Answer: Commensalism
Step-by-step explanation:
This process is called commensalism. Commensalism is considering a long-term biological process and interaction with members of one species in this case marshes and swamps and in this process, they will gain benefits while those other species benefits are not harmed, in this case, mature trees.
Marshes and swamps will become a community that is including other species but they will not be harmful to it.