Which of the following is a hazard associated with tree rescue operations?

Overhead electrical lines are a significant hazard in tree rescue operations because they can pose serious risks to both the rescuers and the individuals being rescued. When performing tree rescues, firefighters must be vigilant about their proximity to power lines, as there is a potential for electrocution. These lines can be obscured by foliage, making them difficult to see, especially in emergency situations. Rescue teams need to assess the surroundings carefully and ensure that safety protocols are in place to avoid accidents.

The other hazards identified, such as extreme temperatures, rescue equipment failure, and water hazards, while relevant in other rescue scenarios or contexts, do not have the same direct and consistent impact on tree rescue operations specifically as electrical lines do. The risk posed by overhead electrical lines is particularly high in this type of rescue, making it a priority concern that must be mitigated to ensure the safety of all involved.