Interacting effects of nutrients, pH - Al and elevated CO2 on the growth of red spruce (Picea rubens Sarg.) seedlings

Abstract

A 4 mo growth chamber experiment was conducted to evaluate the presence and importance of interactions between nutrient supply, atmospheric CO2 concentration, and four different combinations of pH — Al concentration on the growth, vitality, and tissue element concentrations of 1-yr-old red spruce seedlings. Solution chemistry was chosen to simulate soil conditions at a red spruce die-back site at Roundtop Mountain (Quebec) that has high acid loadings. CO2 levels were chosen to simulate ambient levels and those expected in the next century. All three experimental factors affected growth and all factors except CO2 affected the visual symptoms of die-back. There was an important interaction between nutrient levels and the different pH — Al combinations, indicating that the response of red spruce to various pH and Al concentrations changes with soil fertility. The positive growth response to enriched CO2 was not sufficient to offset the negative effects of the acid rain induced stresses. A principal component analysis showed that multivariate functions of foliar element concentrations could clearly distinguish plants from different experimental regimes.