Tree protection when slacklining
The following has to be considered when slacklining with trees as anchors:
- Tree diametre of at least 30cm at anchor point, increase the diameter with higher tensions
- Tree protection under the tree sling, in order to prevent the sling of abrading the bark.
- Treeslings which are at least 5 cm wide (Slings should be spread out behind the tree to increase surface!)
We also recommend you proactively approach slackliners in your community about these issues - this helps the entire community! To do so, you can order these two flyers and distribute them:
The requirements mentioned above are based off DIN 79400 (the industry standard for slacklines) and are valid for slacklines rigged between trees where jumping off is feasible.
The strains that a slackline system puts on a tree can be broken down in three categories, in a simplyfied form.
The tension is the pull the slackline exerts on the tree. The tree needs to be able to withstand the loads pulling on it from slacklines unscathed. It is not easy to assess the maximum pull a tree can withstand. That is why we recommend a minimum diametre of 30cm at the height of the anchor to be sure that we are not damaging the tree. For medium to high tensions larger diameters are recommended. If you want to evaluate the forces in your slackline system you can take a look at this flyer or use this calculator.
The pressure, transferred from the slackline to the tree is, among other things, dependant on the tension of the line, the diametre of the tree, the width of the slings wrapping the tree and the thickness and quality of treeprotection used. The larger the tree and the wider the slings, the greater the area of contact of the sling and the lesser the pressure on the bark. Trees with thin bark are more vulnerable when it comes to pressure compared to trees with thick bark. To protect the tree it is adviseable to use slings of 5 and more cm in width (ideally spread out).
In order to protect the bark of the tree from the friction caused by the slings we use tree protection made from robust materials such as felt or carpet. This allows the sling to rub on the tree protection without damaging the bark and, with it, the tree. Tree protection that is 20cm high and 2-3 metres has proven to be suitable.
Take a look at the flyers if you don't know what tree protection looks like!
The following links contain detailed information (in German and English) on which we base our recommendations.