Resumo: Com a expansão das atividades antrópicas, a floresta tropical amazônica tem sofrido intensas transformações. Após a retirada da vegetação há o abandono desses ecossistemas possibilitando a resiliência natural. Com o intuito de acelerar este processo, é realizado o plantio de diversas espécies nativas para favorecer a ciclagem de nutrientes, com o acúmulo de liteira. Portanto, objetivou-se comparar a deposição de massa seca e as propriedades químicas em floresta em estágio sucessional de desenvolvimento (FSU) Abstract:With the expansion of anthropogenic activities, the Amazon Rain Forest has suffered sweep changes. After the removing of vegetation, there is an abandonment of the ecosystems, allowing a natural resilience. In order to accelerating this process, it is performed the planting of several native species, to promote the nutrient cycling with the deposition of litter fall. Therefore, the objective of this research is to compare the dry mass deposition and the chemical properties in a successional forest ecosystem (FSU) and in Virola surinamensis Rol. (Ward.) (VSU) ecosystem. The experiment was conducted in the coastal tableland of lower in eastern Amazon, and the litter samples taken every two weeks for three years. The study showed that the FSU forest floor were significantly higher (p < 0.05) than the VSU in the stock of litter. The results of forest floor accumulation was 7.94 Mg ha -1 yr -1 and 6.30 Mg ha -1 yr -1 to FSU and VSU, respectively. About chemical properties of litter, K and Mn concentration and content were higher than VSU. To Ca and Mg the concentration was superior in VSU, but the content was not different to two ecosystems. The content and concentration of Fe in FSU, were smaller, and to the same variables, Cu and Zn were not different in the forest and in the monoculture. The deposition of litter and great of elements content showed higher values to successional forest ecosystem because of structural and floristic diversity of species.

<p>O objetivo deste trabalho é identificar, descrever e analisar a literatura técnico-científica nacional sobre a estimativa de carbono em Sistemas Agroflorestais (SAFs), na região amazônica. Foi realizada uma revisão bibliográfica nas bases de dados dos portais eletrônicos mais significativos que tratam sobre o tema, postados entre os anos de 1998 e 2015. Conclui-se que, ainda há poucos estudos realizados sobre SAFs com fixação de carbono e são poucos os estudos apresentados sobre espécies nativas da Amazônia. Da mesma forma que apresentam poucas diferenças nas metodologias encontradas.</p><p align="center"><strong><em>Carbon fixation estimated assessment in agroforestry systems in the Amazon region</em></strong></p><p><strong>Abstract: </strong>The objective of this work is to identify, describe and analyze the national scientific and technical publications to be carried on carbon fixation in Amazon Agroforestry Systems (AFS). We performed a list of online databases literature review of the most significant portal for digital collections of electronic papers that deal with the subject, posts between 1998 and 2012. It follows that there are few studies on AFS considering the carbon fixation and studies presented on Amazon rainforest plants. Therefore, also has been found few meaningful differences focused on Methodology in recent assessment articles.</p><br /><strong></strong>

O Brasil é um dos principais produtores de madeira reflorestada do mundo, ocupando a nona posição no ranking de áreas de povoamentos florestais. O plantio de floresta pode ser uma alternativa significativa para fortalecer o agronegócio sustentável na Amazônia, ao mesmo tempo que possibilitaria a redução da pressão sobre os recursos naturais da região. O objetivo desta pesquisa é analisar a conjuntura do mercado de floresta plantada no estado do Pará, como forma de compreender sua participação relativa no contexto nacional, caracterizando as principais espécies cultivadas, os municípios produtores, as empresas com atuação e expertise no ramo e ressaltar os desafios e oportunidades no setor. Os dados utilizados foram obtidos junto ao Instituto Brasileiro de Geografia e Estatística (IBGE), referente ao período entre 2013 a 2019. As variáveis analisadas foram produção em metros cúbicos (m³), valor da produção em reais (R$), área colhida em hectares (ha), preço em reais por metros cúbicos (R$.m-³). Verificou-se que o estado do Pará participa com 1,9% da produção nacional, ocupando a 11ª posição no ranking brasileiro de produção. O crescimento da produção paraense expande-se a partir do ano de 2015, principalmente a partir do cultivo do eucalipto. O uso de técnicas no manejo florestal de precisão, modernos projetos de plantio no estado, contribuem para uma maior produção de madeira plantada. Os povoamentos florestais são alternativas renováveis de grande potencial econômico, sobretudo para ocupar áreas já alteradas. Contudo, é notável que ainda exista poucos estudos relacionados ao plantio comercial de outras espécies adaptadas a realidade regional.

