[Show abstract][Hide abstract] ABSTRACT: The objective of this work was to study the phyto-sociological structure of a shrub and tree vegetation colonization in an abandoned stand of Eucalyptus spp. in Lavras, MG, Brazil, in order to identify the existence of species groups, vegetation gradients, and Alpha diversity. The phytosociological sampling collected 5 transects of various sizes with 100 equidistant points (14 m), using the quadrant method. The assessment included all individuals with breast diameter ≥5 cm. There were a total of 854.28 sampled individuals/ha, belonging to 91 species, distributed into 67 genera and 31 families. The highest VI values were obtained for Piptadenia gonoacantha, Copaifera langsdorffii, Tapirira guianensis and Ocotea corymbosa. The analysis of trunk diameter distribution showed that the community was in a stage of full regeneration with individuals distributed over all diameter classes. Most species presented syndromes of seed dispersal by animals and regeneration guilds of pioneer and climax demanding light. Perhaps planting may have served as shelter and refuge for fauna species in the region and mortality of individuals of Eucalyptus spp. resulted in gaps of different sizes. Vegetation was identified along a gradient, with a gradual change in evenness between the four groups of species characterized by cluster analysis. The indices of diversity (H’ = 3.58) and evenness (J = 0.794) of the species were similar to those found in other phyto-sociological studies of Eucaliptus spp platations. Furthermore, the tree planting functioned as a catalyst for natural regeneration in the study area
[Show abstract][Hide abstract] ABSTRACT: Despite the major ecological and economical relevance of forest species, little is known about their seedling establishmentand seed germination, as well as the damage effects to seeds at these stages. This work aimed to assess the effects of partial cotyledonloss on the seed germination and early seedling establishment of Anadenanthera colubrina. Therefore, whole (control) and split seeds(with 1/8, 1/4, and ½ of their size cut) were evaluated. The seeds were then germinated and the early growth of seedlings was assessed.The treatments had no effect on seed germination, however, they influenced seedling survival and establishment. The highestmortality and growth reduction values were obtained with the most severe cotyledon removal. This indicates that the tegument andthe partial cotyledon loss do not represent a barrier against seed germination. However, considerable damages may be detrimental toestablishment and survival of A. colubrina seedlings.
[Show abstract][Hide abstract] ABSTRACT: The study evaluated variations in the dynamics of seven arboreal populations (Copaifera langsdorffii, Cupaniavernalis, Sebastiania commersoniana, Luehea grandiflora, Machaerium stipitatum, Machaerium villosum and Tapirira obtuse),in three fragments located in the municipal districts of Ibituruna, Ingaí and Luminárias. The populations were chosen with 15 ormore individuals (including dead and recruited), in the surveys carried out in 2000 and 2005 through permanent plots. Allindividuals with DBH > 5cm were sampled. The analyses were made using the results of the two surveys (number of individuals,basal area and diametric distribution). No pattern was found with relation to the behavior of the populations in the three areasstudied. In Ingaí, C. langsdorffii and C. vernalis increased in number of individuals, S. commersoniana and M. villosum reducedin density and in basal area, T. obtuse in number, and L. glandiflora and M. stiptatum remained the same. All species concentratedmost of the individuals in the smaller diameter classes I and II (from 5 to 10cm and from 10 to 20cm). In Ibituruna, all thepopulations, except C. langsdoffii, reduced in number of individuals and were predominant in diameter class II. There was anincrease in basal area for C. vernalis and L. grandiflora. In Luminárias, S. commersoniana presented gain in density, and M. stiptatum remained the same. The other populations of individuals reduced in density. With respect to basal area, all species, exceptM. villosum, presented an increase with respect to diametric distribution, it was verified that for most of the populations, aconcentration of individuals in class I prevailed.