Various scarification treatments produce different regeneration potentials for trees and forbs through changing soil properties

ABSTRACT

Soil scarification removed surface layers including nutrients and buried seeds. The purpose of this study was to evaluate the success of alternative practices that intentionally leave the surface soil (screening and replacing) along with the standard scarification. We focused on soil properties, the density of buried seeds, the invasion of competitive vegetation, and the regeneration of tree species. There were significant differences in soil properties among the treatments. Soils that were treated with the replacing treatment had the highest water contents from the surface layer to the deep layer in the lower slope in particular. On the other hand, there were higher densities of tall forb germinated from rhizomes, which are likely to shade tree species, with the replacing in the lower slope locations. The residual buried seed densities in the soil were estimated to be significantly higher in the screening than the replacing. Phellodendron amurense, producing seed bank and having dry tolerance, exhibited the greatest seedling density with the screening. However, there was no significant difference between screening and replacing in Betula species which has higher water demands. In conclusion, it is important that screening and replacing should be used properly according to the site condition and target tree species. The replacement had the advantage of retaining higher water content, but it is suggested that the screening is a better option when intended for regeneration from buried seeds and when many tall forb species grow alongside dwarf bamboo prior to treatment.

KEYWORDS:

• Surface soil disturbance
• selection of silvicultural practice
• buried seeds
• tall forb species
• assisted natural regeneration

Acknowledgments

We would like to thank two anonymous reviewers for their helpful comments and suggestions. We would sincerely thank N. Suzuki and technical staff of the Uryu Experimental Forest, for their assistance in the fieldwork, and members of the Nayoro laboratory for their valuable discussion for this study. We also thank A. Okuda for his help to conduct soil analyses.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by JSPS KAKENHI [26450187].