José Roberto Soares Scolforo

Effects of past disturbance and edges on tree community structure and dynamics within a fragment of tropical semideciduous forest in south-eastern Brazil over a five-year period (1987–1992)

Tree community structure and dynamics of a 5.8 ha fragment of montane semideciduous forest in south-eastern Brazil are described based on two successive surveys of trees with dbh ≥5 cm carried out in 1987 and 1992 in 126 20 × 20 m quadrats. The main purpose was to assess whether the spatial variation of dynamic and structural variables were related to edge-effects and past disturbance regimes. The totals for the two surveys were, respectively, 6528 and 6770 trees, and 94.89 and 108.53 m2 of basal area. The forest fragment was at an aggrading sylvigenetic phase, indicated by an overall net increase in density and basal area, and by a declining proportion of trees of smaller size. The overall annual mortality and recruitment rates were 2.6% and 3.0%, respectively. The dynamic process, however, was strongly affected by spatial heterogeneity. The more severely disturbed sectors had lower average canopy heights and basal areas per hectare, and higher tree densities, proportions of smaller trees, and relative area of canopy gaps. They also had higher mortality and recruitment rates, resulting in higher turnover rates compared to the sectors which suffered only moderate disturbance regimes. Edge sectors were also affected by different past disturbance regimes. However, they stood out by having a particularly high frequency of liana tangles and the highest rates of net increase both in density and basal area. A canonical correspondence analysis indicated that the effects of past disturbance regimes and edges were highly related to the species distribution in the area. Pioneer species were concentrated on the edges and more severely disturbed sectors, shade-tolerant species were particularly more abundant on the moderately disturbed sites, while light-demanding ones were more widely distributed. Tree community structure was also undergoing important changes, with less common species enjoying higher recruitment rates and density increase compared to the more common ones. Shade-tolerant species were increasing in relative abundance and had comparatively lower mortality rates and higher recruitment rates. On the other hand, pioneer species were under retreat, with a decreasing relative abundance, higher mortality rates and lower recruitment rates.Nomenclature: Oliveira-Filho et al. 1994a,d.

Plant extracts to control "Alternaria alternata" in Murcott tangor fruits

BACKGROUND Alternaria alternata causes the Alternaria brown spot disease (ABS) in many tangerines and their hybrids worldwide. Plant extracts offer an alternative method for controlling this disease, which control is based on chemical fungicides. AIMS To identify plant species with antifungal properties against A. alternata, the causal agent of the ABS. METHODS Plant extracts prepared from leaves, barks, flowers, and stalks collected from 105 plant species in the State of Minas Gerais, Brazil, were tested for activity against the fungus A. alternata in vitro and in vivo. RESULTS The most promising extract was obtained from Anadenanthera colubrina, which reduced the disease on Murcott tangor fruits to levels obtained with commercial fungicides. Artemisia annua, Cariniana estrelensis, Ficus carica, and Ruta graveolens presented moderate in vitro antifungal activity, but no effects were observed on the disease when the extracts were applied to fruits inoculated with the fungus. Besides, A. colubrina was the most active extract against A. alternata in the in vitro assay. CONCLUSIONS The results obtained in the in vitro and in vivo assays suggested that the fungal growth test, which uses 96-well polypropylene plates, seems to be appropriate for selecting potential plant species for testing new methods to control ABS.

Continuidade espacial para características dendrométricas (numero de fustes e volume) em plantios de eucalyptus grandis

O objetivo deste estudo foi verificar a continuidade espacial do numero de fustes e do volume nas diferentes formas e intensidades amostrais de Eucalyptus grandis com idade entre 3 e 4 anos. A area de estudo abrangeu quatro talhoes, totalizando 104,71 ha, pertencentes a Ripasa S/A Celulose e Papel. Os dados para a realizacao do estudo de variabilidade espacial foram coletados em parcelas circulares e em parcelas em linhas distribuidas sistematicamente na area, nas intensidades de 1:4 (1 parcela a cada 4 ha), 1:7 e 1:10. Foi possivel verificar que, tanto em numero de fustes quanto em volume, os dados apresentaram distribuicao aproximadamente normal. Pela analise variografica, foi verificado que as caracteristicas numero de fustes e volume de madeira apresentaram-se estruturadas espacialmente. O modelo exponencial foi o que se ajustou melhor aos semivariogramas experimentais das caracteristicas nas diferentes formas de parcela e intensidade amostral. A continuidade espacial foi detectada em todas as intensidades amostrais e formas de parcelas avaliadas, quanto a numero de fustes. Portanto, o uso da estatistica espacial no processamento dessa variavel aumentara a precisao das estimativas. No caso de volume, na intensidade amostral 1:10 nao foi possivel detectar continuidade espacial. Em tal condicao, deve-se utilizar a estatistica classica para processamento do inventario florestal.

