Tese apresenta capítulos 1, 2, 3 e 4 em inglês / Orientador: Gustavo Habermann / Banca: Silvana de Paula Q. Scalon / Banca: Ana Sílvia Franco Pinheiro Moreira / Banca: Fábio Socolowski / Banca: Reinaldo Monteiro / Resumo: As espécies Styrax ferrugineus Ness & Mart., S. camporum Pohl. e S. pohlii A. DC. apresentam distintos padrões de ocorrência. S. ferrugineus é comumente encontrada no Cerrado sensu strictu (s. str.), enquanto S. camporum apresenta ampla distribuição no Cerrado sensu latu (s.l.), especialmente nas bordas dos fragmentos e S. pohlii é abundante nas florestas ripárias e de galeria. As performances germinativas das sementes e ecofisiológicas das plantas destas três espécies foram avaliadas através de experimentos de enterrio das sementes e plantio recíprocos em fragmentos de Cerrado s.str, Cerradão (clareira e sub-bosque) e mata ripária, os quais diferem em disponibilidade hídrica no solo e na atmosfera e luminosidade. Simultaneamente, o crescimento e desempenho fotossintético de S. pohlii em resposta ao alagamento do solo foram estudados em casa de vegetação. As sementes das três espécies germinaram em todos os locais experimentais onde foram enterradas. Porém, as plantas jovens de S. ferrugineus e S. camporum não sobreviveram às condições de baixa irradiância e alta disponibilidade de água no solo, encontradas na floresta ripária. A sobrevivência e o sucesso de S. pohlii neste ambiente parece estar relacionado ao rápido crescimento inicial da parte aérea, para obtenção de luz, e à adaptação que ela apresenta em resposta ao alagamento do solo. S. pohlii foi capaz de sobreviver a alagamentos sazonais e mostrou rápida recuperação fisiológica após inundação artificial. S. camporum apresentou maior eficiência fotossintética, crescimento e biomassa quando as plantas foram cultivadas sob altas irradiâncias, em comparação a ambiente sombreados, o que explica o maior número de indíviduos nas bordas em comparação ao interior dos fragmentos de Cerrado. Os dados de trocas gasosas, fluorescência e crescimento de... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The species Styrax ferrugineus Ness & Mart., S. camporum Pohl. and S. pohlii A. DC. show distinct geographical distribution patterns. S. ferrugineus is commonly found in the Cerrado sensu stricto (s. str.), whereas S. camporum is widely distributed in the Cerrado sensu lato (s. l), especially at the edge of vegetation fragments, and S. pohlii is abundant in riparian and gallery forests. Seed germination performances and ecophysiological performances of plants of these three species were assessed through reciprocal burial and planting experiments in a Cerrado s. str. fragment, a Cerradão fragment (gap and understory conditions) and in a riparian forest remnant, where water and light resources are differently availabe. Concurently, growth and photosynthetic parameters of S. pohlii potted plants in response to soil flooding was assessed in a greenhouse experiment. Seeds from each of the tree species were able to germinate in every experimental condition where the seeds were buried. Nevertheless, young plants of S. ferrugineus and S. camporum did not survive the low irradiance and high soil water availability found in the riparian forest. The survival and the success of S. pohlii in such environment seems to be related to a faster shoot initial length in order to capture sunlight, and to the adjustment that this species exhibits in reponse to different levels of soil flooding, enabling this species to fast recover from flooding periods. S. camporum showed higher photosynthetic performance, growth and biomass production when it was cultivated under high irradiances in comparison to shaded environments. These results explain the higher number of individuals of this species observed at the edge in comparison to the interior of Cerrado fragments. Gas exchange, fluorescence and growth parameters measured on S. pohlii and S. ferrugineus... (Complete abstract click electronic access below) / Doutor

