• 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

Decis?es silviculturais para produ??o de ?rvores de eucalipto de grande porte / Silvicultural decisions for the production of large eucalypt trees

Alves, Petr?nio Henrique 28 March 2016 (has links)
Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-05-03T14:57:17Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) petronio_henrique_alves.pdf: 952268 bytes, checksum: c672a103f4c27e5369547a6558985c5d (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-05-17T12:03:12Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) petronio_henrique_alves.pdf: 952268 bytes, checksum: c672a103f4c27e5369547a6558985c5d (MD5) / Made available in DSpace on 2017-05-17T12:03:12Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) petronio_henrique_alves.pdf: 952268 bytes, checksum: c672a103f4c27e5369547a6558985c5d (MD5) Previous issue date: 2016 / Os objetivos deste trabalho foram avaliar a influ?ncia do desbaste e da fertiliza??o p?s-desbaste no crescimento de ?rvores de um povoamento clonal de eucalipto e comparar a idade t?cnica de desbaste (ITD), obtida atrav?s do M?todo dos Ingressos Percentuais, com a idade t?cnica de corte (ITC) de dois povoamentos de clones de eucalipto. Para o primeiro objetivo, os dados foram coletados em 30 parcelas permanentes, sendo 16 convencionais e 14 g?meas, em que foi analisado o efeito do desbaste (parcela convencional) e da fertiliza??o (parcela g?mea) sobre o crescimento das ?rvores. O desbaste foi realizado aos 81 meses, com intensidade de 20%, 35% e 50% de ?rea basal presente, eliminando os piores indiv?duos, e a fertiliza??o aplicada aos 99 meses. As vari?veis analisadas resultantes da totaliza??o dos dados das parcelas foram ?rea basal (B), di?metro m?dio (q), altura total m?dia (Ht) e volume total com casca (Vcc). A an?lise dos dados constituiu-se na compara??o do efeito de vari?veis em rela??o ? idade por meio de modelo de regress?o, e foi realizada aos 99 meses ap?s o desbaste e aos 81 meses ap?s a fertiliza??o. Para atender ao segundo objetivo, os dados foram coletados em 34 parcelas permanentes, instaladas em povoamentos com espa?amento de 3,0 x 2,5 metros, em dois s?tios diferentes. Essas parcelas foram medidas aos 24, 36, 48, 60 e 72 meses, durante o Invent?rio Florestal Continuo (IFC). O M?todo dos Ingressos Percentuais foi empregado para determinar a ?poca de realiza??o do primeiro desbaste. Para projetar as distribui??es diam?tricas, para idades superiores ? ?ltima medi??o, utilizou-se um modelo de distribui??o diam?trica, que consiste na recupera??o dos par?metros de uma fun??o de densidade de probabilidade (f.d.p) ao longo dos anos. Neste trabalho, adotou-se a fun??o Weibull, que foi ajustada pelo m?todo de m?xima verossimilhan?a. A partir das informa??es de n?mero de indiv?duos e valores estimados para os par?metros da fun??o Weibull, ? e ?, de ambas as distribui??es diam?tricas analisadas, calculou-se o ingresso percentual (IP) de ?rvores em classes de di?metro sucessivas ao longo do tempo. Para determinar a ITD, foi ajustado um modelo exponencial justaposto a um modelo linear simples. A ITC foi definida como o momento em que o incremento corrente ? igual ao incremento m?dio, sendo a produtividade volum?trica, ao longo do tempo, estimada pelo modelo de Clutter. O desbaste apresentou influ?ncia para as vari?veis ?rea basal, volume total com casca e di?metro m?dio, por?m n?o influenciou a altura total m?dia. A fertiliza??o realizada ap?s o desbaste n?o influenciou a produ??o das vari?veis analisadas. A idade t?cnica de desbaste de um povoamento de eucalipto localizado em um s?tio de maior capacidade produtiva ocorre antes, comparado com a idade de desbaste de um povoamento em um local de produtividade inferior. Esse mesmo comportamento ocorre para a idade t?cnica de corte. Para um mesmo s?tio, a idade t?cnica de desbaste ocorre ap?s a idade t?cnica de corte. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Ci?ncia Florestal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016. / The objectives of this work were to evaluate the influence of thinning and post-thinning fertilization on tree growth of a clonal eucalypt stand, and compare the thinning technical age (ITD), obtained by the Percentages Ingress Method, with the harvest technical age (ITC) of two clonal eucalypt stands. For the first objective, the data were collected in 30 permanent plots, 16 conventional and 14 twins, in which were analyzed the effect of thinning (conventional plot) and fertilization (twin plot) on tree growth. The thinning was carried out at 81 months, with intensity of 20%, 35% and 50% of present basal area, eliminating the worst individuals, and the fertilization applied at 99 months. The analyzed variables resulting from the summation of data from plots were basal area (B), quadratic diameter (q), mean total height (Ht) and total volume with bark (Vcc). The data analysis consisted in the comparison of variable effects, in relation to age, through regression model, and was held at 99 months after the thinning and 81 months after fertilization. To attend the second objective, the data were collected in 34 permanent plots, installed in stands with spacing of 3.0 x 2.5 meters, in two different sites. These plots were measured at 24, 36, 48, 60 and 72 months, during the Continuous Forest Inventory (IFC). The Percentages Ingress Method was employed to determine the epoch of realization of the first thinning. To project the diameter distributions for older ages after the last measurement, there was used a diameter distribution model, which consists in recovering the parameters of a probability density function (f.d.p) along the years. In this work, it was adopted the Weibull function, which was adjusted by the maximum likelihood method. From the information of number of individuals and estimated values for the parameters of the Weibull function, ? and ?, from both analyzed diameter distributions, it was calculated the percentage ingress (IP) of trees in successive diameter classes along the time. To determine the ITD it was adjusted an exponential model juxtaposed to a simple linear model. The ITC was defined as the moment that the current increment is equal to the average increment, in which the volumetric productivity along the time was estimated by Clutter model. The thinning presented influence for the variables basal area, total volume with bark and quadratic diameter, however did not affect the mean total height. The fertilization performed after thinning did not influence the production of the analyzed variables. The thinning technical age of an eucalypt stand located in a higher productive capacity site occurs earlier compared to the thinning age of a stand in a lower productivity site. This same behavior occurs for the harvest technical age. For the same site, the thinning technical age occurs after the harvest technical age.

Page generated in 0.1427 seconds