How to plant a street tree: Q&A with Greg Packman

We are currently fundraising to plant 200 trees in Islington, to help combat climate change.

Many of the trees will be planted along streets, where they will be maintained by the tree team at Islington Council.

We spoke to Greg Packman, the Council’s Senior tree inspector, to find out more about the task of planting and maintaining these trees.

What is the best part of your job?

Getting to work outdoors most days, alongside the trees!

You can find all manner of unusual species or trees that have grown in an unusual shape, or at certain times of year you can encounter a stunning blossom display or phenomenal autumn colour. Being able to see some of the hidden parts of Islington that I may not have seen otherwise is really nice as well.

Which tree species are best for streets?

Tough question! It depends on various factors such as the size of the road, pavement, overhead space and what is below ground – especially the soil!

On larger streets, trees such as the London plane can be great as they are more tolerant of urban life, filter more pollution, cast more shade, cool the air temperature and so much more. Other large-canopied trees such as Tulip tree or a group of South American trees known as the Nothofagus are also really interesting.

On smaller and residential streets, I’m a huge fan of the hawthorn as a street tree. You can buy special varieties that have fewer thorns and a more upright form that fits into the street. I think they’re great as they are fairly compact and shouldn’t need too much pruning. They are quite tough, have a wonderful flower that is both visually attractive and ecologically important as well as producing berries (haws) in the autumn.

There are a whole range of smaller trees that work very well on residential streets such as cherry trees, Magnolia and Hibiscus that are all wonderful flowering trees. There are a also range of maples that have lovely autumn colour and some amazing species of birch such as the Chinese red birch or American river birch that have stunning bark.

We do have to be quite mindful of the soil type and water demand of the trees we plant. Much of Islington is on shrinkable clay soils, which combined with prolonged drought and trees that have a high water demand can see an increase in subsidence claims – this plays a role in our species selection for certain areas of the borough. With temperatures increasing and reduced water availability in highways we do look for drought resistant trees as well.

What is involved in physically planting street trees?

The tree team goes around the borough looking for suitable locations to plant trees. On highways it could be fairly straightforward if there is an existing tree pit but no tree. Otherwise, if there is a space in the pavement, we’ll look at what else is in the immediate area such as utilities, street furniture, driveways or drop curbs, access routes and the width of the pavement.

If we think the location is suitable we’ll do another check for underground and unseen utility lines. After this, a suitable tree species is chosen which is based on the available growing space, soil type and general suitability of the tree.

For the planting, our contractors have to use machinery or tools to remove the hard surfacing to dig the tree pit which is usually 1m x 1m, but can be larger or smaller depending on the size of the tree and width of the pavement.

They’ll then place the tree in the tree pit, making sure that it is level and has as much growing space as possible and an irrigation pipe will be installed.

The planting hole is then back-filled and staked to stabilise the tree. Sometimes, resin bonded gravel or another surface will be placed over the planting pit, or it may be left as soil and mulch. Planted tree pits add to the biodiversity of the borough and, crucially, provide food for both bees and butterflies.

Pipes and bags work by slow-releasing water into the rooting area and distributing it over a wider area. With pipes there will be an above ground nozzle, then the underground pipe will circle the root ball and release water all around the tree. Bags wrap around the trunk with an opening at the top to pour in water, this takes longer to distribute all of the water so more can filtrate in to the soil.

The amount of watering required depends on the age and size of the tree when it is planted, plus the local environmental conditions. A larger planted tree needs much more water to help it establish than a smaller tree. The general practice is that from May to September then newly planted trees need around 50 litres per week, sometimes more during droughts if the tree is struggling.

Young trees are staked to support them from the wind. Although trees are naturally flexible, especially when they are young, the wind can blow them to the extent that their shape can be distorted. The tie that supports the tree to the stake shouldn’t be so tight that it constricts the tree’s growth. The stake and tie should be removed when the tree no longer needs it.

Often, newly planted trees will also have metal cages placed around them to protect them from vehicle damage.

How can a community get involved?

In my opinion, the best thing that a local community can do is to get to know their local trees and keep an eye on them. If the trees look like they are struggling over summer, then giving them some extra water can really help a lot.

If you think there is something more serious, such as disease or damage, then get in touch with the tree department so we can visit the tree.

You can use free resources from Observatree, The Woodland Trust, The Tree Council or The Arboricultural Association to learn about young tree maintenance and tree health with some of the more common pests and diseases.

After the tree has been planted for over a year, if the location is suitable you could also take part in our tree pit planting.

What are you most excited about in the Islington Forest for Trees project?

Getting new trees is always great and an exciting moment!

Having legacy trees is also special as well. There could be any number of great community projects such as creating a tree trail of the new trees across the borough.

I’ve always been very community focused with my work, so getting to collaborate with community groups and projects is always a nice thing to do.

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The Islington Forest for Change crowdfunder runs until 28th July 2021. For a donation of £150, you can sponsor a tree in the name of an individual or organisation.