The objective of this study were to investigate t he distribution of seedlings, saplings and trees of Podocarpus falcatus along gradients of altitude, light and soil moisture as well as assess its ...regeneration status in Harenna forest. The densities of seedling and their spatial distribution were investigated by using quadrates of 10 x 5 m (50 m2) and those of sapling and trees by using quadrates of 20 x 20 m (400 m2) along line transects established in a north to south orientation between 1500 and 2100 m altitude and having 300 m distance between them. Seedlings showed marked restriction and distinct habitat preferences along the altitudinal gradient occurring between 1500 and 2100 m. The saplings occupied similar altitudes to that of the seedlings and trees occupied altitudes from 1500 to 2000 m. The highest density, 3050 seedlings/ha, was recorded at 1800 m while the lowest density, 750 seedlings/ha, was recorded at 2100 m. Mean density of seedlings in the forest was 1971 individuals/ha. The density of saplings and trees along the altitudinal gradient ranged from 8 to 75 and 32 to 50 stems/ha, respectively. The mean densities of saplings and trees in t eh forest were 32 and 67 stems/ha, respectively. About 74% of the seedling population was found under shade and 26% in the open. Podocarpus preferred soil moisture between 5.6 and 27.2%. Seedling mortality accounted for 20%. The population structure showed that only seven of the 16 height classes were represented by trees and seedlings of P. falcatus, indicating hampered regeneration. This indicates a great risk of local extermination of the species and hence urgent interventions are made for the appropriate management and sustainable utilization of the forest in general and genetic conservation of the species in particular.
The endangered indigenous tree species
Juniperus procera, commonly known as African Pencil Cedar, is an important component of the dry Afromontane vegetation of Ethiopia and was shown to be AM in ...earlier studies. Here we describe the composition of AM fungi in colonized roots of
J. procera from two dry Afromontane forests of Ethiopia. The nuSSU rDNA gene was amplified from colonized roots, cloned and sequenced using AM fungal specific primers that were partly developed for this study. Molecular phylogenetic analysis revealed that all the glomeralean sequences obtained belonged exclusively to the genus
Glomus (
Glomeraceae). Seven distinct
Glomus sequence types were identified that all are new to science. The composition of the AM fungal communities between the sampled trees, and between the two study sites in general, differed significantly. Isolation and utilization of the indigenous AM fungal taxa from the respective sites might be required for successful enrichment plantation of this threatened
Juniperus species.
There are many hardwood species in Ethiopia which can serves as sources, of raw material, e.g. veneer, for wood industries, construction, paneling furniture etc. With the rapid depletion of these ...species, it was timely to explore other unutilized species of trees and generate knowledge about their properties and uses. The general objective of this study was to investigate the suitability of 20 indigenous tree species to obtain quality decorative sliced veneer. Out of the 20 species, the eight best were accepted by the furniture industry. These were Albizia gummifera, Pouteria adolfi-friederici, Cordia Africana, Hagenia abyssinica, Ocotea kenyensis, Olea capensis subsp. hochstetteri, O. capensis subsp. welwitschii and Prunus Africana. All of them proved to be good for high quality furniture, face veneer of plywood and edging and fetched good price in the market. Species differed considerably with respect to the time required by their logs to reach the machine employed. The outputs obtained from slicing activities were, on the average, 0.38 m3 of 0.65 mm thick veneer from one m3 of log and the recovery rate of the final sliced veneer was, on the average, 32.34% for all the species. Intensive planting efforts of those species is recommended to save the meager foreign currency earnings of the country.
Soil seed bank composition and density within a portion of Harenna forest, southeast Ethiopia, was investigated in relation to the influence of wildfire and regeneration. Soil samples were collected ...both from burned and unburned portions of the forest using quadrates of 15 x 15 cm and 9 cm depth along line transects. Monitoring of forest recovery on burned sites was made using permanent plots of 0.1 hectare. Seed germination results showed 18 soil seed bank species from soil collected at unburned sites and only 2 species from burned sites. Seed density at unburned sites was 622 plus or equal to 15 seeds/square m, while burned sites was 67 plus or equal to 2 seeds/square. Analysis of variance between the unburned and burned sites showed significant variation in number of seeds (P= 0.001) and species (P= 0.04). A significant variation in the number of seeds was also observed at litter (P= 0.001), upper (P= 0.001 and middle (P= 0.038) soil layers. Two plant species were only germinated from soil samples collected at burned sites (Ficus sur and Dichrocephala integrifolia). Shannon-Weaver index revealed that soil collected from unburned sites had shown higher species diversity and evenness. Monitoring results at burned sites after eighteen months showed more than 32 plant species that attained less than or equal to 3 m high. The re-growth vegetation is composed of mainly secondary forest species dominated by family Asteraceae. Croton macrostachyus was the dominant species that colonized burned forest sites. Regeneration on burned sites depends on seeds originated (dispersed) from the neighboring forest patches (after disturbance).
