Thesis (Ph. D.)--University of Melbourne, 1978. / Includes bibliographical references (leaves 265-279).

A system of loblolly pine growth and yield models was developed which used database files as input. Using database files as direct input created a compatible link between the growth and yield models and a Geographic Information System (GIS). Since growth and yield models can be used to update forest inventories and a GIS is a common method for maintaining forest inventory data, this compatibility provided a method to rapidly update past forest inventory records. This system was used to evaluate four different loblolly pine growth and yield models. The growth and yield models examined were: a whole stand, a diameter distribution - parameter prediction, a diameter distribution - parameter prediction, and an individual tree. Three different validation approaches were used to create fitting and validation data sets from permanent plot remeasurement data, and evaluate each of the four growth and yield models at varying projection periods. The periods used were zero, three, six, and nine years. Evaluations were based solely on the capability of each to model to predict merchantable volume. In terms of root mean square error of prediction, the individual tree and whole stand models performed superior than the diameter distribution models. At shorter projection periods the individual tree model performed better than the whole stand model, but the whole stand was superior at the nine year period. The parameter recovery models performed better for shorter periods than the parameter prediction model, but this difference diminished with longer periods. / Master of Science

Thesis (MSc (Forest and Wood Science))—University of Stellenbosch, 2007. / The present study investigated double sampling with regression estimators as a quest for efficiency and effectiveness in forest inventory in Namibian woodlands. Auxiliary data used were obtained from Standard QuickBird satellite scenes (phase 1) for Hans Kanyinga Community Forest from October and November 2004 covering an area of 12,107 hectares, amplified with terrestric data (phase 2) of 2002. The relationships between auxiliary and terrestric variables are described and prediction models were constructed. According to the results of the stepwise procedure with the Mallow’s Cp statistic as the selection criteria, photogrammetric stand density and a combination of the photogrammetric crown area with photogrammetric stand density were the best candidates for predicting the stand volume. The resulting volume model explains 56% of the variation. Photogrammetric stand density was found to be highly correlated to the terrestric stand density with the resulting model explaining 81% of the variation. Photogrammetric crown diameter was found to be correlated with the diameter at breast height measured from the plots which were assessed for spatial tree positions, which enabled the derivation of the diameter distribution. The diameter distribution model explains 43% of the variation. In addition, the actual tree positions were determined using the GPS and surveying techniques (polar positions) involving distance and bearings. GPS tree positions showed a considerable shift of up to 8.67 m. However, only the distance measurements of tress from the plot centre using the infield surveying methods were more reliable. Nevertheless, the influences of the tree positional errors are not of high concern for temporary based sample plots which are normally used in Namibian forest inventories. A reduction in inventory cost was found to be 24% i.e. N$25.79 to N$19.67 per hectare. The results of this study are valid for Kavango region or any other region with similar set of physical and climatic conditions, but caution must be exercised in implementing these results elsewhere under different physical and environmental conditions.

