Menengai Forest
   HOME

TheInfoList



OR:

Menengai Forest is an
urban forest Urban means "related to a city". In that sense, the term may refer to: * Urban area, geographical area distinct from rural areas * Urban culture, the culture of towns and cities Urban may also refer to: General * Urban (name), a list of peop ...
situated within the town of
Nakuru Nakuru (nicknamed Nax) is a city in the Rift Valley region of Kenya. It is the capital of Nakuru County, and it is the fourth largest city in Kenya and the largest in the Rift Valley region. As of 2019, Nakuru had an urban population of 570, ...
in
Kenya Kenya, officially the Republic of Kenya, is a country located in East Africa. With an estimated population of more than 52.4 million as of mid-2024, Kenya is the 27th-most-populous country in the world and the 7th most populous in Africa. ...
. The Menengai Crater is within the forest. It was gazetted as a forest in the 1930s. It is surrounded by residential areas of Milimani Estate in the South, Ngachura and Bahati in the East,
Solai Solai is a town in Nakuru County, Kenya. It is located about thirty kilometers north of the county capital, Nakuru. Lake Solai lies to its north. Administratively, Solai is a location In geography, location or place is used to denote a region ...
in the North and Olo-Rongai in the West. Various
Government of Kenya The Government of the Republic of Kenya (GoK) is the Central government, national government of the Kenya, Republic of Kenya located in East Africa. It is composed of Counties of Kenya, 47 Counties, each county with its own semi-autonomous gove ...
facilities have been hived off from the forest; these include the
Kenya Broadcasting Corporation Kenya Broadcasting Corporation (KBC) is the state-run media organisation of Kenya. It broadcasts in English and Swahili, as well as in most local languages of Kenya. The corporation was launched as a radio service in 1928 when Kenya was a B ...
and the Nakuru G.K Prison. There is also a geothermal exploration project by the
Geothermal Development Company The Geothermal Development Company (GDC) is a wholly owned parastatal of the Government of Kenya. It is mandated to execute surface geothermal development, including prospecting for, drilling, harnessing and selling geothermal energy to electrici ...
inside the Menengai Crater floor.


Altitude

It is situated in an elevated area which ranges from above sea level.


Area

The forest covers an area of about . The actual forested area is about .


Flora

The main tree species in the forest are eucalyptus and acacia. Over 169 species of flowering plants and 17 species of grasses have been recorded in Menengai Forest. Example of flowering plants include leleshwa (''
Tarchonanthus camphoratus ''Tarchonanthus camphoratus'' (known as camphor bush for its scent, or leleshwa in Kenya), is a shrub or small tree which is widespread in Africa south of the Sahel, and in Yemen. Description The camphor bush can reach up to 6 meters in height. ...
''), ''Euphorbia'' species and ''Acacia'' species. Common grasses in the forest include geothermal grass (''
Fimbristylis ''Fimbristylis'' is a genus of sedges. A plant in this genus may be known commonly as a fimbry or fimbristyle. There are 200 to 300 species distributed worldwide. Several continents have native species but many species have been introduced to ...
exilis'') and Boma
Rhodes grass ''Chloris gayana'' is a species of Poaceae, grass known by the common name Rhodes grass. It is native to Africa but it can be found throughout the tropical and subtropical world as a introduced species, naturalized species. It can grow in many t ...
.


