No description available.

This study was proposed by the B. C. Fish and Wildlife Branch to evaluate the effect of forestry practices and forest characteristics on deer use of logged and mature forests. The specific factors studied were "time since burning", "elevation", "site index", "aspect", "forest edge", "roads" and "vegetation". The effect of elevation and aspect on deer use was studied for both the mature and logged forest while the other factors were considered only for recently logged areas. The location of this study was the Nimpkish Valley, northern Vancouver Island in British Columbia. This area was selected primarily because it had a large population of Columbian black-tailed deer (Odocoileus heinionus columbianus Richardson), active logging, and variable terrain. The deer response to "time since burning", "elevation", and "site index" was generally determined by plant quality and climate. The importance of vegetative quality to deer is reduced when the climatic conditions become favorable for the animals. Therefore, during a mild winter the deer are less dependent upon the greater plant production found on areas with later seral stages, lower elevation, and higher site index, than they are during a severe winter. Similarly, on an annual basis, high plant production is less important on the warm south aspect than it is on the colder north aspect. Two types of forest edges were studied, the upper which is parallel to the elevation contours and the adjacent which is perpendicular to the elevation contours. The upper edge influences deer use of areas, both inside and outside the forest, by maximizing use near the edge. Deer use declines with increasing distance from the edge. The only apparent effect of the adjacent edge on deer use of recently logged areas was to depress use at the edge. This also occurred at the upper edge. Roads affect deer use of recently logged forests by increasing use adjacent to the road but decreasing use on the road and the road edge. It appears that deer use the road only for travel. Deer exhibit preference for a variety of plant species. The use with increasing cover of an individual species is generally parabolic while the use with increasing cover for all species combined is generally linear. Furthermore, maximum use occurs on those areas where the number of species present is greater than 1. The response of deer to increasing elevation, in the mature forest, is positive on the south aspect and zero, or nearly so, on the north aspect. This relationship is similar to that which occurred on recently logged areas following a mild winter. / Forestry, Faculty of / Graduate

The distribution of the above-ground biomass and macronutrient content of the trees were studied on two sample plots in south coastal British Columbia, near Vancouver. The plots differed in elevation (4,600 and 2,200 feet; 1,500 and 700 m), in soil type and depth. Tree age was similar in both plots, ranging from 150 to 530 years. The tree cover on the high elevation plot consisted of Tsuga mertensiana (Bong.) Carr. (mountain hemlock) and Abies amabilis (Dougl.) Forbes (Pacific silver fir) while the lower elevation plot was occupied by Tsuga heterophylla (Raf.) Sarg. (western hemlock), Thuja plicata D. Don (western red cedar) and Chamaecy- paris nootkatensis (D. Don) Spach (yellow cedar). Twenty-four trees were sampled to determine the biomass and nutrient content of wood, bark, branches, twigs, foliage and cones. Another nine trees were sampled for the biomass and nutrient content of wood and bark only. Multiple regression analysis was used to establish the relationship between d.b.h., tree length, crown length and biomass of the various tree components. The regression equations obtained were used to estimate the total biomass of wood, bark, branches, twigs and foliage contained in the trees on each of the sample plots. The data thus obtained were combined with data on chemical concentration and used to estimate the distribution of macronutrient elements in different above-ground biomass components of the stands. / Forestry, Faculty of / Graduate