Thesis (MSc)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: The aim of the study was to extract elevation information (such as tree height) from stereo satellite imagery (IRS-I C), to scrutinise the performance of the DTM (Digital Terrain Model) tools as provided by the LH (LeicalHelava) Systems' softcopy system, and subsequently to perform a feasibility study on the application of a practically viable forest inventory design. A softcopy photogrammetry workstation (LH Systems DPW 770), IRS-I C stereo panchromatic satellite imagery, and digital aerial photography at a scale of 1:30000 (scanned at 15 micrometers) was used. The study was conducted over various sites in the Sabie area (province of Mpumalanga) in South Africa, where extensive man made forests with pine and eucalypts are to be found. The extraction of stand parameters such as tree height was performed manually, semi-automatically, and automatically. In addition, the compartment area was determined using a GIS tool. The Digital Surface Models (DSM), representing the canopy structure of the stands, was extracted from the IRS-I C imagery and validated through a comparison of the resulting contours with the corresponding contours generated by aerial photogrammetric methods. Due to the coarse spatial resolution of the IRS-IC imagery (5m) and the suboptimal BIH (BaselHeight) ratio (0.57), only objects featuring a height exceeding 20m could be manually measured with confidence. Furthermore, only the edges of the compartments proved to be suitable for the determination of tree heights (i.e. with a sufficiently large parallax difference and image contrast). The manual determination of tree heights in the IRS-I C imagery yielded accuracies of about 95% compared to the height values of the aerial photographs and the ground data. The application of image enhancement techniques had severe effects on the accuracy of the IRS-IC stereo model, resulting in deviations of about -57m from the 'true' value. It was observed that image matching was only a problem where features changed their appearance (e.g. clearfelled or burnt areas) during the acquisition period of the stereo pair of the satellite imagery. LH Systems' Adaptive Automatic Terrain Extraction (AATE) tool performed very well for the creation of digital terrain and surface models when using digital aerial photography with a high scanning rate. In contrast, the automatic creation of canopy surface models from various forest compartments did not yield any useful results when applied to IRS-l C imagery. AATE could not model the canopy structure properly. The coarse spatial resolution of the satellite imagery in conjunction with the sparse post spacing (20m) and matching errors are most likely to be responsible for this poor performance. Two-phase sampling and the Hugershoff method were chosen for automatically derived height values to be evaluated for possible application in forest inventory. Unfortunately, neither for the determination of the regression estimator for the first method, nor for the calculation of timber volume after application of the Hugershoff method could any useful result be obtained. This is mostly due to the fact that image matching errors and blunders (resulting in tree heights of -885m) were not properly accounted for in the terrain extraction software. However, the outcomes for the manual measurement of tree heights performed on the satellite imagery show that under optimal conditions accuracies can be achieved similar to those for the height determination in small scale aerial photographs, but at lower cost. The obtained height values can then be used for the calculation of timber volume according to Eichhorn's law. Keywords: AATE, blunders, digital photogrammetry, DPW770, forest inventory, Hugershoff IRS-l C, matching error, remote sensing, satellite imagery, two-phase sampling / AFRIKAANSE OPSOMMING: N GANGBAARHEIDSTIIDIE VIR BOSINVENTARIS MET BEHULP VAN STEREO SATELLIETBEELDE MET GEBRUIK VAN SAGTEKOPIE FOTOGRAMMETRIESETEGNOLOGIE: Die doel van hierdie studie was om elevasie inligting (soos boomhoogtes) uit stereo satellietbeelde (IRS-I C) te ontrek, en die DTM (Digitale Terrein Modelle) funksies van die LH Systems se sagtekopie sisteem te evalueer en 'n ondersoek in te stel na praktiese toepassing van die tegnologie in bosvoorraadopname. 