Micropropagated Silver Birches (Betula pendula) in the Field – Performance and Clonal Differences

Micropropagated and seed-born silver birches (Betula pendula Roth) were compared for survival, height growth and occurrence of biotic damage (voles, hares, mooses, stem lesions and cankers) in fi eld trials in southern Finland. The material consisted of 11 clones and 10 different lots of seedlings growing in 10 fi eld trials, established in clearcut forest cultivation areas. The plants were 6–7 years old. The micropropagated and seed-born material types did not signifi cantly differ from each other as regards survival, height growth and frequencies of damage caused by biotic agents. Large and signifi cant differences were, however, detected in survival, height and frequencies of all types of biotic damage between single clones. Careful selection and testing of birch clones in fi eld conditions is recommended before wide-scale commercial micropropagation and practical forest cultivation takes place.