Browsing by Author "Dyson, W.G."
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Item A Checklist List of Birds of the Muguga Area Kenya 1967(1967) Gwynne, M.D.; Dyson, W.G.The present list is based on one repaired by Mrs Molly Glover of the East African Agricultural and Forestry Research Organization and Which recorded her observations at Muguga for the year bruilry 1962- February· 1963 Mrs 0 Glover's list was closefisted and circulated to a small number of keen birdwatchers' resident at Muguga 5 who have mended the original list from their subsequent observations. Apart from our own recordItem Experiments on Growing Eucalyptus Wood Fuel in the Semi Deciduous Forest Zone in Kenya(1974) Dyson, W.G.; E.A.A.F.R.O.This paper describes experiments carried out between 1961 and 1972 on growing Eucalyptus wood fuel at the E.A.A.F.RO. Estate, Muguga which lies in the semi-deciduous forest zone in Kenya.Item Experiments on Growing Eucalyptus Wood Fuel in the Semi-Deciduous Forest Zone in Kenya(1973) Dyson, W.G.This paper describes experiments carried out between 1961 and 1972 on growing Eucalyptus wood fuel at the E.A.A.F.R.O. Estate, Muguga which lies in the semi-deciduous forest zone in Kenya. A six year rotation, with regeneration from coppice for the second and subsequent rotations, has been adopted to produce 210 m3/ha (stacked volumes) of 10 cm diameter billets. Eucalyptus grandis from New South Wales, Australia is the most satisfactory and productive species. A hybrid developed in South Africa and Kenya X E. saligna X grandis, is almost as good but gives 6 to 8 per cent lower yields. The first crop is established with seedlings raised for five months in a nursery and transplanted as early in the rainy season as possible into cultivated land. After felling at 6 years old about 90 per cent of the stumps produce coppice shoots which are grown on for the next crop. Neither the method of felling, nor the height of stump left, significantly affect coppicing ability. The coppice crop may be reduced to two or three stems per stump at about 18 months, or later, after felling. Reduction of coppice reduces yields but increases the diameter of the remaining poles. It is of no advantage unless there is a local demand for the withies produced. Yields are variable, depending in part on the rainfall received during the growing period. First rotation crops average 178 m3/ha at age six and subsequent coppice crops 277 m3/ha (stacked volume). A seven year rotation and closer initial espacements are recommended to achieve the objects of management.Item Note on a Preliminary Study of the Effects of an East African Softwood Crop on the Physical and Chemical Condition of a Tropical Soil(1966) Robinson, B.D.; Hosegood, P.H.; Dyson, W.G.; East African Agriculture and Forestry Research Organization, Kikuyu, Kenya.Some soil physical and chemical properties were measured under a secondary indigenous forest cover and a 16-year-old stand of Cupressus lusitanica. No significant differences in the physical parameters were noted; but distinct differences in some of the chemical determinations, viz. nitrogen, exchangeable bases, exchangeable hydrogen and pH, were found particularly at the top of the soil profile; however, the sampling technique requires to be refined. Further detailed studies are planned.Item A note on Dwarfing of Pinus patula grafts(1975) Dyson, W.G.Manuscripts (two copies) should be sent to the editorial office. The items published include original articles and short communications, reviews, announcements and reports on meetings and congresses in German, English or French on forest genetics and forest tree breeding and on related fields of importance to these Reproducing of contributions is not permitted; reproduction of Illustrations is permitted only with the approval of the author and the publisher.Item Revised Heritability Estimates for Cupressus Lusitanica in East Africa(1977) Dyson, W.G.; Raunio, A.L.; East African Agriculture & Forestry Research Organization, Muguga, KenyaA report of progeny trials in Kenya and Tanzania, with a total of 41 open-pollinated families of C. lusitanica. Estimates of heritability ranged from 0.87 to 0.26 for ht. growth, from 0.93 to nil for stem diam., from 0.70 to 0.11 for stem form and from 0.90 to nil for damage by cypress canker disease [caused by the fungus Monochaetia unicornis]. Thinning the trial plots reduced within-family and between-family variances, and resulted in reduced heritability values. No consistent change in heritability values with age (up to 10 yr from field planting) was observed. From authors' summary.Item Silviculture: Introduction(1965) Dyson, W.G.; Forest Department, KenyaThe Reserved Forest Estate of Kenya and Uganda is a dangerously small proportion of the total land area: 2.4 per cent and 7.5 percent respectively. Tanganyika has a higher proportion of reserved forest 14.6 percent but nine-tenths of this is woodland of low productivity as is more than half of the Uganda Estate.Item Variation in Leaf Wax Alkanes in Cypress Trees Grown in Kenya(1970) Herbin, G.A.; Dyson, W.G.; East African Agriculture and Forestry Research Organisation, Muguga, Kenya and Department of Chemistry, University College, Nairobi, Kenya.Gas-liquid chromatographic analysis of alkane fractions isolated from the leaf waxes of Cypress trees has shown the proportions in which they occur to be variable. Variation with species, seed provenance and between individual trees within a plantation is evident. To use the leaf wax alkane composition as a taxonomic discriminant requires careful replicated sampling with concurrent reference sampling of authenticated stands.
