Spatial and temporal heterogeneity of water and nutrient pools is closely associated with the existence of different plant communities in hydrologically-controlled ecosystems such as the Everglades. These various communities differ in their flooding and fire tolerances as well as nutrient requirements. Upland plant communities are of particular ecological significance since they have high biodiversity and provide habitat to terrestrial fauna, yet comprise less than 10 % of the total area. Restoration and maintenance of such communities requires an understanding of their water and nutrient requirements. Chapter 2 compares water source utilization in hammocks and pine rocklands on the Miami Rock Ridge using stable isotopes of water. Hammocks do not flood, while adjacent pinelands may flood between 2-3 months. In the wet season, hammocks were found to use phosphorus (P) rich soilwater, a local pool of water and nutrients while pineland plants primarily relied upon groundwater, the regional pool. Access to a rich pool of P in the oligotrophic Everglades was associated with higher community-level foliar P concentration in hammocks. However in the dry season, hammocks utilized groundwater, which suggests sensitivity to extended droughts. Chapter 3 compares the hammock (upland or head) and swamp forests (lowland or tail) on tree islands in the Shark River Slough. Uplands were associated with P-rich soilwater uptake in the wet season, with regional water uptake in the dry season. Accordingly, tree island heads are rich in foliar P and thereby P-hotspots in the Everglades. Foliar nutrient concentrations can thus indicate limiting nutrient availability in the Everglades. Chapter 4 looks at how leaf phenology patterns are tied to water and nutrient pools. Leaf fall in ridge hammocks is associated with high foliar carbon isotope values over the dry season, which is not the case for tree island hammocks. However, in some species, high levels of foliar nitrogen are also associated with high foliar C13 values indicating stomatal limitation of photosynthesis. Growing season for most hammock species is the wet season coinciding with high availability of P, as reflected in high foliar P in this season. Linking water sources to foliar nutrients elucidates roles of water and nutrient pools in leading to different plant communities within an ecosystem.

Response to fertilization is a function of the degree to which nutrients are limiting growth, the capacity of individual trees to respond to nutrient inputs, the degree to which other factors limit growth, and the possible extrinsic effects of treatment (e.g., root mortality due to fertilizer-induced soil pH effects). Recognition and examination of these factors is essential if response to fertilization is to be predictable. Over the past 25 years numerous western hemlock fertilizer trials have shown responses ranging from negative to positive with no clear trends. Theories for this erratic response include: (a) different nutritional requirements during different stages of stand development; (b) high native N availability or low supplies of other nutrients (P and S, in particular); (c) differential adverse effects of N fertilizers on surface roots, mycorrhizal populations and P nutrition; (d) a requirement for slow release N; and (e) induced water stress. The objective of this study was to develop site-specific guidelines for western hemlock fertilization decision-making for industrial use. This study reports on the first and third growing-season response to two different fertilizer treatments, and identification of possible relationships between fertilizer response and site and stand conditions.

The influence of salal on tree growth has attained considerable attention in coastal British Columbia. Field observations, surveys, and studies in the CWH zone have indicated poor growth performance of crop tree species in salal-dominated plantations and natural immature and old-growth stands. Where sites have been burned and planted, tree growth has improved; similar effects have been observed for naturally regenerated stands. Immature stands that developed after wind disturbance or harvesting feature rapid growth and nearly complete absence of salal. As studies have shown that ericaceous plants negatively impact tree growth, the salal on potential harvest sites has been considered undesirable. This study examined (1) the possible influence of salal on the stand, soil nutrient status and site index, and (2) the relations between site index, salal, plant communities, and site in disturbed, immature, coastal Douglas-fir ecosystems. We compared vegetation and environmental characteristics of 101 ecosystems, and examined differences in foliar and soil nutrient characteristics and site index between stands with high and low salal cover through analysis of variance (ANOVA) and regression analysis.

