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.

Commercial height of the tree is a key variable for estimating the wood stock in tropical forests managed for timber production purposes. Most available measurement devices suffer limitations in this type of forest, promoting low precision measurements with high variation errors. The laser meter device appears as a viable alternative, as in addition to using trigonometric principles, it is not necessary that the device is close to the eyes of the meter to carry out the measurement. The device can be used to measure commercial height of trees on flat or sloping terrain, at different distances from the tree. However, there are no studies evaluating the precision of this device. The objective of this study was to determine the precision of the laser meter method for estimating the commercial height of trees, as compared to the actual measurement in a tropical forest in the Brazilian Amazon. Measurements were made on 300 trees with commercial height between 7 and 14 m. Actual commercial heights were measured with graduated ruler. Applied tests were paired t test, graphical analysis of residuals and calculations of bias statistics, mean absolute deviation, standard deviation of differences, and coefficient of determination (R²). Paired t test indicated that the mean of the heights measured by the laser meter is statistically equal to that of the graduated ruler. Measurements with laser meter did not show bias and had mean error of 0.0745. The standard deviation of the differences indicated dispersion of errors of 0.97, equal to that shown in the graduated rule. Laser meter presents an alternative method for estimating the commercial height of trees in tropical forest in the Brazilian Amazon. There was no tendency to underestimate or overestimate the commercial heights of trees. Use of the laser meter is potentially of use for measuring the commercial height of trees in tropical forests.

This article addresses a case study on the application of criteria for harvesting, aiming at restoration and profitability in a degraded tropical forest in the Amazon. The objective is to provide technical and economic information to promote a truly sustainable silvicultural management system in forests with this profile and turn them into a desirable financial asset for conservation and social development. In the forest census, 85.907 trees ha⁻¹ (100.8566 m³ ha⁻¹) were inventoried with diameter at breast height (dbh) ≥ 25 cm, belonging to 106 commercial species. When applying the harvest criteria, 19.923 trees ha⁻¹ (29.99 m³ ha⁻¹), referring to 53 species, were destined for harvest. Some trees were selected by more than one criterion, totalizing 17.985 trees ha⁻¹ by density, 1.831 trees ha⁻¹ by compromised health, 0.212 trees ha⁻¹ by maximum dbh, 18.933 trees ha⁻¹ by minimum dbh, 1.385 trees ha⁻¹ by tree stem (quality 3), and 0.080 trees ha⁻¹ by species conservation. In all scenarios, the application of criteria for harvesting proved to be profitable with excellent cost–benefit ratios. The selection of trees with a minimum cutting diameter of 25 cm in shorter cycles tends to allow the promotion of new commercial species. The set of actions presented has the potential to favor the maintenance of biodiversity and expansion of low-density populations, health and the potential increment of the forest productivity. In addition, it is more feasible for the supply of forest products in a shorter time than provided for in Brazilian regulations; however, they must respect the specificities of the species and also of the site.

Este trabalho trata de uma experiência inovadora em relação a critérios para colheita de árvores em floresta natural degradada na Amazônia. A pesquisa foi desenvolvida em 535,6 ha de floresta na Fazenda Shet, em Dom Eliseu - PA, usando a base de dados do censo florestal referente a árvores com DAP ≥ 25 cm. Os critérios para colheita das árvores consideraram, prioritariamente, os seguintes elementos: grau de sanidade, qualidade do fuste (2 e 3), diâmetro máximo a permanecer na floresta (DAP < 100 cm), árvores de menor diâmetro (25 ≥ DAP ≤ 55 cm), espécies com maior densidade de árvores por unidade de área, distribuição diamétrica, segundo o coeficiente de Liocourt, manutenção das espécies intensamente exploradas no passado e com população de árvores ≤ 0,15 arv.ha-1. Foram inventariadas 46.012 árvores, pertencentes a 106 espécies, e planejadas para colheita 23,19% (10.671 árvores), aos 12 anos após a exploração anterior. Baseando-se no planejamento da colheita e seguindo os critérios, a previsão de colheita em relação à população total inventariada teve como resultado: 2,16% árvores pelo critério de sanidade; 15,45% pela forma de fuste; 0,26% pelo diâmetro máximo; 93,93% pelo menor diâmetro; 57,50% pela densidade arbórea; e 5,04% pela manutenção das espécies. A colheita foi realizada em 98,79% das árvores com sanidade comprometida; 22,20% com fuste 2 e 3; 97,39% com diâmetro máximo; 95,02% com menor diâmetro; e 90,30% com maior densidade arbórea. Foram mantidas 98,14% das espécies Astronium lecointei, Cordia goeldiana, Copaifera sp., Hymenaea courbaril, Hymenolobium petraeum, Handroanthus serratifolius e Manilkara elata, intensivamente exploradas no passado, e 98,70% de outras 53 espécies com menor abundância (≤ 0,15 arv.ha-1). O planejamento da exploração seguindo os critérios de colheita propostos possibilitou a extração de árvores em ciclos de 10 a 12 anos, sendo um tempo menor que o previsto pela legislação. A manutenção da diversidade de espécies arbóreas e a conservação da floresta em pé, previstas com esses critérios técnicos, podem ser alternativas para o manejo florestal ecológica e economicamente viável.

Studies on applying of soil management practices in the management of paricá and the effects on growth and yield are essential to auxiliary its cultivation and would allow us to inform management and conservation decisions to reconciliate biodiversity, wellbeing, and sustainable production. This case study aimed to evaluate the growth and yield of paricá at different soil management practices, including consortium with an agricultural production, in the Brazilian Amazon. Paricá was implanted, consorted with soybean in the first year, and maize in the second, in a 5 × 2 m spacing. The treatments T1 = subsoiling, basal dressing, top-dressing, inoculation of microorganisms and consortium with soybean/maize were applied. In T2, T3, T4, and T5, we applied the same practices of T1, except subsoiling (T2), basal dressing (T3), top-dressing (T4) and inoculation of microorganisms (T5). T6 was the control, which used none of these practices, including the consortium with soybean/maize. The results indicate that the highest rate of plant survival occurred in T2, while T3 and T4 promoted greater intraspecific competition, compromising the growth in dbh and the yield (m³ ha⁻¹) of plants in future ages. Growth in dbh and th and the yield of plants in the soybean/maize consortium period was higher in T2 and T6. In future ages, the dbh and yield of plants demonstrated higher growth trends in T6, T1, and T5. Agroforestry practices of soil management influence the growth and yield of paricá plants. However, there is a tendency for greater growth and yield for paricá plants cultivated in the absence of agroforestry practices for soil management proposed in this case study. When opting for AFS (paricá intercropped with soybean and maize), it is recommended for paricá a subsoiling, fertilization, and inoculation of microorganisms.