The frost hardiness of 16 European provenances of sessile oak Quercus
petraea (Mart.) Liebl. originating from six European countries was exa
mined from autumn until budburst in spring using the method of relativ
e conductivity. There were significant differences of frost hardiness
between provenances and a strong relationship between phenology and fr
ost hardiness. In spring, provenances that burst bud early dehardened
earlier than provenances that burst bud later. In autumn, provenances
that stopped growing early were more frost hardy than provenances that
continued to grow. The interprovenance ranges of frost hardiness were
greatest in spring and autumn and least in midwinter. Consequently, i
t was not possible to demonstrate significant differences of frost har
diness between provenances in December and January. Overall, German, P
olish and Danish provenances were more frost hardy than French, Austri
an and British provenances. French provenances were least hardy at all
times.