Modern-day arborists have a wide variety of systems available to get them up and about in canopies an almost overwhelming amount in comparison to the choice of spurs or rope of yesteryear. While this helps climbers select not only the system that works best with their particular skill set and preference, but also the requirements of the individual job, it can create confusion and possibly unsafe acts by users who don’t realize that not all systems are alike in their actions and use. A knowledge of some of the basic methods and specific actions of different climbing systems helps crews understand their use, and help employ them more appropriately and effectively.
- Old favorite: Spurs, hooks or gaffs, though more properly a climbing method rather than a system, are certainly a type of climbing that most tree care professionals, and indeed civilians, are at least somewhat familiar with. While to the uninitiated, spur climbing may look like the simplest of activities, it actually has a lot of moving pieces/parts, and requires a fair amount of thought, not to mention physical coordination on the part of the user.
First and foremost, spurs should only be used on a tree that is being removed. This is due to the inherent nature of spurs to punch numerous holes in the bark and living tissue of the tree, providing access for a wide variety of pathogens and causing irreparable damage. The individual techniques of spur climbing have been discussed in other columns, but with an eye toward climbing systems one of the factors that a user needs to consider is the use of some form of rope-based system in addition to the spurs. This will allow the climber to have an additional means of support and stability, along with an escape route to the ground other than spurring down if something happens. The rope-based system may be dynamic or static depending on user preference and situational appropriateness, but its use will make the job easier and more efficient, as well as infinitely safer.
- Dynamic systems: These systems are ones that many climbers think of as “rope and saddle” or “rope and harness” climbing, and involve both parts of the rope moving when in use. In their most basic form, the rope simply goes over a branch or through a crotch and back down to the climber, though a lot of friction can be removed and energy saved by the use of some kind of friction management device.
One of the largest advantages of a dynamic system, and one that makes it fairly easy to ascend, is that the weight of the climber is divided between the two parts of rope, thus the climber is only having to “pull up” half their weight with each ascent movement. This advantage can also be viewed as a disadvantage in that the user has to move twice as much rope to ascend, as to move up 1 foot the climber has to pull 1 foot down on the running end of the rope and 1 foot up on the working end. The forces experienced by the tie-in point (TIP) will be equal to roughly the weight of the user, though this can be magnified fairly seriously by a “drop” into the line or other occurrences that generate some velocity.
Climbers using dynamic systems have a variety of attachment/ascent methods available to them, including mechanical devices, closed climbing hitches and open climbing hitches. The most traditional is to not only tie in with the end of the climbing line, but also leave a long enough tail to create the climbing hitch, typically a Taut-line or Blake’s hitch; and while this method is often neglected by arborists who have “moved on” to more sophisticated and demanding knots, it should be learned and known by all practitioners. After all, if a climber drops their heat-resistant ultra-strong eye and eye while retying in the top of the tree, their options for work, let alone descent, are going to be pretty limited if they don’t know how to use a traditional system.
There are a number of methods to ascend with a dynamic climbing system, most of which require the user to coordinate a number of body movements fairly smoothly. The body thrust is one that many climbers are familiar with, though many may not think of it with fondness, as using this method for long ascents can sometimes seem to be a physical torture designed to punish a climber’s past transgressions. A fairly straightforward, and to most users instinctive, method is to “hand over hand” up the rope; and the addition of a slack-tending pulley beneath the hitch and an attentive ground person can also make this method a safe one by not allowing dangerous slack in the line that could lead to a major “drop.” The footlock can even be used in dynamic systems or even a variety of appropriate ascenders, but, once again, due to the nature of the system, twice as much rope will have to be moved.
- Static systems: This system is one where no part of the rope is moving while it is being used, and includes a variety of uses, including footlocking on both parts of the rope, single rope ascent with ascenders and the like, and even working the whole tree on a single line with the new tools available like the Unicender or Rope Wrench. In addition, a dynamic system may be placed upon a static system, creating a sort of hybrid where the static system is used in the ascent and the dynamic system attached to it used for movement and work within the canopy.
A static system that employs both parts of the line does not change the forces experienced by the TIP all that greatly, regardless of whether it is being used for ascent or in combination with a hybrid system for work, though once again “drops” into the line and possibly rope angles/bending moments can magnify these forces. A static system using a single part of the line, or single rope technique (SRT), does change the TIP forces. Since only one part of the line is being used, both it and the anchored part of the line are seeing the full weight of the climber, which puts twice the user’s weight on the TIP, magnified by any “drops” or impositions by gravity. While this should not be a problem if the climber is judicious in their choice of TIPs and takes the additional precaution of running the line over and through multiple crotches/branches, it is certainly something to be aware of when using single-rope static systems.
Static systems have their own unique requirements that distinguish them from dynamic systems, and in addition will be influenced by what method is being used to ascend. For example, the use of simple footlock technique on both parts of the line can lead the climber into an area of trouble if they advance their hitch into the “spread” of the line, the area immediately beneath the branch or crotch that holds the two parts of rope separate. This can cause the hitch to fail and not grab when the user’s weight is placed on it, but is easily rectified by running an Alpine butterfly or other midline hitch up to the branch to hold both parts of rope fairly close together and eliminate the “spread.”
Climbers using the single rope technique may wish to set up their systems in such a way that the longest part of the line is on the anchor side of the system. This additional rope, and the use of an appropriate belay/lowering device, would allow the climber to be lowered by ground personnel in the event of an emergency, a distinct advantage over a dynamic system. While static systems are not necessarily more complex than dynamic ones, users unfamiliar with them should not only educate themselves on their use, but also practice “low and slow” before incorporating them into work practice, particularly when new devices are being used as part of the ascent/climbing method.
The climbing systems discussed here are no more than a very basic introduction to their individual natures and uses, but that basic knowledge can help interested users start to expand their skill sets to employ different systems in different situations. No one system is going to be perfect for every job; and though individual climbers will certainly develop a “favorite” system, understanding and being able to use all the systems will certainly not only make them a well-rounded climber, but also help them to not force a system into a tree or situation that is not right for it. As always, a climber’s most-effective tool is their own creativity and imagination, used within the parameters of safety and security, so taking the basic natures of the systems and then developing the most personally suitable methods and techniques to use them is going to lead to the most satisfying, and safest, results.
Editor’s note: This article was originally published in July 2012 and has been updated.