Countries of the World/COUNTRYS.BIN/dp/0070/00706.txt

Text File | 1991-06-24 | 40KB | 673 lines

$Unique_ID{COW00706}
$Pretitle{366}
$Title{Cameroon
Chapter 3B.   Climate and Vegetation}
$Subtitle{}
$Author{Harold D. Nelson}
$Affiliation{HQ, Department of the Army}
$Subject{areas
area
population
per
percent
province
near
provinces
towns
north}
$Date{1974}
$Log{Figure 6.*0070601.scf
Figure 7.*0070602.scf
Table 1.*0070601.tab
}
Country:     Cameroon
Book:        Area Handbook for the United Republic of Cameroon
Author:      Harold D. Nelson
Affiliation: HQ, Department of the Army
Date:        1974

Chapter 3B.   Climate and Vegetation

     From its northern extremity in the seasonally dry plains of the Chad
Basin, the country extends for 700 miles southwestward through regions of
upland wooded savanna to the humid mixed forests on the southern plateaus,
equatorial rain forest near the southern border, and mangrove swamps along the
coast, where rainfall may exceed 130 inches per year (see fig. 6). The level
of rainfall is the primary factor determining patterns of vegetation and
population. Elevation is also significant; areas such as the Adamaoua Plateau
and the Bamenda Highlands are high enough to be more comfortable and healthful
than the humid forests and lowlands of the southern and southwestern
provinces.

[See Figure 6.: Cameroon, Vegetation and Rainfall Source: Adapted from France,
Ministere de la Cooperation, Economie et Plan de Developpement: Republique
Federale du Cameroun, Paris, 1965.]

The Subarid North

     The narrow neck of Northern Province is among the northernmost areas
reached by moisture-bearing winds from the equatorial rain belt. Southerly
and southwesterly winds bring about forty inches of rain annually to the
Garoua area and about thirty inches to much of the area farther north. Most
of it is concentrated in a five-month season (May to September) in the Garoua
region and in a shorter season near Lake Chad. For the rest for the year and
intermittently during the rainy season, this northern region is under the
influence of drying winds from the Sahara Desert. Surface water is quickly
evaporated or escapes through poorly developed soil structures to underground
water tables. Daytime temperatures are usually high except during and
immediately after the late summer rainstorms. Midday maximums are often above
90F, especially during February and March, but nights are usually much cooler,
at least during the dry months when the diurnal range often covers thirty
degrees and may be as much as fifty degrees. Natural vegetation in most of
the area consists of fibrous, hardy grasses, thorny scrub, and low trees,
shading into grassier areas south of Garoua, the provincial capital.

     Along the northeastern border, the flood plain of the Chari and Logone
rivers forms an important subregion. For at least part of the year marsh
grasses and a great variety of other swamp plants thrive in waterlogged flood
plains that extend for considerable distances north and south of Fort-Foureau.
Other swamplands, smaller in total area but having considerable local
economic importance, lie east of Garoua along the Benoue River and along
one of its major tributaries, the Mayo Kebi (see ch. 13).

The Central Savanna

     Much of the Adamoua Plateau is an area of humid wooded savanna. At
Ngaoundere, a town near the center of the plateau and near the geometric
center of Cameroon as well, annual rainfall is about fifty-nine inches, twice
as much as the average in the far north. The rainy season extends from April
to October and is longer toward the south, where this region merges into the
region of humid wooded savanna and forests. The central area is a transition
zone, a mixture of tropical and equatorial types of vegetation. Elevation as
well as geographic location adds to the variety; mountains on or near the
plateau may be covered with shrubs and other plants that prefer the cooler
climate of the higher altitudes.

     Through repeated burning, the original forests have been destroyed in
some areas; much of the new growth consists of thorny scrub, marked here and
there by fire-resistant trees. Other areas are a type of prairie, in which
expanses of grass are interspersed with patches of stunted shrubs.

     Much of this subequatorial central area is from 3,000 to 5,000 feet
above sea level, and elevation tends to moderate temperatures. Records taken
at Ngaoundere (3,600-foot elevation) show average daily maximums ranging from
about 82F in June during the rainy season to 95F in March at the end of the
dry season. Daily minimums are about 60F or slightly higher during several
months of the summer rainy season.

     Winter is a period of low humidity, which makes the area more comfortable
for humans than the lower and wetter areas in the south and the southwest.

The Humid South

     Southward the lower plateaus become progressively more rainy and humid.
Between 6 degrees N and 4 degrees N latitude the primary vegetation is a
mixture of deciduous and evergreen forest and areas of open grassland that
shades into wooded savanna farther north. From the capital city of Yaounde
southward and eastward to the national borders, rainfall and warm temperatures
foster a perennially green broadleaf forest. Many trees are over 100 feet
tall; below them are tangled mixtures of vines, shrubs, and ferns.

     Rainfall ranges from sixty inches per year in areas near 5 degrees N
latitude to nearly 100 inches in the southern section of the coastal plains
near the town of Campo. Diurnal and seasonal fluctuations in temperatures and
humidity are within narrow ranges, especially at the lower elevations and
along the coast. Yaounde's temperatures are typical, having an average daily
maximum of 82F and an average minimum of 72F.

     Relative humidity is not often below 50 percent, and it is frequently
above 80 percent. Nevertheless,at 2,300-foot elevation. Yaounde and a large
area to the north and east have a more comfortable climate than the
southwestern coastal zone.

     The southern area comes under the influence of equatorial airmasses from
the south as well as Atlantic airmasses from the southwest. Among other
complex climatic influences, one result is a pattern that includes two
seasonal rainfall peaks annually and two seasons that are less rainy (somewhat
inaccurately known as the dry season and the little dry season). The rains
are moderately heavy in April and May, tapering off to the little dry season
(four to six inches of rain per month) in June and July. Rainfall increases
to more than thirteen inches per month in August and September and then
recedes to as little as three to five inches per month in December and
January.

Coastal and Montane Rain Forest

     The climate along the coast is said to resemble a permanent Turkish bath.
There is no dry season; temperature and humidity change very little from day
to day or from month to month. The western mountains are also a part of this
rainy and humid zone, but altitude brings somewhat greater variations in
the monotonous patterns of prolonged periods of cloud cover, heavy rain, and
high humidity. Temperatures at the port of Douala, in the central coastal
area, range from an average daily high of 84F to average lows of about 72F;
record highs in this area are above 95F. The average relative humidity is
between 85 and 90 percent throughout the year. Rainfall ranges from 100 inches
per year south of the coastal town of Kribi to 158 inches at Douala.

     Rainfall in the mountainous areas of Southwestern and Northwestern
provinces varies greatly. Most areas, including those as far inland as the
Bamenda Highlands, receive between sixty and 130 inches or rain per year. Some
areas in the coastal plains and in the mountains near the sea receive twenty-
five inches of rain per month in August and September, the wettest months.

     Mountains in this western region force moisture-laden onshore winds
upward into cooler strata, creating local microclimates that are especially
wet on their windward sides. The leeward side may be drier than the nearby