Is diversity of ectomycorrhizal fungi important for ecosystem function?

Forum 3 (Kranabetter & Wylie, 1998), almost certainly as a result of the constraint provided by the limited carbon-fixing capacity of seedlings compared with established trees. Concluding remarksInvestigations of the cost-benefit relationships of ectomycorrhizal diversity are a high priority.How are the competing demands for carbon by different ECM met by the plants?Is more carbon allocated proportionally to the partners that provide the most nutrients or other functional benefits?Does ECM diversity have any consistent effect either on individual plants or on ecosystem functioning?These questions are easy to pose.The answers are difficult to obtain.A major challenge lies ahead.