A critical survey of optimization methods in industrial forest plantations management

The application of optimization methods to forest management has given rise to a successful line of investigation in recent decades. However, there have been few publications associated with the application of these techniques to the management of industrial forest plantations (those with short or medium rotations, always less than 50 years), which consider the important role played by these forest systems in the supply of diverse goods and services. This study presents an overview of this literature which, by analyzing 67 articles published in journals contained in the ISI Web of Science, highlight, among other aspects, the techniques employed, their evolution, their planning type (strategic, tactical or operational), the functional objectives and constraints considered, or the type of software deployed in these studies. The results show how Model I has been the one most frequently used in these studies, and how the spatial component is increasing in importance. However, classic optimization methods, such as mixed integer programming, have been those most commonly resorted to, although the employment of multi-criteria techniques such as goal programming and analytic hierarchical process have strongly emerged in recent years.

Optimal selective logging regime and log landing location models: a case study in the Amazon forest / Regime de corte seletivo ótimo em modelos de locação de pátios de estocagem de madeira: um estudo de caso na floresta amazônica

Reduced-impact logging is a well known practice applied in most sustainable forest management plans in the Amazon. Nevertheless, there are still ways to improve the operational planning process. Therefore, the aim of this study was to create an integer linear programming (ILP) to fill in the knowledge gaps in the decision support system of reduced impact logging explorations. The minimization of harvest tree distance to wood log landing was assessed. Forest structure aspects, income and wood production were set in the model, as well as the adjacency constraints. Data are from a dense ombrophylous forest in the western Brazilian Amazon. We applied the phytosociological analysis and BDq method to define the selective logging criteria. Then, ILP models were formulated to allow the application of the constraints. Finally, 32 scenarios (unbalanced forest, UF, and balanced forest, BF) were generated and compared with real executed plans (RE). Robust results were achieved and the expected finding of each scenario was met. The feasibility to integrate ILP models in uneven-aged forest management projects was endorsed. Consequently, the UF and BF scenarios tested were efficient and concise, introducing new advances for forest management plans in the Amazon. The proposed models have a high potential to improve the selective logging activities in the Amazon forest.(AU)

A exploração de impacto reduzido é uma prática bem conhecida e aplicada na maioria dos planos de manejo florestal sustentável na Amazônia. Todavia, ainda há a possibilidade de melhoria do processo de planejamento da operação. Diante da falta de métodos auxiliares à tomada de decisão, o objetivo do trabalho foi desenvolver modelos de programação linear inteira (PLI) para suprir esta demanda. Considerou-se a minimização da distância entre as árvores exploradas e os pátios de estocagem de madeira. Aspectos estruturais, econômicos e produtivos foram incorporados ao modelo, bem como restrições de adjacência. Os dados derivam de uma floresta ombrófila densa na Amazônia Ocidental. Previamente, utilizou-se uma análise fitossociológica e o método BDq como critério de remoção. Posteriormente, modelos de PLI foram formulados para exemplificar as aplicações. Finalmente, 32 cenários (para floresta desbalaceada, UF, e floresta balanceada, BF) foram gerados e comparados com o plano executado no campo (RE). Resultados robustos foram obtidos e atenderam às expectativas de cada cenário. A viabilidade da integração dos modelos de PLI em projetos de manejo de florestas ineqüiâneas foi testado. Os cenários UF e BF testados foram eficientes e concisos, confirmando seu potencial para aumentar a eficiência de planos de exploração madeireira e manejo florestal na Amazônia.(AU)

A critical survey of optimization methods in industrial forest plantations management

The application of optimization methods to forest management has given rise to a successful line of investigation in recent decades. However, there have been few publications associated with the application of these techniques to the management of industrial forest plantations (those with short or medium rotations, always less than 50 years), which consider the important role played by these forest systems in the supply of diverse goods and services. This study presents an overview of this literature which, by analyzing 67 articles published in journals contained in the ISI Web of Science, highlight, among other aspects, the techniques employed, their evolution, their planning type (strategic, tactical or operational), the functional objectives and constraints considered, or the type of software deployed in these studies. The results show how Model I has been the one most frequently used in these studies, and how the spatial component is increasing in importance. However, classic optimization methods, such as mixed integer programming, have been those most commonly resorted to, although the employment of multi-criteria techniques such as goal programming and analytic hierarchical process have strongly emerged in recent years.(AU)

