Evaldo Muñoz Braz

Estudo da dinâmica da floresta manejada no projeto de manejo florestal comunitário do PC Pedro Peixoto na Amazônia Ocidental

On this work we present the results of a forest dynamics study performed in a forest management system designed for small properties. The system prescribes cutting cycles of 10 years, harvesting intensity of 10 m 3 ha -1 and animal traction for skidding. The forest growth was 1 m 3 ha -1 year -1 adequate to the proposed cutting cycle and harvesting intensity. The damage produced by the forest exploitation represented 5 % of the total basal area of the forest and the mortality rate four years after exploitation was 3.2 %.

CLIMATE-TREE GROWTH RELATIONSHIPS OF Mimosa tenuiflora IN SEASONALLY DRY TROPICAL FOREST, BRAZIL

Mimosa tenuiflora is a native pioneer tree from the Caatinga used commercially as firewood due to its high calorific value. It is deciduous, its trunk does not reach large diameters and it has good regrowth capacity. This study intended to determine the annual increment in diameter of M. tenuiflora and its correlation with rainfall, as basis for fuel wood management. Disks from the stem base of M. tenuiflora trees were collected in 2008 in Sertânia and Serra Talhada, Pernambuco State, from regrowth of trees coppiced in 2003 and in Limoeiro do Norte, Ceara State, from a plantation established in 2002. The trees have well-defined annual growth rings, highly correlated with annual precipitation and are well-suited for dendrochronological investigations. Forest managers must consider the influence of previous drier years in the wood production when predicting fuel wood harvesting. The high growth correlation with the previous years rainfall in regions where the rains start after photoperiodic stimulation indicate the necessity of understanding the growth dynamics of the species under dry forest conditions through additional ecophysiology studies.

Manejo da estrutura diamétrica remanescente de florestas tropicais

O incremento de uma floresta sob uma exploracao madeireira depende nao apenas do ritmo de crescimento das especies como tambem da distribuicao diametrica remanescente que devera permanecer pos corte. O trabalho avaliou, mediante simulacao, a estrutura diametrica remanescente de um talhao de floresta ombrofila no estado do Amazonas, visando a garantia de ter incremento que recupere a extracao. A simulacao do crescimento da floresta pos-exploracao, respeitando a taxa calculada e a estrutura, permitiram um incremento que pode recuperar o volume comercial inicial durante o ciclo considerado (25 anos). Observouse nas simulacoes que a remocao de todo volume comercial disponivel das especies estudadas impede a recuperacao da floresta no ciclo considerado. Observou-se tambem que as classes diametricas comerciais remanescentes (acima do centro de classe de 45 cm) sao responsaveis por 81 % do incremento necessario para recuperacao do volume comercial removido. Identificou-se um ponto otimo de classe diâmetro a ser mantida na floresta, acima do qual o retorno do volume comercial e nulo. O ponto crucial da recuperacao do volume extraido e o potencial de incremento da estrutura que deve permanecer no compartimento.

DETERMINAÇÃO DA ÉPOCA DE DESBASTE PELA ANÁLISE DENDROCRONOLÓGICA E MORFOMÉTRICA DE Ocotea porosa (Nees & Mart.) Barroso EM POVOAMENTO NÃO MANEJADO

Commercial plantations of Ocotea porosa available for studying are scarce and therefore should be used as a source of information to establish the potential for management of the species in plantations, even if these evaluations were not been held along the stand development. The recovery of the historical growth of these stands to optimize the management plans is possible by dendrochronology and by the analysis of morphometric and dendrometric data. The aim of this study was to use stand analysis tools, combined with the dendrochronological studies, to recover and to systematize the development of unmanaged stands. The study was conducted in an unmanaged stand of Ocotea porosa , with 44 years old in Rio Negro, PR state, in a UFPR station. Growth inferences recovered by dendrochronology and the competition by the application of methodologies such as slenderness rate and crown cover rate showed consistent results in the analysis of population, indicating the need for a first thinning near 12 years old. Due to the small number of sampled trees, the results do not allow any definitive generalization. However, they are consistent to establish an analysis protocol for unmanaged stands of Ocotea porosa or other species.

