oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 17 )

2018 ( 34 )

2017 ( 29 )

2016 ( 33 )

Custom range...

Search Results: 1 - 10 of 17332 matches for " Leite Helio Garcia "
All listed articles are free for downloading (OA Articles)
Page 1 /17332
Display every page Item
Equa??es de volume e de taper para quantificar multiprodutos da madeira em Floresta Atlantica
Chichorro, José Franklin;Resende, José Luiz Pereira;Leite, Helio Garcia;
Revista árvore , 2003, DOI: 10.1590/S0100-67622003000600006
Abstract: this study was carried out to estimate a volume equation from a logarithmic model of schumacher & hall (1933) for comercial volume determination and a taper equation from the model of demaerschalk (1972), to estimate wood multiproducts yield in floresta atlantica. data were collected in gleba c (c glebe), with 289.5 hectares, owned by floresta nacional do rio preto (rio preto national forest), under the administration of ibama, located in concei??o da barra - espírito santo, brazil. a total of 165 standing trees were measured, subdivided into 10 diameter classes, with bole quality qf1, with the greatest vi, and/or species of commercial value. these trees represented 62 species and 38 families. the volume equation fitted well within the data, with 2 of 0.9815, and normally distributed residues. the taper equation also fitted well within the data, with 2 of 0.9346 and graphic distribution of the residues was normal. the f test (graybill, 1976) showed equivalence between the observed and estimated diameters by the taper equation. the taper equation algebric transformations allowed to estimate the height for a given superior diameter d, and the trunk volume for a desired use, allowing to evaluate the amount of multiproducts for standing trees.
Um método para condu??o de inventários florestais sem o uso de equa??es volumétricas
Leite, Helio Garcia;Andrade, Valdir Carlos Lima de;
Revista árvore , 2002, DOI: 10.1590/S0100-67622002000300007
Abstract: preliminary tests were conducted of on the use of the relative height method, developed originally by andrade and leite (1997), to corry out a forest inventory. the proposed method was compared with one of the conventional methods, that consists of measuring the diameter of all the trees, the height of about 15 trees and the height of about five dominant trees per plot. for processing these data, hipsometric and volumetric equations are used, with the latter being generated from tree scaling data in the stand. the relative height method includes only data obtained in the portions, without the need to scale trees in the stand. data of four plots and 277 tree samples were used to compare the two methodologies (conventional and relative height). the volumes for the two methods were similar (156,21 and 156,19 m3/ha). thus, it can be concluded that the alternative method is promising, even resulting in some advantages, such as: reduction of the number of heights measured in the plots, elimination of the activities of tree sample scaling and adjustment of volumetric and, or, taper models.
Uma proposta para a gera??o de amostras aleatórias nos problemas de simula??o em modelos de planejamento
Peternelli, Luiz Alexandre;Silva, Gilson Fernandes da;Leite, Helio Garcia;
Revista árvore , 2006, DOI: 10.1590/S0100-67622006000500008
Abstract: a cellulose price prediction model was adjusted using time and lagged price as covariates. from the model parameter estimates, 48 possible trends were proposed for future cellulose price. following, three simulation methods were used to predict the future values defined by the various trends: m1t pcel.f = μ; m2 t pcel.f = μ + ef, e m3 μf + ef, where m is the systematic part and ef is the stochastic component. the monte carlo method and a triangular distribution were used for the simulation. to compare the values simulated by the methods and the future values of the various trends, the average relative difference was used. in case of no trend, m1 and m2 were satisfactory, although m2 included disturbances around the mean. in the case of a real trend, m3 had the best performance, though it was influenced by the accuracy in the predicted trend.
