Urban Trees

Urban trees have huge ecosystem service benefit and social value, being close to people: cooling our cities and nurturing our wellbeing. However, they can be costly and challenging to establish in these settings. We wanted to test if new ideas could be cost-effective and yield a high survival rate.

This pilot is led by: Kent County Council

About the pilot

This pilot is assessing whether a Miyawaki style approach to establishing mini-woodlands in urban parks and green spaces can improve results. Newly planted urban trees can have high planting and maintenance costs and low survival rates. We wanted to see if these establishment costs could be reduced via this method.

We initially trialled Miyawaki style planting next to control plots and we continue to monitor the survival of these trees.

Watch our video

This pilot focuses on tree establishment and survival but we are also gathering information about tree growth, biodiversity and soil.

What is the Miyawaki method?

The Miyawaki method (named after its creator, Japanese botanist Dr Akira Miyawaki) involves dense planting of native species into enhanced soil to accelerate establishment.

“The Miyawaki method involves making sure the soil is healthy, aerated and adding mycorrhizal fungi and other biological materials to improve nutrient content, with densely, widely varied planted trees. Our method aims to rapidly create a small natural woodland compared to what might appear after decades and decades of natural growth. ”

Jackie Shallcross, Tree Council

Learnings

  • Survival rates seem to be very high in comparison to control plots, somewhere in the order of 95% compared to 75%, and clearly growth is much faster.
  • So far, Miyawaki establishment costs (so, including all the materials, planting, watering, combined with tree survival rates) are about 30% lower than in the control plots, due partly to the higher survival rates. We experienced a drought in 2022 and the Miyawaki plots remained green and lush in comparison to the control plots.
  • Urban trees face a variety of establishment challenges, and there can be a lot of competition for the underground space. At phase one of the urban trees pilot a report was commissioned to understand more about the potential conflicts between trees and utilities.

“We’re looking at this amazing difference between the two halves, the Miyawaki and the control that’s happened next to it, the difference is astonishing!”

Jon Stokes, Director of Trees, Science and Research, Tree Council

Next steps

Building on what we have learned so far, we are now testing which parts of the method might be more successful than others, for example just high-density planting, different soil preparations and mulch materials.

We also are testing whether elements of the method can be utilised in other settings, such as urban hedgerows and street trees.

Related resources

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