Tree-ring structure determines the temporal coordination between xylem growth and the gain in hydraulic conductivity in the outermost ring.
Fernández-de-Uña L, Rathgeber CBK, Pérez-de-Lis G, Andrianantenaina AN, Cuntz M
Phenology
Oak trees in your local woodland are running a seasonal hydraulic gamble — their spring growth floods the tree with fast but fragile water pipes that are already being sealed off by summer, which is why an oak stressed in May behaves very differently from one stressed in August.
Trees move water through microscopic tubes in their wood, and this study watched those tubes form in real time across three years in oak, beech, and spruce. Oak builds its biggest, most efficient water channels first in spring, then seals many of them off and pivots to slower, tougher channels — creating a two-phase water system within a single year's growth ring. Beech and spruce don't do this split; they add water-moving capacity steadily and predictably as they grow, making their internal plumbing much easier to forecast.
Key Findings
Ring-porous oak shows a clear mismatch between when it adds wood mass (basal area increment) and when it gains or loses hydraulic conductivity — the two curves are out of phase within the same growing season.
Diffuse-porous beech and conifer spruce show tightly coordinated growth and hydraulic gain, meaning a simple delayed growth curve can estimate their water-transport capacity at any point in the season.
Oak vessels are progressively occluded by tyloses (internal plugs) as the season advances, causing measurable conductivity loss even while the ring is still growing — a dynamic not seen in beech or spruce.
chevron_right Technical Summary
Scientists tracked how three common European trees — oak, beech, and spruce — build their water-transport plumbing each growing season, finding that ring-porous oaks like sessile oak have a split personality: early-season wood is highly conductive but vulnerable, while later wood adds bulk with little hydraulic payoff. Beech and spruce, by contrast, grow and gain water-moving capacity in near-lockstep.
Abstract Preview
The study of seasonal xylem hydraulics has predominantly focused on embolism-induced losses, whereas growth-driven increases in hydraulic capacity have received little attention. We assessed the in...
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Quercus petraea, commonly known as the sessile oak, Welsh oak, Cornish oak, Irish oak or durmast oak, is a species of deciduous oak tree native to most of Europe and into Anatolia and Iran. The sessile oak is the national tree of Ireland, and an unofficial emblem in Wales and Cornwall.