Resumo O objetivo do presente estudo foi comparar diferentes métodos de estimativa volumétrica para a espécie Pinus patula. Os métodos estudados foram: fator de forma artificial, modelos volumétricos clássicos, polinômio de 5° grau e método dos dois diâmetros. As estimativas foram avaliadas por meio de: coeficiente de determinação ajustado, erro padrão da estimativa relativo e análise gráfica dos resíduos, e adicionalmente, comparadas por análise de variância ao nível de 5% de probabilidade. Essa análise demonstrou não haver diferenças significativas nas estimativas obtidas pelos métodos testados em relação aos valores paramétricos advindos da cubagem rigorosa. O método dos dois diâmetros com a utilização dos diâmetros do fuste à 1,3 m e 2 m, bem como, o modelo Schumacher & Hall tiveram os menores erros padrões da estimativa relativos e melhor desempenho na análise gráfica de resíduos, mostrando-se mais precisos que os demais estudados. Entretanto, apesar da superioridade desses dois métodos, conclui-se que todos os métodos estudados mostraram desempenho satisfatório para estimativas volumétricas em Pinus patula com 9 anos de idade. Palavras-chave: volumetria, método dos dois diâmetros, cubagem rigorosa.

Species of the genus Pinus are widely cultivated in Brazil, in the south of the country, mainly P. taeda and P. elliottii are responsible for suppling for diverse industrial segments. Although poorly studied, other species from the same region of natural distribution could also possibly present good growth potential. The aim of the present study was to evaluate the development of different dendrometric characteristics of provenances of P. glabra grown in the highlands of south Brazil during 24 years of growth. The values obtained for P. glabra in the studied region was compared with the ones from its natural distribution region and with data of P. taeda in south Brazil. By means of annual dendrometric measurements during almost the entire studied period, especially at age 24 years, the growth and productivity of the species was addressed. All studied provenances shown suitability to the evaluated edaphoclimatic conditions, with initial height growth above 1 m year-1 during the first 5 years. Productivities above 30 m3 ha-1 year-1 at age 24 years, as well as the production of dominant individuals with 30 cm of dbh at age 15 years can be expected. Therefore, the potential for commercial use of P. glabra in the highlands of south Brazil was proven, thus being an interesting alternative to the commonly used species

ResumoAs variáveis morfológicas de mudas florestais podem ser indicativos de sua qualidade, sendo de grande importância para o sucesso de empreendimentos florestais. Nesse contexto, o objetivo do estudo foi correlacionar as variáveis operacionalmente mensuráveis (diâmetro do colo e altura) com as de mensuração destrutiva (área foliar e comprimento de raiz) de mudas de E. dunnii, de modo a formular equações que forneçam estimativas precisas dessas variáveis. Para isso, avaliou-se 77 mudas com 100 dias de idade. As equações foram formuladas através da metodologia "stepwise" para seleção da melhor combinação entre 45 transformações matemáticas das variáveis operacionalmente mensuráveis. As equações foram avaliadas por estatísticas de ajuste e precisão, além de posterior validação por meio de um teste de aderência, a um nível de confiança de 99%, utilizando 50 mudas independentes. Observou-se alta correlação entre as variáveis. Para área foliar, obteve-se coeficiente de determinação ajustado de 0,91 e erro padrão da estimativa de 15,2%. Para comprimento de raiz, coeficiente de determinação ajustado de 0,76 e erro padrão da estimativa de 22,5%. Os dois casos não apresentaram tendenciosidade residual e foram validadas. Diante do exposto, é possível formular equações para obter estimativas de área foliar e comprimento de raiz em E. dunnii. Palavras-chave: Qualidade de mudas; área foliar; comprimento de raiz; modelos matemáticos. Abstract Modeling of morphological variables in Eucalyptus dunnii seedlings.The morphological variables of forest seedlings may be indicative of its quality, having great importance to the success of forest enterprises. In this context, the aim of this study was to correlate the operationally measurable variables (stem diameter and height) with a destructive measurement (leaf area and root length) of E. dunnii seedlings in order to formulate equations that provide accurate estimates of these variables. For this, 77 seedlings were evaluated at 100 days old. The equations were formulated using the methodology "stepwise" for selecting the best combination of mathematical transformations of 45 operationally measurable variables. These equations were evaluated by statistical adjustment and precision, and subsequent validation by means of adherence test, with a confidence level of 99%, using 50 independent seedlings. The results indicated high correlation between the variables. For leaf area, the obtained adjusted coefficient of determination was 0.91 and standard error of estimate 15.2%. To root length, the adjusted coefficient of determination was 0.76 and standard error estimate of 22.5%. The two cases presented no residual bias and had been validated. as result, it is possible to formulate equations to obtain estimates of leaf area and root length in E. dunnii. Keywords: Seedlings quality; leaf area; root length; mathematical models. INTRODUÇÃOA alta produtividade dos reflorestamentos e florestamentos comerciais depende da qualidade das mudas que vão para campo. Qualidade esta que é dependente de...

This study aimed to compare the efficiency of the sampling methods: Fixed Area, Bitterlich, Prodan and Modified Prodan to estimate the commercial volume and other dendrometric estimators for a 34 years old of Pinus taeda L. stands located in Campo Belo do Sul, Santa Catarina, Brazil. It were distributed a total of 10 sample units of the following methods: Fixed Area with 200, 400 and 500 m² of area, Bitterlich, Prodan and Modified Prodan were distributed, both with 6, 7, 8, 9 and 10 trees. In addition to collecting dendrometric data, the installation time of the sample units was timed, whereby the relative efficiency for each method was calculated. The comparison between the harvest volumes and the volumes estimated by the methods was performed by the Skott Knott test, and the results that did not differ statistically were weighted by the parameters of relative error, relative efficiency and proximity to harvest. All variations of the Modified Prodan and Prodan methods had sample insufficiency. The number of trees per hectare presented higher values for the 200 m² Fixed Area method and lower values for Prodan with 10 trees. Prodan with 6 trees got the shortest time. The Bitterlich method obtained sample adequancy at 10% error and presented the best result. Among the alternative methods to Fixed Area, Modified Prodan with 7 trees can be indicated for pilot inventory. However, when more precise results are needed, the Bitterlich method is indicated.

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