Statutory Tree Protection – Time for a Rethink?

By Andrew Igoea, Senior Arboricultural Consultant

Until recently I was the Government’s senior tree officer. Part of my role at DEFA was to administer the Tree Preservation Act 1993 (TPA), so I can speak with some authority about the law and policies which are meant to protect trees on the Island, and I am well placed to critique our current system of statutory tree protection.

The TPA exists to protect amenity trees – those trees which the general population derive pleasure from due to their aesthetic qualities, or their contribution to the character or setting of an area. The current law prevents the felling of any tree with a stem thicker than 8cm (roughly the size of a tin of baked beans) at chest height without a licence issued by DEFA. It is important to point out – for reasons that will become clear – that this includes small trees. The law also provides a higher level of protection for trees which are ‘registered’, preventing any kind of pruning, above or below ground, without a licence. When both these elements are put together, it means that the Island has the highest level of statutory protection provided to trees anywhere in the British Isles – probably the whole of Europe.

So, what’s the problem? Listed below are some issues I discovered during my time working for DEFA.

Don’t sweat the small stuff.
Since the early 90’s research by Helliwell (and many others) has shown that there is a clear relationship between the size of a tree and its amenity value. This was an intuitive, common-sense finding. The bigger a tree is the more visible it is likely to be and, the more visible a tree is, the more likely it is to contribute to the character of an area, and the more likely people are to derive pleasure from it.
Does it matter that the TPA protects small trees, even though these trees are unlikely to deliver few amenity benefits? Surely, more protection is always better than less? Well, not if you also consider the costs of delivering the protection. Under the current law DEFA has cast its regulatory net very wide, and it catches a lot of trees. DEFA processes between 800-900 applications annually and each application must be processed and assessed at a cost to the taxpayer.
The School of Government at Harvard University created the Venn diagram below to explain how good regulation should function and it illustrates where a regulator’s attention should be focused.

My experience in the Isle of Man is that these circles are not overlapping enough; around 99% of applications for a licence are approved. Statutory protection – a function of government that the public pay for through taxes – should be focussed on trees delivering the highest amenity benefit i.e. the highest public benefit. But resource allocation is not the only issue. There are other trade-offs worth considering; trade-offs of a more philosophical nature.

Choose Life. Choose a job…. Choose a f****** big television.
Any regulations imposed by a government on its people are an infringement on their individual liberty – their right to do as they see fit. We accept a range of regulations in our day-to-day lives for the benefits they deliver to society: they save lives, protect us and give us a better quality of life.

As discussed above, the TPA effectively protects all trees, including a great number of small ornamental trees and hedgerow trees in domestic gardens. Some of these trees may be in back gardens, not visible to anybody but the applicant, the owner of the tree.

So, the TPA controls whether you can remove a tree in your garden, but if small trees, particularly small trees in back gardens, deliver few amenity benefits, should the people of the Isle of Man accept this significant infringement on their liberty for potentially meagre benefits?

The times they are a-changin
Shortly before the current law was introduced the 1991 census reported the population to be 69,788. In 2021, the population has increased to 84,069.

In 1991, there were 27,327 private ‘households’. Unfortunately, this headline figure doesn’t tell us what percentage of those private households were flats or apartments – households unlikely to have their own garden. In 2021, the total number of households was 37,220, 30,240 of which were detached, semi-detached or terraced houses (households likely to have a garden).


Total number of households

Total number of households likely to have a garden













This data shows that, due to continued population growth and continued housing development to provide homes for these people, there are many more people affected by the restrictions placed on small trees in private gardens now than there were 30 years ago.

Getting away with murder
Well, not quite. In fact, if a tree is not registered, the only restriction on pruning is that it shouldn’t lead to the immediate death of the tree, but this still gives you a pretty wide remit. This means that whilst the government controls whether you can remove a tree in your back garden, you are free to hack it to bits and remove any amenity value it might have provided to the outside world (unless its registered).

But hang on…the stated aim of the legislation is to preserve the amenity value provided by trees. Why would the government control whether you can remove that tree in your garden if, in doing so, they are not necessarily protecting its amenity value? Its not a very effective way of achieving the stated aim.

 Conclusion: Starve your distractions, feed your focus.

So, if the government was to stop focusing on the removal of small trees which deliver very few amenity benefits, and which are increasingly located in people’s gardens, where they should have the freedom to manage the land as they see fit, where should it shift its focus to?

Firstly, it should deliver the highest level of protection to the highest value trees. Simple.

Secondly, it should tackle the source of the problem. You see, trees only need to be removed or pruned when there is a conflict between trees and society: when we live, work, or travel close to trees they need to be managed. The place where nature and society meet, is often within the planning process. Sustainable development should aim to retain and protect existing trees and deliver quality landscapes with new tree planting. DEFA should be committing more resources to making sure this happens.

In my opinion, DEFA should remove the distraction of small garden trees and refocus on trees which deliver the highest environmental, social, and economic benefits, or on trees that are at risk of damage or removal at the frontier of society’s continued encroachment into nature.