Quick Summary: Arborist knots fall into a few jobs: terminating the line (bowline with a Yosemite finish, figure eight), friction hitches that let a climber ascend and descend (Blake’s hitch, Distel, Valdotain Tresse, Prusik), joining ropes (double fisherman’s, sheet bend) and rigging loads (timber hitch, cow hitch, Munter hitch). Which knots a crew expects varies by region and by company, so treat any list as a starting point and learn each knot hands on with a qualified climber. A knot is only as safe as it is tied, dressed and set, and several common ones need a backup or a finish.

Key entities: bowline, Yosemite finish, figure eight, Blake’s hitch, Distel, Valdotain Tresse, Prusik, double fisherman’s, alpine butterfly, tie dress and set, ANSI Z133.

A knot that slips an inch on the ground is a lesson. The same knot forty feet up is a very different problem.

Arborist knots are part of your life support system, just like the rope, the saddle and the carabiners. You don’t need to know fifty of them. You need a handful you can tie without thinking, a clear idea of what each one is for, and an honest picture of how each one fails.

Most knot guides give you a flat list. That’s not how new climbers learn. It’s more useful to sort knots by the job they do: terminating the climbing line, friction hitches for moving on the rope, knots for joining rope and making loops, and rigging knots for slings, wood and gear.

Which knots a crew expects varies by region and company, so treat this article as a map, not the final word. Your employer’s training, the rope manufacturer’s instructions and the current ANSI Z133 standard come first.

Which Knots Go on the Climbing Line?

The knot at the end of your climbing line carries your weight. It deserves more attention than any other knot you tie.

Bowline and the Yosemite Finish

The bowline forms a non-slipping loop and unties easily even after a heavy load. That’s why climbers like it. It’s also why it needs a backup.

Samson Rope notes that a bowline can loosen under cyclic loads. The Victorian Tree Industry Organisation’s Knots for Arboriculture guide adds that without constant tension it can creep, distort and even unravel.

Online, one source says the bowline isn’t fit for life support, and another says it must be finished with a Yosemite tie-off. Both describe the same rule. The USDA Forest Service National Tree Climbing Guide (2015 edition) says that when a bowline is used for life support, its tail must be secured, commonly with a Yosemite finish or a double fisherman’s. The VTIO guide calls the plain bowline unacceptable as a lifeline attachment and points to the Yosemite bowline instead. The Northwest Line JATC Elements of Rope manual says the same.

So the plain bowline stays off your life support line, while a bowline with a properly secured tail is widely taught for it. If your rope manufacturer says otherwise, follow the manufacturer.

Figure Eight and Stopper Knots

The figure eight on a bight makes a secure loop, and Samson lists the figure eight as a fixed anchor knot for climbing systems. Its main drawback is that it can be hard to untie after heavy loading.

A single figure eight also serves as a stopper, for example on the tail of a Blake’s hitch. The VTIO guide warns that it "has a tendency to undo itself if left unattended," and the USDA guide recommends a double overhand as a more secure stopper. Whichever your training uses, check the stopper every time you check the hitch.

Anchor Hitch and Clove Hitch

The clove hitch is quick and adjustable, which makes it handy for rigging and for sending gear up to a climber. It is not a life support knot. The USDA guide says so directly, the VTIO guide says it must be backed up with at least two half hitches when used as an end line attachment, and Samson notes that it can slip under dynamic loads.

The anchor hitch appears on some knot lists as an end line attachment, often with strength claims we couldn’t confirm in a rope maker’s instructions or a training manual. If your crew uses it, learn it from your trainer.

Friction Hitches for Climbing

Friction hitches grip when loaded and slide when you tend them. The USDA guide sets one rule for all of them: they must be dressed and set, then tested for proper function before you trust them.

Blake’s Hitch

The Blake’s hitch is tied with the tail of the climbing line itself, so there’s no separate cord to forget. Bartlett Arborist Supply points out that it also makes a good fallback. If a mechanical device or another hitch gives you trouble, a climber who knows the Blake’s can still get down.

Two cautions matter. It grips from one direction only, so it has to be tied and loaded the right way. And its tail needs a stopper knot, as the USDA guide, the VTIO guide and the JATC manual all state. The VTIO guide also warns that descending too fast builds heat and friction that can damage the rope.

Distel, Schwabisch and Valdotain Tresse

These hitches are tied with a separate friction cord. Climbers choose between them on feel: how smoothly the hitch tends, how much it grips and how easily it releases.

The Distel is a widely used split-tail hitch. The VTIO guide notes that it needs regular dressing because the bottom wrap tends to work up, and that it generally works in one direction. The same guide describes the Schwabisch as an entry-level hitch in a split-tail system, also one-directional and in need of regular dressing.

The Valdotain Tresse, or VT, is fast. The VTIO guide calls it "too fast for beginners" and an unforgiving knot that can fail to grab if it isn’t tied exactly right, and says it should be mastered on the ground before it goes into a climbing system. The JATC manual adds that it should always be set before any weight goes on it, and recommends that climbers know at least the VT and the Distel.

Prusik

The Prusik is tied with a separate loop of cord. Unlike most climbing hitches, it grips in both directions, according to the USDA guide, which also says the cord must be no larger in diameter than the rope it’s tied on. The downside is that it tends to bind tightly and can be hard to untie. That’s why it often stays reserved for specific tasks, such as tying in for the secured footlock technique.

Sometimes you need to join two ropes or create an attachment point in the middle of a line.

