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In the tree world people are becoming more aware of the importance of trees. The only thing missing is the courage to act when they get older. We (too) often remain routed in our old traditions. The systematic execution of tree safety controls says a lot about our way of thinking when it comes to nature. This system often leads to the removal of trees because they could be a risk. Ever considered that the high risk trees are ecologically the most important? Which raises the question with me: why do we as a race cause so much damage to nature?

Tree safety controls

Since the 1990s tree safety controls have been carried out systematically. This method, visually inspecting trees for problems, often labelled VTA Visual Tree Assessment, was mainly developed by Claus Mattheck and was then eagerly adopted by international tree controllers. Mattheck knew, in an accessible way, how to assess the condition and risks of trees based on their body language. This system has since evolved, but the core of the assessment remains the same. The success of the tree safety check lies in the liability that can arise by damage caused by a tree. The owner of a tree, in cases of damage, needs to show that sufficient care has been taken for the tree. This is called duty of care in the professional world. A broad term, with commercial potential, which lets the owner know what is expected from them. All sounds very reasonable and in theory a good system. Nice to have an overview of your possessions and how it’s going with your ‘green capital’.


Risk avoidant management

We control nearly all trees in towns usually every 3-5 years with a tree safety control. A tree with potential risks is labelled as a ‘risk’ with measures and timescale noted. A woodpecker hole for example is seen as a defect and this can be enough reason to list this tree as a risk. Trees which cannot wait until the next planned assessment to have their defects assessed are listed as ‘trees of attention’. Because of this we let possible risks dictate our tree management. The result? We regularly go over the top to eliminate risks, also in places where there are no risks.

Strong co dominant stems in pine

Strong co dominant stems in pine

Trees are relieved of their dying branches and other potential dangers. We see a rib in a branch junction regularly as a included bark with all its associated risks. Averagely speaking we also find double co dominant stems scary. But is that really the case? Or are we talking about ghosts, or imaginary tree care problems? Branches that stick in the crown, where the risks are not well understood, we put anchors in. And then there is the whole category of impairments and abnormalities which with a lack of experience can be difficult to comprehend and the easy option is then to declare them a risk to safety. And what if I’m a tree manager with a limited budget? The tree safety control is completed and then I receive a bulk list of risk/attention trees. With a limited budget a one-off felling measure is more attractive than further survey, extra measures, more frequent inspections etc. I am convinced that the tree safety system has meant that we have lost of lots of, predominantly older, trees. Analysis of Dutch municipality tree populations shows that only a small percentage (some less than 5%) is older than 60 years old.

‘Prevention is better than the cure’ is the mantra where the importance of man has led to such a poor tree population.


Ecological score

A tree is never an isolated organism. The older they become the more interactions they have with organisms. The oldest trees are therefore the most important for ecology, due to all the connections over the years. A native tree usually has more connections/interactions than an introduced species and plays home to a larger diversity of. Our current tree safety system does nothing to improve the lives of other fauna co-existing with trees. A woodpecker hole can be a defect with potential risks to people, but it represents an ecological value which is not considered.

The new Dutch ‘Omgevingswet’ (environment law), but also societies perception, is that we need to protect and recover biodiversity. This is not only our duty but we owe this to the living environment that we have created. A living environment where we do not know what the ecological values present in trees are, but we have registered all the broken branches. It is time that we find a new balance to our current tree safety management. It could be that our risk and attention trees, the ones most likely to be destroyed by human hands, contribute the largest to our ecology. We just don’t know.


Dendrotelma provide great opportunities to other organism 

To understand what we need to protect we need to know what we have. Unknown is un-loved. There is no system for scoring trees on their ecological value. Therefore Terra Nostra has developed the ecological score in addition to the tree safety control. The method assesses and scores tree habitat and biotope in the field of every individual tree. Among other things the tree habitat scores the presence in or on the tree of epiphyten such as mosses, fungi or algaes. The habitat features that are scored, are broken branches, holes, vertical splits. Also ground created in holes or holes filled with water, called dendrotelma add to tree habitat. Scoring of tree biotope is centred on the surrounds of the tree. What is the location like, are there trees of similar age nearby, what is the replacement time of the tree: now or within 50 years? Do birds or mammals use the tree for resting or nesting? Is the tree species native or introduced, are they known for their large biodiversity, fruit or blossom? In total 12 factors with 5 options each are taken into account scored by ecologists, tree experts and scientists.

 Veteran tree

Veteran tree with ecological biotope

Ecological management

With insight into the ecological value of trees you can start to manage differently. We need to understand that nature, including trees, need to be respected as something that has rights to be there. It is then necessary to separate the domain of humans with the domain of trees, as both have a right to exist. Where the domain of trees threatens that of humans, measures need to be taken to limit the risks. Sometimes you can move the domain of the humans outside the zone of the tree if negative ecological consequences could occur from taking action. Eg parks where risks to humans may occur but can be avoided by moving paths or carrying out more extensive management. A natural way to divert people away from the domain of the tree. Safe areas need to be clearly marked as human domain, outside these zones we are only guests in the domain of other organisms. Where the domain of humans threatens that of trees, humans then need to stand up for the protection of the trees. A tree does not have its own voice. Ecology has the right to exist. I see this as a challenge in our ever more urban environment, but I definitely wouldn’t rule it out. We just need willpower to see the possibilities which are definitely present.

Mesh to clean or ecological diamond

Mess to clean up or ecological pearl

Basic attitude towards nature

Duty of care is a good example of our basic attitude towards nature. It was the environmental philosopher Matthijs Schouten who helped show me global views and our Western attitude towards nature. For more than 2000 years Western culture has believed that it’s above nature and nature is only present for man’s benefit. We need to realise that all crises come from human behaviour. We think that nature is from, and for, us. It’s this behaviour which has brought us to the point we have now reached: a period of time identifiable by environmental, climate and biodiversity crises. We should place ourselves as stewards or partners of nature, instead of controller or owner. In that way we would have a completely different attitude. We would be able to shake loose the idea that nature is a big storage shed and only present to serve us! Let me focus on trees and not get lost in a world which is much too big for me.

I am stubbornly convinced that if we know what we have with regards ecological value, that we will head towards a more nature following management. Of course we have to remain alert for the safety of people in public areas. But it shouldn’t be that we only think about safety.

I would like to propose the following statement: the safest tree is no tree. In other words: there will always be risks, but these should be checked against the values that we do not yet know or recognise. The risks that trees create are very small, very limited when compared to especially traffic. The energy we put into lowering the risks caused by trees is disproportionately high. We could invest a large amount of this energy in keeping old trees standing upright or planting trees with a guaranteed long future. Because in urban environments we are an important partner for trees to help them get established and flourish. And the risks? Did you know wearing a helmet in the car halves the risk of a fatal accident? Helmet on in the car tomorrow?

Bringing change is a question of getting on with it. Not enjoying nature on a Sunday afternoon then making decisions on a Monday which conflict with this! If graphs and statistics could save the world, then it would have happened a long time ago. It’s now down to you to make changes. If you really appreciate the importance of trees, then you give trees a chair at the board meeting and stand up for their importance. How small a step, every step helps.

If not us, then who? If not now, then when?

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