Research highlights: We used Dijkstra Algorithm (DA) to define optimal allocation of yards in order to minimize total skid-trail’s distance in the Amazon Forest. DA minimized trails’ distances and associated transportation costs, leading to an even smaller value when the current planning was disregarded and suggesting the reduction of deleterious environmental externalities. Background and objectives: We sought to answer if it is possible to optimize distances and intrinsic costs in the management of Amazonian forests using DA. The objective was to minimize skid trails distances by best allocating yards using DA and to compare four scenarios of forest harvest planning in the Brazilian Amazon. Materials and methods: Tree census data from Gênesis-Salém Farm, state of Pará, Brazil, were used. The yards and roads located by Grupo Arboris (scenario 1) were compared to three alternative scenarios in terms of total skid distance, trails and road densities, and skidding costs for three successive harvests, seeking to minimize total skid-trails’ distance. Alternative scenarios were to keep the number of yards within work units (WU) and place them in the edge of existing roads (scenario 2); keep the number of yards within each WU (scenario 3); and place 23 yards, disregarding the current planning (scenario 4). Results: Total skid-trail’s distance, number of trees above optimal extraction distance and densities of skid trails and roads were smaller in scenarios 2, 3, and 4, compared to the current yard allocation (scenario 1). Scenario 4, with fewer restrictions, reduced skid-trails’ distances by 23%. Harvest costs decreased from scenario 1 to 4 in all three harvest cycles. Conclusions: DA allowed optimized distribution of yards and skid trails and generated efficient results for harvest planning. This reinforces the importance of optimized planning, which establishes satisfactory results in the effort to reduce costs and environmental impact keeping high efficiency.
The Amazon and the Atlantic Forest are Brazilian biomes that suffered an intense land use and land cover change, marked by the loss of native forest and expansion of agriculture and livestock. This article aims to analyze land use and land cover change history and to propose a sustainable alternative for agriculture and livestock as an opportunity for rural development in these biomes. The statistics of the platform from the Annual Mapping Project for Land Use and Land Cover in Brazil (MapBiomas) were used in an annual historical series from 1985 to 2020. The analysis of land use and land cover changes indicates that the Amazon native forest was reduced by 44.53 million hectares (Mha), while pasture, agriculture and planted forest increased by 38.10, 6.06 and 0.26 Mha, respectively, over the 35 years (1985 to 2020). In the Atlantic Forest, for the same period, forest and pasture reduced by 0.99 and 11.53 Mha, respectively, while agriculture expanded by 8.06 Mha and planted forest by 2.99 Mha. Sustainable land use strategies, such as the Integration Crop-Livestock-Forest (ICLF), can support the increase in agricultural production while recovering and preserving the environment. Policies and programs should consider regional particularities and barriers for more significant adoption of this strategy.
