The Overlooked Benefits of Tree Grilles

Originally, trees became part of the urban landscape usually as remnant trees; trees that were part of a previous rural landscape and had been incorporated into the expanding urban landscape.


Originally, trees became part of the urban landscape usually as remnant trees; trees that were part of a previous rural landscape and had been incorporated into the expanding urban landscape. It was not until arguably the second half of the nineteenth century during the Victorian tree movement, that urban trees started to be thought about and incorporated in the street scape, taking their cue from the much earlier street planting in Amsterdam, and the early nineteenth century boulevards of Paris.

Tree grilles however, have been used for mere decades as opposed to centuries, first appearing as a regular feature in the 1960/70s. Before this, trees were just left with a space in the paving into which they could expand, if they were lucky. Sometimes the tarmac pavement was laid right up to the tree trunk, which never ended up well – for the pavement.

Grilles play an important role in the creation of a successful urban tree pit, and not only for decoration. The most obvious benefits are aeration and irrigation. The grille allows both air and water, and to a small degree sunlight, direct access above and immediately around the root ball, helping the young tree to establish.

As well as this, they protect the area immediately around the rootball from compaction, through either pedestrian footfall, or over-run from bikes or other wheeled vehicles. Without the protective grilles the area above the rootball would become compacted, resulting compromised transmission of air and water, and a damaged rootball, all of which would be detrimental to the tree’s healthy establishment. Added to this, you could well end up with uneven paving, resulting in remedial costs and possible litigation from trips and falls.

Two more secondary benefits are more about helping to keep the area around the tree base tidy. Grilles can reduce the build-up of litter that a recessed dip may otherwise gather, and they can also hold back weed growth, or at least keep it in check below the grille so that it doesn’t look quite as messy.

Grilles also help to improve the aesthetic appeal, offering a stylish visual link between soft and hard landscaping. But they don’t need to be plain or boring. Here at Green-tech we offer a wide range of grilles to suit every environment.

The most often chosen material, and arguably the most hard-wearing is cast iron. Manufactured from recycled engineering grade 250 cast iron, these grilles have a design life of around one hundred years. Made to order in one of our local foundries here in Yorkshire that has been casting since 1907, they can be customised to individual requirements, featuring irrigation or uplighter holes, and can be finished in almost any RAL or BS colour. We have seven standard designs to choose from.

For a more natural look, you may opt for our Resi-grille. Not a grill as such, but a base tray filled with a permeable bound resin/gravel mix, which lets air and water be absorbed into the tree pit. The gravel can be spec’ed to a range of colours to suit the surrounding paving.

Along similar lines, there is the extremely popular Fortress grille, but instead of resin bound gravel, the base tray is designed to take paving or block sets, to form a seamless continuation with the surrounding flag stones or paving. We can see examples of these below at Library Street in London, and Bridlington Station Plaza.

When it comes to something a little different, you can choose from several stainless-steel designs which offer a modern, urban look, able to be custom made to suit your design. First is a contemporary slotted grille with a polished finish, which is both smart and practical, but the real showstoppers are our laser cut grilles.

These laser cut designs still use 316 grade stainless steel, so will stand the test of time, but the geometric or free-flowing patterns which are laser cut into the surface also provide a fantastic range of looks. If you want a particular pattern, that can be accommodated as well. These grilles are so easy to fit and look so good that we wouldn’t be surprised to see more and more being spec’d in the urban realm. The photo below shows a custom-made grille for Blackburn Council, depicting the music industry throughout the decades, part of a set of six.

The stainless steel is finished brush polished, although other finishes are available. The laser cut grilles can be polished, or powder coated in any RAL/BS colour. Or for a rustic effect, you can choose Corten Steel, which is left as bare metal to passivate to a rust-coloured finish.

If you would like to know more on urban tree grilles, or any aspect of urban tree planting, I am always happy to hold a remote CPD presentation through Microsoft Teams at any time to suit. Please just contact me to arrange.

01423 332177


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