Climate changes influencing forest ecosystems include increased air temperatures and CO₂ concentrations as well as droughts and decreased water availability. These changes in turn effect changes in species composition of both host plants and pathogens. In the case of Armillaria, climate changes cause an increase in the activity of individual species and modify the growth of rhizomorphs, increasing the susceptibility of trees. The relationship between climate changes and the biotic elements of Armillaria disease are discussed in overview.

The fungus Phlebiopsis gigantea has been used in Europe as a biological agent for the control of conifer root and butt (caused by Heterobasidion annosum ) for nearly 40 years. P. gigantea competes with H. annosum for the woody resource within conifer stumps, and is applied to stump surfaces at felling. Three distinct biological control products based on P. gigantea have been developed: PG Suspension in the UK, PG IBL in Poland and Rotstop in Finland. The formulations are of oidia, which are maintained in a sucrose suspension, sawdust, or a wettable powder, respectively. PG Suspension and PG IBL are applied to pine stumps, while Rotstop is equally as effective on pine as on Norway spruce stumps. For each product, isolates of P. gigantea are selected from the wild and are screened for their competitive ability against H. annosum before formulation. Viability and purity checks are undertaken throughout the production cycle and during routine use. The increasing use of mechanized harvesting machines to fell and process trees is having an impact on this biological control system, the formulations having to be compatible with the mechanical application systems and vice versa. This paper compares the formulation, testing and application of the three products, and considers some aspects of their future development.

The current nature of forest management in Poland reflects its history and more than 100 years of economic activity affecting forests since independence in 1918. Before that time, different forest management models were used, related to the nature of the Prussian economy in the north of the country, the Russian economy in the central-eastern part, and the Austrian economy in south-eastern Poland. The consequence of these management models, as well as the differing climate zones in which they were used, resulted in varied forest health. Since the end of World War II, forest coverage within Poland‘s new borders has increased from 20.8% to currently 29.6%, mainly as a result of afforestation of wastelands and former agricultural lands. This paper describes changes in the health of forests and their biological diversity in Poland in the context of weather extremes, species composition, forest management, the forest industry, and damage from insects and pathogenic fungi over the last 30 years.

Common mistletoe is increasingly mentioned as contributing not only to the decline of deciduous trees at roadside and in city parks, but to conifers in stands. The presence of Viscum in fir stands has been known for many years, but since 2015 has also been the cause of damage to pine. In 2019, mistletoe was observed on 77.5 thousand hectares of Scots pine stands in southern and central Poland. Drought resulting from global climate change is implicated as an important factor conducive to weakening trees and making them more susceptible to the spread of mistletoe and other pests. This paper presents an overview of the latest information on the development of this semi-parasitic plant in Poland, its impact on tree breeding traits and raw material losses, as well as current options for its prevention and eradication.

Drought in the forest is not only a prolonged state of water shortage, but also an occasion where interactions between plants and fungi are affected. Water efficiency accelerates a range of pathologies in interactions between organisms, influencing the ecosystems and their interacting biological components. This study focuses on the role of mycorrhizal and endophyte fungi in alleviating the effects of soil water shortage, and on the impact of their altered activity during drought on the health of trees. The issues presented here show the fundamental role of the mycorrhizal mycelium and the mechanism of water transport to the plant in the course of other phenomena (withering, pathogenesis, endophytes biology) that occur in trees under influence of drought, with particular attention on managed coniferous stands. Conclusions resulting from published information on this topic emphasize the negative impact of soil moisture deficiency on the ectomycorrhizal fungi functioning and, in contrast, on the promotion of the growth of some endophytes, pathogens and hemi-parasitic mistletoes (Viscumspp.).

Their hyphal structure, the common events of hybridization and horizontal gene transfer, as well as intimate associations with prokaryotes (including endobiotic bacteria) and cooperation with eukaryotes have made fungi very flexible at the genetic, physiological, and ecological levels. It is manifested with the fungal ability to perfectly exploit existing nutrient sources and plastically fit into a changing environment. Although the links between fungi and other ecosystem components are rarely clearly visible and unambiguous, fungi can be ecosystem buffers playing a homeostatic role throughout global ecosystems, reacting to changes in various ways, not only by modifications of gene expression but also by nuclear status and “extended phenotype”. The goal of this review is to underline some ecological interactions involving fungi and other organisms and to indicate high fungal plasticity in terms of ontogenetic perspective.