Effects of seed invigoration and microsite preparation on seedling emergence and establishment after direct sowing of Pinus sylvestris L. at different dates

Seed properties and seedbed conditions influence forest regeneration follow ing direct seeding. It might therefore be possible to improve result by imp roving seed quality and seedbed conditions. In a direct seeding experiment designed to determine the effects of seed invigoration (incubation at 30% m oisture content for 7 days) and microsite preparation (2-cm-deep pyramidal indentations) on the regeneration, sowing was repeated on eight different o ccasions, and seedling emergence, survival and height growth were recorded. Seedling emergence, mainly after early sowing, was improved by invigoratio n when used in combination with microsite preparation. Both survival and gr owth were impaired by delaying sowing until later in the growing season. bu t were not significantly affected by invigoration or microsite preparation. It is concluded that an improved and less varying regeneration result afte r direct sowing may be achieved by using invigorated seeds in combination w ith microsite preparation.