Manejo sustentado para floresta de várzea na amazônia oriental

The aim of this study was to define tree cut options in a sustainable basis for floodplain forests in the Amazonian Estuary. Data were obtained from the survey carried out in the forest lands of Wood Exports of Para Ltda. - EMAPA Enterprise, located in Afua County, North of Para State. Sampling was performed in 29 plots of 5.000 m 2 . There were surveyed all trees, including palm trees with diameter at 1.30m above ground level (dbh) ≥ 45 cm. Trade species with possibility to be harvested for presenting best phytossociological and qualitative indexes were: Virola surinamensis, Carapa guianensis and Hymenaea oblongifolia; among potential species Terminalia dichotoma was chosen; while in the non-trade species group, Eschweilera coriacea, Swartizia racemosa and Licania macrophylla were selected. Results showed that the forest management can be done by adopting a harvesting plan with a De Liocourt value 50% higher than the original (q = 2,61) one and removal of 30% of basal area, which corresponds to a potential income of US

Propriedades de solos sob vegetação nativa em Minas Gerais: distribuição por fitofisionomia, hidrografia e variabilidade espacial

3.945,40/ha.

Estratégias e metodologias de ajuste de modelos hipsométricos em plantios de Eucalyptus sp.

One of the factors affecting the distribution of native vegetation is soil formation. Therefore, soils under native vegetation can be highly informative with regard to a region and the original soil fertility, as records of conditions found before agricultural reclamation (agrosilvopasture). The purpose of this study was to assess soil fertility and texture under native vegetation fragments sampled during the Forest Survey of the State of Minas Gerais, Brazil. In general, the variability in all soil properties was high, except for Al3+. In soils under grassy savanna (Campo Cerrado), the concentrations of soil organic matter were higher than in savanna woodlands (Cerradao and Cerrado Stricto Sensu). In general, seasonal forests were found on soils with higher fertility than Cerrado formations, whereas rainforests (Floresta Ombrofila) occurred on the most acidic and organic matter-rich soils. Linear regression analyses showed that the importance of soil organic matter for cation exchange capacity at pH 7.0 varied among the different vegetation types, and was irrelevant for seasonal deciduous forest (Decidual Seasonal Forest), but significant for the other phytophysiognomies. Data stratification by hydrographic basins, interpreted in combination with stratification by vegetation, allowed inferences about the probable effect of parent material on soil properties, especially on soil texture. By means of geostatistical analysis and based on ordinary kriging, maps of soil pH, organic carbon and clay contents, but not of cation exchange capacity at pH 7.0, were drawn for the state of Minas Gerais. Data of soils under native vegetation fragments could be used as reference standards of natural soil fertility, not only in Minas, but in other states of Brazil as well.

Avaliação de modelos polinomiais não-segmentados na estimativa de diâmetros e volumes comerciais de Pinus taeda .

This study aimed at testing different data gathering and adjustment strategies of traditional and generic hypsometric models in order to improve Eucalyptus sp. tree height estimates. Tree height and diameter pairs were colleted in 36 plots, belonging to Veracel Celulose S.A. The data were divided into different treatments according to age, site, and combination of age and site of the stands, totaling 14 treatments. The data gathering strategies consisted in using a different number of trees with height measurement to form the database used for the model adjustments. When considering the data gathering strategies where the first five trees per plot and the first five trees per plot plus the dominants were selected, it was concluded that the best strategies consisted in using the Curtis model adjusted per plot, and the two generic models from Campos & Leite (2006) and Scolforo (2005). When considering the data gathering strategy in which trees were added based on the absence of an individual on a determined diameter quartiles, only the Curtis model per plot was selected.

Spatial Distribution of Aboveground Carbon Stock of the Arboreal Vegetation in Brazilian Biomes of Savanna, Atlantic Forest and Semi-Arid Woodland.

