How To Protect Trees When Slacklining (Tree Protectors)

If you take a look at the pic above, you’ll see the damage that can potentially be caused by attaching a slackline without first using tree protection underneath. A tree protector may be a professionally made piece of felt with velcro to hold it in place or it may be a homemade DIY piece of old carpet to list but two options.

While the age of a tree and thickness of a tree are key factors of course, they aren’t the only ones.

While we’ve talked on this website about how big a tree should be before attaching a slackline to it, the hardness of a tree can also impact it over time. Some trees have softer wood than others whereas hardwoods are better able to withstand dents and wear.

Let’s take a closer look at the importance of tree protection and what you can do to avoid damaging any tree you attach your slackline to.

Why tree protection for slacklining is necessary

Tree protection doesn’t just protect the tree itself and the bark on the outside.

Using a tree protector before assembling your slackline does the following:

• Tree protection protects the bark and integrity of the tree. A damaged tree can experience infection, insect infestation or other hardship and at the extreme end, eventual death if the damage is severe enough.
• Tree protection protects the slackliner. I’ve heard about cases where tree bark cut through the slackline anchor system and the slackliner got hit in the leg with their own (metal) ratchet.
• Tree protection protects your slackline equipment. As per the picture at the top of the article, the slackline and related equipment may be damaged if it digs deeply into the tree.
• Tree protection protects you from the authorities. If you get caught in some jurisdictions without tree protection, you might get fined by a park ranger or other officer. Using a visible tree protector means you protect the tree and yourself from a fine.

Professional slackline tree protection

Professional slackline tree protectors are sold separately but often come as part of a slacklining kit. too.

Tree protectors commonly come with the following specs so be on the lookout for ones that have the following features to make it worth your time and money:

• Made of non-slip felt or other material to grip the tree while also protecting it.
• Velcro straps to attach the protector in place snugly so it doesn’t move.
• An extra large size of around 10.5″ x 5.5″ x 8.5″ or greater so that it’s big enough for large trees. Some smaller protectors won’t fit trees of a certain large size.

DIY slackline tree protection

If you’re unwilling to purchase a professional tree protector, here are some ideas you can use that might already be available in your home:

• Old carpet. Wrapping the tree bark with a roll of old scrap carpet (plush side touching the tree) will protect the tree from damage.
• Towels. Using old plush towels to wrap around the tree can create enough separation and cushion between the slackline and tree.
• Foam padding. A foam padding may be used around the tree as a tree protector. They’re typically available from a plumbing or hardware store in bulk and can be cut to size.
• Cardboard. Using somewhat thick cardboard may suffice to protect the trees if you’re in a pinch.

Tree hardness varies by tree type

Some trees can withstand more pressure and weight from a slackline than others and it isn’t strictly about the thickness of the tree trunk that you’re attaching to. Some trees are stronger and have harder wood than others.

That’s why you may have heard of trees classified as softwoods (i.e. pine, fir, spruce, cedar) and hardwoods (i.e. oak, walnut, maple, teak, etc). Some woods are suitable for flooring in your home and some aren’t because they aren’t hard enough.

Similarly it doesn’t hurt to know what type of tree(s) you have access to not only for the hardness factor but in case there are trees in your area that are protected, are known to be used by wasps for nests and things of that nature.

The most prevalent trees grown in North America are a combination of softwoods (several types of pine and fir) and hardwoods (maples, oak, aspen and sweetgum).

Janka hardness rating measures how hard wood is

The Janka hardness rating is a scale measured in pounds-force (lbf) to determine the hardness of a wood compared to other wood types. The resulting number in lbf lets us now how much force is required to push a small ball bearing halfway through a piece of a particular wood.

A Janka hardness rating of 1,000 lbf is generally regarded as being the minimum standard for hardwood flooring although lower rated woods can work well too. The purpose of the rating system is really to compare wood hardness to each other. The higher the Janka number the harder the wood.

To give you an idea, here are some popular Janka ratings in pounds-force (lbf):

• White cedar: 320 lbf
• Aspen: 380 lbf
• White pine: 420 lbf
• Douglas fir: 660 lbf
• Spruce: 510 lbf
• Sweetgum: 850 lbf
• Red maple: 950 lbf
• White oak: 1,360 lbf

Note that aspen is considered a hardwood but has a low Janka rating.

So if you’re choosing trees that are made of softer wood, it’s more critical that you properly cover them with tree protection to avoid damaging the bark or the tree as a whole before installing your slackline.

You can view Janka rating databases to see whether the trees you slackline with are hardwoods or softwoods and how they compare to each other in terms of their Janka ratings.