The project sought to identify direct links between calculate hillslope solute fluxes and input/output budgets in a forested drainage basin in the United Kingdom. An intensive, short term monitoring and data collection programme was devised in order to quantify the major components for the hillslope hydrological cycle, the seasonal changes in overstorey and understorey biomass, and the chemical composition of ecologically and pedologically derived samples. Gross and net precipitation, infiltration, and soil moisture fluxes, groundwater movement and streamflow were monitored to identify the possible pathways which solutes might follow. Regular sampling of the oak and bracken vegetation, litterfall and litter enabled calculation of biomass accumulation and the rate of uptake and release of plant nutrients. The spatial variability of soil properties was quantified, but subsequent soil sampling permitted identification of seasonal trends in exchangeable action and soil water solute concentrations. All hydrological and ecological samples were analysed for nitrogen, phosphorus, potassium, calcium, magnesium, sodium and chloride. PH, specific conductance and organic carbon were measured for selected samples. The high infiltration capacity of the soil promoted rapid vertical movement of water towards a perched water table. The presence of soil macropores and the high permeability of the soil precluded the generation of throughflow on the hills-lope. Stream discharge was mainly controlled by groundwater fluxes from the perched water table. Although seasonal trends in the solute concentration of water samples and in the nutrient assimilation of vegetation were identified, isolated events, such as frassfall and storm-period litterfall, were shown to contribute significant quantities of nutrients to the forest floor, The importance of solute movement via macropores, especially phosphorus, was emphasised, with particular reference to plant availability. The relative stability of the ecosystem was reflected in the balance of the input/output budgets of solutes, with, the exception of calcium and magnesium losses which were attributable to weathering of the calcareous bedrock. Bivariate and multivariate statistical analysis showed that no single biogeochemical process on the hillslope could be identified as exerting a dominant controlling influence on stream water chenistry, through isolated events may affect concentrations in the short term.

No description available.

