The work seeks to elucidate the conditions for growth of seedlings in an Afromontane forest. The species studied were <I>Juniperus procera</I> Hochst, ex Endl. and <I>Afrocarpus gracilior</I> (Pilger) C.N. Page from the dry montane coniferous forests of Ethiopia. The main aim was to provide the necessary information for a silviculture based on natural regeneration. The understorey light climate was examined, particularly the photosynthetic photon flux (PPF) and Red:Far-red ratio. An empirical model was developed linking measured PPF to gap fraction as assessed from hemispherical photographs. Air temperatures and soil moisture contents were measured, and comparisons made with an 'open' site. The effects of burning and mechanical scarification on regeneration following clear felling and timber extraction were assessed. Finally, a programme of controlled environment experiments was carried in Edinburgh. The effects of seed pre-germination treatments and simulated forest canopy light on seed germination were tested, the responses of seedlings to simulated forest canopy light conditions and nutrient supply were measured, and the response of seedlings to Red:Far-red ratio was examined. The main findings were: (i) The forest is relatively 'open' with a mean photon flux density at the forest floor of 1.4 mol m<SUP>-2</SUP> d<SUP>-1</SUP> to 12.7 mol m<SUP>-2</SUP> d<SUP>-1</SUP>, and little annual variation. There is a mean Red:Far-red ratio in the range of 0.54 to 0.67 in the forest understorey. (ii) Clear cutting or manipulating the canopy alone did not result in the regeneration of both species, but regeneration and establishment of <I>Juniperus procera</I> could be enhanced by site preparation, particularly controlled burning, which exposes the mineral soil.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:661784 |
| Date | January 1994 |
| Creators | Sharew, Hailu |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/14387 |
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