<p>A mensuração da altura de forma acurada é extremamente importante na ciência florestal, pois, influencia diretamente na predição do volume individual das árvores, bem como na volumetria de um povoamento e em todo o sistema de prognose. Por ser feita de forma indireta, é sujeita a erros, que devem ser minimizados. Assim, deve se usar o hipsômetro que proporcione menor erro, além de um operador treinado para o procedimento. Nesse estudo objetivou-se testar a acurácia do hipsômetro e operador em relação a árvores de <em>Eucalyptus urograndis</em> de tamanhos diferentes. Os dados foram coletados em um plantio de <em>Eucalyptus urograndis</em> em Turmalina, MG. Três árvores foram selecionadas, classificadas em pequena (12,1 m), média (18,9 m) e grande (25,2 m). Seis operadores mediram cada uma das árvores usando 4 hipsômetros (Prancheta dendrométrica, Clinômetro digital, Suunto e Vertex) 5 vezes. Posteriormente, realizou-se o abate das árvores e a obtenção da altura real com uma trena. Para analisar os dados, foi feita uma análise de variância, teste de Tukey e teste T. Os resultados mostram que houveram diferenças entre os valores encontrados pelos observadores, o que salienta a necessidade de treinamento. Todos os instrumentos geraram valores confiáveis. Para árvores mais baixas, o Vertex foi o instrumento mais confiável e para árvores maiores o Clinômetro digital foi o instrumento mais indicado. </p><p align="center"><strong><em>Evaluation of hypsometers and operators in measuring tree heights in </em></strong><em>Eucalyptus urograndis<strong> with different sizes</strong></em></p><p><strong>Abstract</strong><strong>: </strong>The accurate mensuration of tree hight is very important in forest science because it influences directly the individual tree volume, stand volume prediction and all the prognosis system. Due to the fact it is made indirectly, errors can occur, and they should be minimized. Hence, one should use hypsometers, which lead to a minor error and a trained operator to do it. This study aims to test the accuracy of hypsometers and operator, regarding the size of the tree, classified as small (12,1 m), medium (18,9 m) and large (25,2 m). Data was of 3 trees from a <em>Eucalypus urograndis</em> plantation in Turmalina, MG. Six operators measured the trees using 4 hypsometers (Dendrometric clipboard, Digital clinometer, Suunto and Vertex) 5 times each. The trees were felled and the real height of the trees were taken using a measure tape. Data was analysed by Analysis of variance, Tukey test and T test. The results showed difference between values found by different operators and highlight the need for training. All hypsometers were accurate. Measuring smaller trees, Vertex was the best one and measuring the higher ones, Digital clinometer was the best.</p>
O uso de relações hipsométricas é essencial para empresas florestais, uma vez que a medição de altura de todas as árvores da parcela tornaria o inventário oneroso. Objetivou-se com este trabalho avaliar cinco modelos hipsométricos com cinco estratégias de ajuste, usando 5, 10, 15, 20 e 25 árvores. Os dados provêm de um povoamento de Eucalyptus urograndis em Turmalina, Minas Gerais. Foram estratificadas cinco classes diamétricas, sendo mensuradas 10 árvores por classe. A altura foi obtida com uso de um clinômetro eletrônico, e o DAP, com a utilização de uma suta. Posteriormente, as árvores foram abatidas e suas alturas reais foram obtidas com trena. Com os dados reais de altura e diâmetro, foi possível ajustar os modelos hipsométricos. A seleção do melhor modelo foi baseada nos seguintes critérios: coeficiente de determinação (R²), erro padrão residual (Syx), análise gráfica dos resíduos e raiz quadrada do erro médio (RMSE). Foram selecionados os melhores modelos dentro de cada estratégia. Ao analisar o gráfico de dispersão, foi possível perceber se houve tendenciosidade na estimativa, mostrando que existe uma normalidade e homogeneidade da variação entre os dados reais e estimados. Nas estratégias com 5, 10 e 15 árvores, o melhor modelo foi o Parabólico e, para 20 e 25 árvores foi o modelo de Prodan.Acuracy of hipsometric relations to different validations procedures for Eucalyptus urograndisAbstract: The use of hypsometric relationships is essential for forest companies, since a height measurement of all the trees in the plot would make the inventory onerous. The objective of this work was to evaluate five models with five adjustment strategies, using 5, 10, 15, 20 and 25 trees in the fitting. The data come from an Eucalyptus urograndis stand in Turmalina, Minas Gerais. Five diametric classes were stratified, and 10 trees per class were measured. The height was obtained with the use of an electronic physician and a DAP using a clinometer. Later, as trees were felled and their actual heights were obtained with a measuring tape. With the real data of height and diameter, it was possible to adjust hypsometric models. (R²), residual standard error (Syx), graphical residue analysis and mean square error root (RMSE). We selected the best models within each strategy. When analyzing the dispersion graph, it was possible to perceive that there was no tendency in the models, showing that there is a normality and homogeneity of the variation between the real and estimated data. In fitting the models with5, 10 and 15 trees, the best model for the Parabolic and for fitting using 20 and 25 trees, the best model was Prodan.
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