This study aimed at constructing equations with fractionary, unitary and ten magnitude power, in an attempt of representing the top, medium and basis portion of the stem; at constructing polynomial equations compatible with volume equations; at evaluating the accuracy of three non-segmented polynomial taper models for estimating diameters and volumes along the stem of Pinus taeda; and at verifying if the more accurated model for diameters estimates is also the more accurated for estimating partial and total volumes. The database used was composed of 58 trees of Pinus taeda cubed by the Smalian’s method, in the farms of “PISA – Papel de Imprensa S/A” enterprise, located in Jaguariaiva county (PR). The 58 trees were separated in 8 diameter classes. The models were fitted for each diameter class and for the total group of data. Three non-segmented polynomial models were tested: Schoepfer (1966); Hradetzky (1976); and Goulding and Murray (1976). The accuracy of the models in estimating diameters and volumes along the stem of Pinus taeda was evaluated through the following statistics: coefficient of determination; residual standard error; graphic analysis of the medium profile of the stem; mean deviation of the diameters and volumes for each position along the stem; standard deviation of the differences of the diameters and volumes; sum of square of the relative residue; and percentage of the residues of the diameters and volumes. Starting from the last four statistics, it was elaborated a ranking to detect the more accurated model for each position along the stem. It can be pointed out that among the non-segmented models tested, the model of Hradetzky (1976) is more stable than the others in the estimates of the two studied variables. Goulding and Murray (1976) model presented accurated estimates of diameters and volumes along the whole stem profile only when fitted by diameter classes. The model proposed by Schoepfer (1965) showed biased estimates along the whole stem profile, in all diameter classes.

Volume equations for the savannah (cerrado), in Minas Gerais state

The objective of this study was to map the spatial distribution of aboveground carbon stock (using Regression-kriging) of arboreal plants in the Atlantic Forest, Semi-arid woodland, and Savanna Biomes in Minas Gerais State, southeastern Brazil. The database used in this study was obtained from 163 forest fragments, totaling 4,146 plots of 1,000 m2 distributed in these Biomes. A geographical model for carbon stock estimation was parameterized as a function of Biome, latitude and altitude. This model was applied over the samples and the residuals generated were mapped based on geostatistical procedures, selecting the exponential semivariogram theoretical model for conducting ordinary Kriging. The aboveground carbon stock was found to have a greater concentration in the north of the State, where the largest contingent of native vegetation is located, mainly the Savanna Biome, with Wooded Savanna and Shrub Savanna phytophysiognomes. The largest weighted averages of carbon stock per hectare were found in the south-center region (48.6 Mg/ha) and in the southern part of the eastern region (48.4 Mg/ha) of Minas Gerais State, due to the greatest predominance of Atlantic Forest Biome forest fragments. The smallest weighted averages per hectare were found in the central (21.2 Mg/ha), northern (20.4 Mg/ha), and northwestern (20.7 Mg/ha) regions of Minas Gerais State, where Savanna Biome fragments are predominant, in the phytophysiognomes Wooded Savanna and Shrub Savanna.

Nanostructured polylactic acid/candeia essential oil mats obtained by electrospinning

In this work, the physiognomy Savannah (Cerrado), present in three regions of the Sao Francisco River Basin, in Minas Gerais State, was studied with the following objectives: to adjust and to select equations to estimate total volume and stem volume; to test the similarity among volumetric models; to show the behavior of the volume in the stem and branches of the tree, and to evaluate the bark percentage in each diametric class. For this, the rigorous scaling using the method of Huber was accomplished, in which the data base was composed by 497 trees, distributed in six diameter classes, inside the three study areas. The bark thickness at the heights of 0%, 25%, 50%, 75% and 100% of the commercial height was measured. The accuracy of the models was evaluated by the determination coefficient, standard error of estimate and graphic analysis of the residuals. To test model identity, the method used was the one developed by Graybill (1976). The models selected for all the tested variables were the ones of Schumacher and Hall and of Spurr, transformed in logarithm. According to the identity test of models, for all the tested variables, similarity exists among the areas 2 and 3. Regarding to the behavior of volume, it was observed that the smallest diametric classes possess larger stem volume than the branches and that there is also a tendency of decreasing the bark percentage with the increase of the diametric class for the three studied areas.In this work, the physiognomy Savannah (Cerrado), present in three regions of the Sao Francisco River Basin, in Minas Gerais State, was studied with the following objectives: to adjust and to select equations to estimate total volume and stem volume; to test the similarity among volumetric models; to show the behavior of the volume in the stem and branches of the tree, and to evaluate the bark percentage in each diametric class. For this, the rigorous scaling using the method of Huber was accomplished, in which the data base was composed by 497 trees, distributed in six diameter classes, inside the three study areas. The bark thickness at the heights of 0%, 25%, 50%, 75% and 100% of the commercial height was measured. The accuracy of the models was evaluated by the determination coefficient, standard error of estimate and graphic analysis of the residuals. To test model identity, the method used was the one developed by Graybill (1976). The models selected for all the tested variables were the ones of Schumacher and Hall and of Spurr, transformed in logarithm. According to the identity test of models, for all the tested variables, similarity exists among the areas 2 and 3. Regarding to the behavior of volume, it was observed that the smallest diametric classes possess larger stem volume than the branches and that there is also a tendency of decreasing the bark percentage with the increase of the diametric class for the three studied areas.