Orientador: Leonor Patricia Cerdeira Morellato / Banca: Mario Tomazello Filho / Banca: Giuliano Maselli Locosselli / Banca: Ana Carolina Maioli Campos Barbosa / Banca: Claudio Sergio Lisi / Resumo: O conhecimento a respeito do crescimento e da formação estrutural da madeira em árvores, são preceitos básicos para entender como o clima influencia o desenvolvimento arbóreo, aqui exemplificadas pelo estudo das populações de Qualea grandiflora Mart. (Vochysiaceae), Pouteria torta (Mart.) Radlk. (Sapotaceae) e Ocotea pulchella (Nees) Mez. (Lauraceae). O objetivo deste estudo foi investigar a influência do clima no desenvolvimento do tronco das árvores de três espécies nativas do Cerrado, contribuindo assim para a sua conservação e manejo. Para alcançar esses objetivos foram realizados estudos dendrocronológicos, associados ao uso de técnicas de raios-X aplicados no lenho, utilização do conceito de manejo GOL (exploração orientada pelo crescimento), utilização de faixas dendrométricas, fenologia e anatomia cambial. Cada espécie apresentou individualidade no crescimento e houve evidente variação interespecífica. Mesmo considerando o lento crescimento cambial detectado, o incremento radial do tronco foi influenciado pelo déficit hídrico sazonal, reduzindo as taxas de crescimento nos períodos secos, e a fenologia apresentou sazonalidade nas fenofases estudadas. Por meio da construção das cronologias foi verificada a existência de correlação entre as larguras dos anéis de crescimento e clima. O crescimento das espécies foi influenciado pelas variáveis climáticas regionais (precipitação e temperatura) e possuem teleconexão com as anomalias de Temperatura da Superfície do Mar (TSM) ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The knowledge about the tree growth and wood formation is has a fundamental role for the understanding of how environment and climate have influenced the development of tree populations, here explored sstuding three cerrado species: Qualea grandiflora Mart.Vochysiaceae), Pouteria torta (Mart.) Radlk. (Sapotaceae) and Ocotea pulchella (Nees) Mez. (Lauraceae). The objective of this study was to investigate how climate influenced the development of these three species of trees native from Cerrado, contributing for their conservation and logging management. For that end, we conducted conventional dendrochronological studies associated to other techniques: wood X-ray, the management concept GOL (Growth Oriented Logging), the use of dendrometric bands, all associated to phenology and cambium anatomy. Each species showed particularites related to growth patterns and evident interspecific variation. The slow growth rate and the radial increment were influenced by the seasonal water deficit, reducing the growth rates during the dry seasons, and matched the seasonality of the observed leafing and reproductive phenology. The recovered chronologies indicated a correlation between the growth rings and the climatic variables. The growth was influenced by regional climatic variables (precipitation and temperature) and the teleconnection with the El Niño Pacific SST (Sea Surface Temperature) anomalies, but it was not related to the South Atlantic SST. Our data show adequate information on th... (Complete abstract click electronic access below) / Doutor

<p>In this study I investigate the sensitiveness of Bishop's goutweed (Aegopodium podagraria L.)to mechanical damages in an experiment with artificial clipping. Based on personalobservations of A. podagraria during several years I hypothesise that i) A. podagraria indifference with other species, for example different species of grass have difficult to recoverfrom mechanical damages ii) in a site with several other species present A. podagraria willhave harder to recover from mechanical damages than in a pure stand iii) as purer a stand withA. podagraria is, the harder other species will have to establish after the removal of aboveground parts of A. podagraria. The main conclusion of this work is that mechanical damagehas a significant effect on the vegetation cover of A. podagraria. The experiment also provethat a high grade of monoculture favours the ability of A. podagraria to recover frommechanical damage. It could however not be proven that high grade of monoculture of A.podagraria puts constraints on the ability of other species to establish on plots where A.podagraria is removed.</p>

