No description available.

A stand-level growth and yield model was developed to predict future diameter distributions of thinned stands of mixed Appalachian hardwoods. The model allows prediction by species groups and diameter classes. Stand attributes ( basal area per acre, trees per acre, minimum stand diameter, and arithmetic mean dbh) were projected through time for the whole stand and for individual species groups. Future diameter distributions were obtained using the three-parameter Weibull probability density function and parameter recovery method. The recovery method used employed the first two non-central moments of dbh (arithmetic mean dbh and quadratic mean dbh squared) to generate Weibull parameters. Future diameter distributions were generated for the whole stand and every species group but one; the diameter distribution of the remaining species group was obtained by subtraction from whole stand values. A system of tree volume equations which allow the user t o obtain total tree volume or merchantable volume to any top height or diameter completes the model. Volumes can be calculated by species group and summed to get whole stand volume. / M.S.

No description available.

Although remotely sensed data have been employed to assess various environmental problems, relatively few previous studies have focused on the impacts of mining. In Indonesia, mining activities have increasingly become one of major drivers of land cover change. The majority of remote sensing research projects on mining environments have exploited optical data which are frequently complicated by tmospheric disturbance, especially in tropical territories. Active remote sensors such as Synthetic Aperture Radar (SAR) are invaluable in this case. Monitoring by Independent SAR data has been limited due to single polarisation. Dual-polarised data have been employed considerably, although for some forestry applications the data were found insufficient to retrieve basic information. This Masters thesis is devoted to assess fully polarimetric SAR data for environmental monitoring of the tailings deposition zone of the PT Freeport Indonesia Grasberg mine in Papua, Indonesia. The main data were two granules of the AIRSAR datasets acquired during the PACRIM-II campaign. To support the interpretation and analysis, a scene of Landsat ETM February 2001) was used, juxtaposed with classified aerial photographs and a series of SPOT VEGETATION images. Both backscattering information and complex coherence matrices, as common representations of polarimetric data, were studied. Primary applications of this research were on degraded forest and environmental rehabilitation. Most parts of Indonesian forests have experienced abrupt changes as an impact of clear-cut deforestation. Gradual changes such as those due to fire or flooded tailings, however, are least studied. It was shown that the Cloude-Pottier polarimetric decomposition provided a convenient way to interpret various stages of forest disturbance. The result suggested that the Entropy parameter of the Cloude-Pottier decomposition could be used as a disturbance indicator. Using the fully polarimetric dataset combined with Support Vector Machine learning, the outcomes were generally acceptable. It was possible to improve classification accuracy by incorporating decomposition parameters, although it seemed insignificant. Land rehabilitation on tailings deposits has been a central concern of the government and the mining operator. Indigenous plant pioneers such as reeds (Phragmites) can naturally grow on dry tailings where soil structure is fairly well developed. To assist such efforts, a part of this research involved identification of dry tailings. On the first assessment, interpretation of surface scatterers was aided by polarimetric signatures. Apparently, longer wavelengths such as L- and P-band were overpenetrated; hence, growing reeds on dry tailings were less detectable. In this case, the use of C-band data was found fairly robust. Employing Mahalanobis statistics, the combination of HH and VV performed well on classification, having similar accuracy with quad polarimetric data. Extension on previous results was made through the Freeman-Durden decomposition. Interpretation using a three-component image of odd, even bounce and volume scattering showed that dry and wet tailings could be well distinguished. The application was benefited from unique responses of dielectric materials in the tailings deposit on SAR signals; hence it is possible to discriminate tailings with different moisture levels. However, further assessment of tailings moisture was not possible due to security reasons and access limitations at the study site. Fully polarimetric data were also employed to support rehabilitation of stressed mangrove forest on the southern coast. In this case, the Cloude-Pottier decomposition was employed along with textural parameters. Inclusion of textural properties was found invaluable for the classification using various statistical trees, and more important than decomposition parameters. It was concluded that incorporating polarimetric decompositions and textural parameters into coherence matrix leads to profound accuracy.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 346-363).

Thesis (Ph. D.)--Oregon State University, 2002. / Typescript (photocopy). Includes bibliographical references (leaves 181-190). Also available online.

No description available.

