Lucas Rezende Gomide

Sustainable Forest Management of Native Vegetation Remnants in Brazil

A region’s species diversity is an important factor, resulting as a component of social and economical development when used wisely. The correct commercialization of a region’s natural resources guaranties the preservation of local culture and habitat maintenance by means of the obtained income. Hence, the idea of sustainability arises, a widespread theoretical theme which is beginning to gain force in Brazil’s consumer market. The principal conceptual shift was the erroneous notion that timber resources from forests are inexhaustible, since the processes of recomposition/restoration naturally occur after exploration. Indeed a system is capable of regeneration, but this is tied to a series of factors that are usually not respected in areas illegally explored. According to a conference realized in Melbourne by Raison et al. (2001), the concept of sustainability must encompass social and economic conditions such as: respect the forest growth rate; legislation based control; productive capacity; ecosystem’s health and vitality; soil and water resource protection; carbon balance and preservation of biological diversity. Under this scenario, Brazil presents great potential for the use of its natural resources. This is due to the country’s vast territorial extension (8.5 million km2) and high diversity of recurrent vegetation physiognomies. The country possesses about 5.2 million km2 of forest land (60% of its territory), of this total, 98.7% consists of natural forest formation and 1.3% of planted forests. The forest types found in Brazil can be classified as Cerrado (Brazilian savanna), Amazonia (tropical rainforest), Mata Atlântica (Atlantic rainforest), Pantanal (wetlands) and Caatinga (semi-arid forest) as well of transition areas which promotes a mixture of habitats. In many cases, the deforestation of these environments is associated with illegal logging practices coupled with agriculture and cattle-raising. The damage caused by this include modifications of the carbon cycle and consequential rise of CO2 emissions; forest fragmentation; alteration of the hydraulic cycle; species extinction; rural exodus and loss of local fauna and flora diversity. Possibly the most logical use of these forests is the application of sustainable forest management for wood production destined for fire wood, charcoal and logs for industrial purposes. The motives for this strategy are evident, involving aspects attached to the reduction

Modelagem preditiva de distribuição de espécies pioneiras no estado de Minas Gerais

The objective of this work was to determine the potential distribution of 23 pioneer species in the state of Minas Gerais, Brazil, as well as to identify the environmental variables that influence their distributions. The Maxent algorithm was chosen to associate the occurrence of species with the following bioclimatic variables: diurnal temperature variation, isothermality, temperature seasonality, driest month precipitation, precipitation seasonality (coefficient of variation), and actual evapotranspiration. The normalized difference vegetation index (NDVI), flora conservation status, and the spatial heterogeneity of vegetation types were also evaluated, besides erodibility (susceptibility of soil to erosion), groundwater availability, soil texture, organic matter content, mineral occurrence (existing mineral species by lithological unit), pedological simplified map, slope and altitude. The species Anadenanthera colubrina was the most suitable for the Caatinga biome, followed by Casearia sylvestris and Plathymenia reticulate , indicated for the Atlantic Forest and the Cerrado biomes, respectively. The use of Maxent is recommended as a tool to guide conservation plans that require the indication of species, aiming to recover degraded or deforested vegetation areas.

Influence of diameter measuring height on the adjustment of volume and biomass equations of cerrado in minas gerais

Different tree diameter measuring heights are displayed in the literature, which in some cases can lead to different results in the final estimates, if the model used is not compatible with the diameter measurement height. The aim of this study was to evaluate and validate equations of volume and biomass, adjusted by Goal Programming and regression by Ordinary Least Squares Method for the Cerrado Sensu Stricto and Campo Cerrado in Minas Gerais state, using information on diameters measured at 0. 10, 0.30 and 1.30 meters from the ground level. Thus, we rigorously scaled 868 trees in areas of Cerrado Sensu Stricto and Campo Cerrado of Minas Gerais. Two different models were subsequently adjusted, one being dual input with the diameter measured at different heights and total height and the second with only the diameter. The results showed that the height where the diameter was taken may influence the accuracy of the models, the diameter measured at 1.30 m presenting the best fits with more accurate estimates. It was possible to generate an equation that can support the monitoring of deforested areas, using the stump diameter (0.10 cm from the soil).

MODELING ECOLOGICAL NICHE OF TREE SPECIES IN BRAZILIAN TROPICAL AREA

Modeling of the ecological niche of vegetal species is useful for understanding the species-environment relationship, for prediction of responses to climate changes and for correct reforestation programs and establishment of plantation’s recommendation. The objective of this work was to establish a model for the distribution of four tree species (Casearia sylvestris, Copaifera langsdorffii, Croton floribundus and Tapirira guianensis), widely used in reforestation projects in the state of Minas Gerais, Brazil. In addition, we analyzed the relationship between environmental characteristics and the occurrence of species and tested the performance of Random Forest and Artificial Neural Networks as modeling methods. These methods were evaluated by their overall accuracy, sensitivity, specificity, Kappa, true skill statistic and the area under the receiver operating curve. The results showed the species Casearia sylvestris, Copaifera langsdorffii and Tapirira guianensis widely occurring in the state of Minas Gerais, including a broad range of environmental variables. Croton floribundus had restricted occurrence in the southern state, showing narrow environmental variation. The resulting algorithms demonstrated greater performance when modeling restricted geographic and environmental species, as well as species occurring with high prevalence in data. The algorithm Random Forest performed better for distribution modeling of all species, although the results varied for each metric and species. The maps generated had acceptable metrics and are supported by and ecological information obtained from other sources, constituting a useful tool to understand the ecology and biogeography of the target species.