Dendrogramas de densidade para Hovenia dulcis Thunberg na região central do estado do Rio Grande do Sul, Brasil

The objective of this study was to elaborate dendrograms for the management of density, for populations of Hovenia dulcis located in the central region of Rio Grande do Sul, Brazil. To this end, we used information from 4 stands, aged 25 years, located at the Fundacao de Pesquisa Agropecuaria (FEPAGRO) and a population of free trees with diameters at breast height (DBH) ranging from 5 to 45 cm, located on the campus of the Universidade Federal de Santa Maria (UFSM), RS. In stands under competition, the data were collected from trees of the dominant, intermediate, and dominated stratas by the method of density point. In trees free of competition, the data were collected in the form of census. It was found that the model Reineke adjusted satisfactorily to estimate line density of canopy closure and anthropic, with slopes approaching -1.5, showing that the -3/2 self -thinning power law was contemplated and that the hypothesis postulated by Reineke was also satisfied. The population density for canopy capacity was 42.5% of the maximum number of trees, making it possible to construct diagrams for the management of density from 5 to 31 cm in diameter of average basal area of the tree.

UM MODELO OTIMIZADOR PARA ORGANIZAÇÃO DOS COMPARTIMENTOS DE EXPLORAÇÃO EM FLORESTA TROPICAL 1

There is a need to ensure an even flow of timber with commercial potential to make forest management viable on small farms; however, this need is not always met, due to the fact that compartments are small and especially due to the irregular distribution of the species of interest in the native forest because of the heterogeneous ecosystems and forest typologies that form a complex mosaic. The main purpose of this work was to develop a mathematical model to help with the planning and distribution of stands in a small tropical forest farm. The mathematical model resulted in a new concept of stand. Based on the pre-exploratory forest inventory, the compartments were divided into sub compartments with their different values being calculated according to market timber prices. Since the annual logging rate allowed had already been defined based on local and regional studies, the goal was to guarantee that this rate, transformed in monetary value can really be reached annually. The mathematical model GP (Goal programming) was utilized in the selection of the sub compartments by grouping them into a final compartment with size similar to that of the original annual compartment. The proposed stand model was compared with the type of stand normally used in tropical forests and was proved rather superior to the conventional one, thus guaranteeing small farmers a balanced annual income.

Life pattern of urban trees: A growth-modelling approach

Urban afforestation improves life quality in urban centers providing social and environmental benefits. Understanding growth of urban trees exposed to air pollution will support planning, managing and expanding urban areas. This approach intends to determine growth patterns of urban trees to support future urban planning. Non-destructive samples were collected from trees of Araucaria angustifolia (Bertol.) Kuntze in Araucaria city, Parana State, Brazil. Growth rings were related to pollutant concentrations and meteorological series. Growth reduction was observed except in the border areas of the city. Trees established during or after the period of industrialization incentives were most affected by air pollution, indicating that immature plants are more vulnerable. Sulphur dioxide and nitric oxide significantly affected growth of smaller trees. Those greater than 60 cm dbh did not demonstrate significant correlation with any identified pollutant. As the trees established before accentuated urbanization were less affected by air pollution, it is reinforced the importance of preserving remaining urban trees. We suggest that planning urban afforestation should precede industries placing. When urban planning is impossible, new planted trees should not be expected to grow as in free pollution areas, but they will still present satisfactory diameter increment, contributing to improve local urban environment.

SUSTAINABLE MANAGEMENT OF NATURAL FORESTS IN PANTANAL REGION, BRAZIL

The Pantanal region in Brazil has an area of 140,000 km², with approximately 30 % of natural forests distributed as deciduous, semideciduous, and forested savannas. The subregion of Nhecolandia represents 19 % of this area. There is constant concern about the sustainability of these forested areas, as there is a constant demand for wood for farm maintenance, mainly for making fence poles. The objective of this article is to indicate sustainable forest management practices in the Pantanal region of Nhecolandia. The methodology of this novel approach consisted of the recovery and organization of the available information to calculate the sustainable allowable cut per hectare, considering: cutting cycle, wood stock, periodic annual increment (PAI) in percentage of volume from the commercial or interesting species and the stand structure. For forested savannas, the diameter at breast height (DBH) of 529 trees per hectare were estimated as follows: 28 % with a DBH lower than 10 cm, 36 % from 10 to 20 cm, 21 % from 20 to 30 cm, 10 % from 30 to 40 cm and only 4 % greater than 40 cm. The estimated total volume per hectare was 84.2 m³ and the estimated basal area was 18.6 m². The forested areas of the Pantanal region present potential for sustainable use. However, due to regional characteristics and the lack of available information, an enhancement in research is recommended to establish a basic management guide to ensure its perpetuation for future generations.

