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Soil Compaction Effects on Root‐Zone Hydrology and Vegetation in Boreal Forest Clearcuts
Author(s) -
Hansson Linnea,
Šimůnek Jirka,
Ring Eva,
Bishop Kevin,
Gärdenäs Annemieke I.
Publication year - 2019
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2018.08.0302
Subject(s) - environmental science , soil water , hydrology (agriculture) , water content , soil science , vegetation (pathology) , soil compaction , riparian zone , geology , geotechnical engineering , ecology , pathology , habitat , biology , medicine
Core Ideas Impact of forwarding on soil water and vegetation was investigated after 4 to 5 years. Soil water content was highest in wheel tracks and lowest between tracks. Bare soil was more frequent in tracks and between tracks than in undisturbed soil. In wheel tracks, soil aeration may be restricted in periods with high precipitation. Simulated root‐zone pressure heads showed little variation between microsites. Soil compaction is a common consequence of forestry traffic traversing unprotected, moist soils; it decreases porosity and affects hydraulic conductivity even in coarse‐textured soils. The aim here was to study root‐zone hydrology and vegetation in three microsites (in, between, and beside wheel tracks) 4 to 5 yr after forwarder traffic, on stony and sandy till soils in two clearcuts in northern Sweden. Measurements of soil volumetric water content (VWC), vegetation indicators and one‐dimensional hydrological modeling (Hydrus‐1D) of wheel tracks and undisturbed soil were conducted. Soil VWC was monitored hourly during 2017 and 2018 in three or four plots along a slope on each site. Soil VWC was also measured once with a portable sensor in 117 plots along two slopes at each site, where the vegetation was recorded and analyzed using Ellenberg indicator indexes. Soil VWC was highest in wheel tracks and lowest between tracks; this was corroborated by the species composition in the wheel tracks (Ellenberg indicator for soil moisture). Bare soil was more frequent in wheel tracks and between tracks than in undisturbed soil. The model simulations indicated that the changed soil hydraulic properties influenced the VWC results in the wheel tracks. However, the differences in average pressure heads in the root zone were small between the microsites and only apparent during dry periods. In the wheel tracks, air‐filled porosity was <0.10 m 3 m −3 , indicating insufficient soil aeration during 82% (Site T) and 23% (Site R) of the 2017 growing season. Insufficient aeration could be one explanation for the presence of some still unvegetated areas.