CAN LINEAR PROGRAMMING ASSIST METAHEURISTICS IN FOREST PRODUCTION PLANNING PROBLEM?

The planning of forest production requires the adoption of mathematical models to optimize the utilization of available resources. Hence, studies involving the improvement of decision-making processes must be performed. Herein, we evaluate an alternative method for improving the performance of metaheuristics when they are applied for identifying solutions to problems in forest production planning. The inclusion of a solution obtained by rounding the optimal solution of linear programming to a relaxed problem is investigated. Such a solution is included in the initial population of the clonal selection algorithm, genetic algorithm, simulated annealing, and variable neighborhood search metaheuristics when it is used to generate harvest and planting plans in an area measuring 4,210 ha comprising 120 management units with ages varying between 1 and 6 years. The same algorithms are executed without including the solutions mentioned in the initial population. Results show that the performance of the clonal selection algorithm, genetic algorithm, and variable neighborhood search algorithms improved significantly. Positive effects on the performance of the simulated annealing metaheuristic are not indicated. Hence, it is concluded that rounding off the solution to a relaxed problem is a good alternative for generating an initial solution for metaheuristics

EFFECT OF SPACING ON INITIAL GROWTH AND PRODUCTION OF EUCALYPTUS IN A SYSTEMIC “FAN-SHAPED” DESIGN

Considering the importance of optimizing forest production, plant spacing is one of the most relevant silvicultural practices, as it holds ecological, silvicultural, and economic implications to the final product. Therefore, this study set out to assess the influence of spacing on the initial growth and production variables of hybrid clones of Eucalyptus urophylla S. T. Blake x Eucalyptus grandis W. Hill ex Maiden planted in a Nelder (fan-shaped) design. Plant densities ranged from 0.50 m² to 41.25 m² in area-per-plant. Variables such as total height, diameter, and volume were observed at 16, 24, and 36 months. A descriptive statistical analysis, Pearson’s correlation coefficient, and cluster analysis of averages were used to evaluate the effect of spacing on the variables in question. Different spacings were found to exert significant influences on growth in height, diameter, and volume.

Índices de competição na avaliação do crescimento arbóreo em Floresta Estacional Semidecidual

A maioria dos estudos que analisa o comportamento da competição arbórea é voltada para plantios homogêneos e equiâneos. Nota-se, portanto, uma carência de informações deste tipo em florestas naturais de elevada biodiversidade. Objetivou-se com este trabalho avaliar a competição em um fragmento de Floresta Estacional Semidecidual, por grupo ecológico, grupos demandantes e não demandantes de luz para todas as espécies amostradas no fragmento. Foram empregados índices de competição independentes da distância e semidependentes da distância. O índice BAL (basal area in larger trees), sem raio de influência, obteve o melhor desempenho para analisar como a competição afeta o crescimento dos indivíduos no fragmento estudado. Concluiu-se que avaliar a competição por grupo ecológico é mais eficaz, e os resultados confirmam que a competição florestal não pode ser determinada apenas pela aplicação de um raio fixo de influência dos vizinhos em relação à árvore-objeto.Most of the studies that analyze the behavior of tree competition approach even-aged plantations. Therefore, it is possible to notice a lack of this kind of information regarding natural forests with high biodiversity. The objective of this study was to evaluate the competition in a fragment of Semi-Deciduous Seasonal Forest, according to the ecologic group, light depending and non-depending groups for all species sampled in the fragment. The Distance Independent Competition Index and Semi-Distance Independent Competition Index were applied in this study. The basal area in larger trees index, without the radius of influence, was the most efficient to analyze how the competition affects the growth of the specimens in the studied fragment. It was stated that evaluating the competition per ecologic group is more efficient. The results confirm that the forest competition cannot be determined by considering only a fixed radius of influence that embraces the neighbors and the subject tree

