Relationship between seedbed properties and the emergence of spruce germinants in recently cut Norway spruce selection stands in Southern Finland

The purpose of this study was to examine the effects of type and amount of ground vegetation and substrate on the germination and early survival of Norway spruce (Picea abies (L.) Karst) seedlings in uneven-aged stands on mineral soils in Southern Finland. The study was conducted on two permanent plots representing average site quality for spruce stands in the area. A gradient in selection cut intensity and residual stand density was imposed across each of the two permanent plots. Regeneration and vegetation surveys were repeated annually on a grid of unmanipulated microplots and on a set of soil treatment microplots. The results indicated that the number of spruce germinants per unit area was positively correlated with herb cover but negatively correlated with total plant cover. Germinant density was also related to vegetation-free seedbed conditions, high overstory competition index and presence of larger spruce seedlings. Regeneration microsites dominated by moss or with plants with a relatively high light demand were associated with low germinant numbers. Bare humus layer and decayed stumps seemed to promote germinant emergence. Exposure of mineral soil resulted in germination rates that were 4.3-6.9 times higher than in undisturbed conditions during the first growing season.