In this study I investigate the sensitiveness of Bishop's goutweed (Aegopodium podagraria L.)to mechanical damages in an experiment with artificial clipping. Based on personalobservations of A. podagraria during several years I hypothesise that i) A. podagraria indifference with other species, for example different species of grass have difficult to recoverfrom mechanical damages ii) in a site with several other species present A. podagraria willhave harder to recover from mechanical damages than in a pure stand iii) as purer a stand withA. podagraria is, the harder other species will have to establish after the removal of aboveground parts of A. podagraria. The main conclusion of this work is that mechanical damagehas a significant effect on the vegetation cover of A. podagraria. The experiment also provethat a high grade of monoculture favours the ability of A. podagraria to recover frommechanical damage. It could however not be proven that high grade of monoculture of A.podagraria puts constraints on the ability of other species to establish on plots where A.podagraria is removed.

Graduation date: 1991

Thesis (M. Sc.)--University of Hong Kong, 1973. / Typewritten.

The objectives of the study were to provide a documented record of the vegetation of the grassland vegetation of the Red River Valley. The native prairies of this Valley are dominated by various combinations of Andropogon gerardi, Andropogon scoparius, Agropyron smithii, Bouteloua curtipendula, Calamagrostis inexpansa, Calamovilfa longifolia, Koeleria cristata, Muhlenbergia richardsonis, Sorghastrum nutans, Spartina pectinata, Sporobolus heterolepis, Stipa comata, Stipa spartea and Stipa viridula. At present only relicts of these grasslands remain. One hundred and fifty-one stands including 299 species, encompassing a wide range of floristic and habitat variability, were selected for study. The species composition frequency) of each stand was sampled by the use of thirty 0.5 X 0.5 m quadrats. A presence list was prepared for each stand and the dominant graminoid species determined by an estimate of cover contribution to the upper strata. The standing crop of green herbage of .34 stands was sampled by clipping five 0.5 X 0.5 m quadrats, and the material oven dried for weight determination. Environmental measurements were taken to determine physiographic position and soil profile characteristics. Soil samples were collected from the "A" horizon of each stand for textural analysis, field capacity, salinity and pH determinations. An analysis based on indicator species determined by physiographic association, indicated that the various species responded in a continuous manner to a moisture gradient. This was suggested by a gradation of importance from one physiographic habitat to another, with its position of peak performance in association with a specific drainage position. Vegetational types were also associated with physiographic position, but the dominant species and to a lesser degree secondary species showed modification of behavior by soil texture. The total number of species and their levels of importance (frequency) within the various vegetational types was used as a measure of diversity. The mid prairie dominance types with high numbers of species, many with high importance, were the most diverse of all types examined. It was further indicated that mid prairie stands in the northern portion of the area studied had higher diversity than all others. Geographic differences in diversity were related to historical development of the grasslands. The yield of green herbage varied according to prairie division, leading dominant, soil texture and geographic location. A high positive correlation between green herbage yield and length of growing season suggested that geographic location was the most effective determinant in production, with southern stands producing about 100% more green herbage than comparable stands in the north. The species comprising the grasslands of the Red River Valley suggest an amalgamation of species of eastern and western origin. The dominant graminoids, however, are most closely associated with the grasslands to the east and suggest the placement of the Red River Valley grasslands within the True Prairie.

Weed control is the primary challenge in organic dry edible bean (Phaseolus vulgaris L.) production, however no previous Canadian studies have considered cereal cover crops for organic pulse production. The objectives of this study were to characterize the effects of fall rye (Secale cereal L.), barley (Hordeum vulgare L.) and oat (Avena sativa L.) cover crops and tillage management on weeds and the soil microclimate in organic dry beans. Above ground weed biomass was significantly lower in fall rye (3778 kg ha -1) and NT treatments (4867 kg ha -1). Fall rye significantly lowered spring soil nitrate-N by 72% and 74% in 2011 and 2012, respectively. Cover crops did not affect soil moisture or soil growing degree day (GDDsoil ) accumulation in early spring. Further research is needed on fall-seeded fall rye termination in organic conditions to reduce its competitiveness with the main crop. / October 2015

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