Tree-induced soil compaction in forest ecosystems: myth or reality?

Trees subjected to wind loading are supposed to induce a soil deformation. However, knowledge is lacking about this phenomenon. In the present contribution, we hypothesized that soil compaction is higher in the surroundings of the lateral roots and in particular at their distal part where the amplitude of the root movements is expected to be largest. To test this hypothesis, we focused on a shallowly rooted tree, the European beech (Fagus sylvatica), in a large forest situated south of Brussels. Mean soil compaction significantly increased as one moves away from the tree, up to a distance of 5 m. Soil compaction was not evenly distributed around tree trunks, the highest values being in the north direction. Only part of these results supports the hypothesis about soil compaction due to wind-induced movements within near-surface lateral roots in beechwoods on silt loams. The need for additional research is highlighted.