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Flora Biodiversity Assessment in Bonga, Boginda and Mankira Forest

Flora Biodiversity Assessment in Bonga, Boginda and Mankira Forest

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4.3. Vegetation<br />

Accord<strong>in</strong>g to A. Aalbaek &T.Kide, 1993, the vegetation <strong>in</strong> the study area is found with<strong>in</strong><br />

three seed zones: Western Lower Broadleaved Afromontane Ra<strong>in</strong>forest, Central wet<br />

Bradleaved Afromonatne ra<strong>in</strong>forest <strong>and</strong> Eastern Higher broadleved Afromontane<br />

Ra<strong>in</strong>forest. Friis, 1992 classified the study area as “Afromontane Ra<strong>in</strong> <strong>Forest</strong>”. This<br />

Afromontane ra<strong>in</strong> forest is found on altitudes between 1500 <strong>and</strong> 2500 masl, with average<br />

annual temperature 18-20 0 c <strong>and</strong> ra<strong>in</strong>fall between 1500 mm <strong>and</strong> greater than 2000 mm.<br />

The ra<strong>in</strong>y season is between April <strong>and</strong> October (Friis, 1992).<br />

Accord<strong>in</strong>g to Taye Bekele, 2003, there are three types of vegetation, namely: Upl<strong>and</strong><br />

Ra<strong>in</strong> forest Vegetation, Upl<strong>and</strong> Humid <strong>Forest</strong> Vegetation <strong>and</strong> Ar<strong>in</strong>dunaria/Bamboo<br />

thicket. The author described this zonation based on altitud<strong>in</strong>al variation. The upl<strong>and</strong> ra<strong>in</strong><br />

forest vegetation, upl<strong>and</strong> humid forest vegetation <strong>and</strong> ar<strong>in</strong>dunaria thicket are located at<br />

altitud<strong>in</strong>al range between 1500- 2200, 2450-2800 <strong>and</strong> 2400-3050 masl, respectively. The<br />

current survey is conducted with<strong>in</strong> the three zones. Vegetation listed <strong>in</strong> Taye Bekele,<br />

2003 is <strong>in</strong> agreement with f<strong>in</strong>d<strong>in</strong>gs of the current survey.<br />

In this phytogeography, Friis, 1992 listed 23 tree species as medium sized canopy tree<br />

which can atta<strong>in</strong> 10-30 meter high. These species area:<br />

Albizia gummifera, A. schimperiana, A. gr<strong>and</strong>ibracteata, Blighia unijugata, Cassipourea<br />

malosana, Celtis africana, Croton macrostacheyus, Ekebergia capensis, Euphorbia<br />

ampliphylla, Ficus sur, Ficus ovata, Ficus thonn<strong>in</strong>gii, Ocotea kenyensis,Ilex mitis, Olea<br />

welwitschii, Polycias fulva, Prunus africana, sapium ellipticum, syzygium gu<strong>in</strong>eense <strong>and</strong><br />

Schefflera abyss<strong>in</strong>ica. Friis reported that Pouteria adolfi-friederici is the only emergent<br />

species from a 20-30 meter high canopy. On the other h<strong>and</strong>, Chaffey, 1979, reported that<br />

<strong>in</strong> addition to Pouteria adolfi-friederici, Ficus species <strong>and</strong> Syzygium gu<strong>in</strong>eense are <strong>in</strong> the<br />

canopy. Schmitt C. B., 2006 agrees that the top canopy is occupied by Pouteria adolfifriederici<br />

that can atta<strong>in</strong> a height of above 40 meters. Other trees that can grow up to 40<br />

meters, accord<strong>in</strong>g to the same author, are Olea welwitschii <strong>and</strong> Trilepisium<br />

madagascariense.<br />

44

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