'n Sagtekopie fotogrammetriese werkstasie (LH Systems DPW 770), IRS-I C stereo panchromatiese satellietwaarneming en digitale lugfotografie is gebruik. Die studie is uitgevoer oor verskeie areas in die Sabie omgewing (Mpumalanga, Suid-Afrika), waar daar ekstensiewe mensgemaakte woude voorkom met denne en Eucalyptus soorte. Die ekstraksie van opstandparameters soos boomhoogte is uitgevoer met die hand, as ook met semi-outomatiese en outomatiese metodes. Die digitale oppervlakmodelle (wat die kroondakstrukture van die opstande voorstel) was vanaf die IRS-I C beelde onttrek en gevalideer deur vergelyking van die resulterende kontoere met die korresponderende kontoere wat deur lugfotogrammetriese metodes gegenereer is. As gevolg van die growwe ruimtelike resolusie van die IRS-IC waarneming (Sm) en die suboptimale BIH verhouding (0.57) kan slegs voorwerpe met 'n hoogte van meer as 20m met vertroue met die hand gemeet word. Slegs die rande van die vakke is bruikbaar vir die berekening van boomhoogtes (d.w. s. met 'n voldoende paralaksverskil en 'n sterk beeldkontras ). Boomhoogtes wat met die hand bepaal is vanaf IRS-I C beelde is 95% akkuraat in vergelyking met die hoogtewaardes verkry vanaf die lugfoto's en die veldmetings. Die toepassing van beeldverbeteringstegnieke het duidelike invloede op die akkuraatheid van die IRS-IC stereomodel met afwykings van ongeveer -57m vanaf die "werklike" waardes. Daar is ook waargeneem dat beeldooreenstemming slegs 'n probleem is waar terreinvorme se voorkoms verander het (weens afkappings of brande) gedurende die verkrygingsperiode waarin die stereo paar van die satellietbeelde verkry is. LH Systems se Aanpassende Outomatiese Terrein Onttrekkings (Adaptive Automatic Terrain Extraction - AATE) instrument het goed gevaar tydens die gebruik van digitale lugfotografie met Inhoë skanderingstempo. In kontras hiermee het die outomatiese skepping van kroondakoppervlakmodelle van verskeie plantasievakke geen nuttige resultate gelewer wanneer dit op IRS-I C beelde toegepas is nie. Die growwe ruimtelike resolusie van die satellietbeelde tesame met die wye paalspasïering (20m) en passingsfoute is waarskynlik vir hierdie swak resultate verantwoordelik. Twee-fase proefueming en die Hugershoff metode was gebruik vir die bepaling van outomaties afgeleide hoogtewaardes vir evaluering van moonlike toepassing in bosvoorraadopnames. Geen bruikbare resultate kon verkry word vir die vasstelling van die regressieskatter vir die eersgenoemde metode of vir die berekening van die houtvolume volgens die Hugershoff metode nie. Dit is meestal as gevolg van beeld-- ooreenkomsfoute en flaters, (wat tot boomhoogtes van -885m gelei het) wat nie voldoende in ag geneem word in die terreinekstraksie sagteware nie. Die resultate vir die handgemete ('manual') boomhoogtebepaling wat uitgevoer is op die satellietbeelde (op die sagtekopie werkstasie DPW 770), toon dat akkuraathede soortgelyk aan daardie vir hoogte bepaal op klein-skaal lugfotos onder optimale toestande verkry kan word, maar goedkoper. Die hoogtewaardes wat verkry is kan gebruik word vir die berekening van houtvolume volgens die wet van Eichhorn. Sleutelwoorde: AATE, afstandswaarneming, bosvoorraadopnames, digitale fotogrammetrie, DPW770, flaters, Hugershoff, IRS-! C, satellietbeelde, twee-fase proefueming

Submitted by Milena Rubi (milenarubi@ufscar.br) on 2017-08-08T17:10:26Z No. of bitstreams: 1 ALO_Livia_2016.pdf: 35886856 bytes, checksum: e8f725fab0ed2763bd7a05881893a6d8 (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2017-08-08T17:10:37Z (GMT) No. of bitstreams: 1 ALO_Livia_2016.pdf: 35886856 bytes, checksum: e8f725fab0ed2763bd7a05881893a6d8 (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2017-08-08T17:10:47Z (GMT) No. of bitstreams: 1 ALO_Livia_2016.pdf: 35886856 bytes, checksum: e8f725fab0ed2763bd7a05881893a6d8 (MD5) / Made available in DSpace on 2017-08-08T17:11:12Z (GMT). No. of bitstreams: 1 ALO_Livia_2016.pdf: 35886856 bytes, checksum: e8f725fab0ed2763bd7a05881893a6d8 (MD5) Previous issue date: 2016-05-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Forest inventory is an important tool used to estimate forest wood production. However, some methodologies used in forest inventory are based in Classical Statistics, which disregards any spatial continuity that may exist between sample unities. Some geostatistic interpolators such as ordinary kriging (OK) and external drift kriging (EDK) allow us to assess this spatial structure. Furthermore, besides spatial variability, interpolators as EDK use one or more auxiliary variables. Satellite images have different components that interrelate with