Afonso Figueiredo Filho

USING THE WEIBULL FUNCTION FOR PROGNOSIS OF YIELD BY DIAMETER CLASS IN Eucalyptus urophylla STANDS

This study aimed to fit the Weibull probability density function to stand data so as to represent the distribution of number of trees by diameter class, and also to fit models representing stand attributes so as to project growth and yield by diameter class and also yield of multiple wood products at the relevant rotation age (7 years). Data were collected from Eucalyptus urophylla stands owned by Anglo Americana plc (CODEMIM), a company situated in the municipality of Niquelândia, Goias state. Initially a 3P-Weibull probability function was fitted by the percentile method for the aggregate stand. Then models were fitted and selected of stand attributes using residuals plot, residual standard error (s yx ) and coefficient of determination (R²) as selection criteria. The hypsometric model of Trorey was then used to derive the average height of possible diameter classes, and the taper model of degree 5 and volumetric model of Takata were used to check compatibility of generated volumes. Prognosticated results were consistent with local productivity when compared to previous inventories complied by the same company of stands within the same age group. RESUMO: Nesta pesquisa, objetivou-se ajustar a funcao de densidade de probabilidade Weibull aos dados do povoamento, visando a representar a distribuicao do numero de arvores por classes de diâmetro bem como ajustar modelos que representem seus atributos para projetar o crescimento e a producao por classe diametrica e o rendimento dos multiplos produtos da madeira na idade da rotacao adotada pela empresa (sete anos). Os dados provieram de povoamentos de Eucalyptus urophylla da empresa Anglo Americana plc (CODEMIM), localizada no municipio de Niquelândia no estado de Goias. Inicialmente foi ajustada a funcao de probabilidade Weibull tres parâmetros pelo metodo dos percentis, para o povoamento como um todo. Posteriormente, foram ajustados e selecionados modelos dos atributos do povoamento, utilizando-se como criterios de selecao o Grafico de residuos, Erro Padrao Residual (s yx ) e o Coeficiente de Determinacao (R²). Em seguida, foi utilizado o modelo hipsometrico de Trorey para obtencao da altura media das possiveis classes diametricas e utilizado o modelo de afilamento de 5° grau e o modelo volumetrico de Takata, visando a compatibilidade dos volumes por eles gerados. Os resultados prognosticados foram coerentes com a producao do local, quando comparados com inventarios ja realizados na empresa em povoamento com essa faixa de idade.

CURVAS DE SÍTIO E RELAÇÕES HIPSOMÉTRICAS PARA Eucalyptus grandis NA REGIÃO DOS CAMPOS GERAIS, PARANÁ

The study aimed to fit mathematical models for the construction of Site Index curves and to estimate heights at different ages for Eucalyptus grandis in the Campos Gerais region, Parana State. The data used to fit the models came from permanent, temporary plots and pre-harvesting inventory, covering ages from 2.5 to 26.5 years. Several models were tested to represent the sites and the hypsometric relationship. The Site Index curves were constructed by the guide-curve method. For the Site Index, the Chapman-Richards model showed the best fit and precision statistics, generating 5 Site Index curves (range of 5 m) with the Chapman-Richards model. The four hypsometric models tested showed satisfactory performance and similar statistics and the inclusion of the variables dominant height or site index did not substantially improve the goodness of fit statistics, but the residues were more homogeneous and closer to zero.

Comparação de métodos e processos de amostragem para estimar a área basal para grupos de espécies em uma floresta ecotonal da região norte matogrossense

O objetivo do presente estudo foi o de comparar a acuracidade e a precisao das estimativas de area basal obtidas de processos, intensidades e metodos amostrais com valores obtidos pelo censo, numa floresta ecotonal de 120 hectares na regiao norte matogrossense, para oito grupos de especies e para especies individuais para arvores com DAP ≥ 30 centimetros. Aplicaram-se os processos: aleatorio e o sistematico, com uma intensidade amostral de 5 e 10% para 22 tamanhos e formas de parcelas variando de 400 m2 a 10000 m2. A area basal media por hectare foi de 11,08 m2. As parcelas de 2500 m2 (125 m x 20 m) apresentaram erros reais e de amostragem sempre inferiores a 10% na estimativa de area basal para os grupos de todas as especies e para as 15 de maiores valores de importância (VI). Para os demais grupos os erros aumentam na medida em que decresce a quantidade de arvores por hectare. Para as especies, individualmente, os erros variaram de 28,7% (Vochysia sp.) a 250,59 (Hymenaeae courbaril), respectivamente, para a mais e a menos frequente, mostrando inviabilidade na aplicacao de processos estimativos tradicionalmente empregados nos inventarios florestais, notadamente para estimar parâmetros especificos de especies raras (baixa frequencia por hectare).

