VESSEL DISTRIBUTION AT 2 PERCENTAGE HEIGHTS FROM PITH TO BARK IN A 7 YEAR-OLD EUCALYPTUS-GLOBULUS TREE

Pith to bark profiles of vessel area, distribution and shape are prese nted for a 5% height disc sample of one Eucalyptus globulus tree. Resu lts of analyses show that vessel areas, distributions and shape are ve ry ordered. Individual vessel areas increased and vessel numbers decre ased from pith to bark Total vessel area increased slowly across the d isc from pith to bark, but was influenced by position within annual ri ngs; decreasing from latewood (LW) to first earlywood (EW), then incre asing in midwood (MW). Within-ring analyses showed regions containing dramatically different numbers, areas and total areas of vessels. It i s proposed that vessel distributions change in synchrony with EW MW an d LW segmentation shown for fibre dimensions in both E. globulus and E . nitens. These findings may have implications to pulp utilization, fu ture genetic modification technologies and tree breeding.