Current surface mine reclamation in Appalachia involves returning the land to approximate original contour by grading the surface and planting grasses and early-successional trees. This results in a greatly altered ecosystem compared to the native forest that was there prior to mining. The reclaimed land is usually degraded economically and environmentally because mine soils are usually less productive than the native soils, and because the mined sites do not provide the same level of ecosystem services. This research addressed constraints to the return of the native ecosystem by assessing how mine spoil properties and treatments affect native tree species and soil microorganisms. A 4x2x3 factorial greenhouse experiment was used to examine the growth of one-year-old Fraxinus americana, Quercus rubra, and Liriodendron tulipifera as well as herbaceous plant occurrence and microbial biomass and activity. Three mine spoils, brown, weathered sandstone (BWS), white, unweathered sandstone (WUS), and gray, unweathered shale (GUH) were compared with undisturbed forest topsoil (UFT) to determine their suitability for tree growth. Half of each of the four media was inoculated with a 2.5-cm layer of topsoil. BWS was the optimal spoil material for the growth of F. americana, Q. rubra and microbial populations. Foliar nutrient analysis indicated that L. tulipifera was highly dependent on nutrient levels and was unable to grow well on any of the spoil types due to deficiencies. Inoculation with topsoil increased tree growth on the GUH spoil, and increased microbial activity and presence of herbaceous plants across all growth media. The field study was used to determine what spoil properties most influenced three-year-old Quercus alba growth. This information was used to test a mine quality classification model. Northeast facing sites with sandy spoils high in nutrients, moderate in pH, and high in microbial populations were optimal for tree growth. These variables explained 52% of the variation in tree growth. Tree growth was also highly correlated with tree foliar nutrient levels, further suggesting that tree growth was influenced by spoil nutrients. Microbial biomass and dehydrogenase production were also regressed against soil properties and were dependant on a moderate pH, high nitrogen levels, and low salt content. These variables explained 53% of the variability in microbial biomass and 50% of the variability in enzyme production. These studies suggest that tree growth and soil microbial populations are closely linked, and both are affected by mine spoil properties. During mined land reclamation, mine spoils conducive to tree growth should be selected if return of the native ecosystem is the reclamation goal. / Master of Science

Red alder (Alnus rubra) is a tree species with high economic and ecological importance. It is subject to defoliation during unpredictable, episodic outbreaks of tent caterpillars (Malacosoma spp.) that result in reduced growth, decreased wood production, unsightly appearance and mortality in severe cases. Alder trees are weakened by severe and repeated tent caterpillar defoliation, and this can increase the susceptibility of the trees to other pests, diseases and drought. Repeated attack by tent caterpillars can cause decline in red alder populations, which can have potential negative impacts on the ecological and economic benefits of the species. Evidence from other species has shown that plants produce phytochemicals for defense against herbivores at a cost to growth and reproduction, but the relative magnitude of the cost of allocating available resources to defense depends on the level of the resources, and the plant genotype. The quality of a plant as food for herbivores is influenced by leaf physical and biochemical traits, and these traits change during a growing season or upon attack by herbivores. My research aimed to explore the defense mechanisms of red alder against western tent caterpillars (Malacosoma californicum) and determine the resistance variation among and within red alder populations, and to evaluate red alder available resource (nitrogen) allocation to defense and growth. Bioassay feeding trials were conducted in 2014 and 2015 with western tent caterpillars (WTC) (M. californicum) on twenty red alder clones from ten provenances. Phenology and quality of red alder leaves as food for the defoliators were analyzed to determine if budburst, leaf chemical content, water content or physical traits are major determinants of western tent caterpillars preference for red alder leaves. In another experiment, one-year-old seedlings from 100 half-sib red alder families were treated with two levels of ammonium nitrate (NH4NO3) in two growing seasons in a common garden. Growth, herbivore defense-related traits and root nodulation were measured and ranked among the plant genotypes and between the two nitrogen (N) treatments. Leaves from the two N treatments and different alder families were also used for bioassay feeding trials with WTC larvae to determine effects of N and genotype on red alder herbivory resistance. In my final experiments, I harvested and analyzed leaves from three-year-old red alder trees from five different families on eight dates from early April to mid-October 2016 to quantify oregonin and total phenolics concentrations, and wound induction experiments were conducted to determine if the concentrations of the chemicals vary during a growing season and upon attack by insects. Alder clones and families differed in percentage leaf area eaten by caterpillars and in leaf defense traits. The concentrations of foliar phenolic compounds negatively correlated with the percentage leaf area eaten by the caterpillars, but the results suggest a threshold, above which the concentration of each of the chemicals appeared to reduce WTC feeding, individually. Particularly, foliar oregonin concentration above 20 % leaf dry weight consistently appeared to reduce feeding by caterpillars. N availability had significant effects on red alder seedling total dry biomass and leaf N concentration. There was a clear trade-off between red alder seedling growth, and content of the phenolic compounds and leaf thickness, which supports the growth-differentiation balanced hypothesis in relation to resource availability. The concentration of oregonin varied during the growing season and there were no significant responses of any of the measured compounds to wounding. The results suggest that red alder foliar oregonin, condensed tannin and total phenolics are constitutive defenses and are not wound-induced. The effects of leaf total phenolic and condensed tannin concentrations on insect herbivory have been documented by past studies but the effects of oregonin concentration in red alder leaves on tent caterpillar feeding is a novel finding. / Graduate / 2020-04-18

