Miguel Antão Durlo

Relações morfométricas para Cabralea canjerana (Well.) Mart.

Normal 0 21 MicrosoftInternetExplorer4 Utilizando-se uma serie diametrica em substituicao ao conceito de cronosseries, foram estudadas as formas, dimensoes e relacoes morfometricas de Cabralea canjerana (Well.) Mart. em uma floresta secundaria da encosta sul do planalto sul-rio-grandense.

Dinâmica nutricional em floresta estacional decidual com enfase aos minerais provenientes da deposição da serapilheira.

Annual litter fall, the N, P, K, Ca and Mg content, litter decomposition rate and the nutrient use efficiency were studied in a deciduous seasonal forest, from the Serra Geral escarpments, in Santa Maria, Rio Grande do Sul. The annual litter fall reached 7.76 t/ha, with leaf fraction representing 66% of the total. Spring was the most intensive litterfall and nutrients deposition season. This annual deposition added to the forest soil about 206.7 Kg/ha of nitrogen, 11,2 Kg/ha of phosphorus, 37,8 Kg/ha of potassium, 269.2 Kg/ha of calcium and 29.9 Kg/ha of magnesium. The mean forest floor mass was 6.7 t/ha, the instantaneous decomposition rate (K) was estimated to be 1.16 and the time necessary to decay 50% of the total litter was around 7 months. The nutrient use efficiency, given by the biomass/nutrient rate to the N, P, Ca and Mg elements was lesser than those verified for others brazilians regions, showing that the primary productivity of the stand is not limited by the availability of the studied nutrients.

Qualidade da madeira serrada na região da Quarta Colônia de Imigração Italiana do Rio Grande do Sul.

This study was undertaken with the objective of evaluating the quality of the sawed wood produced in the Area of the Fourth Colony of Italian Immigration in Rio Grande do Sul. Three plants processing pine wood were investigated with respect to sawing and drying methods and moisture content of the industrial wood. The main method used was air seasoning and the resulting defects observed influenced the quality of the sawed wood negatively, suggesting the need of improving the process. However, the average moisture content was in agreement with the standards recommended for air seasoned wood. About 75% of the sawed wood of the area was classed as first when green. After drying, only 45% were first while 45% were of third grade. The remaining 10% were classed as super, extra or of second quality.

Características tecnológicas das madeiras de Luehea divaricata, Carya illinoinensis e Platanus x acerifolia quando submetidas ao vergamento.

This work was conducted with the purpose of investigating bending characteristics of the wood of Platanus x acerifolia (Ait.) Willd., Luehea divaricata Mart. et Zucc and Carya illinoinensis (Wangenh) K. Koch. Such species were collected from non-managed forests located in Depressao Central and Encosta Superior do Nordeste, Rio Grande do Sul, Brazil. Five representative adult trees from each species per studied area were cut down, corresponding to a total of thirty trees. From the trunk, a 2.5 m long log was taken and, afterwards, transported to a sawmill for processing. A central 8 cm thick plank was sawn, from which samples for bending were manufactured. The samples were conditioned in standard room to a moisture content of approximately 14%. Then, the samples were placed in boiling water during 35 minutes and bended in rays of 16 and 21cm. For the qualification of the bending defects, the methodology presented by Vorreiter (1958) was used. Results showed that the wood of Carya illinoinensis (Wangenh) K. Koch had the best bending characteristics when compared to the other two species, independently of the ray bending tested. It seems that the ring porosity, characteristic of the Carya illinoinensis wood, contributed to the result. On the other hand, the wood of Platanus x acerifolia (Ait.) Willd. and Luehea divaricata Mart. et Zucc, with diffuse porosity and larger parenchyma proportion, presented more defective pieces.

Características da lenha produzida na região da quarta colônia de imigração italiana do Rio Grande do Sul.

This research was carried out with the objective of evaluating the firewood quality produced in the 4 th Colony of Italian Immigration of Rio Grande do Sul taking into account the conversion factor from stacked to cubic meter, moisture content, basic density and fuel value of the wood. The conversion factor, important in estimating the solid volume, ranged from 0,61 for eucalypt wood to 0,56 for native species. The wood basic density found for eucalypt was 0,44 g/cm 3 compared to 0,46 g/cm 3 for native species, assorting them as slightly dense wood. The estimated heat of combustion for the wood equilibrium moisture content of the region was 1915 and 2002 kwh/m 3 , respectively, for eucalypt and native firewood. However, 13,6% of these values are lost because the wood is burned with an average moisture content of 32%. These results indicate the need of a more careful stacking and drying of the firewood, what would lead to a decrease in energy losses that happens when moist material is burnt.

