Análise Estrutural Da Unidade Conglomerada Cruz De Malta Na Floresta Nacional Do Tapajós, Estado Do Pará, Brasil

Queiroz, Waldenei Travassos de; Netto, Sylvio Péllico; Valente, Mário Diego Rocha; Pinheiro, João Guimarães

doi:10.5380/rf.v41i1.21175

Cited by 7 publications

(15 citation statements)

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“…In inventories carried out in the Amazon Forest, the random, systematic and cluster sampling procedures are the most commonly applied (Higuchi 1987, Ubialli et al 2009, Cavalcanti et al 2011, Queiroz et al 2011, Andrade et al 2015. However, in approaches by species, these procedures have not shown satisfactory performance in the estimates of the present study (Table II), possibly due to low density of trees that affect the composition of representative samples, especially for Terminalia amazonica and, thus, confirming the first hypothesis of this study.…”

Section: Discussionsupporting

confidence: 58%

Sampling procedures for inventory of commercial volume tree species in Amazon Forest

Netto

Pelissari

Cysneiros

et al. 2017

An. Acad. Bras. Ciênc.

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The spatial distribution of tropical tree species can affect the consistency of the estimators in commercial forest inventories, therefore, appropriate sampling procedures are required to survey species with different spatial patterns in the Amazon Forest. For this, the present study aims to evaluate the conventional sampling procedures and introduce the adaptive cluster sampling for volumetric inventories of Amazonian tree species, considering the hypotheses that the density, the spatial distribution and the zero-plots affect the consistency of the estimators, and that the adaptive cluster sampling allows to obtain more accurate volumetric estimation. We use data from a census carried out in Jamari National Forest, Brazil, where trees with diameters equal to or higher than 40 cm were measured in 1,355 plots. Species with different spatial patterns were selected and sampled with simple random sampling, systematic sampling, linear cluster sampling and adaptive cluster sampling, whereby the accuracy of the volumetric estimation and presence of zero-plots were evaluated. The sampling procedures applied to species were affected by the low density of trees and the large number of zero-plots, wherein the adaptive clusters allowed concentrating the sampling effort in plots with trees and, thus, agglutinating more representative samples to estimate the commercial volume.

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Section: Discussionsupporting

confidence: 58%

Sampling procedures for inventory of commercial volume tree species in Amazon Forest

Netto

Pelissari

Cysneiros

et al. 2017

An. Acad. Bras. Ciênc.

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“…O tamanho de subparcela considerado ideal, com localização centralizada na região de máxima curvatura, correspondeu à soma do total de oito unidades básicas (subparcelas), cuja área abrange 0,10 ha. Conforme descrito por Queiroz et al (2011) existe uma relação inversamente proporcional da variabilidade dos valores do coeficiente de variação em função do tamanho das subparcelas, ou seja, à medida que se aumenta o tamanho da subparcela diminui o valor do coeficiente de variação.…”

Section: Resultsunclassified

“…O coeficiente de correlação intraconglomerados foi obtido através da fórmula para populações finitas , o coeficiente de correlação intraconglomerados mostrará se a área amostrada está mais apropriada para um processo de amostragem por conglomerados por estratificação, caso seja maior que 0,4, isso indica que a área é mais apropriada para o processo de estratificação, este coeficiente também foi usado para se determinar o número de subparcelas ideal (Queiroz et al 2011).…”

Section: Análise Estatísticaunclassified

“…Como não houve análise de custos de instalação de parcelas e deslocamento entre parcelas na presente pesquisa, foi utilizado C2/C1=3, este foi o mesmo valor usado pelo autor em inventário florestal realizado na Amazônia equatoriana. Queiroz et al (2011) adverte que o uso da fórmula de Péllico netto e Brena para populações finitas é muito perigoso, pois quando tende a zero o m tenderá a um valor infinito. A variância da média foi obtida através da fórmula descrita por Queiroz et al (2011) para populações finitas em que f 1 : fração amostral n/n; f 2 : fração amostral m/M; : variância estimada entre os valores médios dos conglomerados; : média das variâncias estimadas das subparcelas dentro dos conglomerados; n: número total de conglomerados; n: número de conglomerados amostrados; M: número total de subparcelas; m: número de subparcelas por conglomerado, através desta foi gerado o erro padrão da média, para em seguida obterem-se os intervalos de confiança e limite de erro para as variáveis respostas vT, vO e vC.…”

Section: Análise Estatísticaunclassified

“…Para Queiroz et al (2011), devido à grande divergência de resultados encontrados na literatura, mais trabalhos sobre o processo de amostragem por conglomerados necessitam ser realizados, por isso o Brasil precisa estabelecer um sistema de inventário Florestal nacional (iFn), visando determinar as condições científicas e técnicas necessárias para adoção de políticas públicas que resultem simultaneamente no desenvolvimento econômico-social, e na conservação ambiental.…”

