The elasticity of growth in pure and mixed stands of Norway spruce (Picea abies [L.] Karst.) and common beech (Fagus sylvatica L.)

This study indicates that the growth of mixed stands with Norway spruce (Picea abies [L.] Karst.) and common beech (Fagus sylvatica L.) is more stable across a range of stand densities than it is in pure forests of the same species. Typical density-growth-relationships are derived from 42 long-term experimental areas with 134 plots in total, the oldest of them under survey since 1870. From these results it is apparent that in pure stands maximum growth can be obtained only at medium stand density, whereas in mixed stands growth is almost unchanged over a range of low, medium and high stand density. The finding that mixed stands may perform a superior growth to pure stands with either decreasing or increasing stand density has often been overlooked but is nevertheless of major practical importance.