DNR has plenty of ARMER talkgroups, in fact more than we even know about, but since they have such a high turnover, they are part time employees and they are creatures of convenience and habit, they generally use their VHF resources since that is what they need for their Air to Air and Air to Ground operations since the helicopters that they generally use are leased and they dont have ARMER aircraft mobiles. They can use their ARMER portables in the helicopter, but for the sake of their own operations, they use VHF. DNR coveres many areas and some of them especially, north of the metro along I-94, still have yet to migrate to ARMER. The other consideration is that federal smoke chasers from the Sherburne Nat'l Wildlife refuge use Fed VHF and have no ARMER capabilities, but do have shared resources with DNR.
This does cause a bit of disconnect at the fireground since nearly all non-planned wildland fires have a structural fire department that initially manages the scene, and often is the only resource needed at the scene, but when DNR arrives, their interoperability is generally only achieved by a face to face interaction between a DNR IC and the local IC. There are a bunch of safety considerations to take into account on both sides of the line and with limited budgets, I suspect that VHF and ARMER differences will always continue to exist. I do think that as Chisago county continues to build up and migrate and also as the I-94 corridor migrates, things may change.