Section: Introductionunclassified

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Comparação de tamanhos e distâncias de subparcelas aplicadas em processo de amostragem por conglomerado

et al. 2012

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RESUMOrealizou-se um estudo com unidades amostrais conglomeradas de estrutura cruzada usando banco de dados de inventário florestal 100% de uma unidade de produção Anual (uPA-08), localizada na fazenda Martins no alto Pacajá, Município de Portel, estado do Pará, para estudar os efeitos da variação entre e dentro dos conglomerados usando como referência três variáveis resposta: i) vT = volume total de madeira das 77 espécies florestais encontradas na área de estudo; ii) vO = volume Total das 10 espécies florestais de maior ocorrência e volume na área de estudo; e iii) vC = volume Total das 10 espécies florestais mais comercializadas pela empresa Cikel, tendo como objetivo determinar o tamanho e a distância ideal de subparcelas a partir do Método da Curvatura Máxima, uma vez definido o tamanho, sua área é fixada e então são estudadas cinco diferentes valores para determinar a distancia ideal do centro do conglomerado até as subparcelas e entre as mesmas. Os resultados permitiram inferir que o tamanho de subparcela 0,10 ha, a distância de 50 m entre as subparcelas, e a estrutura cruzada com 8 (subparcelas) são eficientes para estimar os parâmetros estudados. PalavRaS-ChavE: inventário florestal; Amostragem por conglomerado; Tamanho de parcela; Correlação intraconglomerado; estrutura amostral.Comparison of sizes and distances of subplots applied in the process of cluster sampling. aBSTRaCTWe conducted a study with sample units of conglomerate structure using cross-database of forest inventory 100% of Annual Production unit (APu-08), located at the Top Pacajá Martins farm, municipality of Portel-PA to study the effects of variation between and within clusters with reference to three response variables they were: i) vT = Total volume of wood of 77 tree species found in the study area, ii) vO = Total volume of the 10 most frequent tree species and volume in the study area and, iii) vt = Total volume of 10 forest species Cikel more commercialized by the company we aimed to determine the ideal size and distance of plots from the Method of Maximum Curvature, once defined the size, its area was fixed and then there was tested five different values to determine the ideal distance from the center of the conglomerate to the plots and between them. results showed that the size of 0.10 ha plot, the distance of 50 m between plots, and cross-structure with 8 subplots are efficient for estimating the parameters.

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Estimation of volume, biomass, and carbon of coarse woody debris in native forests in São Paulo State, Brazil

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With the objective of increasing knowledge on carbon stocks, and thus improving the accuracy of published estimates, the present study explored wood density and carbon concentration of coarse woody debris by decay class in a Seasonal Semi-deciduous Forest (SSF) area in the Atlantic Rain Forest and in a Cerrado sensu-stricto (CSS) area. For this research, only large elements (diameter geq 10 cm), known as coarse woody debris (CWD), were considered. Data were collected according to the line intersect sampling (LIS) method. Two strata were chosen in each area, and in each stratum ten sampling units were installed according to a systematic sampling protocol. Each unit included: one 200 m transect line in the North-South direction, one 200 m transect line in the East-West direction (crossing the center point of the N-S transect), a 150 m line crossing the N-S line in the East-West direction at 25 m south of the center point, and a 50 m East-West line crossing the N-S line at 50 m south of the center point (for a total of 650 m of transect length per sampling unit). For each element, the diameter, length, and perpendicular width were recorded at the transect intersection point; each element was also classified into a decay class, and when possible the species was identified. Furthermore, disc samples were also taken from each element, from which cylinder samples were extracted then oven dried to determine density. These cylinders were milled and analyzed using a LECO-C632 to determine carbon content (as a mass percentage). The volume of each element was calculated by taking the difference between the cross-sectional area and the hollowed area, then multiplying by the element's length. Biomass was calculated by multiplying an element's volume by its density, and carbon stocks were calculated by multiplying biomass values by carbon factor computed via lab analysis. Data from the 650m line intersect sampling units were used to calculate wood density and carbon concentration averages across the areas. Cross shaped transects (with 150 m segments for the CSS, and 200 m segments for the SSF) were used to calculate estimators of biomass and carbon stock. In both areas, as the decay class increased (from least to most rotten material), wood density decreased, which follows the same pattern as other literature. The present study concludes that carbon concentration barely changes within each decay class. Biomass was estimated at 6.7 and 1.3 Mg/ha for the SSF and the CSS, respectively. Carbon stock concentrations reported from laboratory analyses were 3.3 and 0.7 MgC/ha for the SSF and the CSS, respectively. Using a conversion constant of 50% similar results were obtained, though other studies using the conversion constants found that they had overestimated carbon stock values. Due to this result, we strongly recommend the evaluation of wood density and carbon concentration for CWD at the site-level using decay classes.

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Análise Estrutural Da Unidade Conglomerada Cruz De Malta Na Floresta Nacional Do Tapajós, Estado Do Pará, Brasil

Cited by 7 publications

References 3 publications

Sampling procedures for inventory of commercial volume tree species in Amazon Forest

Sampling procedures for inventory of commercial volume tree species in Amazon Forest

Comparação de tamanhos e distâncias de subparcelas aplicadas em processo de amostragem por conglomerado

Estimation of volume, biomass, and carbon of coarse woody debris in native forests in São Paulo State, Brazil

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