Forest management practices in Ontario are required to emulate natural disturbance in an effort mitigate the anthropological impact on the environment. This is enforced by the Crown Forest Sustainability Act, initiated in 1994, yet inadequate research has been done to support management techniques that satisfy the legislation in regards to the plant diversity and community composition. A series of 435 plots on 139 sites were established in Northern Ontario, consisting of stands of various ages and disturbance origins. Plant diversity and community composition were estimated with a variety of diversity indices and multivariate community analyses. My results show that managed stands are more diverse than those with a natural disturbance origin based on multiple diversity indices. Detrended Canonical Correspondence Analyses revealed considerable variation in community composition among all stands. Plant communities differ between the stands of different disturbance origins (managed/unmanaged), and these differences are influenced by stand age. These results reject the hypothesis that current forest management practices emulate natural disturbance. / Forest Ecosystem Science Coop Inc NSERC CRD Program NSERC Strategic Grant Progam Ontario Ministry of Natural Resources Canadian Forest Service

The vegetation along the north coast of KwaZulu-Natal has long been considered to have originally consisted of forest, scrub forest and savanna. The classical view is that in the last 600 years the early Africans and European farmers were responsible for the removal of forest and scrub forest along the coast. This view was not based on direct evidence but on the theory that the eastern part of the country has a climate "suitable" for forest and scrub forest. The present 'false' grasslands were thus thought to have developed through anthropogenic influences. All of this has its basis in the paradigm of ecological succession and the presence of a "climatic climax". This traditional view has been contested recently, based on archaeological, historical, biogeographical and ecological evidence that has become available since the 1950's. It is suggested that South Africa's grass lands have been in existence for the last two thousand years but probably for more than ten thousand years. This study aims to investigate this controversy in greater detail, using evidence from archaeological records, travellers records, transcripts, historical reviews, and diarised records. The locations of archaeological sites within the study area were determined and mapped out, followed by an analysis and interpretation of the data with reference to vegetation change. Archaeological evidence included shell middens, evidence of iron working and pottery remains. The activities of the early humans included iron smelting, agriculture and stock farming. Their activities required the selective use of vegetation for specific purposes, and vegetation was cleared for homesteads and villages. However, the density of people within the study area was low, and there was limited technological development, such that extensive clearing by relatively few people is unlikely. Furthermore, sites are concentrated along the coastline, with fewer sites away from the coast, suggesting that impacts would have been greatest along the coastline. However, this is where forests presently occur. Overall, the evidence suggests that the natural vegetation on the north coast was not modified drastically by precolonial settlers. Historical accounts of early travellers and settlers indicate a strip of forest along the coastline and a grassland/woodland mosaic away from the coast. Records of mammals suggest a fauna typical of savannas and not forest. With settlement over time, the major activity that impacted on the north coast vegetation, was agriculture. Sugar cane plantations contributed considerably to the clearing of vegetation that seems to have consisted primarily of open grasslands with patches of trees. Colonial settlement of this area resulted in various activities that required the large-scale removal of natural vegetation. It is important to know the human disturbance history of an area as this helps to assess the extent of change and to design appropriate management strategies for conservation of plant resources. The belief that the early vegetation of the north coast was forest has placed great emphasis on the conservation of forests along this coastal area. Based on this study, it seems that this vegetation type should not be the focus of conservation efforts, but that coastal grasslands with scattered bush clumps should be given much greater emphasis. Grasslands were more widespread in the region prior to European settlement, and based on this, conservationists should place greater emphasis on preserving this habitat. / Thesis (M.Sc.)-University of Natal, Durban, 2000.

There is no abstract available for this thesis. / Department of Natural Resources and Environmental Management

The effects of sewage sludge application and the additional effects of clearfelling on nutrient cycling have been assessed in a mature Scots pine stand, north-east Scotland. The forest site was situated in a low rainfall area with high evapotranspiration and low leaching losses. The ground vegetation formed an important sink for N and P following sludge addition and clearfelling. Sludge application caused a foliar N response, increased foliar needle weight, and litterfall showed a significant and rapid potential to immobilize NH₄-N and PO₄-P added in sludge. The soil availability of NH₄-N and PO₄-P together with rates of mineralization of N and P and nitrification in sludge-treated areas were significantly increased compared with that of the control. Concentrations of NH₄-N, NO₃-N, PO₄-P and organic P were increased significantly following sludge addition and fluxes were an order of magnitude greater than that of the control. Peaks in concentrations of NH₃-N in sludge-treated areas exceeded the EC limit of 11.3 mg 1^-1 on several occasions. Of the total N and P applied to the sludge, throughfall and litterfall over a 17 month period, 2.4 % and 0.72 % were measured in the B_s soil horizon flux. After clearfelling, initial increases in soil availability of NH₄-N, NO₃-N andPO₄-P were measured. Felling increased nitrification rates, although increases were significant only in areas previously treated with sludge. Fluxes of NO₃-N, NH₄-N and PO₄-P and organic P were increased at least an order of magnitude greater in felled areas than those of the control. Immobilization of N and P was greater in green and abscised litters placed in previously sludge-treated areas than compared with those placed in control areas.

