Allan Libanio Pelissari

Geostatistical Modeling of Site Index Classes in Teak Stands

More realistic estimates of a local productive capacity, and thus reliable maps of site index, can be obtained in unsampled locations of a forest site when one chooses from among appropriate spatial characterization techniques. This study aimed apply and compare geostatistical modeling techniques to estimate dominant height and to map site index classes in teak stands in the Mato Grosso State, Brazil. Samples were taken and the average dominant height was obtained annually between the 2 nd

Capacidade produtiva local de Tectona grandis em Monte Dourado, Estado do Pará, Brasil

The study aims to determine the local productive capacity of teak in Monte Dourado, Para State, Brazil, with the analysis of site index curves. The data were obtained by stem analysis of ten dominant trees in a stand with 26 years of age. Were adjusted ten regression models and the criterion for selection followed the lowest standard error of estimate, the highest adjusted coefficient of determination, the significance of F test and of regression coefficients and graphical analysis of the residuals. The site index curves were built by the guide-curve method. The Spillman model present the best fit, by which were generated three curves of site index from 16m to 24m, at 26 years of index-age. The region of Monte Dourado - PA showed a productive potential for the development of teak.

GEOSTATISTICAL MODELING OF TIMBER VOLUME SPATIAL VARIABILITY FOR Tectona grandis L. F. PRECISION FORESTRY

Considerando a hipotese de que os volumes de madeira apresentam dependencia espacial, cujo conhecimento contribui para o manejo de precisao, o objetivo deste trabalho foi estimar a variabilidade espacial do volume de sortimentos de madeira e identificar seus padroes espaciais em povoamentos de Tectona grandis. Utilizou-se um conjunto de dados de 1.038 arvores para ajustar funcoes de afilamento e estimar os volumes para fuste total, serraria e lenha em 273 parcelas alocadas em povoamentos de T. grandis ao oitavo ano de idade, o qual representa o segundo desbaste que possibilita volumes comerciais. Modelos de semivariogramas foram aplicados para ajustar a dependencia espacial e a krigagem pontual foi utilizada para compor mapas de volume. A modelagem geoestatistica permitiu estimar a variabilidade espacial de T. grandis e desenvolver mapas de volume de madeira. Assim, tratamentos silviculturais, como desbaste e poda, bem como planejamento de intervencoes espaciais, podem ser recomendados para produtos de madeira almejados.

SPATIAL CONTINUITY IN A MIXED OMBROPHILOUS FOREST WITH DIFFERENT SIZE AND SHAPE OF SAMPLE UNITS

Size and shape of sample units are fundamental for the observation of spatial continuity in native forests and important to characterize patterns structured in space by different scales. Therefore, the objective of this study was to identify the spatial continuity of number of trees and basal area, evaluating the influence of size and shape of sample units in a mixed ombrophilous forest in Parana State, Brazil. An area of 25 hectares was divided in 50 m x 50 m and 25 m x 25 m square sample units, and also in 10 m x 50 m and 20m x 50m rectangular sample units. In these samples, the number of trees (n.ha-1) and the basal area (m².ha-1) were determined in each of them, with the possible spatial continuity analyzed by geostatistics analysis. The influence of size and shape of sample units on the spatial continuity structure was analyzed. Also, adjusted semivariograms were used to observe that the correlation between neighboring sample units for number of trees was stronger than for the basal area. However, due to the similarity of the semiovariograms, both sizes and shapes can be used to describe the spatial structure of number of trees, while the square sample units were more appropriate to describe basal area.

VARIABILIDADE ESPACIAL DOS ATRIBUTOS QUÍMICOS DO SOLO EM POVOAMENTO DE Tectona grandis

Considerando a necessidade por informacoes que visem a identificar e medir as relacoes espaciais dos fatores edaficos que limitam o desenvolvimento dos povoamentos de teca, neste trabalho, objetivou-se caracterizar a variabilidade espacial dos atributos quimicos pH, fosforo, potassio, calcio, magnesio, materia orgânica e aluminio do solo e compara-las em dois periodos de avaliacao, ao segundo e nono ano de idade, de um povoamento de teca no estado de Mato Grosso, Brasil. Foram alocadas 46 unidades amostrais e coletadas amostras de solo, a 0-0,2 m de profundidade, para a posterior modelagem geoestatistica. Foram observadas alteracoes espaciais dos atributos quimicos do solo entre as avaliacoes, o que permite recomendar adubacoes e correcoes de acidez do solo em regioes especificas da area florestada, visando ao estabelecimento dos individuos pos-plantio e o desenvolvimento daqueles conduzidos pos-desbastes.