Fauna

There are mammals, birds and insects. Mammal species include the
tree hyrax The tree hyrax or tree dassie is a small nocturnal mammal native to Africa. Distantly related to elephants and sea cows, it comprises the four species in the genus ''Dendrohyrax'', one of only three genera in the family Procaviidae, which is the ...
,
rock hyrax The rock hyrax (; ''Procavia capensis''), also called dassie, Cape hyrax, rock rabbit, and (from some interpretations of a word used in the King James Bible) coney, is a medium-sized terrestrial mammal native to Africa and the Middle East. Common ...
,
olive baboon The olive baboon (''Papio anubis''), also called the Anubis baboon, is a member of the family Cercopithecidae Old World monkeys. The species is the most wide-ranging of all baboons, being native to 25 countries throughout Africa, extending from ...
, black-faced
vervet monkey The vervet monkey (''Chlorocebus pygerythrus''), or simply vervet, is an Old World monkey of the family Cercopithecidae native to Africa. The term "vervet" is also used to refer to all the members of the genus '' Chlorocebus''. The five distin ...
,
mountain reedbuck The mountain reedbuck (''Redunca fulvorufula'') is an antelope found in mountainous areas of much of sub-Saharan Africa. Subspecies There are three recognized subspecies. * ''Redunca fulvorufula adamauae'' - Adamawa mountain reedbuck * ''Redunc ...
, Kirk's dik-dik and
slender mongoose The common slender mongoose (''Herpestes sanguineus''), also known as the black-tipped mongoose or the black-tailed mongoose, is a very common mongoose species native to sub-Saharan Africa. Taxonomy The scientific name ''Herpestes sanguineus'' ...
. Birds species include the
Verreaux's eagle Verreaux's eagle (''Aquila verreauxii'') is a large, mostly African, bird of prey. It is also called the black eagle, especially in southern Africa, not to be confused with the black eagle (''Ictinaetus malayensis'') of south and southeast Asia. ...
(only found in Menengai Forest in Nakuru),
Abyssinian ground hornbill The Abyssinian ground hornbill or northern ground hornbill (''Bucorvus abyssinicus'') is an African bird, found north of the equator, and is one of two species of ground hornbill. It is the second largest species of African hornbill, only surpass ...
,
lesser spotted eagle The lesser spotted eagle (''Clanga pomarina'') is a large Eastern European bird of prey. Like all typical eagles, it belongs to the family Accipitridae. The typical eagles are often united with the buteos, sea eagles, and other more heavy-set Ac ...
,
African marsh harrier The African marsh harrier (''Circus ranivorus'') is a bird of prey belonging to the harrier (bird), harrier genus ''Circus''. It is largely resident in wetland habitats in southern, central and eastern Africa from South Africa north to South Sudan ...
,
Horus swift The Horus swift (''Apus horus'') is a small bird in the swift family Apodidae that is found in sub-Saharan Africa. Horus, whose name this bird commemorates, was the ancient Egyptian god of the sun, son of Osiris and Isis. Taxonomy The Horus swif ...
, turn-tailed ravens, red-winged sterling, and others. Other animals include spiders, molluscs and butterflies.


Soils

The forest stands on soils derived from volcanic ash. The soil texture is mainly sandy and is very easily eroded.


Management

The forest is under the management of the
Kenya Forest Service The Kenya Forest Service is an agency of the Government of Kenya designated by the Forest Act of 2005 as the replacement for the old Forest Department. It is overseen by the Board of the Kenya Forest Service. The former Forest Department was suppor ...
in collaboration with the Menengai Community Forest Association


