The growth of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) seedlings on hydrologically and nutritionally contrasting till soils in Finnish Lapland

The survival and growth of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies) seedlings were studied on two hydrogeologically and nutritionally contrasting types of till soil. The first study site (Vuotso) is composed of sandy till derived from granite-gneiss bedrock, and the other (Vaalolehto) from chlorite-amphibole schist. The one-year-old paper pot seedlings were planted in spring 1996 on both sites with identical study design, including two greenhouses and a control. The seedlings have grown in two temperature regimes using different ventilation intensities. Three irrigation treatments were applied. The preliminary results of seedling survival, shoot and root biomass, photosynthesis, tanspiration and water potential of the needles are presented in this paper. There were no significant differences in survival between the species. The early development of the Scots pine seedlings was much faster than that of the Norway spruce seedlings. This was seen in the rate of CO2 fixation and accumulation of shoot biomass. The root/shoot ratio was higher in the spruce and in the yellowish pine seedlings than in the fast growing, green pine seedlings. The results suggest that the high shoot/root ratio is the factor that predispose the fast growing Scots pine seedlings to dieback on fine-textured soils with a high water and nutrient content.