Trust serves an important purpose in organizations composed of numerous, specialized, interdependent roles. Supporting confidence that individuals will dutifully fulfill the responsibilities of those roles without causing harm to the organization, trust enables coordinated task execution across multiple roles and facilitates information exchange among individuals by reducing cognitive resources spent verifying information accuracy and reliability. Interactions play an important role in shaping and updating trust, but the mechanisms underlying the relationship between communication networks and trust dynamics remain poorly understood. This paper addresses that gap by directly examining the coevolution of communication networks and trust. During a multi-day military training exercise, participants (n=83) from three distinct units formed a coalition organization largely focused on collecting, analyzing, and acting on information gleaned from the operating environment of roughly 10k units under their command. Over the course of the exercise, each participant provided eight ratings of trust in their own unit and their coalition partners' units. Static and dynamic network models of the organization's communication networks assessed whether trust is an antecedent or product of communication. Results consistently show that when individuals report elevated trust in a unit, they become more likely to form and sustain relationships to members of that unit during the next time period. They also increase their rates of communication to those unit members. However, this relationship does not work in reverse: Increased communication to a unit does not precede increased trust in that unit. These findings suggest temporal directionality in the coevolution of trust and communication.