Knowledge of ecological characteristics of trees, sites and tree growth on different sites is fundamental for silvicultural decision-making and planning. With the biogeoclimatic ecosystem classification in place, silvicultural management in British Columbia has been given an ecological foundation; however, relationships between growth and site have not yet been fully investigated. The purpose of this study was to determine how height growth of Douglas-fir within the drier portion of the CWH zone varies with site. We adopted site index (m @ 50 yr bh) as a species-specific measure of forest productivity, recognizing that it indicates height growth performance at a selected point in time. If forest productivity is correlated with ecological measures of site quality, what site factors should be used to quantify the relationships? Because of compensating effects, the numerous site factors can be reduced to four primary (synoptic) factors that directly affect plant establishment and growth: climate (light and temperature), soil moisture, soil nutrients, and soil aeration (not used in this study).

Orientador: Marcelo Carvalho Minhoto Teixeira Filho / Resumo: A produção de alimento face a demanda mundial é um desafio para este século, devendo-se, obrigatoriamente, destinar atenção ao ganho de eficiência produtiva, incorporada as tecnologias disponíveis. Dentre as hortaliças folhosas, a alface se destaca em toda culinária global. A produção atual da alface tem passado por grandes avanços, atribuídos especialmente à técnica de produção hidropônica, contudo, ainda é necessita melhorias na adaptabilidade da tecnologia hidropônica às condições climáticas das diversas regiões e às diferentes necessidades da gama de cultivares presentes no mercado. Neste cenário, a proposição desta pesquisa surge em resposta à demanda de informações pelo setor produtivo, cumprindo seu papel na integração entre ensino, pesquisa e extensão rural, de maneira a contribuir modestamente com o setor produtivo. Para isso, foram realizados três experimentos isolados em sistema hidropônico NFT (Técnica de Fluxo Laminar de Nutrientes), com o objetivo de avaliar a nutrição e a produção econômica de alface americana em função da vazão, periodicidade de exposição e condutividade elétrica da solução nutritiva, respectivamente. O delineamento experimental foi em blocos casualisados, com cinco repetições e cada tratamento foi composto por 15 plantas. No experimento 1, os tratamentos utilizados constaram da aplicação de solução nutritiva nas vazões de 0,5; 1; 2 e 4 litros por minuto em cada canal de cultivo. No experimento 2, os tratamentos foram quatro combinações de int... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

