Assessment of the Population Structure and Regeneration Potential of Ocotea Usambarensis in Response to Recent Selective Logging on the Southern Slopes of Mt. Kilimanjaro, Tanzania
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Date
2025-01
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NM-AIST
Abstract
East African Camphorwood (Ocotea usambarensis) population in montane forests of East Africa has been declining at alarming rates. The decline is attributed to the historical legal commercial harvesting of the species sanctioned by colonial governments and later on illegal selective logging due to its high timber value. O. usambarensis is a vital component of the Mt. Kilimanjaro catchment forest and plays an important role in its hydro-ecological functions, making its population worth conserving. This study assessed the population structure, relative abundance and regeneration status of O. usambarensis in its range areas with different historical logging intensity and along elevation gradient on the southern slopes of Mt. Kilimanjaro. The age structure varied along the elevation gradient and across different blocks with high and low logging intensities blocks. However, a healthy regeneration status of O. usambarensis was observed, with a higher density compared to other tree species, as indicated by a reverse J-shaped population structure. Relative abundance of O. usambarensis decreased with increased logging intensity and increased along the elevation gradient. Stem density and basal area of seedlings, saplings and adults were compared using Wilcoxon signed-rank test. The comparison between blocks with different historical logging intensity showed no significant difference; adults (W = 67, p = 0.33), saplings (W = 101.50, p = 0.72), and seedlings (W = 102, p = 0.90); however, adults stem density (stems ha-1; W = 41, p = 0.002) and basal area (m2 ha-1; W = 34, p = 0.001) varied significantly along the elevation gradient. Moreover, I computed tree species Importance Value Index (IVI) in both blocks and along the elevation gradient. The IVI in both blocks and along the elevation gradient showed O. usambarensis is still the most important tree species with higher IVI compared to other tree species found in the study plots. The findings suggests that logging targets mainly adults which are located close to the park boundary. Thus, calling for more enforcement efforts in areas adjacent to park
boundaries and participatory approaches towards sustainable management of the species in range areas. Also, more efforts should be put on supporting local communities to plant O. usambarensis and other timber trees in their village lands and farms in areas with favourable climate and at the required altitudes. This will help to reduce pressure in the protected forest resources.
Sustainable Development Goals
SDG :13- Climate Action
SDG :15- Life on Land