Avaliação da influencia dos fatores sitio, idade, densidade e posição sociologica na relação hipsometrica para Pinus taeda nas regiões central e sudoeste do Estado do Parana

The main objective of this research was to analyze the effects of age, site, density and sociologic position on the height-diameter relationship The data carne from the measurement of height and diameter of trees in 137 plots of Pinus taeda, with area of 600 m2, scatered in the State of Parana, Brazil, with ages ranging from 4 to 27 years old. The comparison among regression lines was done through the analysis of covariance. The comparison of means of values h/d was also done through statistic tests. Generic equations including age, site, density and sociologic position as independent variables were also tested a secondary proposed objective was to test the ideal number of trees (pairs of values h/d) for the fitting of the hipsometric relationship. The criteria for the selection of regression models in all phases of this research were the standart error of estimate (syx, syx%), and the residuals distributions. In a preliminary analysis they were selected four regression models (Stoffells, Curtis, Henricksen and Prodan), which were also used for the analysis of the other factors. To analyze the effect of age it was opted for a modal which included the reason height over dominant height (h/hdom =b0 + b1 In d), reducing considerably the standard error of estimate, In a general way, the covariance analysis detected a greater influence of age and site on the intercept (b0) of regression lines. Refering to the inclination coefficient (b1), the influences of density seemed to be stronger, producing steeper regression lines for the greater densities for all analyzed age classes. Refering the sociologic position for the three considered diameter classes, as dominated, mean and dominant, it was detected significant differences among them. The relationship h/d presented decreasing values from the dominated to the dominant diameter class. It was verified that 31 to 40 pairs of values h/d were better to fit the height-diameter equation. The use of a generic equation for the used set of data, seemed quite liable. From the four tested models the one that deserved more attention was: ln h = ln hdom + b0 + b1 ((1/d) - (1/dmax)), with standard error of estimate in percent equal to 6,97%, and presenting a good residual distribution

Viabilidade técnica e econômica da poda em plantações de Pinus Taeda e Pinus Elliottii

Brazil first began concerning about producing pine clearwood 30 years ago, even though it has been quite a common activity in other countries for several years. The wood originated from the first pruned pine plantations began to be harvested in recent years. However, the procedures used in the pruning operation vary from region to region, as well as the thinning regime and quality of the site, which directly affect the growth of the trees and the amount of knot-free wood produced at the end of the rotation. The expected price for this product is equal to or greater than 100% of the wood value for the same grade, without pruning. However, due to the increasing production of composition boards and other changes taking place in the market, clearwood prices have been decreasing, coming close to the prices of unpruned wood. One of the objectives of this study was to quantify the clearwood volumes effectively and potentially generated from pruned logs. Another objective was to establish the minimum price to be charged for the pruned wood so that the same economic result from an unpruned stand could be achieved, considering the costs of pruning and yield in commercial volume in each situation. Yet, the maximum price to be asked for was calculated in order to make it an advantage to buy pruned logs rather than buying clearwood veneer in the market. The cost of pruning only the first log and pruning the first two logs of each tree was considered. The data were taken from eight stands located in the regions of Jaguariaíva, Sengés and Ibaiti, all in Paraná State, and the region of Itapeva, in São Paulo State. The ages of the plantations range between 18 and 24 years old, seven stands being of Pinus taeda and one of Pinus elliottii. The log batches were processed in veneer companies located in Sengés and Ibaiti. The log processing was efficient, for it was possible to measure the diameter of the knotty core as the first knot was shown. The results show that on average 52.9 % of the volume of the batch from the first logs corresponds to the volume of potentially clearwood against 50.1 %, obtained in the batches containing second logs. However, 10.8 % of the volume of these logs was turned into clearwood veneer, whereas in the batches from unpruned stands, this percentage did not exceed 2.3 %. It was observed that the second log has a better shape than the first, both in pruned and unpruned batches, although the volume of the second log is smaller. The pruned trees have a better shape than the unpruned trees and they achieved, on average, 6.5 % more volume than the latter, for the same dbh (diameter at breast height) and height. Regarding the price, the pruned logs must have, in relation to the value of the same grade unpruned, a minimal additional of 53.9 %, so as the same economic result from an unpruned stand and a maximum additional of 77 % can be achieved, so that the buyer might prefer to purchase these logs instead of purchasing the veneers. It is recommended that pruning be performed only on the first log, preferably in very productive sites, due to the uncertainty about the demand for clearwood. Performing pruning on the second log is considered important to make up for the small amount of clearwood in stands of low and medium productivity

