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The primary objective of this paper was to estimate how the mass of Silver fir (Abies alba Mill.) and Scots pine (Pinus sylvestris L.) deadwood in two decay classes affected biochemical processes and the accumulation of soil organic matter, as well as the extent of this impact. We evaluated deadwood mass, as well as the biological activity and influence of the distance from deadwood on biological activity and carbon (C) storage. The investigation was carried out in Magurski National Park, southern Poland, in four randomly selected study plots. The organic C and nitrogen contents and soil pH and texture were analysed. The study also included the determination of enzyme activities. The results obtained demonstrated that soil C storage and the biological activity of the soil were influenced by deadwood form, tree species and decay class. Significant differences in the C content in the soil between the logs of fir and pine trees were noted. With the advancement of the deadwood decomposition process, the C concentration and enzyme activity increased slightly. Lower C accumulation occurred further away from the deadwood. At a 100-cm distance from the deadwood, the influence of the logs was not evident. Higher C storage was found in the soil around the stumps than in the decaying logs. This study confirmed an important role of deadwood in forest ecosystems, i.e., maintaining species biodiversity and increasing C accumulation in the soil environment with a simultaneous increase in the biological activity of the soil.

Bark beetles (Coleoptera: Scolytidae) infesting Norway spruce trees are known to be associated with fungi, especially species of Ophiostoma sensu lato and Ceratocystis. However, very little is known about these fungi in Poland. In this study, we examined the ophiostomatoid species associated with seven species of bark beetles developing in Norway spruce (Picea abies). Fungi were isolated from the beetles and their galleries at ten sites in southern Poland. We identified a total of 2,769 fungal isolates that belong to 19 ophiostomatoid species. These 19 species included a total of 16 associations between fungi and bark beetles that had not been previously recorded. The isolated fungal species were similar to those previously reported. The species spectrum and relative abundance of fungal associates were similar in seven bark beetle species, despite some differences between species. Except for Pityophthorus pityographus, all bark beetles species were frequently associated with ophiostomatoid fungi. The most commonly encountered fungal associates of bark beetles were the following: Ophiostoma ainoae, O. bicolor, O. piceae sensu lato and Grosmannia piceiperda. The results support the hypothesis that pathogenic ophiostomatoid fungi are important for aggressive bark beetles to kill trees. The most virulent fungal associate of bark beetles, Ceratocystis polonica was most commonly associated with Ips typographus. The most frequent ophiostomatoid species isolated from the beetles and galleries of P. pityographus were O. ainoae and Graphium fimbriisporum.

The number of invasive alien pest and pathogen species affecting ecosystem functioning, human health and economies has increased dramatically over the last decades. Discoveries of invasive pests and pathogens previously unknown to science or with unknown host associations yet damaging on novel hosts highlights the necessity of developing novel tools to predict their appearance in hitherto naïve environments. The use of sentinel plant systems is a promising tool to improve the detection of pests and pathogens before introduction and to provide valuable information for the development of preventative measures to minimize economic or environmental impacts. Though sentinel plantings have been established and studied during the last decade, there still remains a great need for guidance on which tools and protocols to put into practice in order to make assessments accurate and reliable. The sampling and diagnostic protocols chosen should enable as much information as possible about potential damaging agents and species identification. Consistency and comparison of results are based on the adoption of common procedures for sampling design and sample processing. In this paper, we suggest harmonized procedures that should be used in sentinel planting surveys for effective sampling and identification of potential pests and pathogens. We also review the benefits and limitations of various diagnostic methods for early detection in sentinel systems, and the feasibility of the results obtained supporting National Plant Protection Organizations in pest and commodity risk analysis.

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International trade in plants and climate change are two of the main factors causing damaging tree pests (i.e. fungi and insects) to spread into new areas. To mitigate these risks, a large-scale assessment of tree-associated fungi and insects is needed. We present records of endophytic fungi and insects in twigs of 17 angiosperm and gymnosperm genera, from 51 locations in 32 countries worldwide. Endophytic fungi were characterized by high-throughput sequencing of 352 samples from 145 tree species in 28 countries. Insects were reared from 227 samples of 109 tree species in 18 countries and sorted into taxonomic orders and feeding guilds. Herbivorous insects were grouped into morphospecies and were identified using molecular and morphological approaches. This dataset reveals the diversity of tree-associated taxa, as it contains 12,721 fungal Amplicon Sequence Variants and 208 herbivorous insect morphospecies, sampled across broad geographic and climatic gradients and for many tree species. This dataset will facilitate applied and fundamental studies on the distribution of fungal endophytes and insects in trees.