dendrometric variables and that can be used as auxiliary variables in order to increase the degree of precision of estimates. The aim of this study was to assess EDK performance on the volume estimation of Eucalyptus sp. stands using satellite image components as secondary variables and to compare it with OK performance. With this purpose, a forest inventory of 210 circular plots of 500 m² was carried out in order to estimate the volume (m³ ha-1 ) in each plot. Images obtained of studied area had blue, green, red and near infrared band. From these bands, it were extracted: gray level in each band, the ratio between bands, vegetation index (NDVI, SAVI e ARVI), texture measures and index generated from textures related to plot area. Covariance model adjustement throughout Stepwise method and selection by AIC (Akaike Information Criterion) method were made to EDK geostatistic. EDK and OK semivariograms were adjusted by different theoretical models through Ordinary Least Squares (OLS) method and the choice of the best model was given by the lowest value of residual standard error. From statistic analysis of images and correlation matrix, it was observed a correlation of variables with volume and also autocorrelation between these variables. The best covariance model selected was composed by band 2, measure of COR texture of band 2, MULCOR texture index of band 1 and by age. In the two semivariograms, the best model adjusted was the exponential one. Analysing the results, volume estimates generated by EDK produced better results than OK estimates and had the lowest value of residual standard error and the best area under curve (AUC) in receiver operating characteristic (ROC) curve analysis. / O inventário florestal é uma importante ferramenta utilizada para estimar a produção dos povoamentos florestais. Contudo, algumas metodologias utilizadas no inventário são embasadas na Estatística Clássica, que desconsidera qualquer continuidade espacial que possa existir entre as unidades amostrais. Alguns interpoladores geoestatísticos, tais como a krigagem ordinária (KO) e a krigagem de deriva externa (KDE), permitem avaliar essa estrutura espacial. Além disso, interpoladores como a KDE utilizam, além da variável espacial, uma ou mais variáveis auxiliares. As imagens de satélites possuem diferentes componentes que se correlacionam com as variáveis dendrométricas podendo ser usados como variáveis auxiliares, visando o aumento do grau de precisão das estimativas. O objetivo deste estudo foi avaliar o desempenho da KDE na estimativa do volume de povoamentos florestais de Eucalyptus sp., utilizando os componentes de imagens de satélites como variáveis auxiliares e compará-la com o desempenho da KO. Com esse propósito, processouse um inventário florestal de 210 parcelas circulares de 500 m², a fim de estimar o volume (m³ ha-1 ) por parcela. As imagens obtidas da área do estudo continham as bandas azul, verde, vermelho e infravermelho próximo. A partir destas, foram extraídos o nível de cinza (NC) de cada banda, da razão simples entre as bandas, índices de vegetação (NDVI, SAVI e ARVI), medidas de textura e índices gerados a partir das texturas referentes à área da parcela. Para a geoestatística KDE, foi feito o ajuste do modelo de covariância através do método Stepwise e a seleção pelo método AIC (Critério de Informação de Akaike). Os semivariogramas da KDE e da KO foram ajustados por diferentes modelos teóricos por meio do método dos Mínimos Quadrados Ordinários (MQO) e a escolha do melhor modelo se deu pelo menor valor do erro padrão residual. Nas análises das estatísticas das imagens e da matriz de correlação geradas, foi possível observar a correlação das variáveis com o volume e também a autocorrelação existente entre as variáveis. O melhor modelo de covariância selecionado foi composto por banda 2, medida de textura COR (correlação) da banda 2, índice de textura MULCOR (correlação multiplicado pela banda) da banda 1 e pela idade. Nos dois semivariogramas, o modelo que melhor se ajustou foi o exponencial. Nas análises dos resultados, as estimativas de volume geradas pela KDE produziram melhores resultados que as estimativas da KO, obtendo o menor valor de erro padrão residual e a melhor área sob a curva (AUC) na análise da curva ROC (Receiver Operating Characteristic).

Ph.d.-afhandling. Den Kongelige Veterinær- og Landbohøjskole, 2006. / Haves også i trykt udg. Thesis (Ph.D.). 22 ill., 14 tables; approx. 90 ref. Summaries (Da, En).

Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: This study aimed to understand how Dukuduku Forest in Kwa-Zulu Natal has changed from 1960 to 2008 and whether the change in political regimes, during and post apartheid eras might have contributed to changes in forest extent. To achieve the aims, the following analyses were made: - Qualitative and quantitative spatial analyses of forest change; - Analyses of the correspondence of change with political changes in the country; - Assessment of perception of people living in the Dukuduku forest area. The Dukuduku land cover was mapped from aerial photos using ArcGIS 9.3 to determine whether or not there has been a significant change in the area from 1960-2008, in response to resource use pressures and to come up with the strategic sustainable management plan from the results found. Five aerial photographs were used to determine the changes in land cover from the year: 1960, 1970, 1992, 2005 and 2008. The Land cover types were classified into four classes, Indigenous Forests, Plantation Forests, Water Bodies and Other (open areas, cultivated land, and all the human disturbed and transformed land). The percentage of cover per class was compared across the years to determine overall change in land cover and the rate of change per year was also calculated. The results from the study showed that: - Natural Forest increased by 11% (700 ha), at the rate of 20.56 hectares per year between 1960 and 1992, which is the apartheid era. Between 1992 and 2008, the democratic era, the forest decreased by 34.4% (2472.31ha), at the rate of 168 hectares per year. - The Dukuduku forest community gains resources (timber and grass for construction, art, firewood, medicinal plants, grazing of livestock and food) from the forest. The people are willing to contribute in protecting the forest only if the governing authorities would include them in decisions made, as the NFA demands Participatory Forest Management, but which does not currently exist in Dukuduku. / AFRIKAANSE OPSOMMING: Hierdie studie ondersoek die verandering van die Dukuduku woud in Kwa-Zulu Natal vanaf 1960 tot 2008, en vernaamlik of die verandering in politieke regimes tydens en in die postapartheid eras tot verandering bygedra het in die woud se vorm. Om hierdie doelwitte te breik is die volgende analises gedoen: - Kwalitatiewe en kwantitatiewe ruimtelike analises van woudverandering; - Analises van die korrelasie tussen hierdie fisiese omgewingsverandering en politieke verandering in die land; - Analise van die persepsie van mense wat in die Dukuduku woudgebied woon. Die Dukuduku gronddekking is gekarteer met behulp van lugfotos, waarvoor ArcGIS 9.3 gebruik is om te bepaal of daar noemenswaardige verandering in die gebied plaasgevind het van 1960 tot 2008, in reaksie op hulpbrongebruike, en om ‘n volhoubare bestuursplan gestel voor wat op die bevindinge gebaseer is. Vyf lugfotos is gebruik om verandering in gronddekking te bepaal vir die jare: 1960, 1970, 1992, 2005 en 2008. Die Gronddekking tipes is geklassifiseer in vier klasse naamlik Inheemse Woude, Plantasiebosse, Waterliggame en Ander (oop gebiede, landerye en al die mens-versteurde en getransfomeerde gebiede). Die persentasie van elke dekkingsklas is oor die jare vergelyk om die verandering in algehele grond-dekking te bepaal, en die tempo van verandering is ook bepaal, asook die tempo van verandering. Die resultate van die studie wys dat: - Die natuurlike woud toegeneem het met 11% (700 ha), teen ‘n tempo van 20.56 hektaar per jaar tussen 1960 en 1992, tgedurende die apartheidsera. Tussen 1992 en 2008, die demokratiese era, het die woude verminder met 34.4% (2472.31 ha), teen ‘n tempo van 168 hektaar per jaar. - Die gemeenskap wat in die Dukuduku woud woon verkry hulpbronne van die woud (hout en gras vir konstruksie, kuns, brandhout, medisinale plante, weiding vir vee, en voedsel). Die mense is gewillig om by te dra tot beskerming van die woud indien die owerhede hulle sou betrek in besluite wat geneem word, veral omdat die nasionale Wet op Bosse voorsiening maak vir Deelnemende Bosbestuur, wat tans nie by Dukuduku gebeur nie.

