Dissertations / Theses on the topic 'Canopy density'

Enhanced understanding of forest stocks and dynamics can be gained through improved forest measurement, which is required to assist with sustainable forest management decisions, meet Australian and international reporting needs, and improve research efforts to better respond to a changing climate. Integrated sampling schemes that utilise a multi-scale approach, with a range of data sourced from both field and remote sensing, have been identified as a way to generate the required forest information. Given the multi-scale approach proposed by these schemes, it is important to understand how scale potentially affects the interpretation and reporting of forest from a range of data. ¶ To provide improved forest assessment at a range of scales, this research has developed a strategy for facilitating tree and stand level retrieval of structural attributes within an integrated multi-scale analysis framework. The research investigated the use of fine-scale (~1m) airborne Light Detection and Ranging (LiDAR) data (1,125 ha in central Queensland, and 60,000 ha in NE Victoria) to calibrate other remotely sensed data at the two study sites. The strategy refines forest structure mapping through three-dimensional (3D) modelling combined with empirical relationships, allowing improved estimation of maximum and predominant height, as well as foliage and crown cover at multiple scales. Tree stems (including those in the sub-canopy) were located using a height scaled crown openness index (HSCOI), which integrated the 3D density of canopy elements within the vertical profile into a two-dimensional spatial layer. The HSCOI modelling also facilitated the reconstruction of the 3D distribution of foliage and branches (of varying size and orientation) within the forest volume. ¶ Comparisons between forests at the Queensland and NE Victorian study sites indicated that accurate and consistent retrieval of cover and height metrics could be achieved at multiple scales, with the algorithms applicable for semi-automated use in other forests with similar structure. This information has facilitated interpretation and evaluation of Landsat imagery and ICESat satellite laser data for forest height and canopy cover retrieval. The development of a forest cover translation matrix allows a range of data and metrics to be compared at the plot scale, and has initiated the development of continuous transfer functions between the metrics and datasets. These data have been used subsequently to support interpretation of SAR data, by providing valuable input to 2D and 3D radar simulation models. Scale effects have been identified as being significant enough to influence national forest class reporting in more heterogeneous forests, thus allowing the most appropriate use and integration of remote sensed data at a range of scales. An empirically based forest minimum mapping area of 1 ha for reporting is suggested. The research has concluded that LiDAR can provide calibration information just as detailed and possibly more accurately than field measurements for many required forest attributes. Therefore the use of LiDAR data offers a unique opportunity to bridge the gap between accurate field plot structural information and stand to landscape scale sampling, to provide enhanced forest assessment in Australia.

Thesis (Honors)--Ohio State University, 2006.
Title from first page of PDF file. Document formatted into pages: contains 19 p.; also includes graphics. Includes bibliographical references (p. 18-19). Available online via Ohio State University's Knowledge Bank.

The influence of rootstock and canopy density on grape berry composition was investigated over the summer of 2003-2004 on a commercial vineyard at Waipara, North Canterbury. This experiment was designed to investigate the influence of rootstock and canopy density on the acid composition, potassium (K) content and final pH of harvested fruit (Pinot Noir AM 10/5 Lincoln Selection). The trial block consisted of eight rootstocks laid out to an 8 x 8 latin square, each plot consisting of five vines of the same rootstock. Two canopy treatments were overlaid the block (down whole rows, assigned randomly, four rows to each treatment); one treatment allowed to grow naturally, in the other treatment the canopy was thinned removing double burst shoots and laterals. The bunch numbers were adjusted in the Unthinned canopy treatment (UCT) to match the Thinned canopy treatment (TCT). Information was gathered to assess: the canopy size and density (Pinot Quadrat Leaf Layer and Percent Gaps and canopy porosity), the plant yield (and berry size, berries per cluster, cluster weight, clusters per plant), plant K levels at flowering and veraison (from petioles and leaf blades) and berry composition at harvest (soluble solids (as brix), K, titratable acidity (TA), tartaric acid concentration, malic acid concentration and pH). The trial area was non-irrigated on clay loam soils and viticultural management was to best commercial practice. It was found that although rootstock influenced the levels of K in the plant and in the juice at harvest, the level of K in the juice did not influence pH in this experiment (range of rootstock juice K: 808 ppm to 928 ppm, l.s.d. = 75 ppm). The level of tartaric acid concentration in the juice was found to be the dominant influence on the level of pH in this experiment (rootstock pH range: 3.21 to 3.39, l.s.d. = 0.05). The juice concentration of tartaric acid was influenced by both rootstock (rootstock range 4.0 to 4.7 g/L, l.s.d = 0.4) and canopy density (UCT = 4.1, TCT = 4.7, l.s.d. = 0.4), decreased shading positively increasing the level of tartaric acid. The malic acid concentration in the juice was positively influenced by increasing canopy density (UCT = 4.7 g/L, TCT = 4.1 g/L, l.s.d = 0.4) and this played a minor role in the determination of pH in this experiment; an influence of rootstock on the level of malic acid concentration was found. The malic acid concentration strongly influenced the determination of TA (UCT = 11.0 g/L, TCT = 10.2 g/L, l.s.d = 0.5); tartaric acid concentration had a minor influence on the recorded TA. Attempts to characterise the influence of rootstock on malic acid, tartaric acid and pH were inconclusive. Rootstock was found to influence the canopy variables measured in this experiment and the recorded average plant yield. Crosses of Vitis rupestris were found to exhibit the most canopy vigour and those derived from Vitis berlandieri and Vitis riparia the least. The Canopy treatment did not show an influence over yield but the rootstock was found to influence plant yield, through the numbers of berries set in a cluster and the final harvest cluster weight. The influence of rootstock on pH may be described by the influence it exerts on canopy growth and yield but this was thought unlikely. Further research is required to describe the nature of the rootstock influence on K, malic acid, tartaric acid and pH.

