Natural regeneration assessment in tiro-boter becho integrated forestry development and utilization project.

Regeneration assessment, floristic composition and gradient analysis study at tiro-boter vecho. Jimma zone, Oromiyaa region, Ethiopia was carried out from January to March 1996 to obtain information on forest status and to see factors governing the ecology of the forest. Data on the vegetation composition and other environmental factors were collected from 51 randomly selected sample plots located at 100 m altitudinal intervals, for altitude ranging from 1800 to 2700 m a.s.l. (i.e. three sample plots for disturbed and three plots for undisturbed forests for each altitude interval). Seedlings height were recorded for woody plants having height less than or equal to 1.5 m and DBH measurements were taken for all tree and shrub species having height greater than 1.5 m. In the sample plots of study area 51 species belonging to 33 families were identified. Relative density, relative frequency, relative basal area and importance value indices were calculated for each species, which showed the overall forest situation. For undisturbed forest IVI was analysed along altitudinal gradients of which five dominant species were identified. These dominant species at 100 m altitudinal intervals were Croton macrostachys at 1900. Maytenus senegalensts at 2000. Syzygium guineense at 2100, 2200, 2300, 2400, and 2500, Olea capensis subsp. hochestetteri at 2600 and ilex mitis at 2700 m. a.s.l. It was found that in most cases Syzygium guineense was the highest contributor to the relative basal area of the forest area. The structure analysis made showed for seedlings and saplings 810 stems/ha for undisturbed and 700 stems/ha for disturbed forest. The general configuration of all species was found to have high density at lower DBH classes and low density at higher DBH classes. Horizontal distribution of the species revealed that the number of species tends to decreases with the increase in altitude and stope. Similarity index between adjacent altitudes indicated no regular pattern. Shrub and less quality species were dominant in the smaller DBH classes. Ordination and classification of the species were analysed by using DECORANA and TWINSPAN. Five vegetation communities: Ilex mitis -Olima rochetiana, Syzygium guineense- Bersema abyssinica, Olea capensis subsp. welwitschii- Teclea nobilis, Croton macrostachys - Clausena anisata and Maesa lanceolata were identified. Species clustering were related to altitude and degree of disturbance