Anatomical Aspects of Water Movement Through Stems of Mountain Ash (Eucalyptus regnans F. Muell.)

Abstract

Introduction of a stain through the severed roots of Eucalyptus regnans of two age classes showed that a spiral interlocked sap ascent pattern in young trees tended towards a vertical sectorial pattern by age 40 years. Microscopic examination of the stained wood suggests that intercellular water movement occurs principally via the pits. Serial transverse sections of wood from a young tree showed a limited degree of intervessel contact, with a network coefficient of 13.7 contacts m^-1 and approx. 0.9% of vessel surface area in contact with other vessels. Analysis of the frequency of vessel endings indicates an average vessel length of approx. 1.8 m. Trunk segments of 40-year-old trees had relative conductivities of approx. 3.3 x 10^-11 m², while small lateral roots had values up to 10 times greater.