RESUMO
A total of 45 native Costa Rican tree species are threatened or in danger of extinction, but the Convention on International Trade Endangered Species (CITES) includes only eight of these in its Appendices. However, the identification of other species based on their wood anatomy is limited. The present study objective was to describe and to compare wood anatomy and fluorescence activity in some endangered or threatened species of Costa Rica. A total of 45 (22 endangered and 23 threatened with extinction) wood samples of these species, from the xylaria of the Instituto Tecnológico de Costa Rica and the Forest Products Laboratory in Madison, Wisconsin, were examined. Surface fluorescence was positive in eight species, water extract fluorescence was positive in six species and ethanol extract fluorescence was positive in 24 species. Almost all species were diffuse porous except for occasional (Cedrela odorata, C. fissilis, Cordia gerascanthus) or regular (C. salvadorensis and C. tonduzii) semi-ring porosity. A dendritic vessel arrangement was found in Sideroxylon capari, and pores were solitary in Guaiacum sanctum and Vantanea barbourii. Vessel element length was shortest in Guaiacum sanctum and longest in Humiriastrum guianensis, Minquartia guianensis and Vantanea barbourii. Finally, anatomical information and fluorescence activity were utilized to construct an identification key of species, in which fluorescence is a feature used in identification.
Assuntos
Espécies em Perigo de Extinção , Árvores/classificação , Madeira/anatomia & histologia , Costa Rica , Fluorescência , Árvores/anatomia & histologiaRESUMO
A total of 45 native Costa Rican tree species are threatened or in danger of extinction, but the Convention on International Trade Endangered Species (CITES) includes only eight of these in its Appendices. However, the identification of other species based on their wood anatomy is limited. The present study objective was to describe and to compare wood anatomy and fluorescence activity in some endangered or threatened species of Costa Rica. A total of 45 (22 endangered and 23 threatened with extinction) wood samples of these species, from the xylaria of the Instituto Tecnológico de Costa Rica and the Forest Products Laboratory in Madison, Wisconsin, were examined. Surface fluorescence was positive in eight species, water extract fluorescence was positive in six species and ethanol extract fluorescence was positive in 24 species. Almost all species were diffuse porous except for occasional (Cedrela odorata, C. fissilis, Cordia gerascanthus) or regular (C. salvadorensis and C. tonduzii) semi-ring porosity. A dendritic vessel arrangement was found in Sideroxylon capari, and pores were solitary in Guaiacum sanctum and Vantanea barbourii. Vessel element length was shortest in Guaiacum sanctum and longest in Humiriastrum guianensis, Minquartia guianensis and Vantanea barbourii. Finally, anatomical information and fluorescence activity were utilized to construct an identification key of species, in which fluorescence is a feature used in identification.
Un total de 45 especies de árboles de Costa Rica se catalogaron como amenazadas o en peligro de extinción, de las cuales, CITES (Convention on International Trade Endangered Species) incluye solamente ocho en sus Apéndices. Sin embargo, la identificación de las especies basadas en su anatomía es muy limitada. El presente estudio tiene el objetivo describir y comparar la anatomía y la fluorescencia de las especies amenazadas o en peligro de extinción de Costa Rica. Muestras de madera de las especies en peligro de extinción o amenazadas de la xiloteca del Instituto Tecnológico de Costa Rica y del Laboratorio de Productos Forestales de los Estados Unidos en Wisconsin se examinaron, se describió su anatomía, se evaluó su actividad fluorescente y se midió su densidad. La superficie de la madera fue fluorescente en ocho especies, el extracto en agua fue fluorescente en seis especies y el extracto en etanol fue positivo en 24 especies. Muchas de las especies presentaban porosidad difusa, excepto algunas Cedrela odorata, C. fissilis, Cordia gerascanthus C. salvadorensis y C. tonduzii que presentaban porosidad semi-anular. Vasos con distribución déndrica se encontró en Sideroxylon capari y poros solitarios en Guaiacum sanctum y Vantanea barbourii. Los vasos más cortos se encontraron en Guaiacum sanctum y los vasos más largos en Humiriastrum guianensis, Minquartia guianensis y Vantanea barbourii. Finalmente, la información de la anatomía y de su fluorescencia se utilizó para construir una clave de identificación, donde la actividad de fluorescencia juega un papel importante en la identificación.
Assuntos
Espécies em Perigo de Extinção , Árvores/classificação , Madeira/anatomia & histologia , Costa Rica , Fluorescência , Árvores/anatomia & histologiaRESUMO
PREMISE OF THE STUDY: Pioneer species of tropical trees allocate wood specific gravity (SG) differently across the radius. Some species exhibit relatively uniform, low SG wood, whereas many others exhibit linear increases in SG across the radius. Here, we measured changes in SG across the radius of Schizolobium parahyba (Fabaceae-Caesalpinioideae), a wide-ranging, neotropical pioneer, used extensively in land reclamation and forest restoration in Brazil. METHODS: Pith-to-bark radial wood cores were extracted with increment borers from 42 trees at five sites, in Central and South America. Cores were cut into 1-cm segments whose specific gravities were determined and analyzed via linear and nonlinear regression. Wood specific gravity, very low initially at 0.15-0.20, doubled or tripled across the tree radius to 0.45-0.65 for large adults. KEY RESULTS: Unlike linear increases in other tropical pioneers, the increases in Schizolobium were nonlinear (convex up). At one site with even-aged trees, the magnitude of the radial increase was similar in all trees, despite a 4-fold difference in diameter among trees, implying that the radial increases in Schizolobium were regulated by tree age, not by tree size. CONCLUSIONS: This unique pattern of development should provide an extended period of growth when SG is low, facilitating hyper-extension of the bole, at some risk of structural failure. Later in growth, the SG rate of increase accelerates, reinforcing what was a precarious bole. Overall, these results suggest a third model for xylem allocation in tropical trees, a model that may be associated with monopodial stem development and limited life span.