Prerazporeditev biomase pri sadikah Fagus sylvatica L. in Pinus sylvestris L. kot odziv na temperaturo

Since the impact of temperature on seedling growth and biomass allocation of different tree species remains relatively unknown, the influence of different temperature conditions on stem diameter (xylem and bark), stem and root extensions, as well as below- and aboveground woody biomass, in three-year old European beech (Fagus sylvatica L.) and Scots pine (Pinus sylvestris L.) seedlings in 2010–2011 were studied. One-year-old seedlings were grown outdoors (mean temperature during the growing season = 17–19°C), in the greenhouse (mean temperature during the growing season = 22–24°C) and climatized room (mean temperature during the growing season = 15–17°C) for two years. In terms of radial increment, xylem increments were narrowest in the case of increased temperature for beech and decreased temperature for pine. There was no difference in the thickness of the bark in beech seedlings exposed to different temperature conditions whereas in pine, the bark proportion was highest in control seedlings with the widest diameters. The periderm thickness was comparable in seedlings exposed to different temperatures and represented 10–14 % and 15 % of the bark tissue in pine and beech, respectively. Comparison of the total radial increments of seedlings of the two species under different temperature conditions showed that they were wider in pine in all three regimes. Increment of the main root was considerably higher in both species and represented about 90 % of the total length increment in beech and 74–87 % in pine. In addition, woody biomass was substantially higher aboveground in both tree species (by about 70–80 %). With beech, above- and belowground biomass was reduced in the case of elevated temperature, with the smallest share of roots. In pine, lower temperature diminished amount of biomass and caused its greatest allocation to belowground, which represented almost half of the total biomass accumulation. The short-term treatments clearly show that biomass allocation shifts of pine and beech in response to temperature seem to be a species-specific. The observed differences could be viewed as a plastic adjustment to environmental heterogeneity.