Sustainable Forest Management in Rural Southern Brazil: Exploring Participatory Forest Management Planning

Historically, agriculture and livestock farming have been the main drivers of land cover conversion replacing natural forests in tropical and sub-tropical Brazil. The consequences for the landscape are well known: habitat fragmentation, biodiversity loss, and reductions in the quality of environmental services. The intense exploitation of natural forest resources tends to generate immediate, but limited, short-term economic wealth, which is generally very poorly distributed. In the long-term, forest resources are depleted thus reducing the ability of small rural owners to move out of impoverished situations. Therefore, while conversion of forest to agriculture can in some cases improve rural incomes, all too often deforestation leads to impoverishment of both ecosystems and communities. In Brazil, forest displacement in favour of agriculture and livestock has occurred since early in its colonization; in the Southern region – the principal agricultural area – this process took place in the late XIX and XX centuries. In this part of the country, past forestry practices such as clear-cutting and predatory harvesting, combined with social and legal encouragement, produced scenarios in which forested lands are now mostly degraded, not fulfilling their ecologic, social or economic roles in our society. In spite of the challenges that forest management faces in sub-tropical Brazil, some promising experiences and experiments are helping to create an environment receptive to the reintroduction of sustainable forest management (SFM) as a means to enhance economic incomes for rural property. Herein, we explore the obstacles related to the adoption of SFM as an economic alternative and propose technical opportunities for both small and large rural properties by presenting two case studies.

Evolution of the hypsometric relationship in Araucaria angustifolia plantations in the mid-south region of Paraná state

The aim of this study was to assess and model the evolution of the hypsometric relationship in Araucaria angustifolia plantations grown in the 1940s and 1960s in the Irati National Forest, in the mid-south region of Parana state, Brazil. Using the complete stem analysis method, it was possible to reconstitute the past annual growth of the diameter at 1.3 m (d) and of the total height (h) of a sample of 30 trees, selected so as to cover diametric and age variability. Eleven discs were removed from each tree at 0.1 and 1.3 m and at 15, 25, 35,..., 95% of the total height. Eleven models traditionally used in hypsometric relationships were tested, two of which were considered generic because they involved the age variable. The models were selected based on the Adjusted Coefficient of Determination (R2Adj), Standard Estimate Error (Syx), absolute (m) and relative (%), and on the graphic distribution of residues in percentage. In the models tested by age, no tendencies were observed and erros (Syx) remained below 14.6%, except for ages 5 and 11. However, the coefficients of determination were low, ranging from 0.29 to 0.55. The Curtis generic model (1970), selected to represent the h/d curve for all ages, also presented a satisfactory performance (R2Adj = 0.87 and Syx = 16%), with results similar to those obtained for the models in each age. As age increases, the h/d curve shifts to the right and changes level, remaining steep at the younger ages and more stable and flat as the population nears the end of its cycle.

Modelagem do volume do povoamento para Mimosa scabrella Benth. na regição metropolitana de Curitiba

2. Em cada parcela, mensurou-se o diâmetro a altura do peito, bem como a altura total de todas as arvores, em bracatingais de 3 a 18 anos de idade. Para a estimativa do volume total com casca, testaram-se varios modelos de regressao selecionados da literatura, o que gerou uma matriz com 58 variaveis independentes, visando construir modelos por meio do metodo Stepwise. As equacoes de melhor ajuste foram validadas utilizando-se o teste Qui-quadrado, a analise grafica de residuos e o erro-padrao da estimativa. Varias equacoes tiveram bom desempenho, apresentaram valores de coeficiente de determinacao ajustados superiores a 0,995, erro-padrao da estimativa inferior a 3% e adequada distribuicao de residuos. As duas equacoes de melhor desempenho foram validadas, apresentando erro-padrao da estimativa de 2,37% e 2,13%, valor nao-significativo para o teste do Qui-quadrado e equilibrada distribuicao dos residuos.

