Survival of Douglas-fir provenances in Austria: site-specific late and early frost events are more important than provenance origin.

These trials were established between 1973 and 1993 by the Austrian Research Centre for Forests BFW across a wide spectrum of site conditions (Fig. 1). The provenance trials were designed as randomized blocks. Within each block (replication) three to four-year-old pre-cultivated seedlings of selected provenances were planted in plots of 20-100 individuals with a spacing of 2m x 2m. The number of alive and dead trees /seedlings was recorded for each trial in ages between 3 and 10 years before any management measures were implemented