Final answer:
To justify or refute the claim that logging decreases the carrying capacity of trout in a stream, data on the number of trout before and after logging can be collected.
Step-by-step explanation:
The claim that the introduction of logging into a forest ecosystem will decrease the carrying capacity of trout living in a stream can be justified or refuted by collecting data on various factors related to the trout population. One way to justify or refute this claim is by collecting data on the number of trout in the stream before and after logging. If the number of trout decreases significantly after logging, it would support the claim. Conversely, if there is no significant change in the number of trout, it would refute the claim.