This thesis explores issues relating to the application of physiological-process models (???process models???) of forest growth to mixed species, mixed age forests, in particular the coastal blackbutt forests of New South Wales. Using a dataset provided by State Forests of New South Wales (Carter 1994 unpubl.) a numeric description of the forest was developed and stand-level parameters of interest were derived, in particular the plot by plot stemwood volume growth from 1975 to 1999. The amounts of harvested volume, volume that died and volume that grew into the measurement population were identified separately, and several different means of accounting for volume change over time were investigated. A method for quantifying the impact of harvesting and other silvicultural practices on the growth of the forest was developed and programs were written to convert the stand-level summary of the harvest impact into a semi-random selection of trees that would be ???harvested??? from the database under the set of silvicultural assumptions (Dore et al. 1999). A number of process models were investigated and reviewed before selecting one particular model, SUSTAIN (Dewar 1997) for adaption to these forests. This model is a relatively simple process model with a small number of input parameters. The model was adapted so that it could be used to compare the SUSTAIN estimate of growth with the growth of an individual stand of trees in the Kendall Forest Management Area, between Wauchope and Taree on the mid-north coast of NSW. To improve the accuracy of the prediction of growth by SUSTAIN, a method of re-setting the state of the stand to the actual condition at the time of remeasurement was developed. In addition, the SUSTAIN model was extended to enable two separate levels of canopy to be described and grown separately. Ultimately the model was only partially successful in mirroring the growth predicted by the empirical data. Its partial success is attributed primarily to the difficulties associated with correctly determining the allocation parameters used by the model to assign net photosynthate to the roots, foliage and stemwood. The nature of the change in allocation parameters when the forest stand is disturbed by harvest or fire needs further investigation.

This thesis sets out to test the hypothesis that the vegetational patterns in the forested region of south western Australia are primarily determined by the interaction of climate and landform. The region is an area of 4.25 million hectares subject to recent agreement between the Commonwealth of '4ustralia and the state of Western Australia regarding long-term protection and management of forest (Regional Forest Agreement). The climate of the South Western forest region is warm temperate and summer dry, matching Koeppen's category Cs, usually described as mediterranean. The dominant geological features of South Western Australia are crystalline and sedimentary plateaus and coastal plains. They are subject to a complex process of weathering, denudation and re-deposition, which is the key determinant of landforms and soil patterns. Deep but infertile soils are prevalent. The dominant vegetation formation of the region is open forest, which reduces to woodland in the drier north and east and increases to tall open forest in the moister south. Floristically the vegetation is very rich, comprising over 3000 vascular plant species. The richness resides in the forest and woodland understorey and in the shrublands, heathlands and sedgelands of edaphically extreme sites. By comparison, the forest overstorey is very simple, only one or two species being often dominant over extensive areas. The validation of the hypothesis that climate and landforms determine the vegetation patterns in South Western Australia is carried out in the following stages: 1) review of past studies of vegetation patterns in relation to the underlying environmental factors, relating them to one another in terms of floristics, 2) conversion of landform and climate maps for the region into vegetation maps by means of toposequences, that is gradients of topography, soils and vegetation within individual landform/climate combinations, 3) production of two sets of vegetation maps, namely six maps of vegetation complexes (1:250,000) and one map of vegetation systems (1:500,000), 4) testing the predictive capability of the resulting maps by comparing the occurrences of individual species of trees, shrubs and herbs predicted by map legends, with their records in FloraBase, the geographic information system of the Western Australian Herbarium, and 5) using the outcomes of the above studies to assess the validity of the hypothesis. Because the above hypothesis is so broad, it will be considered under seven headings: a) nature of the vegetation patterns (continuum or discrete categories), b) regional effect of climate and local effect of landform, c) effect of landforms on soil depth, texture and fertility, d) joint effect of slope, soil depth and texture on water balance, e) interactive effect of landform and climate on vegetation patterns, f) response of individual species to climate and landform, and g) effect of other factors of environment, such as fire, on vegetation patterns. The subsidiary hypotheses are defined in Chapter 5. It is concluded that the vegetation of the region forms a lumpy continuum from the wet south west to the dry north east. Within that broad continuum there are localised continua from waterlogged sites in depressions to drought-prone sites on steep stony slopes. However, the dominant vegetation of the region is open forest on plateau uplands with deep infertile soils. Although climate and landforms have a strong effect on vegetation patterns, they do not determine all vegetation patterns directly. Some tree species have ranges of occurrence that are too broad for that, and others have ranges that are too restricted. A more probable explanation is that climate and landforms, together with fire, set the stage on which the interplay of species takes place and determines the structure and composition of the vegetation. An attempt is made to predict the likely effect of climatic changes on vegetation patterns. The applicability of the methodology developed to the mapping of other regions, especially the adjacent ones, is examined. A review is made of how the products of the study, in particular the maps, are currently being used, and suggestions are made how they could be used in the future.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 78-89).

Thesis (Ph. D.)--University of Nevada, Reno, 2006. / "August, 2006." Includes bibliographical references. Online version available on the World Wide Web.

Thesis (Ph.D.)--Murdoch University, 2003. / Thesis submitted to the Division of Science and Engineering. "Supported by CRC for Sustainable Tourism and Dept of Conservation and Land Management (Western Australia)". Bibliography: leaves 334-355.

Thesis (M.S.)--University of Nevada, Reno, 2006. / "May 2006." Includes bibliographical references (leaves 72-76). Online version available on the World Wide Web.