Which of the following devices is essential for adhering to the tree support system regulations?

The essential device for adhering to tree support system regulations is the drop-forged eye bolts. These bolts are critical in securely attaching support cables to trees or other structures. Their design, which includes a loop or eye, allows for a strong, reliable connection that can handle significant load and stress, ensuring the stability of the tree support system.

Drop-forged eye bolts are manufactured through a hot forging process, which results in a stronger and more durable product compared to other types of fasteners. This durability is essential for outdoor applications, where environmental factors can put additional strain on support systems. Using high-quality materials like drop-forged components also helps in compliance with industry standards and safety regulations, as they are less likely to fail under tension or during adverse weather conditions.

The other devices mentioned, while potentially useful in various applications, do not fulfill the primary requirement for securely attaching and supporting the tree in the context of current regulations. For instance, cable splices and pulley mechanisms serve specific roles in managing cable lengths and facilitating movement but are not the foundational elements of the support system itself. Ground plates can be part of some systems but do not provide the necessary tension and secure anchoring that eye bolts offer in tree support applications.