Double Fisherman’s

The double fisherman’s joins two ropes and also backs up the tail of a bowline. It holds well but can be very hard to untie after a heavy load. The JATC manual warns that if it’s tied incorrectly, it can act as a slip knot, so tying, dressing and setting it properly is not optional. The USDA guide also says not to use it with webbing.

Sheet Bend

The sheet bend joins ropes of different sizes or types, and a variation is used to pass rope up the tree. It’s not a life support knot. The VTIO guide is clear on this and notes its tendency to slip.

Alpine Butterfly

The alpine butterfly makes a fixed loop in the middle of a line, useful for mid-line attachment points and redirects. It’s easy to check visually once it’s dressed and set. The tradeoff, noted by Samson and Bartlett Arborist Supply, is that it can be hard to untie after a heavy load.

Rigging knots hold wood, slings and blocks rather than the climber, but a mistake here still hurts people. For a wider look at the rigging side, see our guide to rigging vs crane removals.

Timber Hitch and Cow Hitch

The timber hitch attaches an anchor sling to a trunk or limb for lowering devices and pulleys. The VTIO guide says it is not for life support, that it is very sensitive to changes in direction, and that a half hitch below it reduces sideways slipping. Training sources give different minimum wrap counts, so use the number your trainer teaches.

The cow hitch does a similar job. The VTIO guide notes it can also slip with sideways movement, though less than a timber hitch, and the JATC manual says it should be finished with a half hitch over the standing end.

Munter Hitch

The Munter hitch adds friction through a carabiner for lowering light loads, belaying and controlled descent. The VTIO guide warns that it tends to twist the rope and recommends a large pear-shaped locking carabiner. For heavier pieces, Bartlett Arborist Supply recommends a dedicated lowering device instead.

Girth Hitch and Knots for Sending Tools

The girth hitch has narrow uses in tree work. The VTIO guide uses it to stop a Prusik loop from rotating on a carabiner, while the USDA guide warns against using it to secure a sling around a trunk or branch. For sending tools up, crews often use a quick hitch such as a clove hitch. A tool line is not a life support line, and those knots should never end up in your climbing system.

Most problems come down to a few failure modes:

A correct knot tied badly is still a bad knot. In the USDA guide’s terms, to dress a knot is to align its parts so they are straight and properly bundled, and to set it is to tighten every part so the strands touch, grab and create friction. Skip those steps and the knot can deform under strain and fail.

Rope type matters too, because diameter, construction and fibre all change how a knot grips. The VTIO guide notes, for example, that some heat-resistant fibres can creep in a double fisherman’s. Whenever you change rope or cord, test your hitches on the ground first.

How to Learn Arborist Knots Safely

You won’t learn knots from an article. You learn them with your hands, on the ground, under supervision.

A sensible order is to start with your termination knot and its finish, then the Blake’s hitch and its stopper, then a joining knot and the alpine butterfly. Split-tail hitches like the Distel and VT come once the basics are automatic. Practice each one at ground level until you can tie it without looking, then with gloves on. Have a qualified climber check each one before it goes into an aerial system.

Keep going back to the source documents. The ISA released the ANSI Z133-2026 edition in May 2026, and the OSHA tree care standards page lists ANSI Z133 as a voluntary standard rather than an OSHA regulation. For the basics around the knots, see our guides to climbing techniques and safety tips and essential safety rules every arborist should know.

Knots depend on rope, and rope wears out. A good knot on a tired line is still a risk.

For a crew, keeping track of which rope was inspected when, and which cord is due for retirement, gets hard fast. Our guides to choosing a climbing rope and the right harness help you buy well. ArboStar’s equipment management software helps you log rope age, inspection dates and retirement in one place, instead of relying on one climber’s memory.

What are the most important knots for an arborist?

Many training programs cover a termination knot such as the bowline with a Yosemite finish, a friction hitch such as the Blake’s hitch, a joining knot such as the double fisherman’s, and rigging knots like the timber hitch and clove hitch.

Is the bowline safe for tree climbing?

A plain bowline is not considered acceptable for life support, because it can loosen or creep when the load changes. Sources such as the USDA National Tree Climbing Guide teach that a bowline used for life support must have its tail secured, commonly with a Yosemite finish. Always check your rope maker’s instructions too.

What is the difference between a Prusik and a Blake’s hitch?

A Prusik is tied with a separate loop of cord and grips in both directions. A Blake’s hitch is tied with the tail of the climbing line, grips in one direction only and needs a stopper knot.

What knots does an arborist use to join two ropes?

The double fisherman’s is a widely used joining knot for secure connections. The sheet bend can join ropes of different sizes, but it is not suitable for life support.

How long does it take to learn arborist knots?

There’s no fixed timeline. Tying a knot takes minutes to learn; tying, dressing and setting it correctly every time, with gloves on, takes repeated practice.

Learning arborist knots is less about memorizing a list and more about understanding jobs. Know which knot terminates your line, which hitch moves you up and down, which knot joins rope and which ones handle rigging. Then know how each one fails.

The rule that matters most is simple: a knot is learned by hand, not from a page. Tie it on the ground, dress it, set it and have someone qualified check it before it goes anywhere near a life support system. Keep your rope maker’s instructions and the current ANSI Z133 standard close.

For more practical guides on climbing, rigging and gear, explore the ArboStar education hub, and build your crew’s training plan around the arborist knots that keep people safely on the rope.