## 1 Introduction  
Ecological restoration, when carried out effectively and sustainably, contributes to protecting biodiversity, improving human health and well-being, and enhancing food and water security, to the provision of goods, services, and economic prosperity, and to supporting climate change mitigation, resilience, and adaptation [1]. At the UN, ecosystem restoration assumptions related to forest ecosystem degradation and conservation have been issued for the next decade (2021-2030). They go in two directions: the issue of global forest degradation (which includes the problem of deforestation) and the analysis of the theoretical basis of forest ecosystem restoration, taking into account application successes.  
This research is part of environmental policy and offers opportunities to counteract land degradation through long-term agricultural use and to restore biodiversity from the perspective of forest landscape restoration (FLR) and to mitigate climate change. The use of organic material demonstrates the need for a comprehensive approach to restoring and protecting natural ecosystems and strengthening their resilience [2].  
The development of post-agricultural land through afforestation carries the risk that the first generation of Scots pine _Pinus sylvestris_ L. will not survive to fell age due to the threat of the fungus _Heterobasation annosum_[3; 4; 5]. Its spores are ubiquitous and cause primary infection when they fall on the stumps produced during the rearing of the first thinning. As it has no natural counterparts (as in the forest ecosystem), it can multiply uncontrollably and cause secondary infections through root contacts between diseased and healthy trees [6; 7; 8]. As a result, gaps appear and, after a certain time, usually at the age of 40, the stand loses its compactness and is only suitable for removal and restoration [6].  
The prevention methods developed involve the removal of tree stumps, which are a niche used by root pathogens. However, they are labor-intensive (mechanical) or environmentally damaging (chemical), and even if they are environmentally friendly (biological), they are expensive, which has recently become important in forestry in the face of strong competition from different employers. The rising costs of forest prevention and protection, as well as ecological considerations, make it necessary to look for other methods, which include increasing the natural resistance of the soil to pathogens.  
Restoring organic levels that ensure the circulation of elements (macro- and micronutrients), the presence of natural antagonists (fungi such as _Trichoderma_ spp. or _Penicillium_ spp.) against pathogens, and fungi that form symbiotic mycorrhizal relationships (e.g., _Ammitta_ or _Rusula_ genus) seems to be the most appropriate direction in the current economic and social situation [9]. For this reason, an attempt was made to use various organic substrates that are often a by-product of timber harvesting, such as wood waste or sawdust (in sawmills) or wood processing (debarking), and that can be used to produce compost (bark) that promotes the number and diversity of beneficial fungi present in the soil [10]. This approach is in line with the concept of the circular economy and European Union policy [11].  
To underline the importance and uniqueness of the study started 20 years ago, we have tried to review its implications and applicability to the field of forestry. Primarily, the study aimed to determine whether the introduction of organic material into degraded soils (after agricultural use) can restore mycobiota characteristic of forest soils.