CONTINUIDADE ESPACIAL DE CARACTERÍSTICAS DENDROMÉTRICAS EM POVOAMENTOS CLONAIS DE EUCALYPTUS SP. AVALIADA AO LONGO DO TEMPO

O objetivo deste estudo foi avaliar a continuidade espacial ao longo do tempo (para 5 idades consecutivas) das caracteristicas dendrometricas altura dominante media, volume e incremento medio anual em povoamentos clonais de Eucalyptus sp no estado de Minas Geais. A area foi plantada em 2003, perfazendo um total de 1.072,6 hectares. Os dados foram oriundos de um conjunto de 116 parcelas permanentes, onde foi realizado inventario florestal sucessivo entre os anos de 2006 e 2010. Aos semivariogramas experimentais, foram ajustados os modelos esferico, exponencial e gaussiano pelo Metodo dos Minimos Quadrados Ponderados, para cada idade, selecionando-se o mais adequado com base no erro medio reduzido e desvio padrao do erro medio reduzido da validacao cruzada. O comportamento dos semivariogramas foram comparados entre as respectivas medicoes com base no plotagem dos mesmos de forma escalonada, permitindo avaliar se a estrutura espacial foi alterada com a idade do plantio. O modelo exponencial apresentou-se como o de melhor ajuste e todas as caracteristicas apresentaram-se estruturadas espacialmente, com os modelos espaciais sendo semelhantes entre as idades do povoamento e para as caracteristicas estudadas. Foi possivel verificar que o grau de continuidade espacial se manteve ao longo dos anos para as caracteristicas avaliadas e que o semivariograma escalonado demonstrou que a estrutura espacial das caracteristicas e semelhante entre as diferentes idades do povoamento. Os resultados evidenciam que a utilizacao de metodos geoestatisticos para avaliar o crescimento de povoamentos de eucalipto ao longo do tempo, consiste de uma importante ferramenta de planejamento, permitindo um melhor acompanhamento e uma predicao mais precisa do volume de madeira da floresta, levando em consideracao a estrutura de dependencia espacial.

DETECÇÃO DA EXPANSÃO DA ÁREA MINERADA NO QUADRILÁTERO FERRÍFERO, MINAS GERAIS, NO PERÍODO DE 1985 A 2011 ATRAVÉS DE TÉCNICAS DE SENSORIAMENTO REMOTO

O objetivo deste estudo foi analisar a evolucao da area minerada no Quadrilatero Ferrifero (QF), Minas Gerais, e quantificar a area coberta com vegetacao florestal nativa que foi suprimida por esta atividade durante os ultimos 26 anos. Foram utilizadas imagens TM/Landsat 5 correspondente a area de estudo nos anos de 1985, 1989, 2000 e 2011. Para cada ano de analise, utilizando tecnicas de interpretacao visual de imagens, foram criados poligonos identificando e delimitando as areas mineradas. Para a analise da supressao da vegetacao florestal nativa pela mineracao, as imagens de 1985 foram classificadas gerando um mapa tematico de uso e cobertura do solo do QF. Em seguida, os poligonos de mineracao identificados em cada ano de analise foram sobrepostos ao mapa da vegetacao nativa possibilitando o calculo da area de vegetacao florestal nativa suprimida pela expansao da mineracao. Entre os anos de 1985 a 2011, observou-se aumento de 213% na area minerada no QF. As areas suprimidas de vegetacao florestal nativa entre os anos de 1985 a 1989, 1989 a 2000 e 2000 a 2011 corresponderam respectivamente a 324,42 ha, 948,98 ha e 1989,68 ha, com uma perda total de vegetacao nativa de 3.263,07 ha

Relationship Between Spectral Data and Dendrometric Variables in Eucalyptus sp. Stands

The present study aims: (a) to assess the correlations between forest stand characteristics (viz., basal area, dominant height, and volume) and the reflectance values derived from Landsat 5 TM spectral bands as well as from vegetation indices and (b) to understand how Eucalyptus sp. stand age influences these correlations. Sampling data comprised a set of 35 permanent plots from a forest inventory conducted annually between 2006 and 2011. Spectral data were derived from Landsat 5 TM images. The results showed that TM4 and TM5 spectral bands, as well as vegetation indices ND54 and TM5/4, were better correlated with basal area and volume, while the TM2 spectral band was better correlated with dominant height. Eucalyptus sp. stand age directly influenced the correlations between spectral data and forest stand characteristics, and could not be disregarded in the spectral characterization of the forest variables.

