Summary The secondary xylem is a complex tissue whose cell proportions and structures alter wood properties, which are essential for characterizing a species for final use. Correlating wood anatomy with technological characterization is important to appropriately qualify materials, especially for Cerrado species, which are typically studied for energy purposes. Therefore, this study analyzed the influence of wood anatomy on wood density, volumetric shrinkage, and anisotropy of four Cerrado woody species. Thirty measurements of different anatomical traits and cell fractions were submitted to Redundancy Analysis (RDA), Extra-Trees Regressor with cross-validation, and partial correlation. These analyses showed that species with a lower proportion of axial parenchyma cells, thicker ray cell walls, a higher proportion of fiber wall and vessel lumen, longer vessels, and fibers with narrower lumens presented high wood density. Species with thick axial parenchyma cell walls, longer vessels and fibers, and a higher proportion of fiber lumen had high shrinkage, whereas a higher percentage of multiple vessels, greater investment in fiber walls, vessel-ray pits and more rays per millimeter decreased shrinkage. Finally, longer fiber and vessel lengths, taller rays in low frequency, and thick-walled fibers are associated with higher wood anisotropy. On the contrary, higher fiber wall proportion and lower rays decreased the anisotropy of wood. Thus, the structural organization of wood anatomical characters directly affects physical properties, demonstrating that the relative proportion of cell walls, lumen sizes and parenchyma cells are definitive drivers of wood technological behavior.
Summary The wood anatomy of Lauraceae is frequently described as homogeneous, making species- and genus-level identification challenging for commercial timber monitoring. In Brazil, economically important genera such as Aniba , Nectandra , and Ocotea , which belong to the Supraocotea group (formerly the “ Ocotea complex”), are particularly difficult to identify accurately. Thus, the objective of this study is to describe the macroscopic and microscopic wood anatomy of 36 Supraocotea and two non-Supraocotea species from Brazil to evaluate potential diagnostic characters for their identification, expand our knowledge of wood anatomy within Lauraceae, and conduct the first formal analysis of wood evolution for the family. Comparative data indicate that Supraocotea have a uniform wood anatomy that was generally insufficient to define clades or genera within the group, but with a few macroscopic ( e.g. , growth rings, oil/mucilage cells) and microscopic traits ( e.g. , ray composition, number of cells in parenchyma strands) having diagnostic value for differentiating a restricted number of species within the sampled species. The evolutionary history of wood anatomical characters was investigated using ancestral state reconstructions, which showed independent gains and losses of particular traits such as oil cells, silica crystals, or scalariform perforation plates, and indicated marginal axial parenchyma with evolutionary transitions exclusively in Praelicaria. While providing the first macroscopic and microscopic characterisation of woods of numerous Lauraceae species, our study demonstrates a conserved anatomical structure across clades and genera within Supraocotea, underscoring the need for advanced analytical approaches to improve wood identification and quality control in commercial timber.
Summary Alnus is a nitrogen-fixing genus of woody plants, widely distributed across temperate regions of the Northern Hemisphere, with several species extending into subtropical and montane tropical zones, including the neotropics. Species vary in growth habit, ranging from tall trees to dwarf trees or multi-stemmed shrubs, and some display flexibility between these forms. In other woody lineages, such differences in growth habit have been linked to variation in wood anatomical traits, but this relationship has not been systematically evaluated in Alnus . Here, we examined 24 species of Alnus , including 11 tree species, 7 shrub species and 6 species exhibiting both habits, for wood anatomical characters following the IAWA Hardwood List. None of the evaluated anatomical traits was found to be predominant in either tree or shrub growth habits. In fact, Alnus demonstrated little inter-species anatomical variability. Nevertheless, this dataset provides the first comparative overview of Alnus wood anatomy across growth forms and offers a foundation for future studies that incorporate broader ecological and geographic sampling in the genus Alnus and beyond.
Pacific yew (Taxus brevifolia Nutt.) is a conifer native to the northwestern United States with unusual microstructural and mechanical properties. These include a high xylem density that decreases only slightly from pith to bark, low stiffness relative to its high density, and a microfibril angle (MFA) that remains at its high initial value throughout growth. The high density and MFA found within the main stem of Pacific yew are reminiscent of compression wood, however no data have been reported for microstructural variation in Pacific yew reaction wood. SilviScan was used to analyse specimens taken from three locations along a branch; patterns of radial variation in density, MFA, and modulus of elasticity (MOE) were compared for the compression, opposite, and lateral wood to characterize the differences between Pacific yew normal wood and compression wood. Density was found to remain relatively constant at 800-900 kg/m3, while MFA increased to 50-55 degrees in regions containing compression wood, and MOE decreased proportionately. These elevated compression wood MFA values were more pronounced near the main stem, and less so toward the branch tip, indicative that the production of growth rings with compression wood is in response to a gradually increasing bending moment as growth occurs. Based on these observations, the compression wood of a Pacific yew branch possesses a higher microfibril angle than the normal wood found in its main stem and generally behaves similarly to branch compression wood found in other conifer species including Norway spruce and radiata pine.
Pachycaul trees are a distinctive group of woody plants with thickened stems that can store significant amounts of water and may have photosynthetic activity in some species. Anatomical observations provide direct evidence of the tissues involved in water storage, yet few studies have examined the wood and bark anatomy of these species. We hypothesise that pachycaul tree species exhibit convergent stem morphology with a specific water-storage tissue, reflecting adaptation to seasonal environments. Such convergent anatomies may occur in distantly related taxa, allowing the identification of groups with similar traits. We analysed anatomical traits of wood and bark in 20 pachycaul tree species from natural populations in Mexico. Our results indicate that the bark, with more than 70% non-lignified tissue, serves as the main site of water storage, although in several species, the wood also contributes to water storage. Non-lignified parenchyma in the wood, along with its cell division and elongation, represents an important trait in many pachycaul species. In the periderm, the phelloderm, characterised by multiple cell layers and the presence of chloroplasts, is a typical feature of most species. Variation in wood and bark traits, including ray dimensions, vessel diameter and frequency, total xylem parenchyma fraction, bark thickness, and cortical cell retention and division, allowed the identification of groups within the studied pachycaul trees. Overall, water storage emerges as a defining feature of this group, consistent with their highly seasonal habitats. However, xeromorphic or mesomorphic wood traits can also occur in pachycaul tree species.