At a moment when the importance of planted forests in the Amazon region is increasing, hypsometric models become highly relevant tools as they allow monitoring of and planning for tree plantations in a way that is practical and economic for the producer. Thus, the objective of the current study was to select and adjust a model of hypsometric relationships for a clonal plantation of Tectona grandis Linn F., submitted to selective thinning, located in Capitão Poço municipality, Pará state, Brazil. Data were collected from permanent plots in five-year-old stands using the fixed area method and systematic process. The best adjusted model was selected with an adjusted determination coefficient (R²aj.%), residual standard deviation of the percentage estimate (Syx%), recalculated residual standard error (Syxr%), diagnosis of distribution of residuals as a percentage and the Percent Average Deviation (PAD%). Hyperbolic models 2 and 3 had the highest determination coefficients (83.42 and 83.40%) and lowest PAD (-0.006 and -0.154%). The polynomial (1) and hyperbolic models (2 and 3) showed the smallest errors in related to the estimates. Model 2 (hyperbolic) was found to generate the best estimate of total T. grandis clonal plantation height. Use of this hypsometric model will allow a significant reduction of costs and time in forest inventory studies.

Post-harvest, wood volume can be calculated with a stacking factor which can be influenced by diameter classes involved. Consequently, the following question arises: there is a difference between the volume conversion factor for stacked to geometric volume between piles of clonal plantation logs of different diameters classes? The hypothesis is: if smaller logs have a higher stacked to geometric volume conversion factor, between-log voids will be smaller and the overall stacks will therefore have lower volumes. Therefore, the objective of this study was to compare stacking and cubing factors in stacks of logs with different diameters for two Eucalyptus sp. clones. The study was conducted in Barra do Corda municipality, Maranhão State, Brazil. Timber was laid in piles of logs by diameter class, composed of logs of smaller (9-10.99 cm) and larger (11-13 cm) diameters. Stacking factor means for clone 1 were 1.88 for the larger diameter and 2.00 for the smaller diameter class, while for clone 2 mean values were 1.62 and 1.65, for stacks with larger and smaller diameter classes, respectively. For logs from the same clone there was no significant difference for the conversion factors between the stacks with the largest and smallest diameter. However, there was a significant difference in the conversion factors between the two clones, proving the hypothesis tested. Thus, for each genetic lineage, a proper stacking factor must be established so that the estimated volume comes close to the real value.

Application of geostatistics in mapping the productive capacity of forest stands is an important tool to guide decision making regarding precision silviculture. In this study, we investigated the productive capacity of teak clonal plantations and its spatial dependence, making the site mapping possible. We also investigated the influence of soil chemical attributes on productive potential. We used dominant height, age and geographic coordinates data from plots during five evaluations in clonal teak plantations of different ages. We performed the classification of the forest sites by the guide-curve method. The principal components analysis was used to group the forest stands according to soil chemical attributes (available P and exchangeable K, Na and Mg). The spatial variability analysis of productive capacity was carried out through geoestatistics. The results show that the productive capacity has spatial dependence. The exponential model has provided the best estimates of dominant height, revealing that 69.2% of the mapped area was from medium and 30.8% from high productive capacity. The multivariate analysis showed that soil fertility has influenced the productive capacity, discerning the most productive sites, in agreement with the soil quality. The geostatistical technique was efficient to estimate the productive capacity in unsampled areas, revealing sites with different productive potentials and their response to edaphic factors. This may assist in the efficient management of planting, when establishing silvicultural actions in specific locations, which are identified in the planted area maps, reducing the management costs.

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