Terra Nova boxes out moose to save the trees

Terra Nova National Park is hoping hundreds of metres of fencing will protect stunted trees from hungry moose.

The park has constructed an eight-hectare moose exclosure, and has planted thousands of balsam fir seedlings inside, in an attempt to regenerate a forest in an open meadow that's been hit hard by big moose appetites.

"Year after year, they browse these same areas so trees tend to never ever get to the heights that they need to," explained Janet Feltham, an ecologist at Terra Nova National Park.

"Balsam fir have a really hard time."

When winter comes, and other vegetation goes away, moose will turn to trees for grazing. According to Feltham, there are about 140 moose living in Terra Nova, and they'll eat, on average, about 20 kilograms of vegetation each day.

"So you can imagine, each moose eating that much vegetation in the park, so they can do quite a lot of damage," she said.

Feltham said in surveys before 2011, Terra Nova staff found that up to 80 per cent of trees in some areas were affected by eating — which ecologists call browsing.

Evidence of that grazing can be found in the trees that have managed to grow to a full size. In those, Feltham said, only branches at the very top of the tree are grown, and others further down have been eaten away by moose.

"You get these really cool but eerie-shaped trees that aren't quite normal," she said.

The newly constructed fence will keep moose out, but let other small animals in. Feltham said it should make a difference, and park staff hope in 15 to 20 years there will be a new balsam fir forest.

"We're hoping that with this new exclosure that we're going to have, in 15 to 20 years, a new balsam fir hardwood forest."

Right time

The moose population in Terra Nova National Park has fallen, from 600 in the 1990s to 140 today, said Feltham.

That means it's the right time to start this project, she said. Once the trees have reached maturity, the fencing around them will be removed. If the moose population is maintained at lower levels, seeds that fall from the once-protected trees will have a better chance of growing.

The fences were installed this year. It will take years before the vision is realized, but Feltham said it's all worth it.

"I think it's one of the most rewarding things I can possibly do in this park, because you know that with each tree that you plant, there's a potential for a habitat for a bird, or a place for another nest," she said. 

"Overall, it's one of the most concrete examples of how we can restore ecosystems." 

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