Antonio Bartolomeu do Vale

Avaliação econômica de um povoamento de Eucalyptus grandis destinado a multiprodutos

The objective of this study was to conduct an economic evaluation of the multiproducts in Eucalyptus grandis stands through the methods VPL, TIR, BPE and B/C. Two wood use alternatives were considered: single use and multiproducts productions. The sensitivity analysis included variations in the discount rate and land cost. The results showed that the multiproducts alternative presented higher economic feasibility in all the situations examined.

Dinâmica da regeneração natural em uma floresta ombrófila densa secundária, após corte de cipós, Reserva Natural da Companhia Vale do Rio Doce S.A., estado do Espírito Santo, Brasil

The objective of this work was to evaluate the succession dynamics, growth and production of a secondary dense ombrophylous forest, after vine cutting. The silvicultural treatment was performed to promote a rapid return of the forest to its primary conditions, or, at least, to shorten the time interval between two successive cutting cycles. Data were collected on an experiment established in 1989 measured every two years at the Vale do Rio Doce Natural Reserve, which is located between the municipalities of Linhares and Jaguare, Espirito Santo, Brazil. Sampling was systematic, and all the individual trees with dbh < 5.0 cm were considered as pertaining to natural regeneration. The effects of the treatment upon floristic composition, species diversity, and natural regeneration structure were evaluated in each monitoring period. It was concluded that, for all the categories analysed, great positive variations occurred in the natural regeneration rates and in the increase of the basal area of these individuals during monitoring. This indicates that this forest compartment was most benefitted from the treatment, as well as, indirectly, the arboreal stratum, with the ingrowth of these individuals. Thus, vine cutting favoured the secondary succession dynamics, decreasing the competition for space, nutrients and light, allowing natural regeneration development and a great increase of the ingrowth rate of new individuals in the arboreal stratum.

Análise de danos de colheita de madeira em floresta tropical úmida sob regime de manejo florestal sustentado na Amazônia ocidental

The objective of this work was to identify, qualify and quantify the intensity of damage from natural causes and forest harvest in a non-exploited old growth forest (FPNE) and in a harvested old growth forest (FPE). The studied area is located in the counties of Manicore, Amazon, Brazil, with an area of 204 ha of FPNE and 202 ha of FPE, respectively. The inventory was carried out applying the randomized sampling method, in both areas. Sampling collection was carried out in two levels of approach. In level I, five plots of 100 x 100 m (1 ha) were established, and the individuals with DBH ³ 15 cm were evaluated. In level II, the plots of level I were systematically subdivided in subplots of 10 x 10 m (100 m2), being randomly sampled only five of these per plot of level I, with an area of 2,500 m2, where all the individuals between 5.0 £ DBH < 15 cm (large samplings) were evaluated. The assessment of damage caused to the remaining trees indicate that only 10% of the adult vegetation presented damages in the non-exploited forest. In the exploited forest, the damage caused by harvest operations, such as felling log extraction, skidding trails and clearcut, was of 29%. The changes in the structures of volume, basal area and diameter were more evident in the greater diameter classes, where reductions of 30%, 29% and 27%, occurred respectively. Nevertheless, this reduction can be considered normal, since the sampling was collected immediately after forest harvest operations.

Dinâmica da composição florística de uma floresta ombrófila densa secundária, após corte de cipós, Reserva Natural da Companhia Vale do Rio Doce S.A., estado do Espírito Santo, Brasil

RESUMO - O objetivo deste trabalho foi analisar a dinâmica da composicao floristica de uma Floresta Ombrofila Densa secundaria, apos o corte de cipos. O tratamento silvicultural foi executado com o objetivo de promover o rapido retorno da floresta as suas condicoes primarias ou, no minimo, diminuir o intervalo de tempo entre dois ciclos de corte sucessivos. Os dados foram provenientes de um experimento implantado em 1989 e medido bienalmente na Reserva Natural da Companhia Vale do Rio Doce S.A., municipios de Linhares e Jaguare-ES, Brasil. A amostragem foi sistematica (35 parcelas permanentes retangulares), tendo sido considerados como individuos adultos as arvores com dap ≥ 5,0 cm. Foram avaliados os efeitos da aplicacao do tratamento sobre a composicao floristica e a diversidade de especies, em cada ocasiao de monitoramento. No tocante as especies arboreas, o tratamento pouco influenciou a dinâmica da composicao floristica. Embora a diversidade tenha aumentado (0,55% pelo indice de Shannon-Weaver), os demais indices apresentaram decrescimo, o que indica que houve elevada taxa de ingresso das especies preexistentes na area, ou seja, o aumento do numero de individuos na populacao esta ocorrendo em taxas maiores do que o incremento no numero de especies. Ja a estrutura da floresta (estrato arboreo) foi bastante influenciada, pois os substanciais aumentos em numero de arvores e area basal indicam que as taxas de recrutamento e crescimento estao superando as de mortalidade. Da mesma forma, os grupos ecofisiologicos das secundarias tardias e climaxicas foram os mais beneficiados, sendo mais um indicativo de que o tratamento esta favorecendo a dinâmica de sucessao secundaria.

