Saproxylic fungi in the Scots pine woody debris

Awareness of the importance of the presence of deadwood in forest ecosystems has increased in recent decades. Today, deadwood is not only recognized as a key element in carbon sequestration, nutrient supply and water retention, but is also known to be a reservoir of saproxylic species (species associated with the decay of wood on living and dead trees). The amount of deadwood in clear−cut forest is currently higher than 100 years ago. The issue of how much deadwood and of what quality (including size) there should be in order to promote the conservation of saproxylic biodiversity and sustainable forest management is still vivid. Mycological analyses to determine (i) structure of fungal communities in Scots pine wood debris, (ii) sources and reservoirs of fungi, (iii) nutritional preferences of fungi, and (iv) potential rate and dynamics of wood decomposition were carried out on an ‘old' and ‘fresh' wood (stumps, branches and boughs) from Jedwabno Forest District (north−eastern Poland). Fungi from 62 wood samples were isolated on two artificial media (PDA and SNA) and identified according to their morphology. Eleven species of Zygomycota, 79 of Ascomycota and 15 of Basidiomycota were detected. The majority of species (91%) colonized many samples. Only 9% of species colonized single samples only. The most common species, with high rates of colonization, included Acremonium spp., Alternaria sp., Aspergillus spp., Aureobasidium pullulans, Cladosporium spp., Epicoccum nigrum, Lecythophora spp., Mariannaea elegans, Ophiostoma + Sporothrix spp., Penicillium spp., Phialocephala spp., Phialophora spp., Phlebiopsis gigantea, Phoma spp., Sarocladium strictum, Scytalidium lignicola, Sydowia polyspora, Trichoderma spp. (mainly T. harzianum and T. viride) and Umbelopsis spp. A few species occurred only on stumps or only on branches. More species occurred on 'old' wood than on 'fresh' wood. The average level of sample colonization by a single fungal species was higher (non−significantly) on 'old' than on 'fresh' wood, and on branches than on stumps. The results show that deadwood is a habitat for many fungal species that occur in succession. The presence of deadwood in clear−cut forest and in its neighborhood is necessary for the conservation of saproxylic fungal diversity and ecological sustainability of forests

Tuning of extended state observer with neural network-based control performance assessment

The extended state observer (ESO) is an inherent element of robust observer-based control systems that allows one to estimate the impact of disturbance on system dynamics. Proper tuning of ESO parameters is necessary to ensure a good quality of estimated quantities and impacts the overall performance of the robust control structure. In this paper, we propose a neural network (NN) based tuning procedure that allows the prioritization between selected quality criteria such as the control and observation errors and the specified features of the control signal. The designed NN provides an accurate assessment of the control system performance and returns a set of ESO parameters that delivers a near-optimal solution in terms of the user-defined cost function. The proposed tuning procedure, using an estimated state from the single closed-loop experiment, produces near-optimal ESO gains within seconds

Mycobiota in trunks of dying spruce trees in the 'Puszcza Bialowieska' Promotional Forest Complex and its ecological function

The European spruce bark beetle (Ips typographus) outbreak observed in the ‘Puszcza Białowieska’ Promotional Forest Complex since 2012 resulted in a total volume of 1.4 million m3 of dead trees in multiple spruce stands. The study aimed to assess the species composition of fungi occurring in spruce trunks at early stages of European spruce bark beetle attack. All the samples used in laboratory analyses were collected in 2016 and 2017 in Białowieża, Browsk, and Hajnówka forest districts. A total of 60 dying spruces selected at random were sampled providing 120 samples. Surface−sterilised samples were used in fungal isolations using malt extract agar medium. The resulting colonies were identified morphologically, additional molecular identification was carried out for representatives of morphotypes using ITS rDNA fragment. In addition to these analyses, the frequently occurring basidiomycete fungi on recently died spruce trees were identified based on the morphology of fruiting bodies. One of the most common symptoms observed on trunks of spruces at the early stages of dieback was the occurrence of sapstains starting from bark beetle galleries. In some trunks the stained wood sections were separated by rusty−red stripes. A total of 51 fungal species including 40 ascomycetes and 11 basidiomycetes were isolated from dying spruce trunks. The number of ascomycete species included 16 ophiostomatoid fungi (members of Ophiostomatales and Microascales). The frequently occurring species in this group were: Endoconidiophora polonica (=Ceratocystis polonica) (17.5%), Grosmannia penicillata (20.8%), Ophiostoma brunneolum (9.2%), O. piceae (5.8%) and O. abieticola (4.2%). Among other ascomycetes only three species were frequently isolated: Neonectria fuckeliana (15.0%), Clonostachys rosea (13.3%) and Cosmospora viridescens (9.2%). The rusty−red coloured areas harboured primarily Amylostereum areolatum and Stereum sanguinolentum. The most frequently detected basidiomycete fungus on trunks at the initial stages of dieback was Cylindrobasidium sp. (=Gloeocystidium ipidophilum), whereas Fomitopsis pinicola was the most frequent species on spruce trunks dead for some years, either standing or wind−snapped. We emphasise the potential role of the detected fungi in forest ecosystems of the Białowieża Forest, both as potential tree pathogens and decomposers of spruce debris remaining in the stand