Pasture-based livestock production is one of the major economic activities in Brazil. In general, the adoption of new forage materials by producers happens before enough information about their characteristics is generated, compromising their use in commercial systems. An experiment was conducted in Piracicaba, Brazil (22º42\' S, 47º30\' W, 580 m asl.), during two summer growing seasons, with the objective to describe and explain the tillering dynamics of the hybrid brachiariagrass Convert HD 364 (Brachiaria hybrid CIAT 36087) under continuous stocking and variable stocking rate. Responses studied were tiller population density (TPD), tillering demography (appearance rate-TAR - and survival rate- TSR), stability index (SI), average tiller weight (ATW), forage mass (FM), leaf area index (LAI), light interception (LI), mean leaf angle (MLA), stem apex height (hapex) and collar height of the youngest fully expanded leaf (hleaf). The experimental design was a randomized complete block with a factorial arrangement including all possible combinations between three sward heights (10, 25 and 40 cm) and growth rates (50 and 250 kg N ha-1 year-1), with three replications. The data were analyzed using the Mixed Models procedure of SAS and means compared using \"t\" test (P<=0.05). At 10 cm canopy height, Convert HD 364 had TPD 10 and 25% greater than at 25 and 40 cm, respectively. High growth rate resulted in 10% greater TPD and 9% lesser AWT. The 40-cm canopy resulted in ATW 80 and 274% greater than those at 25 and 10 cm, respectively. Under low and high growth rate, respectively, FM of 40-cm canopies was 163 and 41% greater than those of 10- -cm swards. Both, hapex and hleaf, responded similarly to treatments and were greater in taller canopies. Except for the 25-cm canopies there was no difference between growth rates in these responses. At greater growth rate TAR was 29% greater, whereas TSR 13% lesser. TAR and TSR varied along the experimental period, suggesting that they are affected by environmental factors. At the lower growth rate, there was no variation in SI along the experimental period, whereas at the high growth rate SI in February was 20 and 35% greater than in January and March, respectively. The determination of meristem location is an important tool to adequate planning of management strategies in animal production system under grazing.
A pecuária baseada em pastagens é uma das principais atividades econômicas do Brasil. Geralmente, ocorre adoção de novos materiais forrageiros sem que haja informações suficientes sobre suas características produtivas o que compromete seu potencial de uso. Um experimento foi conduzido em Piracicaba (22º42\' S, 47º30\' W, 580 m asl.) durante dois verões agrostológicos tendo por objetivo descrever e explicar a dinâmica de perfilhamento da Brachiaria híbrida Convert HD 364 (Brachiaria hybrid CIAT 36087) sob lotação contínua e taxa de lotação variável. Foram avaliados densidade populacional de perfilhos (DPP), demografia do perfilhamento (taxas de aparecimento - TAP- e sobrevivência de perfilhos - TSP), índice de estabilidade da população de perfilhos (IE), peso médio de perfilhos (PMP), massa de forragem (MF), índice de área foliar (IAF), interceptação luminosa (IL), ângulo de inserção da lâmina foliar (ALF), altura do meristema apical (AMA) e da lígula da última folha expandida (AFE). O delineamento experimental foi em blocos completos casualizados, com arranjo fatorial 3x2, correspondendo às combinações entre alturas de dossel (10, 25 e 40 cm) e taxas de crescimento (50 e 250 kg N ha-1 ano-1), com três repetições. Os dados foram analisados utilizando-se o procedimento de modelos mistos e as médias comparadas utilizando-se o teste \"t\" (P<=0,05). Sob altura de dossel de 10 cm, o capim Convert HD 364 apresentou DPP 10 e 25% superiores àquelas sob 25 e 40 cm, respectivamente. O aumento na taxa de crescimento resultou em aumento de 10% na DPP e decréscimo de 9% no PMP. O PMP foi 80 e 274% maior nos dosséis de 40 cm de altura do que nos de 25 e 10 cm, respectivamente. Dosséis mantidos a 40 cm submetidos à taxa de crescimento baixa e alta, respectivamente, apresentaram incremento de 163 e 233 % na MF do que dosséis de 10 cm. Obtiveram-se respostas similares entre AMA e AFE, nas quais houve um incremento na altura de ambas com o aumento da altura do dossel. Houve diferença entre as taxas de crescimento para AMA e AFE somente em dosséis de 25 cm. Com o aumento da dose de nitrogênio, TAP sofreu aumento de 29%, enquanto, TSP sofreu decréscimo de 13%. TAP e TSP variaram ao longo do período estudado, demonstrando a influência de fatores ambientais nas mesmas. Não houve variação no IE ao longo do período experimental em dosséis sob taxa de crescimento baixa, enquanto na taxa alta o IE foi 20 e 35% maior em Fevereiro do que em Janeiro e Março, respectivamente, para ambos os anos. A determinação da localização do meristema apical é uma importante ferramenta para o planejamento adequado de estratégias de manejo em sistemas de produção animal sob pastejo.