Natural resource harvesting still plays an important role in the economy of southern Africa. In Mozambique, the continuous exploitation of the most valuable components of the indigenous woodlands in locations such as the Catuane Administrative Post in Matutuine District, have put pressure on the natural resources so that concern has motivated this research in order to guide such actions in support of sustainable use. This was a preliminary study, the intention being to establish: • what are the necessary environmental conditions for the sustainability of silviculture? • which species may be candidates for cultivation? • whether local people would support cultivation of trees for charcoal and woodfuel; and • what the attitude of government and non-government organizations was to tree cultivation.? The research approach taken in this study was qualitative, relying on interviews, reviewing literature and documentary analysis. Respondents were drawn from different categories such as the local communities of the study area, experts in silviculture, government officials and NGO employees. The study shows that environmental conditions are harsh and are not particularly favourable for the cultivation of trees. Nevertheless, a review of information on the requirements and properties of woody species indicates that there . are candidate species that could be considered for cultivation, but productivity is likely to be low. Although there is some support for cultivation of trees, motivation is weak and strong extension support will be required to achieve success. The findings show, however that whilst there is policy support it is not accompanied by support on the ground. It is suggested that this reflects failure to appreciate the value of co-operative management and suggestions are made as to how these can be improved. / Thesis (M.Env.Dev.)-University of Natal, Pietermaritzburg, 2003.

South Africa has a fragmented past. Attempts to redress inequalities must acknowledge and understand the context of rural South Africa in terms of natural ecosystems. We are used to be being told that forests are good for us all. Certainly, the range of benefits that can be derived from forests, specifically natural woodlands are legion. The woodlands in South Africa are essential in the lives of many South Africans. It is for this reason that woodland resources are regarded as extremely important, not only for the maintenance of rural livelihoods but also as a potential contributor to the national economy. The woodlands are a diverse resource, extending over a vast area of the country and across several provincial boundaries. This as well as varied tenure systems as well as management objectives which exist, make the woodlands of South Africa a complex, yet essential resource to manage, monitor and sustain on a national level. Policy should therefore be able to ensure some kind of balance so that woodlands can be conserved, developed and sustainably managed in the most suitable ways possible. The findings of previous studies conducted on the woodland biome have highlighted the lack of sufficient knowledge of community perceptions with regards to the policy issues. This has been the catalyst in promoting informed reviews of current policies, in effect, which are affecting woodlands in African communal rural areas in South Africa. This particular study illustrates that there are a range of policies, both national and international, that impact either directly or indirectly on the woodlands in South Africa. The research identifies some of the key limitations in the various existing policies. Furthermore, the key concern raised is that current policies remain fragmented and are not in synergy with each other. Additionally, the ability to translate policy intentions into practice (that is, the implementation of policy directives) remain problematic. The gaps in the policy environment as well as the failure to implement are the key threats to ensuring the effective use of policy in promoting the sustainability of the woodlands in the South Africa context. / Thesis (M.A.)-University of Durban-Westville, 2002.

The mapping of forest age is important for effective forest inventory as age is indicative of a number of plant physiological processes. Field survey techniques have traditionally been used to collect forest inventory data, but these methods are costly and time-consuming. Remote sensing offers an alternative which is time-effective and cost-effective and can cover large areas. The aim of this research was to assess the capabilities of multispectral and hyperspectral remotely sensed image data and the statistical method, random forest, for Pinus patula age prediction. The first section of this study used spatial and spectral data derived from multispectral QuickBird imagery to predict forest age. Five co-occurrence texture measures (variance, contrast, correlation, homogeneity, and dissimilarity) were calculated on QuickBird panchromatic imagery (0.6 m spatial resolution) using 12 moving window sizes. The spectral data was extracted from visible and near infrared (NIR) QuickBird imagery (2.4 m spatial resolution). Using the random forest ensemble, various methods of combining the spectral and texture variables were evaluated. The best model was achieved using backward variable selection which aims to find the fewest number of input bands while maintaining the highest predictive accuracy. Only five of the original 64 variables were used in the final model (R2 = 0.68). The second part of this study examined the utility of the random forest ensemble and AISA Eagle hyperspectral image data to predict P. patula age. Random forest was used to determine the optimal subset of hyperspectral bands that could predict P. patula age. Two sequential variable selection methods were tested: forward and backward variable selection. Although both methods resulted in the same root mean square error (3.097), the backward variable selection method was unable to significantly reduce the large hyperspectral dataset and selected 206 variables for the model. The forward variable selection method successfully reduced the large dataset to only nine optimal bands while maintaining the highest predictive accuracy from the hyperspectral dataset (R2 = 0.6). Overall, we concluded that (i) remotely sensed data can produce accurate models for P. patula age prediction, (ii) random forest is an effective tool for the combination of spectral and spatial multispectral data, (iii) random forest is an effective tool for variable selection of a high dimensional hyperspectral dataset, and (iv), although random forest has mainly been used as a classifier, it is also a very effective tool for prediction. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.