Caracterização espectral de mudas de Pinus taeda expostas a incidência de geadas

The frost occurence is a climatic factor that causes negatives consequences to a less or higher degree in all steps of forestry production, and can even be characterized as a limiting factor in commercial plantations in southern Brazil. Through remote sensing and espectroradiometry techniques, its possible to obtain information about the plants stress conditions, caused by the intense cold and the ice formation. The aim of this paper was to evaluate and analyze reflectance curves in the spectral range 400-2000ηm, from seedlings of Pinus taeda exposed to frost incidence in the Nursery of Universidade Federal de Santa Maria in four harsh winter day. The radiometric measurements were made with spectroradiometer FieldSpec\uae3connected to RTS-3ZC unit (integrating sphere). Statistical tests (ANOVA and Tukey), showed the significant differences existence in reflectance curves between measurement periods. Over the time there was a significant increase in reflectance factor in the visible range, which shows the loss of photosynthetic pigments. The disintegration of mesophyll is also evidenced by the substantial increase in reflectance in the near infrared region. In this way, this technique was capable of detecting changes in the physiology of leaves submitted to stress caused by frost. What enhances the use of this tool in planning forest activities subject to losses by this phenomenon.Pages: 3171-317

Estimativa de volume florestal com imagem landsat 5

The arboreal volume estimation studies can be made in faster and economic way by indirect methods, such as the techniques of remote sensing. In this context, this work objective to develop estimating models of arboreal volume for orbital images based on forest inventory data from Rio Grande do Sul state. In the Landsat 5 scene was converted the digital number to radiance and to reflectance, making possible associate a biophysics variable to a digital one. The sample units from the inventory went allocated on the image, whose areas had gotten the digital variable information used like independents on the statistical tests: B1 (0,45 - 0,52 μm), B2 (0,52 - 0,60 μm), B3 (0,63 - 0,69 μm), B4 (0,76 - 0,90 μm), NDVI (Normalized Difference Vegetation Index) and RAZÃO (Reason between bands). The dependent variable was the log volume (m³/ha). The stepwise variable selection method returned one linear model with the RAZÃO index as significant to explain the variation in volume. Finally, the selected model was implemented in the software SPRING, generating a numerical grid whose values of pixels represent the estimated volume in m³/ha and volume thematic maps for Eucalyptus sp. per production units.Pages: 1744-175

DINÂMICA E ESTRUTURA DA ESPÉCIE Dicksonia sellowiana Hook. EM REMANESCENTE DE FLORESTA OMBRÓFILA MISTA