The Miombo woodland vegetation of southern Africa has been subjected to anthropogenic pressures in recent years, resulting in a change in its cover and floristic-structural composition, and the population status of important tree species. The recent land use land cover changes (LULCC) is of concern due to the negative impacts on the Miombo woodland ecological functions. Understanding the overall dynamics of the vegetation that include LULCC, forest cover change, tree species composition, and diversity, population structure (PS) in relation to forest degradation, loss of endangered/rare species, is pivotal in influencing policy and sustainable woodland management. The Malawi Government instituted policies that allowed for improved forest management. However, the impact of forest management regimes on forest cover, tree species diversity, and structure is not well established. The study aimed to determine LULCC and forest cover changes and the associated drivers and how co-management (CM) and government-management (GM) impact on the florist-structural composition, diversity and the population structure of the important tree species in Malawian Miombo landscape. Firstly, the study analysed LULCC and the comparative impact of CM and GM on the forest cover in Malawi, for the period 1999-2018. CM involves a contractual agreement between communities (with a forest management plan who have been empowered to manage forest resources) and the Forest Department (representing the Government) in managing forest reserves. GM is the protection of forest resources by the government through the Forest Department. Since the introduction of participatory forest management (PFM), such as CM, its impact has not been established. Google Earth images (Landsat mosaics) for 1999 and 2018 for Malawi were acquired, registered, and pre-processed in Environment for Visualizing Images (ENVI 4.7) Harris Geospatial Solutions. LULCC estimation using the Inter-Governmental Panel on Climate Change (IPCC) classes was determined using the differences in error-adjusted areas between 1999 and 2018. Overall accuracies were >90%. Woodland net losses of 8.4% were to Plantation, Grassland, and Agriculture transition intensities. Agriculture net gains of 9.6% were from Grassland, Settlement, and Woodland transitions for Malawi. Forest cover within CM and GM indicated losses. Participatory land use plans and monitoring for diversified management in Malawian Miombo woodlands are required to mitigate anticipated irreversible impacts in the landscape. The second study investigated the factors that influence changes in CM and GM forest reserves between 1999 and 2018. CM and GM regimes in Miombo woodlands are possible interventions to mitigate forest degradation and deforestation in southern Africa. However, few studies have investigated the direct and indirect drivers of LULCC using socioeconomic characteristics and Remote sensing data in CM and GM regimes. The drivers of LULCC in forest reserves, and management challenges were identified using participatory assessments in both management regimes. The changes in woodland were observed with varying extent. Communities' perceptions in the factors contributing to changes in CM and GM forest reserves were similar and mostly due to the conversion of woodlands to agriculture while extraction of woody products led to forest degradation. In both management strategies, population pressure, youthful age, poverty, and poor education were associated with forest-based livelihood activities and therefore the woodland changes. The overall woodland cover loss to grassland is attributed to its importance as a source of energy. There is thus a need to harmonize policies for sustainable use and management of woodlands in order to address local, national, and regional ecosystem services. Future studies will need to link Remote sensing and socioeconomic data as part of a monitoring tool that could assist to sustainably adapt to changes in the woodlands and surrounding communities. The third study compared the Miombo Tree species composition and diversity between CM and GM regimes in Malawi. Tree species composition and diversity information is limited between CM and GM regimes. Two CM and two GM forest reserves were purposively selected to act as representatives of management regimes in the northern and southern regions of Malawi. Forest inventory data from 80 randomly selected nested circular plots were used. Two plot sizes: a large plot (0.16 ha; radius 22.6 m) to record stems ≥30 cm DBH, and the main plot (0.04 ha; radius 11.28 m) to record stems 5.0-29.9 cm DBH and species names. In total, 109 tree species belonging to 38 families, 87 species in GM FRs (Kaning’ina 58, Thambani 52), and 69 in CM FRs (Perekezi 45, Liwonde 43) were recorded. The largest families (number of species between brackets) were Fabaceae (34, with 3 subfamilies, Caesalpinioideae (17), Papilionoideae (12), and Mimosoideae (5), an indication of their adaptive potential in the area. Other important families were Combretaceae (7), Rubiaceae (7), and Clusiaceae (4). Species similarity between management regimes was low and was attributed to site factors, species characteristics and intensity of disturbances. TWINSPAN classification results were related to differences in site conditions and disturbances caused by historical and current resource use in management regimes. The eigenvalues ≥0.3 across CM and GM sub-communities indicated high stability. Brachystegia and Julbernardia species were highly important in CM and GM sub-communities. Uapaca species were highly important in agriculture and settlement abandoned areas in GM forest reserve. The study recommends selective harvesting to allow for dominant (Brachystegia and Julbernardia) and associated Miombo species to regenerate. Species richness and evenness (diversity) was high in more disturbed CM and GM sub-communities compared to intact areas. The high diversity was related to tree species high abundances of smaller stems with few scattered big trees. These results call for a Forest policy review to allow planned harvesting in GM forest reserves. Law enforcement is also required in both management regimes to mitigate unsustainable harvesting in sensitive areas. Future studies should include zonation to improve differentiation between site factors and wood extraction in stand development stages in management regimes. The fourth study compared the Miombo population structure (PS) between CM and GM regimes. Such information is limited in CM and GM regimes since the introduction of PFM in Malawi. The size class distribution (SCD) of sub-canopy/canopy species showed a reversed J-shaped profile in CM and GM forest reserves (South), when compared to CM and GM, in northern Malawi. These findings may reflect differences in the historical woodland utilization in the two regions. The bell-shaped SCDs in CM sub-communities with high stem density of Brachystegia and Julbernardia species suggest strong demand for light for successful recruitment from regeneration to adult trees and could be related to wood utilization. The reversed J-shape SCDs in northern GM sub-communities with high regeneration stem density of Pittosporum viridiflorum suggest an increase in shade-tolerant evergreen tree species under a low-level disturbance. Timber species showed interrupted SCDs with few to no stems, indicating challenges in regeneration. Pioneer species were associated with disturbances under CM indicating woodland recovery. The patterns in SCD showed similarities and differences between CM and GM sub-communities between the two management strategies. In Community 2, there were significant differences (p = 0.002) between management strategies with low canopy densities in CM, which could be attributed to unsustainable harvesting. Furthermore, saplings showed significant differences with a higher stems ha-1 in CM compared to GM. Trees and regeneration SCDs suggest a thorough analysis of the PS of varied species associations to guide sustainable resource use. An adaptive management approach that uses silvicultural systems to promote sustainable forest management is recommended. Additionally, selective harvesting in recovery stages would reduce intense competition in the dense, even-aged stands. However, there is need for instituting enabling policies and to monitor changes in both management regimes to promote biodiversity conservation, resource use, and diverse ecosystem services at all levels. / Thesis (PhD (Forest Science))--University of Pretoria, 2020. / Malawi Government Scholarship Program and the African Forest Forum / Plant Production and Soil Science / PhD (Forest Science) / Unrestricted

