A comparison was made of the wood structure of trees from a tropical rainforest and a tropical deciduous forest. Qualitative as well as quantitative differences were found. In the species from the tropical deciduous forest the wood is darker, harder and inclusions like crystals and resin are more abundant than in the rainforest species. Species from the deciduous forest have generally shorter and narrower vessel elements, shorter fibres and rays, greater pore abundance, greater specific gravity, and greater vessel wall thickness than the species from the rainforest.
The specific gravity of 220 woody species, half of them from a tropical rainforest, half from a tropical deciduous forest was measured. The two groups were compared using a Student t-test. The results show highly significant differences in specific gravity between the species from the two areas: woods from the dry deciduous forest tend to be much heavier than those from the rainforest.
Three types of fossil woods with similarities to the Leguminosae are described, Mimosoxylon tenax (Felix) Müller-Stoll ' Mädel, Bajacalijomioxylon cienense Cevallos-Ferriz ' Barajas-Morales, gen. et sp. nov., and Copaijeroxylon matanzensis Cevallos-Ferriz ' Barajas-Morales, sp. nov. These woods are from the EI Cien Formation in Baja California Sur, Mexico, which is dated as Zemorrian-Saucesian, i.e., late Oligocene–early Miocene. Although two of the names of the fossil woods suggest affinity with a particular extant taxon, differences in some quantitative and qualitative features preclude their identification with a single extant taxon. The similarity among wood of some groups of extant Leguminosae and limited knowledge of character variability in woods of this family explains this taxonomie uncertainty. These fossil woods from Baja California underscore the need for an extensive systematic study of the wood anatomy of Leguminosae, add to the poorly known plant history of the Peninsula, suggest a tropical South American influence in the fossil flora of Baja Califomia, and indicate that the climate during the Zemorrian- Saucesian was different from the xeric conditions that prevail today in the area.
Species identification of logs, planks, and veneers is difficult because they lack the traditional descriptors such as leaves and flowers. An additional challenge is that many transnational shipments have unreliable geographic provenance. Therefore, frequently the lowest taxonomic determination is genus, which allows unscrupulous importers to evade the endangered species laws. In this study we explore whether analysis of wood using a Direct Analysis in Real Time (DART) Time-Of-Flight Mass Spectrometer (TOFMS) can assist in making unequivocal species determinations of Dalbergia. DART TOFMS spectra were collected from the heartwood of eight species of Dalbergia and six other look-alike species. In all, fourteen species comprising of 318 specimens were analyzed and the species chemical profiles were examined by statistical analysis. Dalbergia nigra (CITES Appendix I) was differentiated from D. spruceana; D. stevensonii (Appendix II) was distinguished from D. tucurensis (Appendix III), and all the look-alike timbers could be readily distinguished. Surprisingly, D. retusa (Appendix III) could not be differentiated from D. granadillo, and we postulate that they are synonymous. We conclude that DART TOFMS spectra are useful in making species identifications of American Dalbergia species, and could be a valuable tool for the traditional wood anatomist.