Paulo Cesar Botosso

Remarks on Age and Growth Rate Determination of Amazonian Trees

Specific data and comments are given on age and growth rate determination in trees of the Brazilian Amazon basin, based on longterm observation and research of diameter increment, radiocarbon dating, microscopic wood structure, and gamma- and X-ray densitometry; special attention is given to species of the unflooded Terra Firrne forest. Annual dry seasons in eastern Amazonia provoke periodical cambial activity which may be measured as variation in girth increment and is recorded in the wood anatomy as well as its density. Gamma radiation densitometry is discouraged because of poor results. X-ray densitometry and the radiocarbon method are promising but must be refined. Irregular specific climatic events should be considered to be possible natural marks.

Fenologia Vegetativa e Crescimento de Cedrela fissilis na Floresta Atlântica, Paraná, Brasil

A fenologia, o incremento em circunferencia do tronco e a atividade cambial de individuos de Cedrela fissilis (Meliaceae) foram observados mensalmente em duas tipologias de Floresta Ombrofila (Densa e Mista) na Floresta Atlântica, Estado do Parana, Brasil. As observacoes se deram por meio do metodo de indice de atividade, leitura de incremento em circunferencia do tronco com o uso de dendrometros permanentes e amostragens periodicas de tecido cambial de 24 arvores da especie. O ritmo de incremento observado e sazonal, iniciando-se apos a expansao total do limbo e interrompendo-se quando as folhas maduras estao em senescencia adiantada e/ou em sua ausencia. Analises estatisticas mostraram relacoes significativas entre incremento, variaveis climaticas e fenologia. A especie apresenta formacao de aneis anuais de crescimento, sendo observadas flutuacoes anatomicas intra-anuais. Os resultados indicam que a fenologia vegetativa dos individuos parece ser influenciada mais fortemente pelo fotoperiodo e temperatura do que pela precipitacao.

Wood anatomy and growth ring boundaries of Copaifera lucens (Fabaceae)

ABSTRACTThe wood anatomy of Copaifera lucens Dwyer was studied with an emphasis on its growth ring boundaries. Growth rings are visible to the naked eye and demarcated by marginal parenchyma bands and, sometimes, by thick-walled fibers in the latewood. Secretory canals are associated with marginal parenchyma bands, but not all marginal parenchyma bands are associated with canals. Paratracheal parenchyma is vasicentric to lozenge-aliform. Rays are 1–4-seriate, heterocellular and non-storied. Vessels are visible to the naked eye, diffuse, predominantly solitary, some in multiples, sometimes filled with gums. Crystals present. Wood anatomical characteristics of C. lucens are in agreement with those previously reported for other species of Copaifera . In addition to what had already been described for C. lucens , we observed gelatinous fibers, and some bifurcate fibers, and extremely rare clustered vessels. The growth ring boundaries are well-defined in mature wood but less distinctive near the pith. There are also partial and confluent (wedging) rings, which are difficult to classify by anatomy only, but which represent false rings and complicate tree-ring analysis in this species.

Wood anatomy of Sebastiania commersoniana (Baillon) Smith & Downs (Euphorbiaceae): functional and ecological aspects

Sebastiania commersoniana is a very common tree species in alluvial environments with diverse soil conditions due to its plasticity and ability to tolerate periods of flooding. In this study we sampled 21 adult individuals of this species on the Iguacu River plain, for wood anatomy characterization and interpretation using a functional approach. S. commersoniana has diffuse porous, solitary vessels and multiples of two to six, radially arranged with simple perforation plates; low vessel frequency (12-16-20/mm2), with diameter of 54-88-117 µm, and vessel elements 164-602-1025 µm in length. The fibers are 656-1222-2050 µm in length, 10-26-42 µm wide, the walls are 1.0-2.8-5.1 µm thick. Fibers with a gelatinous layer are common. Apotracheal parenchyma diffusein-aggregates is found, while paratracheal parenchyma is scanty. Rays are uniseriate, 164-805-2787 µm tall and 12-22-35 µm wide. Perforated ray cells are frequent, as well as scar tissue containing starch grains. Starch also occurs in the radial and axial parenchyma. This species develops tension-wood in inclined trees. Most of the features observed coincide with available descriptions of the genus and family to which the species belongs. Some qualitative features are discussed on the base of possible roles and implications for species autoecology.