Influence of clonal variability on the impregnability of poplar hybrids. (+ correction document of 23 April 1990)
J Van Acker Van, M Stevens, C De Haas
The new Western European poplar clones (Populus nigra x deltoides and Populus trichocarpa x deltoides) were compared with the reference clone 'Robusta' and some old hybrids. Samples (5x5x50 cm³) with pure tangential/radial surfaces were sawn, including the transition zone between heartwood and sapwood. Treatment by a standard vacuum-pressure impregnation cycle with CCA showed a range of retentions from 2 to 10 kg/m³ for the 23 poplar clones studied. Only minor differences in impregnability were observed between samples of different trees belonging to the same hybrid. Although the new poplar clones in general show no substantial differences in uptake compared to the reference clone "Robusta" and the older poplar hybrids, the penetration of Cu and As was lower. No relation between wood density and impregnability was found. The radial and tangential penetrations were identical. Cu penetration in sapwood was significantly better than in heartwood. Samples of 1 m length revealed a poor longitudinal penetration.
Keywords: CCA; CLONAL VARIABILITY; HYBRIDS; POPULUS NIGRA X DELTOIDES; POPULUS TRICHOCARPA X DELTOIDES; REFRACTORY ZONE; TREATABILITY