Forma de fuste de árvores de Eucalyptus em plantios com diferentes densidades iniciais

Abstract

ResumoO objetivo deste trabalho foi avaliar o efeito do arranjo espacial de plantio na forma do fuste de árvores de eucalipto. Foram utilizados dados de um experimento implantado em dezembro de 2002, no delineamento em blocos (três blocos), sendo testados os arranjos espaciais de 3,0 x 0,5; 3,0 x 1,0; 3,0 x 1,5; 3,0 x 2,0 e 3,0 x 3,0 m. Aos oito anos de idade foram abatidas e cubadas 180 árvores. Esses dados foram utilizados para ajustar os modelos de afilamento propostos por Garay e de Schöepfer. Testes de identidade de modelos foram aplicados nas equações com a finalidade de verificar a igualdade entre a forma dos fustes. O modelo de Garay é o mais indicado para descrever o afilamento de eucalipto nos arranjos espaciais avaliados. Foi aceita a hipótese de nulidade no teste de identidade de modelos não linear, indicando a igualdade entre as equações nos arranjos de 3,0 x 0,5 e 3,0 x 1,0 m. Para uma distância de 3 metros entre fileiras, quanto maior a distância entre plantas, mais cônica é a forma do fuste.Palavras-chave: afilamento, espaçamento, identidade de modelos. AbstractThe objective of this study was to evaluate the effect of the spatial arrangement of planting on the stem form of eucalypt trees. Data used were from an experiment established in December 2002, in random blocks design (three blocks), with the spatial arrangements of 3,0 x 0,5; 3,0 x 1,0; 3,0 x 1,5; 3,0 x 2,0 and 3,0 x 3,0 m being tested. At eight years of age 180 trees were harvested and cubed. These data were used to adjust the taper models of Garay and Schöepfer. Model identity tests were applied on the fitted equations in order to verify the equivalence between the shapes of the boles. The Garay model is the most suitable to describe the taper of eucalypts in the evaluated spatial arrangements. The null hypothesis in the identity test of nonlinear models was accepted, indicating equality between the equations in the arrangements of 3,0 x 0,5 and 3,0 x 1,0 m. For a distance of 3,0 m between the rows; the greater the distance between plants the most conical shaped is the bole.Keywords: taper, spacing, identity of models. INTRODUÇÃOA forma do fuste ou seu afilamento é definida pela taxa de decréscimo do diâmetro (d) ao longo do fuste da árvore. Ela pode variar com a espécie ou material genético, arranjo espacial e tratos silviculturais (poda e desbaste), além da capacidade produtiva do local (CAMPOS; LEITE, 2013), e o seu estudo é feito por meio de modelos matemáticos que expressam o afilamento do fuste.

Bole Profile of Eucalyptus Under Two Conduction Regimes in the Southwest Region of the Brazilian State Bahia

“…By validating this model, it was proved that both equations selected to estimate the diameter along the bole are statistically valid, which allows estimating precisely the diameter along the bole for each conduction regime. This model also was highlighted due its precision and consistence in estimating the tapering of the bole in Eucalyptus grandis x Eucalyptus camaldulensis stands under different spatial disposition (Souza et al, 2016), for Eucalyptus grandis X Eucalyptus urophylla stands (Campos et al, 2014), for the Virola surinamensis in the Amazon forest (Leite et al, 2006) and heartwood and bole tapering in a Tectona grandis stand (Leite et al, 2011). According to Leite et al (2006), this model derived from the Chapman Richards function, its flexible enough to describe the variations in shape of the trees of different species and sizes and consistent with the variables d, h and volume, as demonstrated by Garay (1979).…”

“…Several factors can affect the bole profile of a tree, among them: species, genetic material, age of the tree, stand spacing, cut regime and thinning, stand conduction regime, site and length and width of the crown (Nogueira et al, 2008;Queiroz et al, 2008;Campos and Leite, 2013;Batista et al, 2014;Andrade et al, 2016;Rodríguez-Toro et al, 2016;Souza et al, 2016;Kohler et al, 2016;Vendruscolo et al, 2016). These factors have encouraged the researchers to develop and apply the bole profile modeling under different conditions.…”

MODELOS POLINOMIAIS PARA DESCREVER A FORMA DO TRONCO DE Pinus taeda L.

“…Esse procedimento procura comparar os volumes obtidos pela cubagem rigorosa dos troncos das árvores de P. taeda com os valores estimados pelas equações polinomiais avaliadas. No entanto, os volumes também podem ser calculados pela integral dos modelos polinomiais conforme realizados por outros autores (SOUZA et al, 2016a;SOUZA et al, 2016b;STEPKA et al, 2017).…”

VOLUME AND TAPER EQUATIONS FOR COMMERCIAL STEMS OF Nothofagus obliqua AND N. alpina

“…Any natural dynamic process or silvicultural practice affecting the future shape of the trees, and has effect on tree growth modifying the stem profile (Souza et al 2016). However, the shape equations showed enough flexibility to estimate the stem profiles of the sampled trees, which were not exempt to the influence of natural or anthropogenic phenomena.…”

“…A taper equation is defined as the diameter reduction rate of the tree stem from the base toward the apex, which determines a form of thereof (CRECHI et al 2009, SOUZA et al 2016. The outputs generate more precise volume estimations, and are more efficient their use to build growth and yield models and sawmill simulators (GEZAN et al 2009).…”