Geldenhuys, C.J. (Coert Johannes)2020-07-142020-07-142020-09-012020-07-14Aromye, T, 2020. Composition and Stand Dynamics of the Ntabelanga Natural Forests around Maclear, Eastern Cape, South Africa http://hdl.handle.net/2263/75213S2020http://hdl.handle.net/2263/75213Dissertation (MSc (Forest Science))--University of Pretoria, 2020.Abstract Management of the large Ntabelanga Catchment for development of a water reservoir in the Eastern Cape has to consider the scattered, very small and fragmented natural forests within the matrix of montane grasslands. The forests cover altitudinal, topographical and disturbance gradients, and are affected by fires and intensive utilization of forest resources by rural society; and they are surrounded by alien plant invasions. The forests have not been studied before and their relationship with the national forest types are not clear. Therefore, a management plan framework for the natural forests within the catchment management plan needs to be developed. The objectives of this study are therefore to assess the composition and stand dynamics of natural forests within this catchment as basis for sustainable management of their ecological status and resources, and ecological restoration where needed. The study of the forest patches was done in all five catchments of the Ntabelanga in the Maclear area in the Eastern Cape. Sampling of forest floristic and structural composition covered the altitudinal, topographical and disturbance gradients within the catchment representatively. Each randomly selected point on a forest patch was a point on a transect line to locate plots to sample the variation through the forest. Circular sample plot 11.3 m radius (0.04 ha) was used to conform to South African forest sampling standards. Sub-sampling within each sample plot was used for trees regeneration and understory vegetation. Data analyses included forest type classification, ordination between species and environmental variables, stem diameter class distributions, and related analyses on species diversity patterns, and response of species to resource use. In total, 63 species of trees and large shrubs were identified from 56 plots. These species represented 49 genera in 30 families. The TWINSPAN output table has revealed four forest communities: two mixed low altitude forest communities, each with sub-communities (Scolopia zeyheri-Cussonia spicata regrowth forest, Scolopia zeyheri-Celtis africana-Afrocarpus falcatus-Elaedendron croceum high forest, Dovyalis zeyheri-Allophylus decipiens-Calodendrum capense disturbed forest, Cussonia spicata-Commiphora harveyi scrub-forest), and two mixed high-altitude forest communities, one with three sub-communities (Podocarpus latifolius-Halleria lucida-Olinia emarginata high forest, Olinia emarginata-Euclea undulata-Cryptocarya woodii regrowth forest, Podocarpus latifolius-Olinia emarginata-Pleurostylia capensis regrowth forest). The Leucosidea sericea and Hippobromus pauciflorus stands are different communities on their own, hence resulting into six forest communities. Grain result has shown that at low altitude sub-community Scolopia zeyheri-Cussonia spicata regrowth forest is very fine grained, However, sub-communities Cussonia spicata-Commiphora harveyi scrub-forest and Scolopia zeyheri-Celtis africana-Afrocarpus falcatus-Elaedendron croceum high forest) are fine grain. In contrast, sub-community Dovyalis zeyheri-Allophylus decipiens-Calodendrum capense disturbed forest is coarse grained. In high altitude forests, sub-community Podocarpus latifolius-Halleria lucida-Olinia emarginata high forest) is fine-grained. Nonetheless, sub-communities Olinia emarginata-Euclea undulata-Cryptocarya woodii regrowth forest and Podocarpus latifolius-Olinia emarginata-Pleurostylia capensis regrowth forest) are coarse-grained forests. The size class distributions were assessed at different levels: firstly, for all canopy and sub-canopy tree species in each sub-community; secondly, for different groupings of canopy tree species; and thirdly, for different groupings of sub-canopy tree species. For all histograms where canopy trees are included, the X-axis show stem diameter (DBH) classes up to 35+ cm DBH. For histograms with only sub-canopy tree species, the X-axis show DBH classes up to 25+ cm DBH. The Y-axis scales varied, depending on the maximum number of stems included in specific DBH classes. The canopy and sub-canopy species have shown the diameter class of 35+ cm DBH and 25+ cm DBH along the X-axis respectively. The general trend of size class distributions across most sub-communities is towards the inverse J-Shaped DBH class distribution for both canopy and sub-canopy tree species. However, the trend is not strong in Cussonia spicata-Commiphora harveyi Scrub-forest, Podocarpus latifolius-Halleria lucida-Olinia emarginata high forest and Podocarpus latifolius-Olinia emarginata-Pleurostylia capensis regrowth forest. Species which have shown good presence at both low and high altitude forest sub-communities are Podocarpus latifolius, Scolopia mundii, Scolopia zeyheri, Cussonia spicata complex and Ilex mitis. Some species are mainly confined at low-altitude forests (Afrocarpus falcatus, Celtis africana and Commiphora harveyi) or mainly high altitude forests (Olinia emarginaata) or both (Calodendrum capense and Ptaeroxylon obliquum) across identified forest sub-communities. In conclusion, the natural forests within the Ntabelanga catchment that lie at low altitude is related to Transkei Mistbelt forests and those which lie at high altitude is related to Drakensberg forests. Altitude is the strongest environmental gradient accounting for most variation within the forest communities and is strongly correlated to CCA1 by 99%. However, other environmental variables, such as Slope and the Radiation Index, have contributed 34% and 29% respectively to variation in species composition. The main natural and human disturbances noted within the catchment were resource use for firewood and poles, and bark for medicinal use. Nevertheless, other disturbances (e.g. grassland fires, crown breaks) were common at high altitude. Wattle remains the main source of firewood and non-wood for the rural communities within the catchment. A sustainable resource use framework was developed to guide the resource use and natural forest rehabilitation within the catchment. Keywords: Altitude, Composition, Dynamics, Fire, Plant invasion, Resource use.en© 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.Forest ScienceUCTDDissertation