Comparison between linear and nonlinear systems of feed formulation for broilers

Two experiments were simultaneously carried out to compare feed formulation models: a linear model for minimum cost with a nonlinear model for maximum profitability for one-to 42-d-old broilers. One-d-old male or female Cobb 500 broilers (n=2368) were allocated to one of the two trials according to sex. The experiments were performed simultaneously in an experimental poultry farm. Two housing densities were used: high density (HDH), with 14 birds/m2, and low density (LDH), with 10 birds/m2. The following treatments were evaluated: linear feed formulation and LDH (LF10); nonlinear formulation and LDH (NF10); linear formulation and HDH (LF14); and nonlinear formulation and HDH (NF14). A completely randomized design with four treatments of eight replicates each was applied. Performance and cost per kg of poultry were evaluated. Both formulation systems promoted similar broiler performance. However, the high-density feed using linear formulation reduced body weight in 42-d-old males, but not when nonlinear formulation was used. The NF10 treatment yielded the worst feed conversion ratio (p 0.05) and the lowest cost/kg broiler (p 0.05) for both sexes. The results demonstrate that the nutritional program that yields the best performance is not always the most economical one.(AU)

Comparison between linear and nonlinear systems of feed formulation for broilers

Two experiments were simultaneously carried out to compare feed formulation models: a linear model for minimum cost with a nonlinear model for maximum profitability for one-to 42-d-old broilers. One-d-old male or female Cobb 500 broilers (n=2368) were allocated to one of the two trials according to sex. The experiments were performed simultaneously in an experimental poultry farm. Two housing densities were used: high density (HDH), with 14 birds/m2, and low density (LDH), with 10 birds/m2. The following treatments were evaluated: linear feed formulation and LDH (LF10); nonlinear formulation and LDH (NF10); linear formulation and HDH (LF14); and nonlinear formulation and HDH (NF14). A completely randomized design with four treatments of eight replicates each was applied. Performance and cost per kg of poultry were evaluated. Both formulation systems promoted similar broiler performance. However, the high-density feed using linear formulation reduced body weight in 42-d-old males, but not when nonlinear formulation was used. The NF10 treatment yielded the worst feed conversion ratio (p 0.05) and the lowest cost/kg broiler (p 0.05) for both sexes. The results demonstrate that the nutritional program that yields the best performance is not always the most economical one.

Correlações genéticas e fenotípicas entre características de tipo e produção de leite em bovinos da raça Holandesa / Genetic and phenotypic correlations between type traits and milk production in Holstein cattle

Correlações genéticas e fenotípicas entre 21 características lineares de tipo e produção de leite em até 305 dias de lactação foram estimadas pela máxima verossimilhança restrita sob modelo animal, a partir de dados da Associação de Criadores de Gado Holandês de Minas Gerais. Nas análises das características lineares, os efeitos fixos utilizados no modelo incluíram estádio da lactação, idade do animal, grupo contemporâneo de rebanho, ano e estação de classificação, e o efeito aleatório do pai da vaca. As características lineares que apresentaram maiores correlações genéticas com produção de leite foram largura do úbere posterior (0,60) e largura de garupa (0,37), indicando não haver antagonismo genético entre a seleção para essas características e a produção de leite. As correlações fenotípicas entre características lineares de tipo e produção de leite foram, em geral, menores do que as correlações genéticas correspondentes. As correlações fenotípicas entre as características lineares apresentaram-se altas dentro das seções de conformação/capacidade e de sistema mamário. Correlações genéticas entre algumas características lineares foram altas, possibilitando a exclusão de algumas delas do programa de classificação linear adotado para a raça Holandesa no Brasil.(AU)

Genetic and phenotypic correlations between 21 linear type traits and 305-day milk production were estimated by restrict maximum likelihood methodology, in a multiple-trait animal model, using data from Associação de Criadores de Gado Holandês de Minas Gerais. The highest genetic correlations between milk production and rear udder width (.60), and rump width (.37), indicated no genetic antagonism between selection for these type traits and gains for milk production. In general, phenotypic correlations were lower than genetic correlations between milk production and linear type traits. Phenotypic correlations between linear traits were greater for conformation traits and udder traits. Some type traits presented high genetic correlations between them, suggesting that some of them could be excluded from the genetic programs for linear type traits adopted by Holstein Breed Association in Brazil.(AU)