Avaliação de um modelo de passo invariante na predição da estrutura de um povoamento de Eucalyptus sp.

This study was carried out to evaluate the step-invariant diametric distribution model, proposed by Guimaraes (1994), for the prediction of a Eucalyptus stand production, simulating the alterations in the horizontal and vertical structures with time. Data were taken from annual measurements, with measurement age between 25 and 89 months, of the first rotation of hybrid eucalyptus stands (Eucalyptus grandis x Eucalyptus urophylla), plant spacing of 3.0 x 2.0 m, located in the northeast region of State of Bahia. To perform prognoses percentiles were taken at 50 and 75% of the diametric distribution, and the heights corresponding to the diameters in these positions. The prediction model was proved to be feasible for efficient use, since there were similar tendencies between the forecasted and the observed volumes in the plots. Besides, its use in growth and production prediction of Eucalyptus sp. studies is recommended for its simplicity and result compatibility.

Emprego de um modelo de crescimento e produção para determinação da rotação em povoamentos de eucalipto

The objective of this study was to conduct a growth and yield projection of an eucalyptus stand at any age, associated to cost and revenue information, with cycles of one, two and three cuts, as well as to determine the technical and economic rotations. The criterion for determination of the technical age of cut was the maximization of the mean annual increment, while the economic age of cut was obtained based on the net present value, with the horizons being compared to the infinite for comparison of the different ages. The results indicated that the technical and economic rotations differed from each other with both varying in function of the site index; thus, adopting a medium rotation per project may cause significant revenue losses.

Otimização de multiprodutos em povoamentos florestais

This work aimed to optimize log harvesting by converting them into multiproducts. Thus, data originated from Eucalyptus grandis stands, located in Sabinopolis-MG, were used. Optimized conversion was carried out based on information obtained on available commercial alternatives for logs produced in the stands and on product characteristics. Three alternatives were selected for log use cellulose, energy and sawing, with different maximum and minimum diameter and log length dimensions.The initial problem was to establish an optimized combination that would promote the greatest yield for each utilization alternative. Optimization results show that 1.1; 2.0 and 2.2 m lengths (for energy, sawing and cellulose use, respectively) resulted in greater volumetric production. After selecting the optimum length for each utilization alternative, the combination of these lengths was considered to verify the viability of using the stands for multiproducts. To verify whether optimization was a profitable option an economic analysis of the production was carried out focusing multiproducts versus a single product (cellulose, energy or sawing), by applying the Net Present Value method. The results indicate that multiproduct harvest is more profitable than single use, being the best alternative for forest stand-product profitability.

Um modelo alternativo para a quantificação de multiprodutos em árvores individuais

Preliminary tests were conducted with the objective of evaluating a taper model, proposed from the adaptation of the models developed by Ormerod (1973) and Turnbull (1979), characterized by the simplicity and adjustment easiness. After adjustments and comparisons with other consecrated models, it was observed that the alternative model presented consistency in the carried out adjustments. In conclusion, the presented model can be recommended for multiproduct quantification of individual trees.

Projeção da distribuição diamétrica e produção de povoamentos de eucalipto empregando diferentes formas da função weibull

The projection of the diametrical distribution and production is of great importance for the planning and decision taking in the management of forest stands. The objective of this work was to apply a diametric distribution model in the prediction of distribution and yield of a eucalyptus stand by adjusting and application of the Weibull function with two fitting parameters and truncated. The use of the truncated Weibull estimates provided slightly superior estimates than the Weibull function with two fitting parameters.