Changes in soil properties in a low-quality broadleaf mixed forest after cutting strip reforms in a 9-year period in Northeastern China

Abstract. Strip reforms with widths of 6 m, 10 m, 14 m and 18 m were carried out in a low-quality broadleaf mixed forest in Greater Khingan Mountains. The influence of time on soil properties, including physical and chemical properties, were analysed on the basis of data of the soil components obtained from nine consecutive years (from 2010 to 2018). In the meantime, a principal component analysis was used to determine the weight of each soil indicator, and the fuzzy comprehensive index method was applied to provide further insight into the variation of soil quality. We found that most soil physical properties were damaged by cutting within 3 years and can be restored after 6 years. Over the 9 years, soil physical properties displayed some differences across cutting strip widths, while chemical properties did not display any differences. In terms of chemical properties, they need more time to recover. In view of the current research years, the soil quality could not be restored in the 18-m harvesting zone within nine years. The cutting width of 10 m is more obvious than that of other transformation widths, so 10 m is the best width for cutting strips for the forest. This study has important implications for sustainable management of the mixed natural broadleaf forest in the study region and beyond. A larger width of the cutting strip in this type of forest in the region should be avoided. Moreover, for forest soil conditions, we need to continue long-term observations.