The effect of site preparation on vegetation restoration in young hemiboreal mixed stands

Abstract

Tree logging significantly impacts environmental conditions, increases soil and air temperature, and changes the microclimate and soil hydrology. This contributes to the changes in bryophyte and vascular plant cover and species composition. Site preparation positively affects the growth of planted trees in young stands but also causes forest understorey disturbance. During site preparation in young stands by spot mounding and disc trenching methods, new microtopographies, e.g. soil tumps and hollows are made in young stands. Site preparation generally increases vascular plant diversity, but there is a lack of information about the vegetation differences between microtopography depending on different site preparation methods and soil types. The aim of this study was to investigate how the microtopography formed during site preparation by spot mounding or disc trenching affects bryophyte and vascular plant communities in hemiboreal young stands two to three years after tree logging. Spot mounding altered vegetation composition more than disc trenching. Bryophyte species cover decreased in prepared soil, but Ellenberg’s moisture value increased; therefore, site preparation before planting contributes to the conservation of typical forest bryophyte species in young stands. Hollows lead to better typical forest habitat species preservation, but soil tumps diversify environmental conditions by providing new patches for the development of grassland habitat species that are not typical in this ecosystem, but temporally provide new ecosystem services. Keywords: bryophytes, spot mounding, disc trenching, vascular plants, plant growth forms, Ellenberg’s indicator values