Bibliography: pages 71-83. / A variety of studies have shown the problems of energy supply faced by low-income communities in southern Africa. Most of these communities are dependent upon indigenous fuelwood supplies. In addition, many of these communities use indigenous wood for construction. This largely uncontrolled utilisation imposes severe threats on woody vegetation communities. The Eastern Cape/Ciskei region is an area where energy supply problems are particularly severe and impacts on woody vegetation correspondingly severe. This study aimed to investigate the feasibility of using remote sensing techniques to monitor the the impact caused by collection of wood in the Eastern Cape/Ciskei forest and thicket communities. A variety of remote sensing techniques for landcover analysis were investigated. In all cases, visual interpretation was used because it is considerably cheaper and demands less technical expertise than would computer processing. In addition, many studies have shown visual interpretation to be superior. Maps were drawn from multitemporal aerial photograph sequences and from Landsat and SPOT satellite images. These maps showed that there has been relatively little change in area of woody vegetation in the study area since 1956. However, field studies showed that vegetation community structure had been degraded as a result of intense and sustained human impact. This qualitative decline also reflected a decline in usefulness of the woody vegetation of the area to local communities. This substantial degradation was not visible on any of the remote sensing imageries. This emphasises that field-based checks to monitor human impacts on forest and thicket formations are essential. Strategies for reducing the dependence of low-income communities on indigenous vegetation for energy supplies and constructional timber have been reviewed from the literature and these are descibed in Appendix 1. Most successful strategies in other parts of the world have been the result of a national commitment to tree planting, recognition of a multiplicity of constraints and the voluntary involvement of the communities the strategies are intended to assist.

Thesis (Ph.D.)--University of the Witwatersrand, Faculty of Science, School of Animal, Plant and Environmental Sciences, 2004

Understanding spatiotemporal variation in net primary productivity (NPP) continues to be of fundamental importance to basic ecology and to applied conservation and management efforts for human well-being. Diversity is an important driver of NPP variation, but its effect is variable depending on ecosystem context and spatial scale as well as more closely linked to functional traits. Explicitly considering processes of trait-based community assembly and maintenance at relevant scales at which they occur can potentially resolve some of this variation. In my thesis, I address this gap by considering various processes that structure and maintain diversity in communities and analyze NPP as an outcome of these processes. I examine processes in high diversity tropical forests, relatively less explored in the context of biodiversity-ecosystem functioning. In Chapter 1, through a manipulated experiment, I show that diversity effect on biomass gain in seedling communities is modulated by light. This interactive effect holds across different functional groups that are known to respond uniquely to light. In Chapter 2, I expand the spatial scale of inquiry to community assembly processes that maintain diversity at regional spatial scales – dispersal and competition, akin to island biogeographic contexts. Through simulations, I show that dispersal and competition acting on correlated traits explain a range of variation in BEF curves observed in nature. Finally, in Chapter 3, expanding the focus of inquiry to include human aspects, I consider the impact of a biodiversity-driven human intervention, protected areas, in maintaining NPP. I show that at the landscape scale, mean annual NPP and temporal stability are both influenced by protection status, but the effectiveness of protection is contingent on environmental factors. Taken together, my thesis suggests that understanding the combined drivers of diversity and NPP can improve predictions for spatiotemporal variation of this ecosystem function. Further inquiry integrating diversity-gradients at multiple scales can improve process-based understanding of the effect of biodiversity on ecosystem functioning.

Declining oak (Quercus spp.) dominance across the eastern U.S. is often attributed to fire exclusion and abundant white-tailed deer (Odocoileus virginianus). Fire restoration can negatively affect acorn germination and survival directly but also indirectly through impacts on seed predation. Similarly, masting events could influence oak regeneration success by altering deer behavior. To date, virtually no information exists assessing indirect effects of acorn consumers on oak regeneration. I developed two experiments to address this knowledge gap. In the first experiment, I determined if burning acorns affects predator removal rates. In the second experiment, I assessed the indirect effects of mast seeding on plant communities mediated by deer. Burning acorns decreased acorn removal rates. This could increase survival to spring for acorns that survived exposure to fire. Mast seeding increased local deer use, decreased the competitive advantage of local oak seedlings, but increased beta diversity in the understory.