMERAElke is delighted to announce she has won the Award of Excellence for Research and Communication in Landscape Architecture at the AILA NSW (Australian Institute of Landscape Architects) Awards. Nov 2014.

Elke and Simon won a 2nd award for this book through The Australian Institute of Horticulture (AIH) in 2015. Literature Award.

The book provides a set of ready-made soil specifications that will suit most landscape projects. It also provides a method for determining minimum soil volumes for trees in limited spaces which was developed in 2014 with the book and then updated to the online Soil Volume Simulator in 2017 which is available here.

Soils for landscape development

Soils for landscape development.

Jury citation: “The book makes an important contribution to the profession of landscape architecture and the community by providing a useful and functional set of assessment, specification and design tools based upon the rigour of a scientific methodology tested by extensive consultation framed by the significant and relevant experience of the authors”.

Jury citation: ‘This book demonstrates the excellence in an innovative and objective approach to the analysis, planning and specification of soils for landscape use that provides leadership and improvement to the whole landscape industry.  The influence demonstrated by this project is based upon extensive experience and collaboration in all areas of landscape works by both authors’.


Simon Leake, is this award winning book’s co-author with Elke. Simon has 30+ years of experience as Principal Soil Scientist of SESL Australia.