Submitted by CLEITON DALASTRA null (sauems@gmail.com) on 2017-10-29T21:52:25Z No. of bitstreams: 1 Cleiton Dalastra_29_10_2017_ PG Agronomia.pdf: 4821380 bytes, checksum: fad04c9fa5853e9c381aeb892db6a996 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-11-09T15:35:04Z (GMT) No. of bitstreams: 1 dalastra_c_dr_ilha.pdf: 4821380 bytes, checksum: fad04c9fa5853e9c381aeb892db6a996 (MD5) / Made available in DSpace on 2017-11-09T15:35:04Z (GMT). No. of bitstreams: 1 dalastra_c_dr_ilha.pdf: 4821380 bytes, checksum: fad04c9fa5853e9c381aeb892db6a996 (MD5) Previous issue date: 2017-08-31 / A produção de alimento face a demanda mundial é um desafio para este século, devendo-se, obrigatoriamente, destinar atenção ao ganho de eficiência produtiva, incorporada as tecnologias disponíveis. Dentre as hortaliças folhosas, a alface se destaca em toda culinária global. A produção atual da alface tem passado por grandes avanços, atribuídos especialmente à técnica de produção hidropônica, contudo, ainda é necessita melhorias na adaptabilidade da tecnologia hidropônica às condições climáticas das diversas regiões e às diferentes necessidades da gama de cultivares presentes no mercado. Neste cenário, a proposição desta pesquisa surge em resposta à demanda de informações pelo setor produtivo, cumprindo seu papel na integração entre ensino, pesquisa e extensão rural, de maneira a contribuir modestamente com o setor produtivo. Para isso, foram realizados três experimentos isolados em sistema hidropônico NFT (Técnica de Fluxo Laminar de Nutrientes), com o objetivo de avaliar a nutrição e a produção econômica de alface americana em função da vazão, periodicidade de exposição e condutividade elétrica da solução nutritiva, respectivamente. O delineamento experimental foi em blocos casualisados, com cinco repetições e cada tratamento foi composto por 15 plantas. No experimento 1, os tratamentos utilizados constaram da aplicação de solução nutritiva nas vazões de 0,5; 1; 2 e 4 litros por minuto em cada canal de cultivo. No experimento 2, os tratamentos foram quatro combinações de intermitência de exposição da solução nutritiva em intervalos de bombeamento / intervalo de ausência de bombeamento em minutos: 15/60; 15/30; 15/15 e FI (Fluxo initermitente). No experimento 3, os tratamentos foram a manutenção diária da solução nutritiva em quatro valores de condutividade elétrica, de 0,8; 1,3; 1,8 e 2,3 dS m-1, em função da concentração de nutrientes. A maior produção e lucratividade de alface americana foi obtida com a vazão da solução nutritiva de 1 L/min, devido ao maior acúmulo de nutrientes na parte aérea e eficiência de sua utilização; também houve a maior produção e lucratividade de alface americana obtida com fluxo contínuo da solução nutritiva (FI), devido ao maior acúmulo de nutrientes na parte aérea e raízes, maior assimilação de nitrato e eficiência de utilização de nutrientes; economicamente, a condução em intervalo 15/30 minutos acarreta em prejuízo financeiro; o acompanhamento dos tratamentos de condutividade elétrica no decorrer do ciclo da alface aponta para produção superior com condutividade elétrica recomendada por fase de cultivo, sendo: 0,8 dS m-1 até os 10 dias após o transplantio (DAT); 1,30 dS m-1 dos 10 aos 17 DAT; 1,80 dS m-1 dos 17 aos 24 DAT e 1,30 dS m-1 dos 24 aos 31 DAT. / The food production to meet global demand is a challenge for this century, should be compulsorily intended attention to productive efficiency gains incorporated the available technologies. Among the leafy vegetables, the lettuce stands out in all global cuisine. The current production of lettuce has undergone great advances, especially attributed to the hydroponic production technique. However, it is still necessary to improve the adaptability of hydroponic technology to the climatic conditions of the different regions and to the different needs of the wide range of cultivars present in the market. In this scenario, the proposition of this research arises in response to the demand for information by the productive sector, fulfilling its role in the integration between teaching, research and rural extension, in order to contribute modestly with the productive sector. For that, three experiments were carried out in a NFT hydroponic system, with the objective of evaluating the nutrition and economic production of American lettuce as a function of flow rate, periodicity of exposure and electrical conductivity of the nutrient solution, respectively. The experimental design was in randomized blocks, with five replicates and each treatment consisted of 15 plants. In the experiment 1, the treatments used consisted of the application of nutrient solution at the flow rates of 0.5; 1; 2 and 4 liters per minute in each culture channel. In experiment 2, the treatments were four combinations of intermittent exposure of the nutrient solution at pumping intervals / no pumping interval in minutes: 15/60; 15/30; 15/15 and 15/0. In experiment 3, the treatments were daily maintenance of the nutrient solution in four values of electrical conductivity, of 0.8; 1,3; 1.8 and 2.3 dS m-1, depending on the concentration of nutrients. The conclusions were: The highest production and profitability of American lettuce was obtained with the flow of the nutrient solution of 1 L/min, due to the greater accumulation of nutrients in the aerial part and efficiency of use of these; The highest production and profitability of American lettuce was with cycles of 15/0 minutes, that is, with continuous flow of the nutrient solution due to the greater accumulation of nutrients in the aerial part and efficiency of use of these; Economically, driving in interval 15/30 minutes under the conditions studied, does not supply the cost of production and entails financial loss; The treatments were monitored during the lettuce cycle, indicating a higher yield than the one obtained with the recommended electrical conductivity at each cultivation stage: 0.8 dS m-1 until 10 days after transplanting (DAT) of lettuce; 1.30 dS m-1 from 10 to 17 DAT; 1.80 dS m-1 from 17 to 24 DAT and 1.30 dS m-1 from 24 to 31 DAT.