The volume and complexity of their vascular systems make the dynamics of long‐distance water transport in large trees difficult to study. We used heat and deuterated water (D₂O) as tracers to characterize whole‐tree water transport and storage properties in individual trees belonging to the coniferous species Pseudotsuga menziesii (Mirb.) Franco...
We determined the axial and radial xylem tension gradients in trunks of young Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees. Axial specific conductivity (ks-a) and sap flux density (Js) were measured at four consecutive depths within the sapwood at a stem height of 1 m. By definition, at a given position...
Our goals were to quantify how non-embolism-inducing pressure gradients influence trunk sapwood specific conductivity (ks) and to compare the impacts of constant and varying pressure gradients on ks with KCl and H2O as the perfusion solutions. We studied six woody species (three conifers and three angiosperms) which varied in pit...
The air‐seeding hypothesis predicts that xylem embolism resistance is linked directly to bordered pit functioning. We tested this prediction in trunks, roots, and branches at different vertical and radial locations in young and old trees of Pseudotsuga menziesii. Dimensions of bordered pits were measured from light and scanning electron micrographs,...
Despite renewed interest in the nature of limitations on maximum tree height, the mechanisms governing ultimate and species-specific height limits are not yet understood, but likely involve water transport dynamics. Tall trees experience increased risk of xylem embolism from air-seeding because tension in their water column increases with height due...
The cohesion-tension theory of water transport states that hydrogen bonds hold water molecules together and that they are pulled through the xylem under tension. This tension could cause transport failure in at least two ways: collapse of the conduit walls (implosion), or rupture of the water column through air-seeding. The...
The Willamette Valley (WV) race of ponderosa pine (Pinus ponderosa) is being widely planted for timber in the Willamette Valley, western Oregon, because it grows in habitats that are either too wet or too dry for Douglas-fir (Pseudotsuga menziesii). Compared to the eastern Cascade Mountains (CM), the WV has 3...
Every wood anatomist knows that the wood near the center of a tree (juvenile wood) differs from the wood laid down at some distance from the pith (mature wood), and that the wood produced during the spring (earlywood) differs from the wood produced during the summer (latewood). There is a...