Optimal selective logging regime and log landing location models: a case study in the Amazon forest

Reduced-impact logging is a well known practice applied in most sustainable forest management plans in the Amazon. Nevertheless, there are still ways to improve the operational planning process. Therefore, the aim of this study was to create an integer linear programming (ILP) to fill in the knowledge gaps in the decision support system of reduced impact logging explorations. The minimization of harvest tree distance to wood log landing was assessed. Forest structure aspects, income and wood production were set in the model, as well as the adjacency constraints. Data are from a dense ombrophylous forest in the western Brazilian Amazon. We applied the phytosociological analysis and BDq method to define the selective logging criteria. Then, ILP models were formulated to allow the application of the constraints. Finally, 32 scenarios (unbalanced forest, UF, and balanced forest, BF) were generated and compared with real executed plans (RE). Robust results were achieved and the expected finding of each scenario was met. The feasibility to integrate ILP models in uneven-aged forest management projects was endorsed. Consequently, the UF and BF scenarios tested were efficient and concise, introducing new advances for forest management plans in the Amazon. The proposed models have a high potential to improve the selective logging activities in the Amazon forest. A exploracao de impacto reduzido e uma pratica bem conhecida e aplicada na maioria dos planos de manejo florestal sustentavel na Amazonia. Todavia, ainda ha a possibilidade de melhoria do processo de planejamento da operacao. Diante da falta de metodos auxiliares a tomada de decisao, o objetivo do trabalho foi desenvolver modelos de programacao linear inteira (PLI) para suprir esta demanda. Considerou-se a minimizacao da distância entre as arvores exploradas e os patios de estocagem de madeira. Aspectos estruturais, economicos e produtivos foram incorporados ao modelo, bem como restricoes de adjacencia. Os dados derivam de uma floresta ombrofila densa na Amazonia Ocidental. Previamente, utilizou-se uma analise fitossociologica e o metodo BDq como criterio de remocao. Posteriormente, modelos de PLI foram formulados para exemplificar as aplicacoes. Finalmente, 32 cenarios (para floresta desbalaceada, UF, e floresta balanceada, BF) foram gerados e comparados com o plano executado no campo (RE). Resultados robustos foram obtidos e atenderam as expectativas de cada cenario. A viabilidade da integracao dos modelos de PLI em projetos de manejo de florestas inequiâneas foi testado. Os cenarios UF e BF testados foram eficientes e concisos, confirmando seu potencial para aumentar a eficiencia de planos de exploracao madeireira e manejo florestal na Amazonia.

ANÁLISE ECONÔMICA DA ROTAÇÃO FLORESTAL DE POVOAMENTOS DE EUCALIPTO UTILIZANDO A SIMULAÇÃO DE MONTE CARLO

The objective of this study was to determine the economic cycle rotation of eucalyptus plantations in three productivity sites over hazardous conditions. The data used on this study, released by the company Fibria Celulose. Besides the timber production data, it was also given the company cash flow. It was from an even-aged stand and a monoclonal stand both of Eucalyptus urograndis . For the risk analysis, the study used Monte Carlo method, having as a result of the simulation the Net Present Value for Infinite Series, using as an input variable and/or source of uncertainty, the probability distributions of the land and wood prices, the costs of harvesting and transportation activities, the interest rate and also the timber production. The simulation consisted in carrying out 10,000 interactions, where it was obtained the necessary information for the development of the next analysis. As a conclusion the optimal rotation for cutting was 6, 8 and 11 years on the good sites (I), regular sites(II) and poor sites(III) respectively, being consistent with the biological laws of growth. Another conclusion is that even under the same management conditions, more productive sites generate greater economic returns and therefore lower risk in adverse economic scenarios.

Pruning of Eucalyptus grandis X Eucalyptus urophylla Planted at Low Density in Southeastern Brazil

Tree pruning is a silvicultural operation that aims to improve wood quality, but care must be taken regarding the timing and height of the lift to ensure that tree growth is not negatively affected. The objective of this work was to evaluate the effects of different pruning heights on height and diameter growth of Eucalyptus grandis × Eucalyptus urophylla. The experiment was done in a one year old stand which was planted at 9 × 3 m spacing, managed under a silvopastoral regime, and located in Joao Pinheiro, Minas Gerais, Brazil. Pruning treatments removed branches carrying the lower green crown as follows: 0% (unpruned), 20, 40, and 60% of total tree height. Diameter at breast height (DBH at 1.3 m) and total height of all trees in the sample plots were measured prior to pruning and one year after pruning. Compared to the unpruned control, pruning significantly reduced mean DBH and total height in the 40 and 60% treatments but not in the 20% treatment. Thus, it was concluded that when pruning operation is done before canopy closure not more than 20% of lower green crow should be removed to avoid tree growth reduction. Key words: Silvopastoral regime, silvicultural intervention, forest management.