O presente estudo teve por finalidade analisar aspectos inerentes a dinâmica e estrutura da espécie Dicksonia sellowiana Hook. em remanescente de Floresta Ombrófila Mista localizada na Floresta Nacional de São Francisco de Paula, RS. Foram inventariadas dez parcelas permanentes com dimensão de 1 hectare. Todos os indivíduos com circunferência a altura do peito (CAP) ≥ 30 cm e altura ≥ 1,30 m foram incluídos. Foram efetuadas distribuições diamétricas e de altura nas medições de 2.000, 2.003, 2.006 e 2.009 e as taxas de ingresso e mortalidade. Neste estudo, foram encontrados 178 indivíduos da espécie no período de monitoramento, estando presentes em todas as parcelas instaladas. Não foram observadas mudanças expressivas na estrutura diamétrica nos quatro períodos de avaliação, mantendo-se praticamente constantes os números de indivíduos nas respectivas classes diamétricas. As análises da distribuição de altura (estrutura vertical) denotaram claras variações entre os anos. O número de indivíduos da população que ingressaram e morreram não diferiram de forma notável, mantendo valores praticamente constantes no decorrer do estudo. As taxas de ingresso e mortalidade mantiveram-se dentro dos limites esperados para formações florestais maduras. Os Incrementos Periódicos Anuais (IPA) em diâmetro foram de 0,20 cm, -0,015 cm e 0,28 cm e em altura foram de a 0,097 m, 0,067 m e 0,093 m. A espécie D. sellowiana, o incremento negativo no período de 2.003 a 2.006 pode ser justificada por um período de menor intensidade de chuva. Conclui-se a partir do presente estudo que pesquisas referentes a populações naturais de D. sellowiana são de fundamental importância para a ampliação do conhecimento biológico e ecológico da espécie, a fim de subsidiar estratégias de preservação e/ou conservação. Palavras-chave: Floresta com Araucária, xaxim, Pteridófita.   DYNAMICS AND STRUCTURE OF Dicksonia sellowiana Hook. SPECIES IN REMAINING OF MIXED OMBROPHYLOUS FOREST ABSTRACTThe present study had purpose to analyze inherent aspects to the dynamics and structure of Dicksonia sellowiana Hook. species in remainder of Mixed Ombrophylous Forest localized in Nacional Forest of São Francisco de Paula, RS. Had been inventoried ten permanent plots with 1 hectaredimension. All the individuals with circumference at breast height (CBH) ≥ 30 cm and height ≥ 1.30 m had been included. Diametric and altimetric distributions had been effected in the 2000, 2003, 2006 and 2009 measures and calculated the taxes of ingression and mortality. This study found 178 individuals of the species in the monitoring period, being presents in all the installed plots. Expressive changes in the diametric structure in four years of evaluation were not observed, the individual numbers in the respective diametric class remaining themselves practically constant. The analyses of altimetric distribution (vertical structure) denoted clear variations through the years. The individual number in population who have entered and died did not differ remarkably, keeping practically constant values during the study. The taxes of ingression and mortality had been remained inside of the limits waited for mature forest formations. The Annual Periodicals Increments (API) in diameter was 0.20 cm, -0.015 cm and 0.28 cm and height of 0.097 m, 0.067 m and 0.093 m. In D. sellowiana species, the negative increment in the 2003-2006 period can be justified for a period of lower rain intensity. It is concluded from the present study that researches referring to the natural populations of D. sellowiana are fundamental importance for the increase to biological and ecological knowledge of the species, in order to subsidize strategies of preservation and/or conservation. Keywords: Forest with Araucária, xaxim, Tree fern. DOI: http://dx.doi.org/10.14583/2318-7670.v03n03a0

Análise multitemporal do uso e cobertura da terra no município de Faxinal do Soturno-RS nos anos de 1986, 1996, 2006 e 2011

The objective is to evaluate changes in land use and cover, in the municipality of Faxinal Soturno, Rio Grande do Sul, in the years 1986, 1996, 2006 and 2011. The images from the Landsat TM sensor 5, four classes were classified use and land cover: "Forest" "Field", "Bare Soil" and "Water". The classification was supervised way, using the algorithm MaxVer (Maximum Likelihood). The data processing was performed on application SPRING 5.1.8. The results showed that there was an increase of 12,1 km2 in area woods, 1986 to 2011. In areas of the field there was an increase of 25,5 km2 between 1986 and 2006, but from 2006 to 2011 were reduced 10,54 km2. The areas of exposed soil 27,52 km2 decreased throughout the study period. Areas occupied by water are very common in the region, mainly formed by flooded rice fields, this class has remained virtually unchanged in terms of this crop is the main source of income for farmers for many decades. These events may be related to the growth of native forests in areas that were previously occupied by agriculture and livestock, indeed elapsed largely rural RS due to the rural exodus and increased enforcement of environmental violations forest.Pages: 7361-736

Análise multitemporal do Uso e Cobertura da Terra no município de Caçapava do Sul - RS nos anos de 1991, 2001 e 2011

This study aims to analyze the evolution of the use and land cover in the city of South Caçapava through images of the sensor TM, Landsat 5 satellite in 1991, 2001 and 2011. For the study were used remote sensing techniques, digital processing of images which were found at INPE. The study area, municipality of Caçapava South, lies in the micro saws Southeast and is located between the geographical coordinates: 30° 00' and 31° 00' south latitude and 54\ub0 00' and 53° 00' west longitude and altitude approximately 400 meters above sea level. The digital classification algorithm used was supervised Maximum Likelihood. Held digital supervised classification using the Maximum Likelihood algorithm. The thematic classes were chosen: Planted Forest, Native Forest, Field, Bare Soil, Water and Crops of Winter. Analyzing classes in some years it can be said that the significant changes that had been the Planted For0est where it increased by more than 50% in 2011 compared to 1991, however its area does not correspond to 1% of the territory the municipality. The class with the highest expansion was the Bare Soil, for the period 1991-2011 grew 117.40 km² 58% in the period 1991 to 2011. Classes Native Forest and Field, have coverage of 90% and other uses, distributed in the remaining 10% of the municipal area.Pages: 7540-754