PHYSIOLOGICAL AND BIOCHEMICAL ALTERATIONS ON THE STORAGE OF Cedrela fissilis VELLOZO SEEDS

 In order to ensure the ex-situ conservation of a species, knowing the behavior of the seed during storage is necessary, as it is influenced by several factors inherent to the seed and by characteristics of the environment, such as temperature and relative humidity. This study aimed to evaluate the physiological and biochemical alterations on Cedrela fissilis (pink cedar) seeds during storage under different environmental conditions. Seeds were stored at 20ºC in desiccators containing salts that established the relative humidity of 34%, 55%, 75%, and 93%. Analysis were performed on fresh seeds (without storage - time zero), which were used as control, and every two months through a period of eight months of storage. At each assessment, the following aspects were quantified: water content; lipid peroxidation; and the activities of catalase and glucose-6-phosphate dehydrogenase. Germination and electrical conductivity tests were analysed. Seed vigor decreased on humidity at 20 °C. It correlated mainly with decrease of glucose-6-phosphate dehydrogenase activity and increase of lipid peroxidation.Keywords: Pink cedar; germination; vigor; enzymes, lipids. ResumoAlterações fisiológicas e bioquímicas durante o armazenamento de sementes de Cedrela fissilis Vellozo. Para garantir a conservação ex-situ de uma espécie, é necessário conhecer o comportamento das sementes durante o armazenamento, visto que este é influenciado por vários fatores inerentes à semente e às características do ambiente, tais como temperatura e umidade relativa. Este estudo teve como objetivo avaliar as alterações fisiológicas e bioquímicas em sementes de Cedrela fissilis (cedro rosa) durante o armazenamento sob diferentes condições ambientais. As sementes foram armazenadas a 20ºC em dessecadores contendo sais que estabeleceram as umidades relativas do ar de 34%, 55%, 75% e 93%. As análises foram realizadas em sementes frescas (sem armazenamento - tempo zero), usadas como controle, e a cada dois meses durante um período de oito meses de armazenamento. Em cada avaliação, foram quantificados: teor de água; peroxidação de lípidos; e as atividades das enzimas catalase e glicose-6-fosfato desidrogenase. Também, foi analisada a germinação e condutividade elétrica das sementes. O vigor das sementes diminuiu em todas as umidades a 20 °C, correlacionando-se, principalmente, com a diminuição na atividade de glicose-6-fosfato desidrogenase e com o aumento na peroxidação lipídica.Palavras-chave: Cedro rosa; germinação; vigor; enzimas, lipídios

Taper modeling and economic evaluation of multi-products obtained from wood of short-rotation eucalyptus stands

This study aims at defining the appropriate model to describe the stem tapering of trees of Eucalyptus urophylla x Eucalyptus grandis hybrid, and at evaluating the economic viability of obtaining wood multi-products at different interest rates. The volume of 60 sample trees were determined, and stem tapering was described according to the models proposed by Demaerschalk, Prodan, Kozak, and Ormerod. The best model was used to convert the trees into assortments so that the wood could be optimized for the product that offers the maximum economic return with the minimum possible waste. Then, an economic viability analysis was performed for wood multi-product production, using the Net Present Value (NPV) and applying interest rates of 8 to 12% p.a. The Demaerschalk model is the most appropriate one for the study of stem tapering and assortment determination in short-rotation stands of the Eucalyptus urophylla x Eucalyptus grandis hybrid intended for multi-products in the region covered by the study. The allocation of wood for multi-products is a viable option for stands of the Eucalyptus urophylla x Eucalyptus grandis hybrid, according to the interest rates applied in the present study

Growth and yield of commercial plantations of eucalyptus estimated by two categories of models

O objetivo deste trabalho foi avaliar e comparar duas categorias de modelos de crescimento e produção em plantios comerciais de eucalipto. Para isso, foram ajustados um modelo de crescimento e produção para povoamento e outro para árvore individual, por meio de equações simultâneas e redes neurais artificiais, respectivamente. O volume de madeira por área foi estimado em diferentes idades e classes de produtividade. Foram avaliados dados de 63 parcelas permanentes de plantios clonais, não desbastados, do híbrido Eucalyptus grandis x E. urophylla, com os dados de 33 parcelas utilizados para o ajuste do modelo e o treinamento das redes neurais, e os das 30 parcelas restantes, para a validação dos modelos. As duas categorias de modelos ajustaram-se bem aos dados observados. No entanto, na validação dos modelos com dados independentes, o volume de madeira por área foi mais bem estimado com o modelo para árvore individual.The objective of this work was to evaluate and compare two categories of growth and yield models of commercial plantations of eucalyptus. For that, a whole stand model, and an individual tree growth model were adjusted through simultaneous equations and artificial neural networks, respectively. Wood volume per area was estimated for tree different ages and productivity classes. Data of 63 permanent plots of unthinned clonal hybrid Eucalyptus grandis x E. urophylla were evaluated, from which those referring to 33 plots were used for model fitting and neural network training, and those referring to the other 30 plots were used for model validation. The two categories of models adjusted well to the observed data. However, for the validation of the models with independent data, the wood volume per area was better estimated with the individual tree growth model

