uplands experience more severe winters, greater precipitation, and
shorter growing seasons than the surrounding lowlands, but climatic
conditions are not as harsh as in the Cape Breton highlands. The
climate of this Region is reflected in the dominant hardwood vegetation
characterized by a Sugar Maple, Yellow Birch-Fir association.
the eight plateaus (District 310) which compose the Region are sharply
defined, with level plateau surfaces at elevations between 100 and 300 m
above sea level. Margins of the plateaus generally fall abruptly, 100
m or more, with little dissection by stream valleys. The remaining two
uplands (District 330) are at lower elevations and have a less severe
climate and a greater proportion of softwood trees. Mainland parts of
this Region are bordered by ancient sedimentary rocks on which soils
are deeper and river valleys more deeply carved (District 320). All of
these uplands provide excellent moose ranges.
Click to enlarge
Geology and Landscape
The blocks are made up of very
resistant metamorphic and igneous rocks, among which are some of the
most ancient rocks in Nova Scotia. In most cases, the blocks are
bounded and crosscut by faults. At the margins these give steep scarp
slopes; within the blocks, where harder and softer strata are
juxtaposed, they produce rugged hills and valleys.
The crests of the blocks are often narrow and dissected but are
usually uniform in height along their length. Their height
relationship is cited as evidence for a Cretaceous planation surface.
The crests progressively decrease in elevation southeastwards as they
intersect an almost uniform surface now dissected and tilted to the
southeast. Subsequent erosion has removed soft strata and left the
resistant blocks as uplands. The prominence of the blocks varies
according to the hardness of the adjacent rocks and their position on
the tilted peneplain.
Elevation is the dominant influence on the climate of this somewhat diverse Region. The climate in different areas is modified by proximity to water masses. The main climatic features are wide daily and seasonal temperature rangers, and high precipitation, especially snowfall.
Winters are generally long and cold. Because of their greater elevation, the Cobequids record the coldest temperatures within the Region. The uplands south and east of the Bras d'Or Lake are slightly warmer than the rest of the Region because of lower elevations and the moderating influence of the Bras d'Or Lake and the Atlantic Ocean. Spring is late, although somewhat earlier in the Bras d'Or area. Mean temperatures do not rise above 0°C until April. Summer temperatures are cool at the higher elevations, but warmer towards Cape Breton. Freezing temperatures return before the end of November in the Cobequid Hills and Antigonish Highlands, and one or two weeks later in Cape Breton.
Total annual precipitation exceeds 1200 mm in the mainland. The Region is noticeably wetter in Cape Breton, where precipitation exceeds 1400 mm. Snowfall is greatest on the highest parts of the Mainland, exceeding 300 cm. In Cape Breton, 200-250 cm falls close to the Bras d'Or Lake, and over 250 cm elsewhere. The snow-cover season follows the same pattern, being longer in the mainland areas (more than 140 days) and somewhat shorter (130 days) in the rest of the Region. In midwinter, snow accumulations of more than 40 cm occur in the Cobequid Hills and Antigonish Highlands.
Cloud cover occurs frequently, and the relative humidity is high. Exposure to wind is an important factor at the highest elevations and in areas close to the Gulf of St. Lawrence.
The main features of the bioclimate of the Avalon Uplands are the short frost-free period, the short growing season, cool moist summers, and low evapotranspiration.
are relatively few lakes across this Region, but there are many rivers
and streams. Most uplands in this Region tend to function as drainage
divides for watershed areas. The headwaters are not especially
main influences on soils in this Region are the high precipitation, the
presence of somewhat more basic igneous rocks, steep terrain that
provides good drainage, and a prevalence of deciduous trees. Soils
here are strongly leached but in many areas have higher natural
fertility than soils found on the more acid upland rock. Soils are
usually well-drained, shallow, and stony sandy loams, often of the
Ferro-Humic Podzol Great Group. Because of low evapotranspiration,
substantial levels of organic matter accumulate in the upper layers.
