Wood cell morphology characteristics of some oak species and mediterranean shrubs

Some characteristics of wood cell morphology of three oak species (Quercus conferta, Q. flex, Q, coccifera) and five Mediterranean shrubs (Arbutus andrachne, A. unedo, Erica arborea. Phillyrea me- dia, Pistacia lerebinthus) were investigated at height 30 cm above ground. The mean fiber length of oak species ranged between 1.10 and 1.35 mm and that of Mediterranean shrubs between 0.56 and 0.82 ram. The mean wtlues of vessel dimensions ranged as follows: 0.22q).31 mm (vessel length) and 0.080-0.087 mm (vessel diameter) for oaks and 0.19-0.40 mm (vessel length) and 0.033-0.043 mm (ves- sel diameter) for Mediterranean shrubs. The pith to bark variation of fiber length appeared to follow the general patterns of length var- iation but differences were observed between the species tested with regard to the rate of fiber length increase and to the number of years necessary to reach a typical length. The horizontal variation of vessel length and diameter was not consistent between the species: from pith to bark, vessel length and diameter increased in a few species and decreased or remained more or less unchanged in the others. For each species, a similar horizontal variation pattern of fiber length and, to a lesser extent, of vessel length was observed between the trees. The greatest pith to bark variation of three-ring mean values relative to the first three growth rings occurred in Quercus conferta for fiber and vessel length and in Quercus coccifera and Q. ilex for vessel diameter.