Although forest properties are known to influence snowpack accumulation and spring runoff, the processes underlying the impacts of forest canopy cover on the input of snowmelt to the catchment remain poorly characterized. In this study I show that throughfall and canopy shading can combine to result in maximal snowpacks in forests of moderate canopy density. Snow depth and density data taken shortly before spring melt in the Jemez Mountains of New Mexico show strong correlation between forest canopy density and snow water equivalent, with maximal snow accumulation in forests with density between 25 and 45%. Forest edges are also shown to be highly influential on local snow depth variability, with shaded open areas holding significantly deeper snow than either unshaded open or deep forest areas. These results are broadly applicable in improving estimates of water resource availability, predicting the ecohydrological implications of vegetation change, and informing integrated water resources management.

Reduced plant population in glyphosate-resistant soybean [Glycine max (L) Merr.] may influence the critical time of herbicide application. Field studies were conducted in 2007 and 2008 at two locations in Kentucky to determine the effect of four weed control programs on soybean seed yield, seed quality, crop canopy, and weed pressure when planted at three densities - 185,000, 309,000, and 432,000 plants ha-1. Plots were treated with glyphosate at either 3 weeks after planting (WAP), 5 WAP, 7 WAP, 3 & 7 WAP, representing common weed control protocols within the state. No differences in seed yield were discovered between plant densities in two of four siteyears. 254,500 plants ha-1 was sufficient for maximum yields in all site-years and was also sufficient to achieve maximum canopy amongst those populations tested in the study. Sequential applications at 3 and 7 WAP provided the highest seed yield, while the 5 WAP and 7 WAP application timings were generally the single applications that allowed for the highest yield and canopy closure, along with the highest visual estimate of weeds controlled. Plant density did not influence the critical period for weed control.

The term 'Culmination chromatic density' (CCD) is devised for the thesis to describe perceived unusual chromatic harmony which occurs towards the end of a few of Bach's free organ fugues. The thesis seeks to determine the nature of the harmony, to establish if seventeenth and eighteenth-century theorists discuss fugue culmination harmony, and whether composers before Bach wrote fugues with unusual culmination harmony. After establishing an outline organ fugue chronology, historical music theory and fugues before Bach are examined for the purpose of identifying influences upon Bach's fugue culmination harmony. The main body of the thesis is an harmonic and structural analysis by chronology of thirty-six of Bach's fugues, individually and collectively. The analysis establishes fugue structure through tables of thematic entries, and the examination of thematic material, counterpoint, and tonal structure. The analysis also examines the accidentals, which are discussed and presented in graphs. The analysis of intervals gives detailed insight into the use of consonances and dissonances. Figured bass is used in music examples to show harmony and progressions. The analysis establishes that there is CCD in certain fugues of Bach, and that there are specific structural features, procedures and advanced compositional techniques associated with CCD. There is a clear link between incidences of CCD and fugue chronology. CCD is linked with fugue structure; and advanced fugues with CCD possess unique structures, procedures, and harmony. The analysis establishes that Bach uses background structures, an important additional compositional tool which is related to CCD. There is evidence of historical precedent in some aspects of CCD, both from music treatises, and in some fugues of antecedent French, German, and Italian composers. Areas for further research are suggested. Implications are that Bach uses previously undiscovered methods for fugue composition, and that there are potential changes to the established chronology.

