Pedro Luiz Braga Lisboa

Revisão taxonômica das espécies amazônicas de Rhizophoraceae

Durante o Curso de Botânica Tropical, na disciplina de Sistemática, realizamos em conjunto o estudo da família Rhizophoraceae, a fim de demonstrarmos os métodos e proceclimentos de um estudo taxonômico. A escolha desta família entre várias outras não menos interessantes, deu-se em razão de ser Rhizophoraceae uma família razoavelmente pequena, com diversos gêneros, e larga distribuição por toda a Amazônia, ocupando habitats os mais diversos, desde o mangue até a mata da terra firme. Devemos ressaltar também que desde o trabalho de Engler (1876), não houve outra revisão nos gêneros amazônicos, a não ser as interessantes observações de Pires & Rodrigues (1971), sobre os gêneros Po/ygonanthus e Anisophyl/ea. Rhizophoraceae é uma família constituída de 16 gêneros com cerca de 120 espécies distribuídas nas regiões tropicais e subtropicais do mundo, com apenas 5 gêneros representados na região amazônica. Em Rhizophoraceae o gênero típico e mais conhecido é Rhizophora ou mangue, típica desse habitat, havendo porém vários gêneros da família que habitam as matas altas longe do mar.

Variação estrutural quantitativa no lenho de Terminalia ivorensis A. Chev., Combretaceae

In order to verify anatomical stem variation of the Terminalia ivorensis wood, were studied wood samples at three different heights in the radial and axial planes. Proof bodies were gotten at a 2cm interval from the pith towards the vascular cambium. The utilized methodology to develop the job followed the traditionally recommended methodology for vegetable anatomy studies. The anatomical description followed the recommendations of the IAWA Committee. In the radial stem direction, some anatomic elements showed a well defined trend, which are statistically significant when using the Tukey test for measures comparison. They were: frequency, diameter and length of the vessel elements, ray frequency/linear mm, length of rays in number of the cells and fiber length and thickness. On the other side, in the axial stem direction, was not found anything statistically significant. This results were observed principally due the clear presence of the juvenile and adult wood in the lumber of Terminalia ivorensis.

Some effects of colonization on the tropical flora of Amazonia: a case study from Rondonia

Summary. We analyzed the effects of recent human colonization on the Amazonian forest flora in the region of the cities of Ji-Paranai and Presidente Medici, in the state of Rondonia, in the Western part of the Brazilian Amazon. Areas of natural forest and of secondary vegetation of one, five, 10 and 15 years growth were inventoried. Comparative analysis of the data shows that there has been little regeneration of the species that existed earlier, although the new vegetation soon becomes structurally similar to the original forest. Loss of primary forest species is the most serious consequence of deforestation. The study area had previously been the best lumberproducing area of the state. This production has now noticeably declined because of the widespread loss of forests in the region. The two principal effects of timber extraction in the forest are the local extinction of the species that are used for lumber, and the genetic erosion of survivors. Based on current demand, Mahogany (Swietenia macrophylla King), and Brazilian cherry (Torresia acreana Ducke) and even the Brazil-nut tree (Bertholletia excelsa H. & B.) are the most vulnerable species. Other results of deforestation and aspects of immigration are also discussed, including the inadequacy of the Brazilian law that requires farmers to leave 50% of their plot as forest. The need is for the establishment of large contiguous areas of reserves rather than a checkerboard effect created by each farmers leaving half of his land as forest. The situation in Rondonia has reached a critical state and it is crucial that every effort be made to obtain reserve areas to protect the unique fauna and flora of the Rond6nia region.

The relationship between stem vessel parameters and the development of strata in the early stages of secondary forest succession in Amazonia

In order to compare the development of strata in the early stages of secondary forest succession with vessel parameters of the tree species, a forest inventory was carried out in 4-year (Q1: 48 m2), 11-year (Q2: 400 m2) and 20-year (Q3: 400 m2) forests and vessel parameters were investigated from stem cross sections of 18 species obtained in Q2. Thirty three species (21 families), 77 species (35 families), 39 species (20 families) were found in Ql, Q2, Q3, respectively. The percentage of dead individuals, dead stems and the percentage of individuals with multiple stems increased with time after clear cutting. Also, the total D2H of Q3 was 26.1 times that of Q1, and the development of strata started in Q2 and Q3. The image analysis of vessel size, area and number of vessels revealed that species which reach the forest canopy had a large D2H value, vessel diameter and area, while species which remain near the forest floor had smaller ones. Poecilanthe effusa (Huber) Ducke is an example of the latter case, with a large number of individuals and abundant sprouting of new stems from stumps, but with high mortality.

NOTAS SOBRE OS DORMENTES DA ESTRADA DE FERRO DO TOCANTINS

General observations were made on the durability of wood ties used in the old Tocantins railroad. Nine different timbers were identified, with Itauba (Mezilaurus itauba) showing the greatest durability. Other species that also showed high durability were Acapu (Vouacapoua americana), Macaranduba (Manilkara huberi), Sucupira da-terra-firme (Bowdickia nitida) and Mata-mata (Eschweilera sp.).

Anatomia do lenho de seis espécies de Ormosia (Leguminosae) da Amazônia

This paper presents the macroscopical and microscopical descriptions of the structure of wood of the following amazonian species of Leguminosae: Ormosia coccinea, Ormosia costulata, Ormosia flava, Ormosia macrocalyx, Ormosia nobilis and Ormosia paraensis. 18 illustrations of the woods described, 6 esquematic prints of different shapes of vascular elements encountered in the species studied, common uses and a list of principals anatomical characteristics are included in this paper.