In the west all of the wildland fire dispatching at the federal level is done from interagency centers, 105 of them in total. They all include the BLM and the USFS. National Park Service units vary depending on the characteristics of the park unit, some have all functions included in the interagency center as in the case of Death Valley, Mojave, and Joshua Tree being dispatched by the federal interagency communications center in San Bernardino. Some NPS units include just the fire function and not law enforcement as with Lassen, Grand Canyon and Lake Mead. Some parks have their own centers for all functions due to their size and workload, as in Yellowstone, Yosemite and Sequoia-Kings Canyon. In California, Nevada and Oregon, National Wildlife Refuges use interagency centers, but I'm not as familiar with this situation in other states. A few centers provide service to Indian Reservations, but as with the NPS size and workload can cause this to vary.
Many centers include state natural resource agencies as well. This is most often true for state forestry agencies but sometimes includes state wildlife agencies as well as state parks. The state forestry agencies of Nevada and New Mexico are included in the interagency centers in those states. In California the workload of the state forestry agency, Cal Fire, is heavy and complex enough that only six centers are co-located with the Forest Service. Of these six only three include the BLM as well. The California Department of Fish and Wildlife and the Department of Parks and Recreation have three consolidated dispatch centers in the state.
The trend to consolidate the communications centers of wildland fire agencies started slowly in the 1970's, sped up in the 80's and became ubiquitous by the mid to late 1990's. The increased efficiency in terms of cost and facility maintenance, increased hours of coverage, better coordination and fewer points of communication for the Geographic Area Coordination Centers (11 in the U.S.) make consolidation a winner. Federal agencies that have their own dispatch centers are still included in the logistical and command function of the nearest interagency center. For instance the ordering point for resources (engines, command teams, supplies, personnel, etc.) for the national park units in Hawaii is the Mendocino National Forest Interagency Center while the daily dispatching of those units is obviously in Hawaii.
Consolidation didn't happen easily as some units wanted to hang onto their own dispatch centers due to a resistance to change and the old "we've always done it this way, it can't work any other way" outlook. Some National Forests in Idaho and Montana had a dispatcher for each ranger district and didn't even want to consolidate into one National Forest wide dispatch center, so interagency centers were a big jump for them.
Look for additional consolidation of centers of this type in the future. There was talk of reducing the number of centers in Arizona and New Mexico from twelve to seven, with a reduction to just two, one for each state possibly in the works. Too much reduction will begin to accumulate liabilities in my opinion as dispatchers cannot possibly know the terrain they are dealing with at such a large scale. The federal agencies in California are under some pressure to consolidate into fewer centers, which in my opinion, given the workloads and complexities each agency has, will probably not work as well as it does in Wyoming and Montana.
**EDIT** In these centers frequencies are shared, the best example being the air to ground and air to air frequencies being pooled from those of each agency. There is now a nationwide set of air to ground frequencies named AG1 through AG65 and each center has 2-3 assigned to them. The frequencies used for large incidents, often called the NIFC ("nif cee" - National Interagency Fire Center) frequencies, consist of dozens of frequencies assigned to each agency separately, but shared in this NIFC frequency set. Some centers dispatch all agencies on one or two frequency pairs (output/input for repeaters) such as the two repeaters on the Inyo National Forest where I live, and keep the BLM net as a spare for large incidents. The center in Porterville, California is similar. Keep in mind though that the fire service is more integrated than law enforcement. Large and small mutual aid situations occur in the fire service than those in law enforcement, the reasons for being an entire topic unto itself.