Planting density and genotype have close relationship with the water relations in plants. The scenario of increased occurrence of extreme weather events and the change of Eucalyptus forest plantations to high water deficit regions, led us to the three key questions of this study: (1) What is the relationship between planting density and the potential water stress? (2) The planting spacing interferes the water use efficiency (WUE), i.e. the amount of biomass produced by the amount of water transpired? (3) Can the planting density change the soil water balance (BHS)? To develop this work, we settled a field trial in Mogi Guacu, SP, in February 2012. We planted four genetic material (Eucalyptus grandis x E.urophylla1 {Urograndis1}, Eucalyptus grandis x E.urophylla2, E.urophylla and E.grandis x E.camaldulensis {Grancam}) with different levels of tolerance to drought and four planting spacings (3.4, 7.0, 10.5 and 16.9 m2 plant-1, which correspond to densities of 2,949 , 1,424 and 1,028 and 591 plants ha-1). In Chapter 1, we evaluated the leaf water potential (representing potential water stress) of the four clones for 1 year, between 1.5 and 2.5 years. Regardless of the genetic material, the higher the wood productivity, the greater the leaf water potential. The denser planting (2,949 plants ha-1) stands generated 39% more wood, however, water stress potential reached up to 33% higher than the least dense planting (591 plants ha-1). In the second chapter, during the same period, we evaluated the efficiency of water use, which did not vary according to the change of planting density, but showed differences between genotypes with US 2.3, 2.2 and 1, 5 g L-1 to Urograndis, Urophylla and Grancam, respectively, at a density of 1,424 plants ha-1. Finally, the third chapter evaluated for two years, between 1.7 and 3.7 years, transpiration (T), soil evaporation (Es) and canopy interception (Ei), which together made up evapotranspiration (ET). Subtraction of precipitation (P) per ET resulted in soil water balance (SWB). The SWB was positive or near zero for the two clones evaluated (Urograndis1 and Grancam) when planting density was less than or equal to 1,028 trees ha-1. In the denser planting, the balance was -25%. These studies show that: a higher wood growth results in a higher potential drought stress, generating a clear trade-off between production and survival of trees. However, the detailed study of genetic materials fall under that there are increasing opportunities in water use efficiency, though without the increase in water use, bringing a greater share of water in the watershed scale. Finally, plantations above 1,028 ha-1 trees resulted in a negative soil water balance of -25% at the peak of growth. Together, this study reveals that spacing associated with genotypes can serve as tools in the search for balance between timber production and conservation of natural resources.
A densidade de plantio e o genótipo possuem estreita relação com as relações hídricas nas plantas. Sob um cenário de maior ocorrência de eventos climáticos extremos e do avanço dos plantios florestais de eucalipto para regiões de elevado déficit hídrico, elaboramos três perguntas-chave para esse estudo: (1) Qual a relação entre a densidade de plantio e o potencial estresse hídrico? (2) O espaçamento de plantio interfere na eficiência do uso da água (EUA), i.e., na quantidade de biomassa produzida pela quantidade de água transpirada? (3) Pode a densidade de plantio alterar o balanço hídrico do solo (BHS)? Para responder a essas questões, instalou-se um ensaio de campo em Mogi Guacu, SP, em fevereiro de 2012. Foram plantados quatro materiais genéticos (Eucalyptus grandis x E.urophylla1 {Urograndis1}, Eucalyptus grandis x E.urophylla2, E.urophylla e E.grandis x E.camaldulensis {Grancam}) com distintos níveis de tolerância à seca e quatro espaçamentos de plantio (3,4, 7,0, 10,5 e 16,9 m2 planta-1, que correspondem às densidades de 2.949, 1.424 e 1.028 e 591 plantas ha-1). No capítulo 1, avaliou-se o potencial hídrico foliar (representando o potencial estresse hídrico) dos quatro clones durante 1 ano, entre 1,5 e 2,5 anos. Independentemente do material genético, quanto maior a produtividade madeireira atingida, maior o potencial hídrico foliar. Os plantios mais adensados (2.949 plantas ha-1) geraram povoamentos 39% mais produtivos, no entanto, o potencial estresse hídrico chegou a atingir 33% acima do plantio menos adensado (591 plantas ha-1). No segundo capítulo, durante o mesmo período, avaliou-se a eficiência do uso da água, que não variou conforme a mudança de densidade de plantio, mas apresentou diferença entre os genótipos, com EUA de 2,3, 2,2 e 1,5 g L-1 para os clones Urograndis, Urophylla e Grancam, respectivamente, na densidade de 1.424 plantas ha-1. Por fim, o terceiro capítulo avaliou durante dois anos, entre 1,7 e 3,7 anos, a transpiração (T), evaporação do solo (Es) e interceptação de água pela copa (Ei), que somados compunham e evapotranspiração (ET). A subtração da precipitação (P) da ET resultou no balanço hídrico do solo (BHS). O BHS foi positivo ou próximo de zero para os dois clones avaliados (Urograndis1 e Grancam) quando a densidade de plantio foi inferior ou igual a 1.028 árvores ha-1. No plantio mais adensado, o balanço foi de -25%. Estes estudos demonstram que: a maior produtividade madeireira acarreta em maior potencial estresse hídrico, gerando um claro dilema entre a produção e a sobrevivência dos plantios. No entanto, o estudo detalhado dos materiais genéticos releva que há possibilidades de incremento na eficiência do uso da água sem que ocorra o aumento no uso da água, trazendo um maior compartilhamento da água na escala da microbacia. Por fim, plantios acima de 1.028 árvores ha-1 resultaram em um balanço hídrico do solo negativo médio de -25% no pico do crescimento. Em conjunto, o presente trabalho releva que o espaçamento associado a materiais genéticos específicos, podem servir como ferramenta na busca pelo equilíbrio entre a produção madeireira e a conservação de recursos naturais.