Menengai Crater

The Menengai Crater is found within the forest. The possible date of formation of the Menengai Caldera was during the third and last major faulting of the
Gregory Rift The Gregory Rift (''Ufa la Gregori'', in Swahili) is the eastern branch of the East African Rift fracture system. The rift is being caused by the separation of the Somali Plate from the Nubian Plate, driven by a thermal plume. Although the te ...
valley in the middle
Pleistocene epoch The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...
of the Quaternary period less than one million years ago. This major
faulting In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...
resulted in very complex grid patterns, dropping the Rift valley a further approximately (from the original drops of approximately and with the first and second major faulting respectively). These latter minor faultings which both occurred during the upper Pleistocence led to the formation of new fractures and renewals on older fracture lines in Nakuru Basin and West of
Lake Nakuru Lake Nakuru is one of the Rift Valley lakes, located at an elevation of above sea level. It lies to the south of Nakuru, in the rift valley of Kenya and is protected by Lake Nakuru National Park. About 10,000 years ago, Lake Nakuru, together wi ...
respectively. The first minor faulting was accompanied by the emission of
pumice Pumice (), called pumicite in its powdered or dust form, is a volcanic rock that consists of extremely vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicula ...
showers from the Menengai Crater forming a pumice mantle, mainly on the western flank of Menengai. The pumice mantle forms a crudely stratified deposit, up to thick. The pumice mantle was originally believed to represent the first stage in the formation of a
caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcanic eruption. An eruption that ejects large volumes of magma over a short period of time can cause significant detriment to the str ...
of the
Krakatoa Krakatoa (), also transcribed (), is a caldera in the Sunda Strait between the islands of Java and Sumatra in the Indonesian province of Lampung. The caldera is part of a volcanic island group (Krakatoa archipelago) comprising four islands. Tw ...
n type. After reconsideration of the whole mechanism of caldera formation by comparing the form of Menengai with the form of the deeply eroded syenitic ring-complex west of
Oslo, Norway Oslo ( or ; ) is the Capital city, capital and List of towns and cities in Norway, most populous city of Norway. It constitutes both a Counties of Norway, county and a Municipalities of Norway, municipality. The municipality of Oslo had a populat ...
it is now believed that cauldron subsidence and deep seated migration of
magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma (sometimes colloquially but incorrectly referred to as ''lava'') is found beneath the surface of the Earth, and evidence of magmatism has also ...
were contributing factors. The process is envisaged as: * Cauldron Subsidence - migration of magma at depth and fracturing of the retaining roof of the magma chamber * Sudden lowering of pressure resultant on subsidence - rapid release of gas. Catastrophic eruption of gas-charged pumice from numerous fissures formed by subsidence * Further collapse and engulfment of volcano super-structure - due to void formed by the evisceration process Near Menengai summit, a few ejected blocks of these black vitreous
lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...
are mixed with the pumice mantle on the outer slopes. To the south-west the lavas overlie the pumice mantle. The mode of origin of the pumice
lapilli Lapilli (: lapillus) is a size classification of tephra, which is material that falls out of the air during a volcanic eruption or during some meteorite impacts. ''Lapilli'' is Latin for "little stones". By definition lapilli range from in dia ...
eruptives is not certain, but stratification, sorting and lack of lithic inclusions suggest vulcanian showers rather than flowing avalanches, and their concentration to the west of Menengai suggest a control by wind direction. Later volcanic flows during the recent times (up to 2000 years ago) resulted in the formation of the Upper Menengai big lavas, which fill the caldera and are represented by trachyte lava flows and scoria cones.
Trachyte Trachyte () is an extrusive igneous rock composed mostly of alkali feldspar. It is usually light-colored and aphanite, aphanitic (fine-grained), with minor amounts of mafic minerals, and is formed by the rapid cooling of lava (or shallow intrus ...
lavas completely cover the floor of the caldera, concealing the rocks of the older volcano. The products of these late eruptions which are believed, from the complete absence of vegetation on some of the younger flows, to have continued up to the last few hundred years, have been described by McCall, 1957, p. 66.7. They form slaggy tongue- shaped flows emanating from various points in the caldera but mainly from the vicinity of the secondary summit and their flow was restricted by the caldera walls. They are characterized by beautifully developed pressure ridge patterns resembling those of a glacier. They include blocky flows apparently entirely composed of jumbled boulders, some massive flows, and also flows composed of twisted ropes of vitreous lavas. The lavas are characteristically black in colour and are for the most part vitreous, though they grade from nearly holocrystalline types to streaky obsidian. There are many conical piles of cinders of similar material within the caldera, but no well defined secondary crater. Similar cinder piles being products of their waning stage. These upper lavas are almost entirely restricted within the caldera but have spilled out over the caldera rim on the outer slopes at two points. The most conspicuous overspill is close to a line of small craterlets South-West of nakuru and there may be some genetic connection. The massive trachyte exposed in the Amolak Sigh Quarry is believed to belong to the upper lava series, though unlike most of these late lavas it is holocrystallive. The overspill probably represents one of the very earliest of these second series eruptions. The later lava seems to continue down the caldera wall into the caldera, and this may well be a ring feeder structure similar to the famous backward flow Crater Lake, USA,Williams, H. (1942) The Geology of the Crater Lake National Park, Oregon, p. 50–52 a ring feeder actually cut through by the caldera fault. Similar structures are seen in
Mount Suswa Mount Suswa is a shield volcano in the Great Rift Valley, Kenya. It is located between Narok and Nairobi, the capital of Kenya. The northwestern part of Mount Suswa is in Narok County, while the eastern and southern parts are in Kajiado Count ...
caldera.


Gallery

Menengai Crater.jpg, Menengai Crater Menengai Crater 1.jpg, Menengai Crater Menengai Crater 3.jpg, Menengai Crater Menengai Crater 4.jpg, Menengai Crater Black Vitreous Lava.jpg, Black vitreous lava Menengai Forest Summit.jpg, Menengai Forest summit


References

{{coord, 0, 15, S, 36, 05, E, display=title, region:KE_type:forest_source:GNS-enwiki Nakuru Forests of Kenya