Terra Nova National Park of Canada

Terra Nova's Forest…Taking a Turn for the Worse

The forest in Terra Nova is changing. Usually this would mean a good thing. Trees eaten by insects, burned by fire or dead from old age are all a part of the natural cycle of the forest. New forests are created when young flowering plants, shrubs and tree saplings take advantage of the open space created when older trees die. This natural change provides new homes for a variety of animals such as the red fox, the Newfoundland marten and a variety of songbirds. It also provides food for native animals such as the beaver.

Unfortunately, a large portion of the forest in Terra Nova is dying a quick death and the change is not good. In places, balsam fir, birch, maple, and a host of other trees and shrubs that are an important part of the forest are disappearing. For example, the fir forest along Blue Hill Road that was killed by insects in the late 1970’s should be a thriving new forest. The entire area has changed from a healthy forest to an open area consisting of only grasses, ferns, shrubs and non-native plants.

This is the result of 20 years of moose browsing - open areas with no new tree regrowth
This is the result of 20 years of moose browsing - open areas with no new tree regrowth
© Parks Canada

Why have things taken a turn for the worse?

The answer can be found in the fenced off areas along Blue Hill road. Over ten years ago park staff erected two animal exclosure fences (fences that keep animals out) to study the effects that moose and snowshoe hare are having on the forest's natural regrowth. Are moose the culprit, the snowshoe hare or a combination of both these two introduced species? Since this time, additional exclosures have been erected to measure the severity of the impact on forest regrowth.

The foliage growing inside the moose exclosure.
The foliage growing inside the moose exclosure.
© Parks Canada
The foliage outside the Blue Hill exclosure
This is the result of 20 years of moose browsing - open areas with no new tree regrowth
© Parks Canada

What did the exclosures tell us?

We know two things for certain:

Firstly, snowshoe hare, even though abundant, do not affect the natural change in the forest to any great extent.

Secondly, and more importantly, moose browsing has been shown to be the biggest culprit in preventing the fir and deciduous forest from growing back. The trees inside the fenced exclosures are doing great in the absence of moose. This means that the fir and deciduous forest will not regrow with the current number of moose in the park. For more information on this important issue, please visit www.pc.gc.ca/terranova or talk to a park biologist at the park.

The effect of moose browsing
The effect of moose browsing

Moose Browsing: The effect of moose browsing is evident when examining these two trees. To the left, a 1-foot tall, browsed balsam fir is more than 20 years old and should be over 10 feet tall, while this deciduous tree has lost much of its foliage and branches.
© Parks Canada