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The aim of this study was to evaluate the effect of different density classes of canola seeds over the physiologic quality, as well as the effects on different depth of sowing and in conditions of water deficit. Also, the hydration curve was employed as auxiliary element on identification of better quality classes. Seeds of two hybrids of canola, Hyola 61 and Hyola 401, were separated into six classes of density. These classes were submitted to tests to characterize their physiological potential: germination, fist count of germination test, length and seedling dry mass. Also was determined the germination evaluation and vigor in water deficit condition into potencies, zero, -0,25, -0,5 and -1MPa, simulated with polyethylene glycol (PEG 6000) and, also in different depth of seeding (1, 2, 3 and 4 cm). According to results presented by the hybrids Hyola 61 and 401, we can conclude that there is an association between seed density and the characteristics of physiological quality (first count of germination test, germination, seedling length and index of emergency speed). The osmotic potentials reduction, from -0,25 MPa on, reduces the germination and vigor of all hybrid seed classes evaluated, being the vigor more affected than the germination. The critical potential for germination is of -1,0 MPa, regardless of the seeds densities. There is a different behavior by the hybrids about the tolerance of stress conditions caused by the PEG 6000, and Hyola 401 was more tolerant than Hyola 61. The physiologic quality affects the water content reached by the canola seeds during hydration, for both hybrids, being that the seeds with less vigor present higher water uptake and water content until 15 hours, when compared to seeds with higher vigor. At last, sowing deeper than 2 cm reduces drastically the germination and vigor of the all class in both hybrids seeds. In this way, was not verified the interaction between seeds density with the depth of sowing.
O objetivo deste trabalho foi avaliar a ação de diferentes classes de densidade de sementes de canola sobre a qualidade fisiológica, bem como seus efeitos sobre diferentes profundidades de semeadura e em condições de déficit hídrico. Utilizou-se a curva de hidratação como elemento auxiliar na identificação de classes de melhor qualidade. Foram utilizados sementes de dois híbridos de canola, Hyola 61 e Hyola 401, separados em seis classes de densidade. Cada classe foi submetida a testes para caracterizar seu potencial fisiológico: germinação, primeira contagem do teste de germinação, comprimento e massa seca de plântula. Também foi efetuada a avaliação da germinação e vigor em condições de déficit hídrico nos potencias, 0, -0,25, -0,5 e -1MPa, simulado com polietilenoglicol 6000 (PEG 6000) e, também em diferentes profundidades de semeadura (1, 2, 3 e 4 cm). Em função dos resultados obtidos para os híbridos Hyola 61 e 401, pode-se concluir que existe uma associação entre a densidade de sementes e os atributos de quantificação da qualidade fisiológica (primeira contagem do teste de germinação, germinação, comprimento de plântula e índice de velocidade de emergência). A diminuição dos potenciais osmóticos, a partir de -0,25MPa, reduz a germinação e o vigor de todas as classes de sementes dos dois híbridos estudados, sendo o vigor mais afetado do que a germinação. O potencial crítico para germinação é de -1,0MPa, independentemente da densidade das sementes. Há comportamento diferenciado dos híbridos quanto à tolerância à condição de estresse provocada pelo PEG 6000, sendo o Hyola 401 mais tolerante que o Hyola 61. A qualidade fisiológica afeta o teor de água alcançado pelas sementes de canola durante a hidratação, para ambos os híbridos, sendo que as sementes de menor vigor apresentam maior velocidade de hidratação e teor de água até 15 horas, quando comparadas com sementes de maior vigor. Semeaduras mais profundas que 2 cm reduzem drasticamente a germinação e o vigor de todas as classes de sementes de ambos os híbridos, não ocorrendo interação entre a densidade das sementes com a profundidade de semeadura.

