Planting trees is a positive step for the environment, but the tree guards that are provided to protect the saplings are frequently not. Traditionally, these guards are made of polypropylene – a type of durable plastic – and used to protect young trees against weeds, sprayed herbicides and animal predators for the first few years after planting. Guards can be tube-shaped sleeves, or flexible spirals, which work well for newly planted hedgerow species. On certain sites, the use of tree guards can really improve the success rate of tree planting programmes.
Plastic guards are popular, as their durability allows for the extended protection of young trees without breakdown due to sunlight damage. However, there are many concerns about their use, as once a tree outgrows its shelter, the guards are often forgotten, resulting in the scattering of plastic pieces in the soil.
Alternatives to plastic tree guards
Currently, there are few available alternatives to plastic tree guards. For those that exist, such as guards made of plant-based materials or compressed paper and card, the cost may be prohibitive, particularly for larger planting schemes. Tree planters have also reported mixed results, with the guards often snapping.
However, while they can be brittle, the need for them to be durable – to withstand harsh weather and damage from wildlife – means that even guards described as ‘eco’ or biodegradable may take 200 years to fully break down, potentially outliving the trees they are designed to protect.
If you are using guards, it is therefore essential to develop a good management plan to avoid environmental damage. The plan should consider how long guards will need to be in place, who will remove them, and the budget needed for these activities. Consider bringing in hospital volunteers or “Friend of” groups on a longer term basis; this can be a good opportunity to educate the wider community in tree and woodland management, and some of our NHS Forest sites with woodlands have been very successful with this approach.
There are companies that recycle many types of plastic guard – so this needs to be factored in, too. If the guards are still in good condition, or have been used for a shorter time, you may even be able to reuse them on your own site.
You may also be able to look into whether the guards themselves are made of recycled plastic – this still needs management on the ground, but reduces the environmental impacts further up the supply chain.
Do I need a tree guard?
A better approach is to look into whether the guard is needed at all. Trees planted on healthcare sites, in particular, may not be exposed to the main threats that exist on other site, reducing the impact of the tree guards.
Deer, rabbits and voles can pose problems for young trees, but they will not be present on many sites, particularly those in more urban areas, or if trees are planted close to buildings. Ensuring a weed-free space around the base of the tree – or around a metre diameter – can also reduce the chances of attack by certain predators, as well as reducing competition for water and nutrients, giving you tree the best chance of survival.
Squirrels may pose more of a threat, especially if planting whips (young trees under a metre tall) – discuss the issue with the estates and grounds teams to assess the risk, and speak with the tree nursery to see what they advise.
Getting grounds teams on board
Working closely with the grounds teams is essential for any successful tree planting project; this can include avoiding spraying harmful herbicides and pesticides close to newly planted trees. Some trusts and health boards have already committed to phasing out the use of certain chemical sprays. Weeding should be part of a management plan, too: by grounds teams, or hospital volunteer groups.
One of the biggest risks posed to young trees comes, unfortunately, from people – often unknowingly. Whips (young trees under a metre tall) can be damaged or destroyed by lawnmowers and strimmers, and guards or other markings can make them more visible – but again, working with grounds teams is the best way to reduce the likelihood of this happening.
Although the NHS Forest typically encourages opportunities for people to engage in green spaces, fencing off young trees may be advisable while they are still small. This can protect them from accidental damage, without the need for tree guards, if there are a number of new trees clustered in one area. The fences can be removed when the trees have grown – tree planting produces long-term benefits!
A future without plastic tree guards?
The Woodland Trust has committed to no more single-use plastic tree guards on its land since the end of 2021; currently, around half of its newly planted trees need protection from deer. The organisation is trialling a range of biodegradable tree guards made from waste products, to find the best alternatives, and is also funding research into new materials.
Guidance from the Woodland Trust
Study: The environmental performance of protecting seedlings with plastic tree shelters for afforestation in temperate oceanic regions: A UK case study
Banner photo: Tree planting at Fairfields, York. Credit Alexis Percival / Yorkshire Ambulance Service 2022. Attribution 4.0 International (CC BY 4.0).