The connection between climate change, wildfire and moose abundance

May 23, 2018

People can question climate change all they want, but according to a couple Kenai Peninsula scientists, one change in the climate in 1968-69 might be exactly why there is an abundance of moose in our back yard today.

Exactly how interconnected the natural world is on the Kenai Peninsula became obvious when KDLL welcomed retired Kenai National Wildlife Refuge ecologist Ed Berg and the refuge’s John Morton, the supervisory biologist to the studio.

The hour long Conversation covered multiple areas of study that have occupied Berg’s time since moving to the peninsula over 40 years ago, including climate change. 

In the regular “Refuge Notebook” column for the Peninsula Clarion about 20 years ago, Berg noted the shrinking ponds on the Kenai Peninsula and explored the cause.

“The drying ponds was one of the first things I noticed here. The ponds that were blue on the old maps in the '40s and '50s. were disappearing," Berg said. "And when we look at the climate records, especially or the Kenai weather station at the airport, we see that in 1968 and 69 there was a drought. Two summers of drought and dry winter between them. And there was a tremendous fire in 1969 around Kenai, that was a scorched earth fire. And we only get these kinds of fires under the driest of conditions. And this is where everything burns right down to mineral soil so there are thousands of acres of mud left behind when the snow melts next year.”

Now, when a spruce forest burns, spruce, an evergreen, is not the first tree to grow back — birch do, which is what refuge managers saw in the summer of 1970.

“Here were baby birch, coming up by the millions. They were only an inch high. And those birch grew up to provide what we call the ’69 Burn. And the moose and hares loved eating all that birch, and of course everything that eats moose and hares also enjoyed this — including human beings," Berg said. "So that was our primary hunting area for many years.”

Morton said the peninsula’s climate was reset during the 68-69 drought, and has become increasingly hospitable to moose.

“The moose population responded to an earlier fire, the 1947 fire. But that wasn’t quite — it was a larger fire in the sense of the area covered, it was about 300,000 acres, and the ’69 burn that’ Ed’s talking about is somewhere what was it, around 80-90,000 acres? 86,000 is the number we throw around. So it was a smaller fire, but it was a much more intense fire," Morton said.

"And as a result of that, we got that hardwood regeneration that Ed’s talking about and the population really took off here in the 80s and 90s. So people that have moved in during that time window, they really got to experience lots of moose. It really is an artifact of that fire.”

Through counting tree rings and drilling sediment cores in lake bottoms, Berg discovered the “mean fire return interval,” for the forests of the Refuge north of the Sterling Highway. Morton says the clock is running out on the next one.

“A lot of the black spruce we have north of the Sterling Highway up in Sub Unit 15a, the mean fire return internal up there is about 80 years or so," Morton said. "And if you kinda date back to 1947, we’re starting to come back into that period where we expect a big burn up in 15a any day now, literally.”

Conversely, Berg said he didn’t think the Sitka spruce forest on the south side of Kachemak Bay has ever burned to mineral soil in a wildfire because it is just too wet there.