The adjustment plant arrangement is one of the fundamental management techniques for canola show positive reaction in the ability to absorb light energy, nutrients and water, which reflects on maximizing the production of photosynthate directed to the plant and grains. The aim of this study was to assess the interference of arrangement plant on direct and indirect components of yield in canola, and includes determining the effects produced in oil content. The study was conducted at the Instituto Regional de Desenvolvimento Rural do Departamento de Estudos Agrários da Universidade Regional do Noroeste do Estado do Rio Grande do Sul (IRDeR/DEAg/UNIJUÍ) in Augusto Pestana, RS, involving the execution of three experiments for different spacing of 0.20, 0.40 and 0.60m. The experimental design consisted of a factorial arrangement in randomized blocks with four replicates of 2 x 2 x 4, for the crop year (2008 and 2009), genotype (Hyola 432 and 61) and plant density (20, 40, 60 and 80 plants m-2) in each set line spacing. Components were determined direct and indirect grain yield, oil content, morphological and adaptive, as well as the thermal and solar radiation during the grain filling. The year of cultivation was more effective in changing the grain yield and other traits in canola direct production and oil content, followed by the genetic potential to grow and smaller share of the planting density. The cv. Hyola 432 shows greater effectiveness in maximizing grain yield over Hyola 61 regardless of year, row spacing and planting density. Moreover, in the shortest space of culture, the character of direct and indirect yield high values of heritability and character number of tertiary branches shows stability when subjected to strong variations in the plants arrangement. The thermal shows no correlation with grain yield and oil content. On the other hand, variables related to the crop cycle are associated with the thermal and solar radiation accumulated in the grain filling stage of canola.
O ajuste do arranjo de plantas representa um dos termos de manejo fundamental para a canola mostrar reação positiva na capacidade de absorção de energia luminosa, nutrientes e água, o que reflete em maximizar a produção de fotoassimilados direcionados a planta e aos grãos. O objetivo deste trabalho foi verificar a interferência do arranjo de plantas sobre os componentes diretos e indiretos do rendimento de grãos em canola, incluindo também, a determinação dos efeitos proporcionados no conteúdo de óleo. Nesse sentido, foi desenvolvido um experimento nos anos agrícolas de 2008 e 2009 no Instituto Regional de Desenvolvimento Rural, pertencente ao Departamento de Estudos Agrários da Universidade Regional do Noroeste do Rio Grande do Sul (IRDeR/DEAg/UNIJUÍ), localizada no município de Augusto Pestana, RS. Para o estudo dos diferentes arranjos de população, foram utilizados três espaçamentos entrelinhas (0,20, 0,40 e 0,60 m), quatro densidades de plantas por metro quadrado (20, 40, 60 e 80 plantas m-2) e utilizando dois híbridos de canola (Hyola 432 e Hyola 61). O delineamento experimental foi o de blocos completamente casualizados com quatro repetições, num esquema fatorial 2 x 3 x 4, para ano, genótipo e densidade de cultivo em três distintos espaçamentos entre linhas, respectivamente. Foram determinados os componentes direto e indiretos do rendimento de grãos, o conteúdo de óleo, caracteres morfológicos e adaptativos, bem como a soma térmica e a insolação durante o período de enchimento de grãos. O ano de cultivo foi mais efetivo em alterar o rendimento de grãos e demais caracteres diretos de produção em canola, bem como o teor de óleo, seguido do potencial genético de cultivar e de menor participação da densidade de cultivo. A cultivar Hyola 432 mostra maior efetividade em maximizar a produção de grãos em relação a Hyola 61, independente do ano, espaçamento entre linhas e densidade de cultivo. Além disso, no menor espaçamento de cultivo, os caracteres diretos e indiretos do rendimento de grãos apresentam elevados valores de herdabilidade e o caráter número de ramos terciários evidencia forte estabilidade quando submetido a variações no arranjo de plantas. A soma térmica não apresenta correlação com o rendimento de grãos e teor de óleo. Por outro lado, variáveis relacionadas ao ciclo da cultura apresentam associação com a soma térmica e com a insolação acumulada na fase de enchimento de grãos de canola.

