Callesen, I., Raulund-Rasmussen, K., Jørgensen, B. B. and Kvist–Johannsen, V. 2006. Growth of Beech, Oak, and Four Conifer Species Along a Soil Fertility Gradient. Baltic Forestry, 12 (1): 14-23

Growth of beech, oak, and four coniferous species (Norway spruce, Douglas–fir, Larch and Sitka spruce) was compared in a 33–year–old tree species trial on eight field soils in Denmark. Height and volume growth were fitted in difference equations, and parameter estimates a(H100) and a(Vtot) were tested as biotic site quality indicators against climate and soil fertility indicators. Site quality indicators for height a(H₁₀₀) and volume growth a(V_tot) increased significantly with soil nutrient availability (PC1) for Sitka spruce, Norway spruce and oak (height), and oak and beech (total volume). Principal component analysis explained 64 % of total variance in soil and climate variables by the first component (PC1), which was interpreted as a gradient in soil nutrient availability. The volume growth of oak and beech responded stronger to increasing soil nutrient availability than the conifers, and the correlation was stronger. Conifers were able to maintain a high production on very nutrient poor soils in contrast to oak and beech. Therefore, volume growth a(V_tot) of conifers as an indicator for soil fertility is inappropriate within the study area, as conifer growth does not reflect soil nutrient availability. However, the correlations observed in growth–site–soil variables in this study suggest that soil information should be used in forecasting growth performance e.g. in planning afforestation of arable land.

Key words: Tree species trial – soil – site relationship, soil nutrient regime – afforestation – set – aside farmland