EVALUATION OF OPTIMAL ECOLOGICAL TOURISM ROUTES OBTAINED VIA GOOGLE EARTH SOFTWARE IN AN ENVIRONMENTAL PROTECTION AREA

Ecological tourism stands out as an economic activity that can be reconciled with nature conservation. Such activities have been carried out in several conservation units in Brazil. However, for satisfactory implementation, it is necessary to effectively plan the activities to be conducted, places to be visited, and paths to reach those places. In this context, we aimed to assess whether Google Earth software can assist in the expansion of the plan to use these areas for ecotourism, especially the routes that may be taken by tourists within the conservation unit. For this purpose, tourist interest sites were defined in the State Environmental Protection Area of Rio Pandeiros in the northern region of the state of Minas Gerais. The shortest routes between the pairs of locations obtained using Google Earth and QGIS software were evaluated. Additionally, it was necessary to perform vectorization and classification of all roads in the area. The lengths of the paths obtained were compared using a method identity test. The results showed that for most routes, Google Earth showed longer paths than QGIS. It can be concluded that for the purpose of ecotourism, precise planning should consider the vectorization of roads in areas with many rural roads

Análise fitossociológica e do estoque de carbono no estrato arbóreo de um fragmento de Floresta Estacional Semidecidual

http://dx.doi.org/10.5902/1980509814569The studies directed to quantify the carbon fixed stocks by natural forests are in ample evidence, as well as discussion about the effectiveness of the recovery of degraded areas as a strategy to reduce atmospheric CO2 levels. In this sense, this study had two purposes: i) quantify the carbon stocks present in the shoot biomass of a tropical semi-deciduous Montana fragment, which belongs to the Atlantic Forest biome in Minas Gerais state and; ii) incorporate the variable carbon stock in the horizontal phytosociological analysis structure and compare the results to those obtained by the standard methodology without using the variable in the calculation of the species importance value. The results indicate that the carbon stock equals to the fragments found at the intermediate succession stage, and that the carbon variable use greatly influences the species importance value. This methodology serves as a support for the selection of species which present the greatest potential to sequester carbon and may support programs for the remnant restoration of the Atlantic Forest biome.http://dx.doi.org/10.5902/1980509814569Os estudos direcionados para quantificação de estoques de carbono fixado por florestas naturais estão em ampla evidência, assim como a discussão sobre a efetividade da recuperação de áreas degradadas como estratégia para reduzir os níveis de CO2 atmosférico. Neste sentido, tiveram-se dois objetivos neste artigo: i) quantificar o estoque de carbono presente na biomassa da parte aérea de um fragmento de Floresta Estacional Semidecidual Montana, pertencente ao Bioma Mata Atlântica no estado de Minas Gerais e ii) incorporar a variável estoque de carbono na estrutura horizontal da análise fitossociológica e comparar os resultados aos obtidos pela metodologia padrão, sem utilizar essa variável no cálculo do valor de importâncias das espécies. Os resultados indicam que o estoque de carbono encontrado equivale a fragmentos em estágio médio de sucessão, e que a utilização da variável carbono influencia sobremaneira o valor de importância das espécies. Esta metodologia serve como suporte para a escolha de espécies arbóreas de maior potencial para sequestrar carbono e pode subsidiar programas de restauração de remanescentes florestais do Bioma de Mata Atlântica

OPTIMIZATION AND ECONOMIC ANALYSIS OF MULTIPRODUCTS OBTAINED FROM WOOD OF EUCALYPTUS STANDS UNDER DIFFERENT PRODUCTIVE CAPACITY CLASSES AND ROTATION AGES

The present study aimed to analyze the yield and economic viability of the destination, for lumber and energy, of the wood from non-thinned stands of the hybrid Eucalyptus urophylla x Eucalyptus grandis under different productive capacity class and whose production was projected by individual tree growth model to different ages. The simulation of the growth of individual trees was performed by applying the height and diameter growth, and mortality sub-models for three productive capacity classes: high, medium and low. The Kozak model was adjusted to study the stem taper and, in addition, used to optimize patterns for sawing logs and to produce lumber. The economic viability of the projects was evaluated by Net Present Value, Equivalent Periodic Benefit and risk analysis using the Monte Carlo method. It was observed that in areas with less productive capacity the volume of wood destined for energy was greater than 80% and, in areas with greater productive capacity the volume of lumber was greater than 26%. Economic indicators showed that the lumber production was viable at any of the studied rotation age. The risk analysis using the Monte Carlo method did not indicate the possibility of the project being unfeasible under the conditions analyzed. The quantity of different types of products obtained and the wood yield depends on the productive capacity class and age of the stand. The destination of the wood for multiproducts is the most viable option, regardless of the productive capacity class