The objective of this work is to analyze the dry wood anatomical microstructure of Eucalyptus nitens, from an eight-year commercial plantation, by computed microtomography. 3D images with a voxel size of 500³ nm³ were acquired to study the tissue in areas without vessels. Quantitative and qualitative data of fibers, parenchyma, and pits were obtained. Permeability was estimated by numerical simulations using virtually segmented 3D microstructure, this technique allowed the simulation without pores of vessels. A bulge was identified inside the tangential wall of the fibers (Tangential Bulge in Fibers), which is connected with parenchyma cells and presents evidence of interfering with deformations. The cell wall and the lumens presented deformation values, and the onset of the microcracks were located on the radial face of the fibers. The Lumens connectivity was measured in the 3 main directions, the radial and tangential ones showed the lowest values since the connectivity is through the pits. This affected the permeability, being the more complex path flow lines in the tangential direction. It is concluded that Eucalyptus wood present characteristics that affect its quality and that the application of this technique increases the possible level of analysis for wood.

Conifer forests in Michoacán are facing climate change. Pinus devoniana Lindley, with natural distribution in the state, has shown certain adaptability, and knowing the influence of anatomy in the flow system is essential to delimit how it contributes to safety margins and water efficiency. For this, the pressure gradients in the cell lumens and their ramifications were analyzed by numerical simulations of flow throughout the real microstructure. Xylem were evaluated in radial, tangential and longitudinal directions. With the skeletonization of lumens and their constrictions, a branching system of interconnection between tracheids, ray cells, intercellular chambers, extensions, and blind pits were identified. In the simulation, the branched system bypasses the longitudinal fluid passage through the pores in membranes of pairs of pits to redirect it through the direct path branching, contributing to safety margins and water efficiency. Thus, resilience at low pressures because of the lower pressure drop in the extensions. The interface between the branching system and the cell lumens are sites of higher pressure gradient, more conducive to water-vapor formation or air leakage in the face of the lowest pressure system. The flow lines move along easy paths, regardless of the simulated flow direction. Deposits in the cell extensions were shown to be attached to the S3 layer of the cell wall, leaving the center of the duct free to flow. It is concluded that the spatial architecture of the xylem anatomy of Pinus dvoniana is a factor in the resilience at low pressures due to high water stress of the species.

In the present work, numerical simulations on 3D images of Dalbergia ruddae wood are used to analyze the influence of porosity characteristics on the fluid flow through it. Image acquisition was performed with X-ray computed tomography. Flow throughout the three main directions, longitudinal, radial and tangential is estimated by numerical simulation inside sapwood and heartwood tissue. Numerical simulations were performed on images of wood tissue without vessels, only vessels and the complete wood tissue by virtual separation of each phase. Results indicate that flow through the vessels is obstructed by the presence of gums, which reduces their permeability in the longitudinal direction, causing flow in that direction to be conducted through gaps in the fibers and parenchyma. In the radial direction, gums do not hinder flow within the vessel unlike in the tangential direction. The estimation of permeability in the segmented tissues indicates the null contribution of the vessel when is obstructed by gums and the high contribution of the axial parenchyma to the flow of fluid encapsulated in a vessel. Flow lines illustrate the flow pathways throughout the woody tissue, which made it possible to highlight the flow problem in this species as vessel-encapsulated flow.