Sclerotinia stem rot (SSR) disease is one of the most devastating diseases of canola in the Canadian prairies caused by the fungus Sclerotinia sclerotiorum (Lib.) de Bary. Yield losses ranging between 5 to 100 percent can be experienced as a result of this disease. This study evaluated the impacts of weather and microclimate on SSR development in canola with varying canopy density. Ascospore dispersal and disease incidence were compared under modified canopy densities and misting regimes to alter microclimate. The effectiveness of crop rotation and the influence of neighbouring non host crops were also analyzed in this study. A randomized complete block design was used to compare values for canopy density, microclimate and disease development under 3 seeding rates and 3 fertilizer treatments. This design was implemented over 4 site-years, in Winnipeg and Carman during 2011 and 2012. Weather stations were installed to monitor environmental conditions at each site and compare these to disease. At each site, a wheat plot was created to examine ascospore release under a non-host crop to determine the influence such a crop may have on neighbouring canola fields. Results of this study showed that peaks in ascospore concentrations occurred simultaneously between Winnipeg and Carman fields during both years indicating that regional weather conditions are important for ascospore release. Disease development in canola fields occurred where adequate precipitation and relative humidity were present prior to ascospore release and dispersal. A decrease in relative humidity and an increase in temperature were required for spore release from apothecia. Disease development was greater in Carman, where relative humidity values overall were higher and temperatures remained lower compared to those in Winnipeg in 2011 and 2012. Ascospore release did occur under the wheat canopy and ascospores were dispersed to a distance of at least 7 meters from the plot.

Crown fires, the fastest spreading of all forest fires, can occur in any forest type throughout the United States and the world. The occurrence of crown fires has become increasingly frequent and severe in recent years. The overall aim of this study is to estimate the forest canopy fuel parameters including crown base height (CBH) and crown bulk density (CBD), and to investigate the potential of using airborne lidar data in east Texas. The specific objectives are to: (1) propose allometric estimators of CBD and CBH and compare the results of using those estimators to those produced by the CrownMass/FMAPlus software at tree and stand levels for 50 loblolly pine plots in eastern Texas, (2) develop a methodology for using airborne light detection and ranging (lidar) to estimate CBD and CBH canopy fuel parameters and to simulate fire behavior using estimated forest canopy parameters as FARSITE inputs, and (3) investigate the use of spaceborne ICEsat /GLAS (Ice, Cloud, and Land Elevation Satellite/Geoscience Laser Altimeter System) lidar for estimating canopy fuel parameters. According to our results from the first study, the calculated average CBD values, across all 50 plots, were 0.18 kg/m³ and 0.07 kg/m³, respectively, for the allometric equation proposed herein and the CrownMass program. Lorey’s mean height approach was used in this study to calculate CBH at plot level. The average height values of CBH obtained from Lorey’s height approach was 10.6 m and from the CrownMass program was 9.1 m. The results obtained for the two methods are relatively close to each other; with the estimate of CBH being 1.16 times larger than the CrownMass value. According to the results from the second study, the CBD and CBH were successfully predicted using airborne lidar data with R² values of 0.748 and 0.976, respectively. The third study demonstrated that canopy fuel parameters can be successfully estimated using GLAS waveform data; an R² value of 0.84 was obtained. With these approaches, we are providing practical methods for quantifying these parameters and making them directly available to fire managers. The accuracy of these parameters is very important for realistic predictions of wildfire initiation and growth.

Enhanced understanding of forest stocks and dynamics can be gained through improved forest measurement, which is required to assist with sustainable forest management decisions, meet Australian and international reporting needs, and improve research efforts to better respond to a changing climate. Integrated sampling schemes that utilise a multi-scale approach, with a range of data sourced from both field and remote sensing, have been identified as a way to generate the required forest information. Given the multi-scale approach proposed by these schemes, it is important to understand how scale potentially affects the interpretation and reporting of forest from a range of data. ¶ To provide improved forest assessment at a range of scales, this research has developed a strategy for facilitating tree and stand level retrieval of structural attributes within an integrated multi-scale analysis framework. ...

This study was conducted on two rangeland sites in south Texas with large populations of huisache (Acacia farnesiana (L.) Willd.); the Bush Ranch in Goliad County, and the Hitchcock Ranch in Bee County. The purpose of the study was to evaluate the effect of three herbicide treatments and three seasons of application on 1) apparent mortality of huisache, 2) huisache canopy cover, 3) huisache stem density, and 4) herbaceous ground cover. Herbicide treatments included aminocyclopyrachlor alone at a rate of 0.315 kg a.i. ha-1, aminocyclopyrachlor + triclopyr at a rate of 0.210 kg a.i. ha-1 + 0.420 kg a.e. ha-1, and triclopyr + picloram at a rate of 0.560 kg a.e. ha-1 + 0.560 kg a.e. ha-1. Herbicide treatments were applied over 3 x 30 m plots containing previously mowed huisache in May, July, and October of 2010 with ground-broadcast equipment at a rate of 140 L ha-1. Randomly selected huisache individuals and herbaceous ground cover at randomly selected points were monitored for the duration of the study. Statistical analyses of huisache mortality, canopy area, and stem densities revealed that at both sites one year after treatment, huisache mortality across the three seasons of application was consistently higher in plots treated with aminocyclopyrachlor + triclopyr (50 to 99%) versus those treated with aminocyclopyrachlor alone (16 to 78%) or triclopyr + picloram (4 to 70%). This mixture also provided the greatest reductions in huisache canopy area (60 to 99% reduction) and stem density (61 to 99% reduction). Also at both sites, spring applications consistently provided the greatest huisache control and canopy and stem reductions. Herbicide treatment and season of application had little effect on post-treatment herbaceous ground cover, likely due to extreme drought conditions in 2011. Of the possible combinations of seasons of application and herbicide treatments, the application in the spring of aminocyclopyrachlor plus triclopyr provided the most desirable results in terms of huisache mortality, canopy reduction, and stem density reduction. However, for sites invaded by huisache that are located near to potentially susceptible crops, the application of aminocyclopyrachlor plus triclopyr or aminocyclopyrachlor alone in the fall after the harvest of those crops may be more appropriate in order to avoid non-target injury while still providing acceptable huisache control.

