Ndangalasi, Henry Joseph2021-01-232021-01-231997Ndangalasi, H. J (1997) Studies on canopy gap characteristics and regenerating species composition in Pugu forest reserve, Tanzania, Masters dissertation, University of Dar es Salaam, Dar es Salaamhttp://41.86.178.5:8080/xmlui/handle/123456789/14350Available in print form, EAF Collection, Dr. Wilbert Chagula Library, (THS EAF QK938.F6N4)Canopy gaps were studied in Pugu Forest Reserve, Tanzania in order to determine the causes of their formation, their size and regenerating species composition and diversity. The results show that canopy gaps were caused by both natural processes and anthropogenic activities such as felling trees for charcoal burning and building poles. Charcoal gaps ranged in area between 35m2 and 1462.5m2 with a mean area ± SD of 325.9m2±309.3. the northern part of the forest, with 92% of all the charcoal gaps recorded, was the most affected area when compared to the southern part. Estimates show that 7.65% of the total forest area was charcoal gaps. Panicum trichocladum and Trema orientalis (with a relative density of 22.2% and 15.3% respectively) were the most frequent colonizing species in these gaps. Manilkara sulcata, Scorodophloeus fischeri, Diospyros verrucosa, Vitex zanzibarensis and Haplocoelopsis Africana were the species most preferred for making charcoal. Natural canopy gaps ranged in size between 36m2 and 147m2 with a mean±SD of 88m2±29.6. Estimates show that 16.49% of the total Pugu forest Reserve was natural canopy gaps. The main cause of natural gaps were trecfalls, snapped-off branches and dead-standing trees, each of which accounted for 48.3% 31.0% amd 26.7% of all natural gaps respectively. In total 108, 227 and 207 species were recorded from the charcoal gaps, natural gaps and the undisturbed forest sites respectively. Natural gaps recorded the highest mean species diversity (Shannon’s Diversity Index) ±SD 2.4581 ±0.4875, followed by the undisturbed forest 2.3350±0.1252. charcoal gaps recorded the lowest species diversity at 2.2844±0.4613. Similarity in floristic composition between the charcoal gaps and adjacent undisturbed forest sites was low, with 86.5% of all the compared sites registering similarity indices of between 20% and 40%. On the contrary natural canopy gaps showed relatively higher similarity with 65.5% of all the compared sites recording similarity indices of greater than 40% with the adjacent undisturbed forest. There were no significant differences (t-test, p˃0.05) in the number of seedlings, saplings, poles and trees of 19 most frequent species occurring between the natural gaps and the undisturbed forest sites except for the saplings of Brachylaena huillensis (p=0.01) and poles of Rinorea angustifolia (p=0.047). the first two recorded more saplings in the canopy gaps than in the undisturbed forest sites, whereas the latter recorded more poles in the undisturbed forest sites than in the canopy gaps. Dominance-diversity profiles for 21 most frequently occurring species for seedlings, saplings, poles and trees from the canopy gaps and undisturbed forest sites indicated that only few species dominated each size class. Rinorea angustifolia was overwhelmingly dominant in the first three size class strata both in the bcanopy gaps and the undisturbed forest sites. Diameter size class distributions for the most frequently occurring tree species indicated that some species had negatively skewed distributions, while others had positively skewed distributions. However, in the case of Dialium holtzii and Newtonia paucijuga the majority of their members were in the above 35cm dbh size class. Poor representation of these species in the lower size classes probably indicates that recruitment of new members of these two species is currently not taking place.enTanzaniaForest reservesPugu forest reservePlant conopiesThesis