Effects of soil compaction on growth and survival of tree saplings: A meta-analysis

Soil compaction due to mechanized harvesting operations in forests can have profound effects on forest soils and, hence, can have a detrimental effect on subsequent forest regeneration. We performed a meta-analysis to quantify the effect of soil compaction on height growth, diameter growth, and survival of tree saplings. These effects were predominantly insignificant, varied strongly and were thus not unambiguously negative. Only on silty soils, growth and survival were significantly reduced by soil compaction, which contrasted with sandy and loamy soils, where the effect of soil compaction was negligible or even slightly positive. A weighted analysis revealed an overall decrease of height growth on the compacted areas, but this result should be interpreted with caution due to the limited number of observations. Although results did not show an overall negative effect of soil compaction, harvesting activities should focus on minimizing soil compaction degree and extent to prevent a decrease of soil productivity. From a methodological point of view we suggest providing more basic statistics in the articles and to include more shade-tolerant tree species in future experimental designs. These species are currently underrepresented.