Dissertation submitted in partial fulfilment of the requirements for the degree of Master of Science in Geospatial Technologies
It is becoming more present in agriculture’s practices the use of Unmanned Aerial Systems with sensors capable of capturing light, in the visible and in longer wavelengths of the electromagnetic spectrum once reflected on the field. These sensors have been used to perform Remote Sensing also in other knowledge fields, describing phenomenon without the risk, cost and the time consuming processes associated with in site samples collection and analysis by a technician or satellite imagery acquisition. The Vegetation Indexes developed can explain the vigor of the cultivation and its data collection processes are more cost and time efficient, allowing farmers to monitor plant grow in every critical stage. These Vegetation Indexes started by being calculated from satellite and airborne imagery, one of the main source for crop management tools, however UAS is becoming more present in Precision Agriculture, achieving better spatial and temporal resolution. This gap in spatial resolution when studying low density cultivations like olive groves and vineyards, creates Vegetation Index’s maps polluted with noise caused by the soil and therefore difficult to interpret and analyse. Hence, when the agriculture has spaced and low density vegetation becomes challenging to understand and extract information from these vegetation index’s maps regarding different spatial variability patterns of the tree canopy vigor. In these cases, where vegetation is spaced it is important to filter this noise. A Classification Model was developed with the objective of extracting just the vegetation’s canopy data. The soil was filtered and the canopy data interpolated using spatial analysis tools. The final interpolated maps produced can provide meaningful information regarding the spatial variability and be used to support decision making, identifying critical areas to be intervened and managed, or be used as an input for Variable Rate Technology applications.

Analysis of forest canopy density based on textural features of high resolution imagery and airborne laser scanning data Abstract The objective of this thesis is to assess the forest canopy density in the Šumava Mountains, Czech Republic. The spruce forests in this area have been suffering from the bark beetle outbreak for almost 20 years resulting in a mixture of dead and young trees, mature forest stands and peat bogs. The canopy density was evaluated using a very high spatial resolution panchromatic imagery and low point density LiDAR, combined with an object oriented approach. The classification based on three GLCM texture measures (contrast, entropy and correlation), which were derived from the image objects, resulted in a kappa index of accuracy of 0.45. Adding the information from the LiDAR data, the accuracy of the classification improved up to 0.95.

Canola is an important crop in western Canada that has become intensively managed with purchased inputs. By knowing the relative contribution of seed treatment, seeding rate, and cultivar to canola competitiveness against weeds and yield producers can adjust input decisions and maintain yield goals but increase net gain. Field experiments took place during 1999 and 2000 in the Brandon region of western Manitoba. Treatments included; two canola cultivars (Invigor 2273 &, Exceed), the presence/absence of volunteer barley, four target canola densities (37.5, 75, 150 & 300 plant/m2) and four seed treatments (non-treated, mixture of thiamethoxam, difenoconazole, fludioxonil and metalaxyl-M (Helix), and a mixture of lindane, carbathiin and thiram (Vitavax RS) with and without furrow placed terbufos (Counter). Using greenhouse experiments we examined the effect of seed treatment on canola's competitiveness in the absence of pests using a target neighbour design. In general, cultivar and seeding rate influenced canola growth, yield and competitiveness greater than seed treatment. Crop stand was only affected by seeding rate. Seed treatment offered excellent protection from flea beetles, but protection did not always translate into improved canola growth, weed suppression or yield gain. In the absence of pests Vitavax RS hindered canola competitiveness, while Helix was similar to bare seed. The hybrid variety Invigor was more competitive with weeds and higher yielding than Exceed canola. Early, vigorous seedling growth resulting from using a seed treatment may not be as important for canola competitiveness as vigor from heterosis and crop density. Thiamethoxam was a good replacement for the environmentally problematic lindane for flea beetle management; however, producers with moderate to low flea beetle infestation or those interested in integrated pest management may be better off increasing seeding rate or using a hybrid variety to help control weeds and better optimize yield.