What does Game Management Unit 20A, otherwise known as the Tanana Flats, have that the rest of the state doesn't that makes it such productive moose habitat?

Actually, it's what the Tanana Flats doesn't have that makes it the state's most prolific moose hunting area.

"It's the lack of predators that makes 20A so incredibly productive, not incredible forage," said Tom Seaton, a state wildlife biologist with the Alaska Department of Fish and Game in Fairbanks who studied browse in Unit 20A for his master's degree thesis. "There are lots of other places in the state where there's just as much food for moose.

"The reason why (Unit) 20A is so incredibly productive is the high survival rate."

Almost 50 percent of the moose calves born on the Tanana Flats survive the winter, which compares to a survival rate of about 10 to 20 percent in the rest of the state.

"That's unheard of in the rest of the state," Seaton said.

Situated close enough to Fairbanks for easy access, the Tanana Flats are home to dozens of wolf trappers and bear hunters. More wolves are killed in Unit 20 than any other management unit in the state and, not surprisingly, more moose are killed in Unit 20 than anywhere else.

Hunters and trappers take about 270 wolves a year from Unit 20, more than half of which are killed in Unit 20A.

The black bear harvest in Unit 20A is also high as a result of bear baiting, Seaton said.

Toss in the fact there aren't many grizzly bears on the Flats because the habitat is not necessarily suitable for grizzlies, and you have a perfect recipe for high calf survival.

"Unlike a lot of other areas, bears have a much lesser impact on calf survival," state wildlife biologist Don Young said.

Another reason the Tanana Flats are so productive is that the area features excellent summer and winter ranges that are close together. Moose don't have to go far from the Flats at the end of the summer to reach prime winter range in the foothills of the Alaska Range. In the spring, those same moose move back down into the Flats to have their calves.

"Almost 90 percent of the moose in Unit 20A end up on the Tanana Flats for the summer," Young said. "There are other areas of the state that have good habitat like that, but in 20A you have good fall and winter range next to excellent summer range."

The Tanana Flats also benefit from several wildfires in the past 65 years that have produced forage.

"We've had some pretty good burns that have helped in terms of habitat," Young said.

Burns in the early 1940s, late 1950s and the Blair Lakes burn in 1980 all helped maintain high moose densities on the Flats.

The state also conducted wolf control in Unit 20A for about 10 years in the mid-1970s and '80s, as well as the early 1990s.

"That certainly helped," Young said.

News-Miner staff writer Tim Mowry can be reached at 459-7587 or tmowry@newsminer.com .
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