Geoscience Reference
In-Depth Information
A yellow birch, a climax species of the New England/Acadian Forest, clings to a rocky outcrop.
Nicolas Denys, the author of the first natural history of Acadia (the old French territory that encompassed all
three Maritime Provinces and parts of Maine), commented on the bountiful forests. The trees were so large that
they created a kind of wilderness parkland through which it was possible, he claimed, to pursue a moose on
horseback. Other early chroniclers commented on the great size of the trees—yellow birch 3 to 4 meters (10 to
13 feet) in circumference, beech 2 meters (6.5 feet) in diameter, and white pine 38 to 53 meters (125 to 175
feet) tall.
Before European settlement, these late-successional forests, consisting of climax species, were rarely sub-
ject to catastrophic disturbances, such as fire caused by lightning. In New Brunswick and Nova Scotia, only
about 1 percent of fires are caused by lightning today, with the remainder attributed to human causes, and char-
coal evidence indicates that large-scale fires occurred only every eight hundred to a thousand years in north-
eastern Maine and New Brunswick. The long fire-cycle intervals meant that there was enough time between
disturbances for the forest to develop into an old-growth, late-successional type—a climax forest.
The climax species—sugar maple, yellow birch, American beech, red spruce, eastern hemlock, and eastern
white pine—live an average of three hundred to four hundred years, and their natural regeneration occurs with-
in canopy gaps that result from small-scale disturbances, such as blowdown of older trees, rather than stand-re-
placing events, such as the large fires typical of boreal forests. The result is a self-sustaining forest with trees
of various ages, a multistoried canopy, and some dead or dying trees in various stages of decay, as well as large