Modelo de incremento para árvores singulares – Nectandra megapotamica (Spreng.) Mez.

Sustainable forest management requires knowledge of forest stock and future growth of forests. In the forest sector growth models are used to predict the growth of trees, stands or forests. In heterogeneous uneven-aged forests of Rio Grande do Sul, models on an individual tree basis are appropriate. The present work was established to contribute to the formulation of growth models for one species of the seasonal deciduous forests of Rio Grande do Sul: Nectandra megapotamica . Sampling was realized in the district of Vale Veneto, near Santa Maria in the years of 1994 and 1997. Vegetation was classified into different successional stages and within these permanent sample plots (uap) were installed. In every sample plot the trees with diameter at breast height above 5 cm were identified, numerated and measured. Additionally, the sociological position and site parameters were estimated. In every uap individual basal area increment, basal area per ha and basal area larger (BAL), as competition indexes, were calculated. Then growth equations were established by using the ‘stepwise’ procedure. The general formulation of the model is: Increment (g/year) = f (dimension, competition, site). The best model for Nectandra megapotamica is: ICA = 0,002084 + 0,000001039 x DBH² - 0,0003498 x Degradation - 0,000375 x Sociological position - 0,00000904 x Soil stonyty - 0,0000103 x BAL.

O sub-bosque de reflorestamentos de pinus em sítios degradados da região da Floresta Estacional Decidual do Rio Grande do Sul.

In the central part of Rio Grande do Sul State understoreys of 12 stands of Pinus sp . and one of Araucaria angustifolia O.Ktze were studied, all growing on soils, degraded by agriculture. One pine stand, 10 years old, originated from a natural renovation, the others had been planted 25 to 30 years ago, Araucaria was seeded directly. A total of 575 plots were sampled, 25 m² each, distributed systematically within the stands. Measurements included pines overstorey, and all understorey woody species, separeted into layers of more than 1,3 m high and 1,3 to 0,3 m; the layer lower than 0,3 m included only natural renovation of pines. Understoreys were composed by 121 species, ocurring common and high value timber species, ornamental trees, native and exotic fruit tree species. A higher number of species was present with a very few individuals only. The presence of non woody species like grasses, herbs, ferns and lians also was quantified. The number of tree species and the presence of non woody species did not correlat with density of overstorey pines. Abundance and frequency of species showed no significant diferences, when samples were grouped according to their location in the center or close to stands edge. Distribution pattern of understorey trees within stands was quantified, using Cox’ index, species diversity was compared by means of Shannon-index. Similarity of stands was compared by Sorensen-Index. It was concluded, that exotic species planted on poor agricultural soil may not only be of farmers interest because of their high potential for wood production. These plantations also may be considered from conservationist point of view, since they show an unexpected high diversity, so contributing in a longer run to landscape improvement, possibly due to the small extension of stands.

Variáveis morfométricas e relações interdimensionais para Cordia trichotoma (Vell.) Arrab. ex Steud.

The present work was developed to observe the morphometric features and the morphometric relations for Cordia trichotoma trees in a planted forest, at Santa Maria municipality, state of RS, Brazil. The analised variables were: total height, comercial height of stem, diameter at breast height (dbh), crown diameter, crown length, crown proportion, crown projection area, slenderness rate, salience index, range index and crown formal. For the interdimensional relations study, the morphometric variables were related to diameter at breast height (dbh), by regression analysis. The results showed significative statistic relations between dbh and variables such as total height, crown diameter, crown length, crown proportion, slenderness rate and range index.

Influência da temperatura de secagem no comportamento higroscópico da madeira de Pinus elliottii Engelm.

This work deals with the higroscopicity of the wood of Pinus Elliotti Engelm. After dryying at different temperatures (50oC; 75oC; 100oC; 125oC E 150oC). After drying the samples were submited to distinct observation of the equilibrium moisture content, established with the different climatc conditions, it was demostrated that drying temperature is inversely related with the higroscopicity in the analysed material.

BRUSHWOOD VEGETATION IN THE REGION OF THE MID FLOW OF THE JACUÍ RIVER, RS

This work describes the floristic composition and structure of the brushwood vegetation in the region of the mid flow of the Jacui River, RS. This forest type is highly heterogeneous. Forty five woody species were found, of which the pioneer vegetationis the most abundant. Species of economic importance occur less frequently. Also identified were ninety-six non-wood species.