I. An original methodological discussion is proposed on the problem of the typology of tropical rain forest’s plant communities, based on the study of forest types across gradients of continentality and elevation, within Atlantic central Africa. These investigations were based on the statement that the main problems in forest typology are related to the non-zonal or zonal character of the different vegetation types and to non considering the relations and differences between forest strata.<p><p>II. Field data consisted in phytosociological homogeneous sample plots localized within different recognized phytogeographical entities, in a region of tropical Africa where these entities are known to be well conserved. A total of 37 such plots were inventoried in the region extending from the littoral forests of Ndoté, Equatorial Guinea, which are wet evergreen forests, to the continental forests of the Dja, Cameroon, known as evergreen seasonal forests. The studied region also included the oriental Atlantic forests of Equatorial Guinea, known as moist evergreen forests or caesalp forests. In various parts of this continentality gradient, some plots were localized within climax non-zonal formations, namely the submontane rain forests. The emphasis was put on the vegetation of the Monte Alén National Park.<p><p>The sampling methodology was willing to be as "complete ", including all strata, "quantitative ", enumerating all individuals, and "representative ", within each stratum, as possible. These multi-layers plots were realised using nested sub-plots, with a sampling size of 100 individuals for every ligneous stratum recognized (dominant trees, dominated trees and shrubs) and a sampling size of 200m² for the herbaceous and suffrutex stratum.<p><p>Forest types were defined independently for each stratum and the differences were analysed. A method was proposed for the simultaneous analysis of all floristic data, converting and standardizing the values from ligneous strata, on the one hand, and from understorey strata, on the other hand.<p><p>III. Ten forest types were described using IndVal and discussed in the general context of the guineo-congolian region, from a syntaxonomic view point (agglomerative classification) and from a phytogeographical view point (divisive classification). Homologies between these two approaches are described. The proposed phytogeographical system is based on an "open " conception of hierarchical classifications, combining advantages of agglomerative and divisive classifications. In concrete terms, the non-zonal criteria, for example the submontane variants, are categorised separately and in analogy with the zonal criteria, related to the usual phytochoria.<p><p>Analysis of ecological relationships for the 10 communities showed that the main variables related to the floristic variability in our mainland rain forests are elevation, rainfall, hygrometry (estimated using bryophytes cover levels) and distance to the ocean. The two extremes on the vertical microclimatic gradient, dominant trees stratum and herbaceous stratum, give similar typologies, however canonical analysis showed that for the herbaceous layer, non-zonal variables (hygrometry and elevation) were gaining more importance when the influence of the two zonal variables was attenuated. In every case, spatial autocorrelation was less important than the environment in explaining floristic variability but its role increased in the spatial arrangement of understorey species, whose dispersal capacity is generally lower than canopy trees. The phytosociological, phytogeographical and ecological description of forest types is accompanied by a physiognomical description using biological types spectrum, as well as architectural models, leaf sizes, etc.<p><p>With regard to diversity, we have demonstrated that species richness was higher from upper to lower strata because of the accumulation in lower strata of species from various strata. On the other hand, the proper stratum diversity, i.e. the structural set, decreased from dominant trees to shrubs. The proper diversity of the herb layer showed relatively high figures mainly due to the higher individual density in relation to the existence of microstrata. Within the 37 sample plots, 1,050 taxa have been identified to species or morpho-species levels, for a total of 25,750 individuals. These taxa represent 442 genus among 104 families. The richest forest type is found on the foothills of the Niefang range, on the windward side. This forest type is also characterised by a high number of oligotypic genus and by species belonging to functional types indicators of glacial refuges. These functional types are defined on the basis of the dispersal capacity and on kind of stand needed for effective germination. We formulated the hypothesis that this kind of "foothills refuge ", characterised by his zonal nature, could have been one of the rare refuges for species from mainland rain forests, while montane and fluvial refuges would mainly have preserved species from non-zonal forest types: (sub)montane and riverine.<p><p>Based on indicator species of submontane forests, a potential distribution map of this forest type has been realised at the Atlantic central African scale. More than 400 submontane forest localities have been mapped. These forests begin at 400m of altitude near the ocean, and progressively at higher altitude for increasing distance to the ocean. Many lowland localities also comprised submontane species, which could indicate the existence of ecological transgressions. These transgressions would allow migratory tracks for submontane species between isolated mountain ranges, not only during glacial periods, through heights at the northern and southern borders of the congo basin, but also contemporarily through the lowland riverine forest network, in the centre of this basin. Finally, a special attention has been attributed to littoral forests and to some cases of choroecological transgressions, coupled to the ecological equalization phenomenon.<p> / Doctorat en sciences agronomiques et ingénierie biologique / info:eu-repo/semantics/nonPublished