ConForest - The Challenge

Since the Middle Ages and into the 20th century, human forest management has expanded the borders of coniferous species beyond their respective natural range. Norway spruce and pine species were notably promoted in this process, which was motivated by widespread over-exploitation / devastation of forests, as well as the fear of timber shortage. Consequently, extensive coniferous forests are presently found in many European countries and have changed the natural species composition to the detriment of broadleaf forests. ConForest studies the options and consequences of conversions of coniferous forests on sites naturally dominated by broadleaves.

chart Figure 1: Changes in tree species composition in central European forests. The area of broadleaved species has been reduced while the area of conifers has increased (Spiecker 2000 based on data by Mayer 1984).

In recent years, forest disturbances caused by abiotic or biotic influences, e.g. storm, insect attacks, etc., has brought about large scale salvage cuts, in pure and commonly, even-aged coniferous stands. These occured often on sites that were naturally dominated by broadleaves. In some European regions, the volume of the impact of these events is so high, that stability and resilience of the stands are affected. Negative effects of coniferous forest, linked to the possibility of soil degradation, endangers continuous and multifunctional forest use, and may also impact landscape aesthetics and the sustainable development of certain (e.g. rural) areas. A demand is placed towards a full re-evaluation of the silvicultural options available for conifer forests.