Efeito da Idade no Afilamento e Sortimento em Povoamentos de Araucaria angustifolia

The objective of this research was to evaluate the effect of age on adjust taper functions and evolution of the assortment of male and female trees of Araucaria angustifolia stands. Sixty trees were sampled in a plantation located in the municipality of Laranjeiras do Sul, Parana state, Brazil. The fifth degree polynomials were adjusted to the whole data set, and they were stratified into age classes. The evolution of the tapering and assortment of trees was analyzed with age. The results showed a slight advantage in the use of equations adjusted for age classes and a significant improvement in the stem form with increasing age. The female trees presented higher growth (0.9975 m3) than the male trees (0.9384 m3) at 30 years of age. Volumes for the noblest assortments are produced only when the stand reaches the age class of 11 to 15 years.

Efeito da Idade no Afilamento e Sortimento em Povoamentos de Araucaria angustifolia / Effect of Age on Tapering and Assortment in Araucaria angustifolia Stands

The objective of this research was to evaluate the effect of age on adjust taper functions and evolution of the assortment of male and female trees of Araucaria angustifolia stands. Sixty trees were sampled in a plantation located in the municipality of Laranjeiras do Sul, Parana state, Brazil. The fifth degree polynomials were adjusted to the whole data set, and they were stratified into age classes. The evolution of the tapering and assortment of trees was analyzed with age. The results showed a slight advantage in the use of equations adjusted for age classes and a significant improvement in the stem form with increasing age. The female trees presented higher growth (0.9975 m3) than the male trees (0.9384 m3) at 30 years of age. Volumes for the noblest assortments are produced only when the stand reaches the age class of 11 to 15 years.

Dinâmica do afilamento do tronco e da produção de madeira em plantios de Araucaria angustifolia

The research aimed to evaluate the evolution of stem taper and wood assortment in plantations of Araucaria angustifolia. The data came from 30 sampled trees in plantations established between the decades of 1940-1960 in Irati National Forest, Parana State, Brazil. The trees were subjected to the technique of complete stem analysis that allows reconstitution of the entire past growth. The data generated allowed the obtaintion of diameter at different heights at various ages. The mean stem profile by age was obtained from taper functions and cubic splines functions were used to evaluate the evolution of wood assortment by age classes. We also conducted studies on the stem taper dynamics with the use of form factors. The results were presented with the mean of all trees and grouping them into two site classes, when the trees are 50 years old they reach an average volume of 1.20 m 3 , of which 14% could be used for lamination, 66.2% for sawmill 2, 15.9% for sawmill 1, 3.7% for pulpwood and only 0.3% would be residuals. In this same age the sites I and II had mean total volume of 1.94 m 3 and 0.57 m³, respectively. The 5 th degree polynomial function adjusted by age classes allowed to infer that stem tapering improves with age, with the stem becoming more cylindrical. This same trend can be established on the form factor, which practically stabilized after the 35 years of age, at a value of about 0.6.

Prognose do crescimento e da produção em classes de diâmetro para povoamentos desbastados de Eucalyptus grandis no sul do Brasil

This study aimed to develop growth and yield models by diameter classes for Eucalyptus grandis plantation with thinnings. The data used for modeling are from Eucalyptus grandis plantation located in Telemaco Borba, Parana state, and came from permanent, temporary plots and pre-harvesting inventory, with ages ranging from 2.5 to 26.5 years. The Weibull probability density function was used to generate the diameter distribution. The stand attributes modeling process was divided into steps, considering the development stages of stands. Thus, two prognosis systems were generated to predict the attributes in the age of first thinning, second thinning or for the final cut. The modeled attributes were those required for recovery the Weibull function parameters at the ages of intervention by the moments method. To evaluate the prognoses the Kolmogorov- Smirnov adherence test and the L&O identity test proposed by Leite and Oliveira (2002) were used. Both prognosis systems presented good estimates of adjustment and accuracy. The methodology allowed to simulate the growth and yield in Eucalyptus grandis stands trough the rotation, generating logical results, especially for the final cut where the best trees was harvested with higher added values.