• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • Tagged with
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Modelagem da produ??o de povoamentos de eucalipto utilizando diferentes metodologias

Penido, Tamires Mousslech Andrade 10 March 2017 (has links)
Data de aprova??o retirada da vers?o impressa do trabalho. / Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-09-05T18:36:05Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) tamires_mousslech_andrade_penido.pdf: 7601696 bytes, checksum: 5db79c506834a030e0682976f71d2692 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-09-18T17:02:44Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) tamires_mousslech_andrade_penido.pdf: 7601696 bytes, checksum: 5db79c506834a030e0682976f71d2692 (MD5) / Made available in DSpace on 2017-09-18T17:02:44Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) tamires_mousslech_andrade_penido.pdf: 7601696 bytes, checksum: 5db79c506834a030e0682976f71d2692 (MD5) Previous issue date: 2017 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A modelagem ? um procedimento estat?stico empregado por gestores florestais para esbo?ar o desenvolvimento vegetal com precis?o. Informa??es confi?veis do crescimento e da produ??o s?o essenciais para predizer e quantificar a estrutura futura do povoamento. O presente trabalho foi dividido em dois cap?tulos. Os objetivos foram avaliar a efici?ncia de se estimar a altura empregando diferentes modelos hipsom?tricos, crit?rios de estratifica??o e m?todos de ajuste, al?m de comparar tr?s categorias de modelos de crescimento e produ??o (MCP) em planta??es comerciais de eucalipto. Foram definidas quatro unidades de manejo florestal, totalizando 293,43 ha. O invent?rio florestal cont?nuo foi realizado em 34 parcelas permanentes de 400 m2. O espa?amento de plantio foi de 3,0 x 2,5 m. Avaliou-se a precis?o do ajuste de treze modelos hipsom?tricos. Foram treinadas RNA empregando as mesmas vari?veis de resposta e preditoras adotadas nas equa??es selecionadas. As categorias de MCP testadas foram: em n?vel de povoamento (MP), pelo sistema de equa??es simult?neas de Clutter; de distribui??o diam?trica (MDD), pelo ajuste de fun??o densidade de probabilidade de Weibul-2P e de ?rvores individuais (MAI), pelo modelo de Pienaar e Schiver. As equa??es provenientes do modelo de altura em fun??o do di?metro e da altura dominante forneceram estimativas confi?veis da altura para diferentes crit?rios de estratifica??o, demonstrando superioridade em rela??o aos modelos locais. A modelagem por regress?o e redes demonstraram-se adequadas para estimar a altura, com ou sem estratifica??o do banco de dados. A estratifica??o ? um procedimento que pode melhorar a qualidade das estimativas de altura obtidas por regress?o e RNA. As tr?s categorias de modelo proporcionaram estimativas confi?veis da produ??o em volume com casca, aos 36, 48, 60 e 72 meses, para as unidades de manejo estudadas. O MAI foi a categoria mais precisa e consistente na estimativa do volume por hectare. As proje??es com MP e MDD podem gerar estimativas similares de volume para idades al?m daquelas em que se realizou o invent?rio florestal. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Ci?ncia Florestal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017. / Modeling is a statistical procedure employed by forest managers to sketch plant development with precision. Reliable growth and production information are essential to predict and quantify the future stand structure. The present work was divided in two chapters. The objectives were to evaluate the efficiency of height estimation using different hypsometric models, stratification criteria and adjustment methods, beside to evaluate and compare three categories of growth and yield models (MCP) in commercial eucalypt plantations. Four forest management units were defined, totaling 293.43 ha. The continuous forest inventory was realized in 34 permanent plots of 400 m2. The planting spacing was 3.0 x 2.5 m. The accuracy of the fit of thirteen hypsometric models was evaluated. ANN were trained using the same response e predictive variables adopted in the selected equations. The MCP categories tested were: in level of stand (MP), using Clutter?s simultaneous equations; diameter distribution model (MDD), by adjustment of the Weibull-2P?s probability density function and individual trees (MAI), by Pienaar and Schiver model. The equations from the height model according to the diameter and the dominant height provided reliable height estimates for different stratification criteria, showing superiority in relation to local models. Regression and networks modelling were suitable for estimating height, with or without stratification of the database. Stratification is a procedure that can improve the quality of the estimates obtained by regression and ANN. The three model categories provided reliable estimates of the volume with bark production at 36, 48, 60 and 72 months for the management units studied. MAI was the most accurate and consistent category in estimating volume per hectare. Projections with MP and MDD can generate similar estimates of volume for ages beyond those in which the forest inventory was carried out.

Page generated in 0.1012 seconds