Equations to estimate tree gaps in a precision forest management area the Amazon based on crown morphometry.

The precision forest management technique still has much to be improved with the incorporation of forest biometric techniques and forest profiling with airborne LIDAR. When planning the cutting of a tree in forest management, the volume to be produced for industry is estimated but not the area impacted by removal of the tree. The objective of the present study was to develop equations for the Amazon rainforest that are able to estimate the impact area of gaps from harvesting individual dominant and co-dominant trees based on the canopy morphology obtained through forest profiling. On two separate occasions profiles were made in an annual forest-production unit in the Antimary State Forest (FEA) in the state of Acre, Brazil. The first was done a few days before the start of logging in 2010 and the second was done after completion of harvest activities in 2011. With field measurements and processing of the cloud of LIDAR points, dendrometric and morphometric variables were obtained for the canopy in order to develop equations for estimating gap areas. After evaluation of the explanatory variables with the highest correlation with gap area, the method used considered all possible models and included 2-4 parameters. The explanatory variables that best represent the impact of clearings are volume of the crown (VCop) and crown-projection area (APC). Ten equations were selected, of which two were chosen for use; these had R2 aj > 75% and Syx <23%. The good fit of the equations demonstrates the potential use of LIDAR to obtain information for estimating in advance the gaps in the forest cover that will be created from harvesting trees of different sizes.

Vinte anos monitorando a dinâmica de crescimento de uma floresta tropical explorada na Amazônia ocidental

We performed a forest growth dynamics study in Acre State, Brazilian southwestern Amazon, where a 20 ha area was logged in 1992. The study was based permanent sample plots (1 ha) established in the logged area and in an unlogged forest immediately after logging operations finished. Forest dynamics parameters were assessed in terms of aboveground dried biomass (AGB). During the study period, three extreme climate events triggered a high impact on both logged and unlogged areas, producing AGB losses greater than those estimated for logging. Twenty years after logging, ingrowth and mortality rates were similar to those expected in an undisturbed forest, and AGB recovery was significantly faster in the logged areas. Forest management, when properly applied, can promote faster forest AGB recovery. We suggest that forest management could be considered as an alternative to adapt to extreme climate events, by promoting controlled disturbances, which should minimize tree mortality and biomass loss. Vinte anos monitorando a dinâmica de crescimento de uma floresta tropical explorada na Amazônia ocidental Resumo Foi conduzido um estudo sobre a dinâmica de crescimento em floresta localizada no Estado do Acre na Amazônia sul ocidental, onde uma área de 20 ha foi explorada para extração de madeira em 1992. O estudo foi baseado em parcelas permanentes (1 ha) estabelecidas dentro da área explorada e na floresta não manejada, imediatamente após o fim das operações florestais. Os parâmetros da dinâmica florestal foram analisados em termos da biomassa seca acima do solo (BAS). Durante o período do estudo três eventos climáticos extremos causaram um elevado impacto tanto nas áreas exploradas como nas não perturbadas por exploração, produzindo perdas de biomassa superiores às estimadas para a exploração. Vinte anos após a exploração, as taxas de ingresso e mortalidade foram semelhantes às esperadas em uma área de floresta não perturbada por exploração e a recuperação da BAS foi significativamente mais alta nas áreas cortadas. Quando praticado de forma adequada, o manejo de floresta pode promover uma recuperação da BAS mais rápida. Nós sugerimos que o manejo florestal pode ser considerado como uma alternativa para adaptação a eventos extremos de clima por meio da promoção de perturbações controladas que minimizem a mortalidade de árvores e a perda de biomassa. ISSN: 1983-2605 (online) *Corresponding author: marcus.oliveira@embrapa.br