Wood basic density variation of eight willow clones (Salix spp.)

Inter and intraclonal variation of wood basic density was studied on eigth 13 year old Salix clones (willow) implanted in the Delta Paranaense (Villa Paranacito, Entre Ríos; 33° 45´S; 59° 05' W). Clones were: american, "A 131-25", "A 131-27", "A 13-44", "NZ 26992", "A 250-33", "A 250-36" and nigra 3.

Disc samples of three centimeter thick were taken from the shaft at three different heights (1.30 m, 4.30 m and 6.50 m) and their basic density was determined according to TAPPI standard 258- om -94. Variability analysis among clones was carried out for average basic density values, according to different heights. Tukey tests were applied for general average values (P<0.05).

Density highest values were generally found at 1.30 m. In some clones the density vary significantly at the different heights chosen. American and cv. "A 13- 44" clones showed the highest densities while cv A- 250- 36 was always within the lowest density group.

These comparative studies should be complemented including other heights, chosen in a relative (percentual) form, considering the commercial height of the tree, and characterizing density variation within growth cones.

Key words: Salix spp., wood density, patterns of axial variation, variability between clones.