SAP-FLOW VELOCITIES AND DISTRIBUTION OF WET-WOOD IN TRUNKS OF HEALTHYAND UNHEALTHY QUERCUS-ROBUR, QUERCUS-PETRAEA AND QUERCUS-CERRIS OAK TREES IN HUNGARY

Sap-flow of Quercus robur, Quercus petraea and Quercus cerris oak tree s were studied. K-43 radioisotope tracing, the heat pulse velocity tec hnique and the Granier-method were employed. Numerous intense pulses w ere observed in healthy Quercus petraea superposing onto the usual diu rnal change. Only a few pulses were observed in unhealthy Quercus petr aea, in healthy Quercus cerris and healthy and unhealthy Quercus robur trees. Proportion of wet-wood assessed by gamma- and X-ray computer t omography and magnetic resonance imaging was significantly less in hea lthy Quercus petraea trees than in healthy Quercus cerris trees. Propo rtion of wet-wood was higher in healthy trees than unhealthy trees of both species. (C)1998 Elsevier Science Ltd.