This paper is a compilation of nine different vegetation types, and a synthesis of forest fire management practices in Ethiopia, beginning with a general background. It describes the salient features ...and effects of fire, i.e. types and occurrence of fire, factors that influence the behaviour of fire, effect of fire on soils, plants, animals and ecosystem processes. Fire behaviour in different ecological zones of Ethiopia and the causes and impacts of forest fires are discussed, as are actual forest fire management practices, and the problems related to a weak fire management system in the country. Community participation in controlling fires and the need for public awareness at all levels are emphasized. suggestions made by various authors that could help prevent fires, and different fire prevention/control measures, are summarized. The very few research papers on fire in Ethiopia are mentioned and the need for more research on all aspects of fire is stressed.
Various aspects of seed and regeneration ecology: germination requirements of seeds, seed longevity in the soil, soil seed banks in forests, gaps and arable land as well as density, survival and ...growth of seedlings were investigated within the dry Afromontane region in Ethiopia. In laboratory germination tests, 60% of the species studied exhibited some degree of initial dormancy and the optimum constant temperature for gemination was between 20 and 25 deg C in the majority of the species. A few species showed a requirement for fluctuating temperatures and germination was suppressed or completely inhibited in several, mainly small-seeded, species when they were incubated in darkness or in light filtered through green leaves. Hard-seeded species required scarification treatments to improve germination, indicating seed-coat imposted dormancy. Dry storage reduced the germinability of seeds in a few species, suggesting a recalcitrant behaviour, while seeds of many species remain unaffected. During four years of storage in forest soils, seeds of 2 out of 8 species germinated in the soil almost completely within a year, 2 of the species maintained nearly full viability, while 4 were intermediate. The generally high levels of dormancy and somewhat extended viability of seeds in the soil may have been selected for under a climate of seasonal drought and unreliable rainfall that characterises the dry Afromontane region. The viable soil seed flora in the 0-9 cm soil layers ranged between 58 and 92 species in four different forests and the density ranged between 12300 seeds/m2 and 24000 seeds/m2. In forest gaps sampled two years after their formation at one of the forests, the soil seed density in the 0-3 cm soil layers was 9400 seeds/m2 representing 51 species. A year later the density had increased to 14790 seeds/m2 and represented 55 species, reflecting heavy seeding by a few herbs. The density in the arable land formerly covered by forest was 20740 seeds/m2 representing 69 species in the 0-3 cm soil layers. In all cases, the soil seed bank was dominated by herbaceous species and woody species were represented by very few species, suggesting that the soil seed bank is not the main regeneration route for woody species, However, serveal woody species produced coppice shoots from damaged stems in the gaps, indicating the potential of these species to regenerate vegetatively. In surveys of seedling populations in two of the forests, large populations of seedlings of woody species were found ranging in density between 16290 seedlings/ha and 32650 seedlings/ha and representing 57 species. The seedling bank and sprouting from stumps are the main routes of regeneration in woody plants of the dry Afromontane forests. Annual mortality of monitored seedling populations varied greatly among species. Mean annual height increment was generally low (less than 15 cm) both in gaps and under shade. Dry Afromonatane forests have a potential to recover in relatively short time after natural and man-made disturbances, e.g. after carefully managed selective cutting. However, the common practice of clearing forests and converting them into permanent arable land destroys the sources of regrowth thereby preventing regeneration of the forest vegetation
Seed viability of Afromontane tree species in forest soils Demel Teketay; Granstrom, A. (Swedish University of Agricultural Sciences, Faculty of Forestry, Department of Forest Vegetation Ecology, S-901 83 Umea (Sweden))
Journal of Tropical Ecology (United Kingdom),
(1997), Letnik:
13, Številka:
1
Publication
Shade trees of coffee in Harerge, eastern Ethiopia Demel Teketay; Assafa Tegineh (Faculty of Forestry, Alemaya University of Agriculture, PO Box 138, Dire Dawa (Ethiopia))
International Tree Crops Journal (United Kingdom),
(1991), Letnik:
7, Številka:
1-2
Publication
