Proposed Comments to the City of Boulder

With thanks to Katie Frayler – though many of the words are my own, and each slackliner should feel free to send what they think best.

Katie’s original comments are available on her Facebook page.



Jeff Haley
Planning, Design and Community Engagement Manager
Boulder Parks and Recreation
3198 Broadway, Boulder, CO 80304




Dear Mr. Haley:

As a member of the Boulder slacklining community, I’m excited to work with you on the movement to legalize this sport in Boulder parks. Slacklining has been an important part of my life and family; I first walked a slackline over 30 years ago in college, and both of my sons have become accomplished slackliners, active in the community and competing at a high level.  I’m really proud of them, and what they’ve learned since they took their first steps on the line.

I’ve reviewed the proposed slacklining rules from the City of Boulder, and have some suggestions that I think better fit how our community slacklines. Most of the rules are great, and the only area I have suggestions is under Rule 8.

I would suggest that Rule 8 be changed to read as follows:

8. Slacklines may only be affixed to trees in the manner set forth below:

A. Only trees greater than one foot in diameter at a height of 48″ from ground level may be used as anchor posts.  Only trees approved by the City Forester may be used as anchors for this activity.

B. To protect the bark on the trees some type of tree protection material must be placed between the tree and the line that is tied to the tree.  Material must be at least 1/4″ inch thick such as carpet squares, form padding or similar material.  At no time should any cabling, wires or lines be in direct contact with the bark of the tree.

C. The slackline may not be elevated to a height of more than four feet at the center of the span, when the slackliner is on the line. A clear and flat landing surface must be present under the full length of the slackline.

D. The slackline may not obstruct the intended uses of the greenspace, sidewalks, buildings, roads, streets, playgrounds, bikeways, water features, sports courts, bike racks, handrails, art objects, fences or light poles.

E. When the slackline length exceeds 50 feet, visible safety tags or flags must be used in order to alert park users that the line is in place.

F. The center of a slackline may not be within 20 feet of sidewalks, buildings, roads, streets, playgrounds, bikeways, water features, sport courts, bike racks, handrails art objects, fences or light poles.

G. Trees and/or landscape areas showing damage from slacklining activities may be restricted from future slacklining activities at the discretion of the City Manager.

H. Slacklines may only be attached to approved trees, and may not be affixed to other infrastructure including but not limited to buildings, bike racks, handrails, art objects, fences or light poles.

My suggested changes are focused in the following areas:

  • Sub-section A: We were expecting that the acceptable trees would be identified on the City’s website, and that we would help support a sign or two at each park, referencing the city’s site for more information. I’m not sure it makes sense to have a sign on each tree.
  • Sub-section C: Depending on the location, we’d suggest that the high restriction be changed to read ‘no higher than 4 feet when the slackliner is on the line’ – because of variations in the ground in parks, that seems to make more sense, and meet the spirit of keeping the lines at reasonable height.
  • Sub-section D: Many slackliners prefer longer lines than 50 feet. In many cases, these are the preferred line to walk on.   When we presented suggested trees to the City, we identified parks where longer lines can be safely used, and don’t obstruct other park users.
  • Sub-section E: I would suggest only requiring flagging on longer lines; shorter lines are typically much more visible.
  • Sub-section H: I would suggest that we eliminate the requirement to post notice on each approved tree

Under CU Boulder Campus regulations, along with the Business School and Naropa, if a space is reserved in advance, students are permitted to rig slacklines from 250 up to 600 feet long. For reference, the current longest slackline crossed on the ground is about 2,000 feet long. For longer lines, we think it’s reasonable to use safety tags to ensure the line is visible to all.

The slacklining community is excited and willing to organize and fundraise to support the enactment of regulations that reflect the work we have put in to help define what reasonable slacklining regulations will look like. We hope that you can take our comments under consideration, and we can jointly create a set of rules that are not only acceptable to our community members, but easier to enforce.

Last week, the Spot Bouldering Gym held one of their ‘Slacktopia’ events. It was a huge success, with around 200 people attending. The Spot gave me some time to speak to the crowd, and we’ve encouraged people to reach out with comments to you. Several people came up to me afterwards and were excited to hear about the changes – and one person even asked me to make sure we included tree protection in the rules.

Thank you for taking the time to review my comments on the Rules regarding slacklining and permitting slacklining only in designated locations. Please contact anytime me if you have any questions.



Ken Wagers


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