Effects of seedbed substrate on moisture conditions and germination of Pinus sylvestris seeds in a clearcut

The objective of the investigation was to describe moisture conditions and germination of Scots pine (Pinus sylvestris L.) seeds in different seedbed substrates (feather mosses, mineral soil, humus and ground organic material ) with and without irrigation during 2 weeks, in a clearcut: in northern Sw eden. Without irrigation no seeds germinated, which could be explained as a n effect of the low moisture conditions of the seedbed substrates. This was shown in the seeds' low moisture content, with highest values in mineral s oil, 10-20%, and for the other seedbed substrates 5-15%. The moisture condi tions were highest during the night and lowest in the afternoon. With irrig ation, moisture conditions improved (seed moisture content 20-50%) and diur nal changes were moderated. Seeds germinated in all substrates with most se edlings in mineral soil (60% of sown germinable seeds). The moisture condit ions of the seedbed substrates proved to be in poor agreement with the seed s' requirement for germination, especially during warm weather with no prec ipitation.