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Central Newfoundland has the most continental climate of any part of insular
Newfoundland. It has the highest summer temperatures and lowest winter temperatures.
However, night frost can occur in any summer month. Due to the warm summer and high
evapo-transpiration losses, soils in the northern part of this ecoregion display
soil moisture deficiency.
The Hylocomium-Balsam Fir forest type occupies the zonal soils of this area. These soils
are generally lighter in colour and have lower organic matter content compared to other
ecoregions. Forest fires have played a more important role in the natural history of
this region relative to other ecoregions. Much of the Balsam Fir-Feathermoss forest
types have been converted to Black Spruce and some of the richer site types to
hardwood forests dominated by White Birch and Aspen. Although Aspen occurs in
other regions, it is most abundant and vigorous in Central Newfoundland. Yellow
Birch is absent from this region primarily because of the short frost-free period.
Alders rather than Mountain Maple are the most common problem on wet seepage
slopes.
A. Northcentral Subregion
The Northcentral Subregion has higher summer maximum temperatures, lower rainfall and
higher fire frequency than anywhere else in Newfoundland. The subregion extends from
Clarenville in the east to Deer Lake in the west and for the most part has a rolling
topography below 200m. Pure Black Spruce forests and Aspen stands dominate this area
because of the prevalence of fire in the natural history of the subregion. Also,
the high summer temperatures are thought to stimulate Aspen root suckering and
contribute to the local success of Aspen (Damman 1983). Relatively low moisture,
coarse soils and the prevalence of Black Spruce cover types make this subregion
particularly susceptible to regeneration failure. Furthermore, where tree
regeneration is lacking, succession to dwarf shrub heath dominated by Kalmia
angustifolia occurs on the nutrient-poor coarse textured till that is
prevalent through much of this area.
The rolling to undulating topography is
characterized by shallow, medium quality till with a soil texture range from
sandy loam to loam. Midslopes are dominated by the Hylocomium-Balsam Fir type,
or the Black Spruce-Feathermoss type on seepage gleysols after fire. There are
also local areas covered by poor sandy till over galcio-fluvial deposits and
outwash deposits along some of the major river systems such as the Terra Nova,
Exploits and Indian River. It is in these landtypes that succession of
productive Black Spruce forest types to ericaceous heath dominated by Kalmia
angustifolia is most prevalent.
B. Red Indian Lake Subregion
This subregion is cooler than subregion A with more precipitation and a shorter
growing season. Balsam Fir cover types predominate and White Birch rather than Black
Spruce is most prominent in the landscape.
Much of the topography of this subregion is similar to subregion A, however there
are some local areas of deeper, nutrient rich till. The southern slopes of Red
Indian Lake to Noel Paul and Harpoon River systems provide good examples of this richer
landtype. The Rubus-Balsam Fir and Dryopteris-Lycopodium-Balsam Fir types dominate the
landtype. The soils have a texture ranging from silt loam to loam usually with a
fragipan that promotes seepage in the rooting zone. These are by far the most
productive forest types in Central Newfoundland. However, succcession to Alder
thickets after cutting and fire is a serious silvicultural problem.
C. Portage Pond Subregion
This subregion is characterized by rugged topography including the Annieopsquotch
Mountains. Balsam Fir is the dominant tree on upland sites. However, there are a
number of very productive Black Spruce fire stands in this subregion.
D. Twillick Steady
This subregion occurs immediately to the north of the Bay d’Espoir Subregion of the
Western Newfoundland Ecoregion. Trembling Aspen is absent from this area and Balsam
Fir is the most common upland cover type.
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