Urban Structural Tree Soil

A strongly alkaline, non-saline, non-calcareous, and stone-free sand with an adequate structure. It contains sufficient organic matter and most major plant nutrients, although it is slightly deficient in total nitrogen. None of the potential contaminants exceeded their respective guideline values, confirming the material's suitability for landscaping applications.

The horticultural and geotechnical properties indicate that this sample is appropriate for structural urban tree soil applications. However, reduced air-filled porosity suggests that in a compacted state, aeration could be limited, potentially affecting root function. To address this, additional aeration measures within the tree pit design are recommended. Furthermore, incorporating a suitable soil conditioner would enhance the material’s nutrient retention capacity and help remedy the nitrogen deficiency.

To minimise the risk of anaerobic conditions in the tree pit, it is advisable that this material is not placed deeper than 600 mm. Beneath this layer, a suitable washed sand, ideally matching the particle size distribution of this sample, should be used to maintain proper drainage.

With these considerations in place, this structural urban tree soil can be effectively utilised to support healthy tree growth in hard landscape settings.