Leaf litter from the hardwood forests develops into a mull or moder
C.D. Howe made the following observations on soil-forest
relationships in 1912: "The felsites and syenites are similar to
granites ... they vary in hardness, and the softer forms give rise to
very vigorous soils which rank with alluvial soils in fertility, while
the harder forms results in a soil similar in fertility to that of the
more compact sandstones. They are, therefore, feeble soils."
The more recent Cumberland County Soil Survey (1973) reports: "The
somewhat higher base status derived from ferro-magnesian minerals may
have something to do with the prevalence of hardwood trees in the
Cobequid Mountains and the rich undergrowth there, but this effect is
difficult to separate from the adverse effect of exposure on the
Most of the
Region falls within Loucks' Sugar Maple, Yellow Birch-Fir Zone and
these are the predominant species. Parts of the Region south and east
of the Bras d'Or Lake are in the Sugar Maple-Hemlock, Pine Zone. The
major influences on the regional vegetation are the fertile soils, cold
winters and cool summers, good drainage, and relative lack of
disturbance. The high elevation and well-drained fertile sites favour
hardwoods or mixed woods, with softwoods appearing on poorly drained
sites and cool, moist ravine slopes and valley bottoms. Shallow soils
on parts of the plateau surfaces support only Balsam Fir with lesser
amounts of spruce.
Sugar Maple, American Beech, and Yellow Birch are the main species
on the hills. White Spruce, Red Spruce (mainly in the Cobequid Hills),
and Balsam Fir form mixed or softwood stands on valley slopes, while
Black Spruce, White Spruce, scattered Eastern Hemlock, and White Pine
predominate on the valley bottoms. A prominent feature in this Region
is the vigorous shrub growth, particularly of Mountain Maple, Witch
Hazel, and Hobblebush. This shrub community develops in cut-overs and
insect-killed stands, with the prominent addition of Rubus
spp. Following disturbance, shade-intolerant hardwoods are found
throughout but are more prevalent on lower slopes, mixed with spruce
and fir. There are few bogs in this Region, but seepage sites are
Plants of the Alleghanian floral element, whose main range is further
south, are associated with intervale habitat in this Region.
Region provides a range of forested habitats but does not have
significant aquatic habitats. It includes large areas which are
relatively undisturbed and inaccessible, and provide good habitat for
ungulates, bears, and the larger carnivores.
sites by the Bras d'Or Lake were Mi'kmaq burial grounds, and these
spots continue to be important to the Mi'kmaq today. In general,
highland areas such as the Avalon Uplands were settled by Scots in the
first half of the nineteenth century, when fertile valley lands were no
longer available. Farmlands were established as forests were cleared;
however, most emigrants were squatters on the land. According to the
1851 census, many backland settlers had cleared 10-20 acres, enough to
pasture cows, sheep, goats and horses and to grow essential crops.
Soils were often only marginally productive. For the majority of these
highland emigrants, seasonal employment was sought in the Sydney coal
mines, the fishery (particularly with American vessels fishing in the
Gulf), and selling timber stripped from unprotected Crown land. Poor
livelihoods and meagre agricultural potential led backland settlers to
abandon their farmlands; consequently, successional forest
regeneration of the land took place. Today, a limited amount of
farming is practised. A century ago, 100,000 sheep roamed the uplands
and meadows of Cape Breton but, with the waning of rural life, by the
1970s only 2,700 animals remained. Upland areas are now used for
commercial maple syrup production and mining ventures; however,
forestry is the dominant economic land use. The impressive upland
scenery of these environs has attracted recreation and tourism.
Introduction to the Geological History of Nova Scotia
The Avalon and Meguma Zones
The Carboniferous Basin
Development of the Ancient Landscape
Post-glacial Colonization by Plants
Nova Scotia's Climate
Plant Communities in Nova Scotia
Plants and Resources
Freshwater Open-Water Lotic
Freshwater Bottom Lotic
Hardwood Forest (Sugar Maple, Yellow Birch, Beech Association)
Softwood Forest (Spruce, Fir, Pine Association; Spruce, Fir
Mixedwood Forest (Spruce, Fir, Pine-Maple, Birch Association)