The Effects of Soil Compaction on Morphology and Biomass Variables of Chestnut-leaved Oak (Quercus castaneifolia C.A.M.) in Greenhouse Situations

The use of heavy machinery in forestry operations such as logging has increased worldwide during the last decades. However, these machines may seriously influence the soil ecosystem as they induce rutting, disturbing the upper soil layers, and soil compaction. Severe compaction of soil adversely affects the growth of plants.This study was done by using a penetration resistance experiment in a greenhouse to test the hypotheses that increasing soil strength would affect adversely the seedling morphology (size) and growth (biomass) by changing the above- and below-ground patterns. We created four soil compaction intensity treatments. The lowest compaction intensity (no compaction, control), low, moderate, and high intensities of compaction were achieved by manually applying 3, 5 and 7 blows with a compaction hammer from a height of 20 cm above the soil surface, respectively. We studied the effects of soil compaction in a loam to clay-loam textured soil with optimal conditions of water on a continuous scale (0.1–1.0 MPa penetration resistance) on the growth responses of the deciduous Quercus castaneifolia (C.A.M.). Above- and below-ground metrics of seedling size (i.e., stem length and diameter, leaf length, main root length and diameter, and lateral root length) and biomass (i.e., total, shoot, and total root) were negatively affected by soil compaction. Seedling sizes and growth parameters responded nonlinearly to increasing the soil strength. We conclude that growth of roots and height of oak seedlings are restricted with any increases in soil strength.