String trees are tiny and often go unnoticed, but they play a vital role on flat, Fender-style headstocks. Also called string retainers or guides, they secure the first two (or sometimes four) strings between the nut and tuners. Photo 1 shows a guitar configured with two “butterfly” string trees holding down the top four strings.
On both guitar and bass, a string tree’s primary function is to provide the correct amount of downward pressure on a string so it doesn’t rattle and buzz within its nut slot. This downward pressure also ensures that a string will sustain properly when played open. If an open string isn’t securely seated in its slot—essentially pinned down the way you’d press a string against a fret—it won’t sound as loud or clear as it should.
Whether or not a guitar or bass requires string retainers is determined by how its headstock is constructed. For example, Gibson headstocks tilt back at an angle from the fretboard, and this angle is sufficient to create the necessary downward pressure to keep strings firmly seated in their slots en route to the tuner posts. By contrast, Strats, Teles, and most other guitars with six-in-a-row tuners have flat headstocks that run parallel to the fretboard. On these headstocks, the strings that have to travel the longest distance from the nut to the tuner posts need hardware to create this essential downward pressure.
Most of us never think twice about string trees until there’s a problem. I’ve already described one—the rattle or sitar-like buzz that results from insufficient downward pressure behind the nut. But if a string tree creates excessive pressure, this can cause premature wear in the affected nut slots and also create tuning issues. And here’s another consideration: If you have a whammy bar, certain types of string trees can interfere with the string returning to pitch after you release the bar.
To summarize, string trees can help or hinder your guitar’s performance. Let’s take a closer look and discuss ways to deal with potential problems.
Design and construction. String trees come in a variety of materials and styles. Most are metal, like the butterfly, disk, and barrel types found on Fender guitars. The metal trees will work, but if you do a lot of bending or use a whammy bar, you’ll probably experience tuning problems. Why? Every time the string changes tension against the tree, the metal-to-metal contact creates friction that can cause the string to hang slightly at this point of contact.
To reduce friction—and thus improve tuning stability—you have two options: use a string tree made from a slippery material such as graphite (Photo 2), or install a string tree with built-in rollers that turn with the string as you bend or use the whammy bar (Photo 3).
Both types of retainers accomplish the goal of reducing metal-to-metal friction. I’ve had great success with Graph Tech string trees, which are made from a synthetic material impregnated with a Teflon-like lubricant, and roller string trees from All Parts.
What’s your angle, man? The amount of downward pressure a string tree creates is determined by its location and how high it sits off the headstock. Assuming an identical location, a lower retainer—one that’s close to the headstock—will create a steeper angle between it and the nut than a retainer that sits higher off the headstock. Getting the correct angle is critical for avoiding wear (too steep an angle) or sonic artifacts (too shallow an angle).