Importancia das variáveis altura dominante e altura total em equa??ea hipsométricas e volumétricas
Leite, Helio Garcia;Andrade, Valdir Carlos Lima de;
Revista árvore , 2003, DOI: 10.1590/S0100-67622003000300005
Abstract: this study was carried out to evaluate the following hypotheses: a) hipsometric equations should be obtained by plot, only in function of the dbh and b) volumetric equations should be local only in function of the dbh. data of 4 and 50 plots were randomly distributed in a 67.81 ha and 121.3 ha eucalypt stand, respectively. a rigorous scaling of all the trees in the 4 plots was initially carried out to obtain total height and solid volume. data of 277 trees rigorously scaled in the stand were also used. the statistical procedure proposed by leite & oliveira (2002) was used to evaluate the accuracy of the estimates and hypotheses. based on the results, hypotheses a and b were rejected at 1% probability. it was concluded that, in a forest inventory, the variable dominant height should be considered and the volumetric equations should be regional.
Uso do método da altura relativa em inventário florestal de um povoamento de pinus
Leite, Helio Garcia;Andrade, Valdir Carlos Lima de;
Revista árvore , 2004, DOI: 10.1590/S0100-67622004000600011
Abstract: a test of the relative height method in stands of pinus is presented in this work. the first study of case presented utilized data of 1200 trees scaling from eucalyptus grandis w. hill ex maiden and eucalyptus urophylla s. t. blake hybrid to make inferences about the accuracy provided by the method, to develop one formula allowing the elimination and/or reduction the number of sample-trees in a forest inventory. the formula developed was hr= (ht - 2)/ 2, where diameter together with dap and total height (ht) were used to generate taper equations using procedures of analytical geometry. in a second case, the relative height method was tested in a forest inventory of a pinus stand. this same stand was inventoried by the usual method. according to thesc evaluations it was possible to conclude that the relative height method ressults in precise, now-based taper and solid volume estimates and trees be used instead of the usual method.
Hipsometric relationship modeling using data sampled in tree scaling and inventory plots
Andrade, Valdir Carlos Lima de;Leite, Helio Garcia;
Revista árvore , 2011, DOI: 10.1590/S0100-67622011000100019
Abstract: this work evaluated eight hypsometric models to represent tree height-diameter relationship, using data obtained from the scaling of 118 trees and 25 inventory plots. residue graphic analysis and percent deviation mean criteria, qui-square test precision, residual standard error between real and estimated heights and the graybill f test were adopted. the identity of the hypsometric models was also verified by applying the f(ho) test on the plot data grouped to the scaling data. it was concluded that better accuracy can be obtained by using the model prodan, with h and d1,3 data measured in 10 trees by plots grouped into these scaling data measurements of even-aged forest stands.
Equa es de volume e de taper para quantificar multiprodutos da madeira em Floresta Atlantica
Chichorro José Franklin,Resende José Luiz Pereira,Leite Helio Garcia
Revista árvore , 2003,
Abstract: Este estudo foi conduzido com o objetivo de ajustar uma equa o de volume, a partir do modelo logaritmizado de Schumacher & Hall (1933), para estimar o volume comercial, e uma equa o de afilamento (taper), a partir do modelo de Demaerschalk (1972), para estimar a quantidade de multiprodutos de madeira de espécies da Floresta Atlantica. Os dados foram coletados na Gleba C da Floresta Nacional do Rio Preto - IBAMA, no município de Concei o da Barra-ES. Foram mensuradas 165 árvores em pé, subdivididas em dez classes de diametro, com qualidade de fuste QF1 e pertencentes às espécies com maior VI e, ou, espécies de valor comercial. Essas árvores reuniram 62 espécies e 38 famílias. A equa o de volume ajustou-se bem aos dados, com 2 igual a 0,9815 e resíduos normalmente distribuídos. A equa o de taper também ajustou-se bem aos dados, com 2 igual a 0,9346 e distribui o gráfica dos resíduos normal. Pelo teste F (Graybill, 1976), constatou-se que houve igualdade entre os diametros observados e os diametros estimados pela equa o de taper. A partir de transforma es algébricas da equa o de taper, foram estimados a altura para um determinado diametro superior d e o volume do tronco ou de parte dele. Em seguida, podem ser estimados o número de toras e o respectivo volume, em fun o do comprimento da tora, do diametro superior d mínimo e do uso desejado, o que permite avaliar a árvore em pé.