Sampling system for estimating woody debris in an urban mixed tropical forest

Woody debris, defined as standing and downed deadwood, consists in an essential component of the forest carbon stock. However, few studies have been carried out to get an efficient and accurate sampling procedure for estimating it. This work proposes two methodologies to estimate the woody debris volume in a Brazilian mixed tropical forest: 1) two-stage systematic sampling, using a mixed methodology, in which the Strands method is applied to standing dead trees and stumps, and line intercept sampling is used to fallen trees and branches; and 2) ratio estimate of the sum of cross-sectional areas of deadwood pieces and forest basal area, aiming to obtain the total woody debris volume indirectly in the natural forest. Conversions for biomass and carbon stocks were made applying the mean basic density on the estimates of deadwood volumes. Both methodologies are accurate for woody debris volume estimates, with a sampling error equal to 16.1% (methodology 1) and 5.7% (methodology 2), at a 95% probability level. Thus, the methodology 2 has potential to be used in strategic forest inventories of woody debris, such as in National Forest Inventories, due to increasing importance of its quantification in all forest ecosystems.

Spatial Variability and Sampling Structures for Forest Fuel Material Estimation

The aim of this work was to model the spatial dependence of fuel material deposition on the ground in a pine stand, and to simulate and evaluate sampling procedures for estimating it. Branches with diameters up to 0.7 cm (A) and from 0.71 to 2.5 cm (B) were collected. Subsequently, the structures of systematic sampling and linear clusters were simulated for 50%, 33% and 23% of the total sample size, and the spatial dependence was evaluated through geostatistical modeling. The systematic sampling was suitable, with representative spatial coverage and accurate estimators, whereas linear clusters were inadequate. The reduction of the number of sample units affected the estimators, but their sampling errors did not exceed 10% for the sample sizes of 23% for class A of fuel material and 50% for class B in the systematic structure, resulting in consistent estimates.

Estimativa do Afilamento do Fuste de Araucária Utilizando Técnicas de Inteligência Artificial

ABSTRACT The aim of this study was to compare the performance of artificial intelligence techniques with taper functions and evaluate the effect of age on this estimate. The data set was comprised of 135 observations covering the ages 6, 12, 18, 24 and 43 years of age of a stand of Araucaria angustifolia. Adjusted taper functions were Kozak Schoepfer, Hradetzky and Garay modified. The artificial intelligence models used were: ANN and tree model. The input vectors are the same variables used in taper equations and also the same arrangement with the addition of age. 70% of the data was used for adjustment and 30% for validation. The taper function Hradetzky provided the best fit. Among the models evaluated, the ANN provided the best estimates, highlighting the ANN by adding the age variable. The performance of M5P was satisfactory, however, less effective than the other techniques. Keywords: taper function, M5P, multi layer perceptron . 1. INTRODUCAO Tendo em vista a tendencia do setor florestal brasileiro em manejar as florestas visando multiprodutos para maximizacao da renda, se faz necessaria a adocao de tecnicas que possibilitem a quantificacao e qualificacao desses produtos ( Mendonca et al., 2015 ). Nesse contexto, as funcoes de afilamento tem se mostrado como

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

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.

MODELING OF THE COMMERCIAL VOLUME STOCK IN AN OMBROPHILOUS FOREST IN THE SOUTHWEST OF THE AMAZON

The abundance of tree species in tropical rainforests with different shapes and dimensions, as well as the great structural diversity, makes difficult the employment of form factors or equations to estimate individual volumes. However, the employment of equations at the population level makes possible to predict the volumetric stock per unit of area from forest attributes, excluding the necessity of individual tree volume evaluation. Thereby, the aim of this study was to select variables, fit statistical models and propose stand equations to estimate total and exploitable commercial volumes in an Amazon forest under concession regime. For this, variables commonly measured, like density and basal area, were inserted on traditional commercial volume models; besides the application of variables that considered the diversity and forest structure on models generated by the Stepwise process. After analysis, it was observed that the models obtained through Stepwise propitiated more precise estimation of the volumetric stock, reducing estimation errors and reducing problems with heteroscedasticity of residuals. The insertion of variables that express diversity and forest structure on the equations, like Shannon’s and diametric variation indices and the commercial trees ratio, contribute to predictions’ improvement, especially for the exploitable commercial volume, being recommended for the precise evaluation of timber potential of areas under Amazon forest concession.