INHIBITION OF SCOTS PINE SEEDLING ESTABLISHMENT BY EMPETRUM-HERMAPHRODITUM

Poor establishment and reduced seedling growth of Scots pine (Pinus silvestris L.) in northern Sweden is related to an allelopathic inhibition by the dwarf shrub Empetrum hermaphroditum Hagerup. Indoor bioassays with green and brown leaves of Empetrum have strong negative effects on rooting ability, radicle elongation, and growth of Scots pine seedlings. Bioassays with soil samples show that phytotoxic substances leached from Empetrum foliage accumulate in the soil. Field experiments reveal that chemical inhibition by Empetrum, causing high mortality and slow growth of pine seedlings, can be reduced by adding activated carbon to the soil.