BLOOMINGTON, Minnesota — The U.S. Fish & Wildlife Service is tightening requirements imposed on the Minnesota Department of Natural Resources when the state wants to cut trees in wildlife management areas. The federal agency is essentially asking the state to prove that any logging on WMAs has wildlife management as its primary purpose at each logging site and not simply cutting trees for the state’s timber industry. The feds say they will withhold money for each proposed project until the state proves the wildlife purpose. The new requirements are just the latest twist in an ongoing saga over how much, where and why timber should be cut on the state’s 1,440 public wildlife management areas, at least those that have trees. …The debate impacts a relatively small amount of the state’s share of timber.