Importancia das variáveis altura dominante e altura total em equa ea hipsométricas e volumétricas
Leite Helio Garcia,Andrade Valdir Carlos Lima de
Revista árvore , 2003,
Abstract: Este estudo foi conduzido, visando avaliar as seguintes hipóteses: a) equa es hipsométricas devem ser obtidas por parcela, apenas em fun o do dap; e b) equa es volumétricas devem ser locais, em fun o apenas do dap. Foram utilizados dados de quatro parcelas distribuídas ao acaso em um povoamento de eucalipto de 67,81 ha e de 50 parcelas distribuídas ao acaso em um povoamento de 121,3 ha, da mesma espécie. Em uma análise inicial, a fim de obter valores reais de altura total e de volume sólido, realizou-se uma cubagem rigorosa de todas as árvores das quatro parcelas. Foram utilizados, ainda, dados de 277 árvores cubadas rigorosamente nos povoamentos. Para avaliar a exatid o das estimativas e as hipóteses formuladas, empregou-se o procedimento estatístico proposto por Leite & Oliveira (2002). Com base nos resultados, as hipóteses a e b foram rejeitadas a 1% de probabilidade. Concluiu-se, portanto, que em um inventário florestal a variável Hd deve ser considerada e que as equa es volumétricas devem ser regionais.
Um método para condu o de inventários florestais sem o uso de equa es volumétricas
Leite Helio Garcia,Andrade Valdir Carlos Lima de
Revista árvore , 2002,
Abstract: Neste trabalho foram conduzidos testes preliminares sobre o uso do método altura relativa, desenvolvido originalmente por Andrade & Leite (1997), para condu o de inventário florestal. O método proposto foi comparado com um dos métodos usuais, que consiste em medir o diametro de todas as árvores, a altura de cerca de 15 árvores e a altura de cerca de cinco árvores dominantes por parcela. Para processamento desses dados s o utilizadas equa es hipsométricas e volumétricas, sendo estas últimas geradas com dados de cubagem de árvores no povoamento. No método da altura relativa s o utilizados apenas dados obtidos nas parcelas, n o sendo necessário cubar árvores no povoamento. Os dados de quatro parcelas e de 277 árvores-amostra foram utilizados para compara o das duas metodologias (usual e altura relativa). Os volumes estimados pelos dois métodos foram iguais (156,21 e 156,19 m3/ha). Portanto, pode-se concluir que o método alternativo é promissor, resultando ainda em algumas vantagens, como: redu o do número de alturas medidas nas parcelas e elimina o das atividades de cubagem de árvores-amostra e de ajuste de modelos volumétricos e, ou, de taper.
Parametros morfológicos na avalia??o de qualidade de mudas de Eucalyptus grandis
Gomes, José Mauro;Couto, Laércio;Leite, Helio Garcia;Xavier, Aloísio;Garcia, Silvana Lages Ribeiro;
Revista árvore , 2002, DOI: 10.1590/S0100-67622002000600002
Abstract: an experiment was carried out to study the morphological parameters used to evaluate the quality of eucalyptus grandis seedlings producedin different tube sizes. a mixture of 80% organic compound (co) and 20% charcoal powder fertilized with and without n, p and k was used as substrate. four sizes of hard plastic tubes at the volumes of 50, 110, 200 and 280 cm3 were used as packaging. height and height/weight relationship of the aerial part dry matter should be considered, since although providing a satisfactory contribution to seedling quality pattern, the parameters did not present a destructive process. the use of height only to estimate the quality of eucalyptus grandis seedlings in the 110 cm3 volume tube when they were 90-day old should be used, since it presents a satisfactory relative contribution, besides being a nondestructive, easily determined and measured parameter.
Page 1 /17332
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.