Avaliação da influencia dos fatores sitio, idade, densidade e posição sociologica na relação hipsometrica para Pinus taeda nas regiões central e sudoeste do Estado do Parana

The main objective of this research was to analyze the effects of age, site, density and sociologic position on the height-diameter relationship The data carne from the measurement of height and diameter of trees in 137 plots of Pinus taeda, with area of 600 m2, scatered in the State of Parana, Brazil, with ages ranging from 4 to 27 years old. The comparison among regression lines was done through the analysis of covariance. The comparison of means of values h/d was also done through statistic tests. Generic equations including age, site, density and sociologic position as independent variables were also tested a secondary proposed objective was to test the ideal number of trees (pairs of values h/d) for the fitting of the hipsometric relationship. The criteria for the selection of regression models in all phases of this research were the standart error of estimate (syx, syx%), and the residuals distributions. In a preliminary analysis they were selected four regression models (Stoffells, Curtis, Henricksen and Prodan), which were also used for the analysis of the other factors. To analyze the effect of age it was opted for a modal which included the reason height over dominant height (h/hdom =b0 + b1 In d), reducing considerably the standard error of estimate, In a general way, the covariance analysis detected a greater influence of age and site on the intercept (b0) of regression lines. Refering to the inclination coefficient (b1), the influences of density seemed to be stronger, producing steeper regression lines for the greater densities for all analyzed age classes. Refering the sociologic position for the three considered diameter classes, as dominated, mean and dominant, it was detected significant differences among them. The relationship h/d presented decreasing values from the dominated to the dominant diameter class. It was verified that 31 to 40 pairs of values h/d were better to fit the height-diameter equation. The use of a generic equation for the used set of data, seemed quite liable. From the four tested models the one that deserved more attention was: ln h = ln hdom + b0 + b1 ((1/d) - (1/dmax)), with standard error of estimate in percent equal to 6,97%, and presenting a good residual distribution

AVALIAÇÃO DA INFLUÊNCIA DOS FATORES IDADE E SÍTIO NA RELAÇÃO HIPSOMÉTRICA PARA Pinus taeda NAS REGIÕES CENTRAL E SUDOESTE DO ESTADO DO PARANÁ

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COMPORTAMENTO DA BRACATINGA (Mimosa Scabrella Benth) SOB CINCO NÍVEIS DE FÓSFORO - INFORME PRELIMINAR

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Recommended thinning regimes for Araucaria angustifolia plantations on small properties in southern Brazil – a case study

Araucaria angustifolia has economic and productive potential in southern Brazil, due to its high wood quality and seeds appreciated by humans and wild animals, besides playing an important role in the rehabilitation of degraded areas. Moreover, the species represents an opportunity of higher incomes for small farmers through the establishment of plantations in small lots managed for timber production. However restrictive environmental laws, and little knowledge about the silviculture of the species has led to a lack of interest in planting and in developing new researches on A. angustifolia. So the objective of this research was to better understand the outcomes of management systems used in A. angustifolia plantations and to evaluate the feasibility of establishing araucaria plantations on small farms. For this purpose, we carried out an inventory in an 8-year-old, 0.92 ha araucaria plantation, with a spacing of 3 x 3 m, in Rio Negro, Paraná, Brazil. Based on the results, we used the SisAraucaria software to simulate thinning regimes, varying in age and type of thinning (systematic, selective or only selective), and clear cut at age 25. The regimes with two selective thinning episodes were more productive than those with only one or no thinning. The best economic return was obtained with the regime that included thinning at 10 and 20 years, with the first removing 80 % of the trees and the second 20 % of the trees. We conclude that the plantation model evaluated may be feasible if the appropriate thinning regime is applied

Determinação do comprimento ótimo de transectos para estimativa de necromassa florestal

O objetivo deste trabalho foi avaliar diferentes comprimentos de transecto para determinação da necromassa florestal caída sobre o chão. Os dados são provenientes de transectos de 10 metros, medidos durante o teste de metodologia do Inventário Florestal Nacional na Amazônia, Cerrado e Caatinga, e no inventário em Santa Catarina, representando Floresta Ombrófila Mista e Floresta Estacional Decidual. O comparativo do coeficiente de variação, para transectos de 10 a 150 m indica que as maiores alterações desse estimador ocorrem no intervalo de 10 até 50 m, estabilizando-se a partir deste comprimento. A adoção de transectos de 10 m nas tipologias avaliadas é recomendável, pois com este comprimento ocorre uma redução de 35% na distância total de caminhamento em relação aos transectos de 20 m, para obter o mesmo erro amostral