Tree climbing spikes, gaffs, hooks, or climbers are just that, steel or aluminum spikes that attach to the climbers boots to aid in the movement throughout the tree. Many different methods exist for climbing and moving through a tree. Trees destined for removal are "almost always" dismantled with the climber wearing spikes. A small pointed climbing gaff easily punctures the bark, cambium layer, and into the meatier sapwood of the tree so that the climber can move in places where no limbs exist.
Many different manufacturers make climbing spikes. Some are aluminum or titanium for those interested in weight management. Some are made of steel for those that feel bigger is better. All in all, each have their own trade-offs that can persuade a tree climber one way or another.
Steel hooks tend to be heavier but will last the lifetime of the climber if they are treated even relatively well throughout their lifetime. Many times, climbers treat their climbing gear very hard. If this is the type of climber you are, then steel hooks are for you. Aluminum and titanium climbers are light weight but tend to get "dinged up" a bit easier than steel spikes. By treating your equipment with respect, any piece of gear will last.
Tree climbing spikes are made up of several different components: first off is the gaff, or the spike that enters the tree. Some sets of spikes have replaceable gaffs while others are fixed. Next up is the shank, which sits under the arch of the foot and supports the climber while standing in the spikes. Next to the ankle is the stirrup which leads up to an adjustable piece that attaches the pad to the climber’s calf. Pads come in a variety of different forms from simple straps with a bit of leather on them to protect the climbers leg to Velcro wrap enclosures that are heavily padded and also have a steel insert for added comfort.
Climbing spikes should fit with the top of the pad two finger widths under the bony part of the knee for the most comfort. Wearing boots with some sort of steel or plastic shank in the arch of the boot make climbing with spurs much more comfortable as well.
All in all tree climbing spikes are a great tool while removing a tree. Keep in mind, they should never be worn for the pruning of trees as the gaffs damage the cambium layer of the trees and can give pathogens and insects an easy place to infect the tree. Every tool has its place in the arboricultural industry, by knowing the best time to use each tool is what makes us professionals.