No abstract

No abstract

No abstract

Brazilian forest-based industries are supported by more than 5.5 million hectares of Eucalyptus growing under different climatic conditions with different degrees of favourability for rust Puccinia psidii, including both traditional and expanding areas, where such disease is of major concern for the industry, foresters and scientists. The main objective of this study was to define favourable climatic zones for Eucalyptus rust in Brazil with the following aims: (i) to develop a spatial method for estimating the mean night-time temperature (T ng ); (ii) to assess and validate a Eucalyptus rust model;and (iii) to map Eucalyptus rust favourability zones in Brazil based on the proposed model. A straightforward method, based only on latitude, day of the year, maximum and minimum air temperatures, was developed to estimate T ng , which is a key variable for a proper application of Ruiz rust model. Based on 37 field experiments with natural rust occurrence, it was observed that climatic conditions are determining factors for disease severity. Significant correlations between disease severity observed in the field and climatic conditions were found: a negative correlation with temperature (r = .50, p < .01) and a positive correlation with relative humidity (r = .89, p < .0001). A significant correlation (r = .81, p < .0001) between the normalized infection index, produced from Ruiz model, and the average rust score was also observed. Once the model was validated under field conditions, it was applied using historical average data of air temperature and leaf wetness duration to obtain monthly Eucalyptus rust favourability maps for the whole country. These final maps show that favourable climatic zones for Eucalyptus rust are extremely dynamic, with high temporal and spatial variability in Brazil and that climatic conditions should be considered for expansion of Eucalyptus to new areas, in breeding programmes, and for defining the most suitable seasons for forest establishment in each climate of the country. These results provide forestry managers with practical tools to reduce uncertainty about the expected severity of Eucalyptus rust in Brazil.

Drought stress promotes biochemical and physiological alterations in plant metabolism that limit growth and yield. This study investigated the accumulation of caminobutyric acid (GABA) in plant tissue, the stomatal conductance (gs) and changes in leaf anatomy in Eucalyptus following drought stress situation. In this study, eight Eucalyptus clones were evaluated under normal water supply (control) and drought stress conditions (stress). For the control treatment, plants were irrigated every day with an automated system until the soil was saturated, and for the stress treatment, drought stress was imposed by non-irrigation of plants, and pots were covered using plastic sheeting to avoid rainfall and humidity. This study has shown that: (1) all clones decreased gs with increasing vapor pressure deficit (D) in both treatments. All plastics and drought-tolerant clones (except GG) presented lower stomatal sensitivity to D under stress conditions than drought-sensitive clones; (2) GABA concentrations increased fast after drought stress, but we could not find correlation with these changes and resistance to water stress; and (3) all clones increased the number of stomata and reduced leaf thickness after water stress. The finding is that GABA is a fast stresssignaling molecule in Eucalyptus, but the response of gs to D is a best physiological variable to differentiate droughttolerant and drought-sensitive Eucalyptus clones.

Caracterização da sazonalidade do crescimento do lenho, da copa e da eficiência do uso da luz em clones do gênero Eucalyptus AGRADECIMENTOSAos meus tios Gilberto e Magali, por terem me acolhido em sua casa como um filho.Sem a intervenção de vocês, talvez nem os caminhos que me levaram à universidade teria alcançado.A toda minha família, em especial à tia Ângela, pelas conversas e devaneios sobre a vida e sobre nossa passagem, meu exemplo de sabedoria.À minha noiva, Larissa Bortoletto Miyata. A quem escolhi amar e compartilhar o resto da vida. Obrigado por ser minha companheira em todos os momentos.Ao professor José Luiz Stape, pelas oportunidades a mim oferecidas desde os primeiros anos da graduação. Exemplo de paixão e dedicação incondicionais às ciências florestais, uma pessoa incrível de quem tive a felicidade de ser orientado.

Our study aims to provide a comprehensive overview of forestry programs in Brazil, including a comparative analysis with other countries while considering geographical factors. Over the past 25 years, the number of forestry programs in Brazil has increased from 43 to 75, leading to a rise in the annual number of graduates from 850 to 1500. Nevertheless, our findings reveal that only 60% of the available vacancies at universities are filled. On average, each institution enrolls 169 students (from 40 to 360 students per program). We also observed that, on average, each program employs 13 professors with a background in forest engineering (from 4 to 33). The results show that, among the professors from the ten oldest programs in the country, 78% had no prior professional experience outside academia, and 48% remained affiliated with the same university where they completed their undergraduate or graduate studies. There is a concerning and significant decline in the number of applicants for forestry programs, representing a strategic risk for the country. We identified a direct relationship between the number of programs, the population size, and the country’s total forest cover area when comparing Brazil with 12 other countries.