Assessment of leaf damage in oak stands in the flood-affected Wolow Forest Division

This study examines the effect of flood on oak stands in the Wołów Forest Division by assessing the loss of leaf area due to insect feeding as determined in laboratory analyses of samples collected from standing trees. We compared stands, in which water stagnated for at least one month and stands with no water stagnation. It was found that the mean damage to the carbon assimilating organs of stands with stagnating water was lowered by approximately 6% compared to stands that were not affected by flood. Thus, no definite effect of flood contributing to losses of carbon assimilating organs in oak trees could be shown

Determination of profiles of volatile metabolites produced by Trametes versicolor isolates antagonistic towards Armillaria spp.

Armillaria root disease is one of the most important diseases causing losses in forestry, horticulture, pomiculture and agriculture. Fungi from Armillaria spp. infest roots and stem base in trees and shrubs, causing white wood rot. In Poland the most common species include Armillaria ostoyae (Romagn.) Herink, found both in coniferous and deciduous stands, and A. gallica Marxm. et Romagn. found in deciduous stands. Identification of antagonistic interactions between microorganisms in the soil medium enables to use their activity to protect plants against pathogens. Analyses were conducted on two Trametes versicolor isolates TR31 and TR55, collected from oak stumps, and 5 fungal species from the genus Armillaria: A. borealis Marxm. et Korhonen, A. cepistipes Velen., A. gallica, A. mellea (Vahl) P. Kumm. and A. ostoyae. Profiles of volatile compounds produced by T. versicolor isolates TR31 and TR55 determined in this study varied in their effect on growth of pathogens Armillaria borealis, A. cepistipes, A. gallica, A. mellea and A. ostoyae. TR31 more effectively than isolate TR55 inhibited growth of fungi from the genus Armillaria. Profiles of volatile compounds biosynthesised in the examined fungal cultures were assessed by headspace microextraction in a gas chromatograph coupled with a mass spectrometer. We detected 179 compounds in the analysed fungal cultures. They belonged to the following groups of chemical compounds: amines, alcohols, terpenes, aldehydes, ketones, hydrocarbons, heterocyclic compounds, esters and aromatic compounds (tab. 2). The most numerous group among the isolated volatile compounds comprised hydrocarbons, alcohols and esters at 32.4%, 16.2% and 14.5%, respectively. The highest concentrations reported in RU (i.e. the peak area of a given substances in relation to the peak area of the internal standard, i.e. tridecane) were recorded for aldehydes, alcohols and hydrocarbons. Among all the identified volatile compounds the highest concentration was observed for 2−methylbutanal. However, it was characteristic only of isolate TR31, which exhibited a greater capacity to inhibit growth of Armillaria spp. in comparison to isolate TR55 (fig.)

Changes in elm (Ulmus) populations of mid-westernPolandduringthepast35years

Abstract: Three elm species are native to Poland: wych elm (Scots elm) (Ulmus glabra Huds.), field elm (U. minor Mill.), and European white elm (fluttering elm) (U. laevis Pall.). The epidemic of Dutch elm disease (DED) has led to a decrease in the popularity of elm cultivation. An analysis of forestry data was the first step in the assessment of elm resources. The area of forest stands where elms are dominant has more than doubled since 1978. Lowland alluvial forests rank first in regards to the number of elm localities per unit area of a given forest site type. While this site type is clearly preferred by elms, the majority of elm trees are actually scattered among sites of oak-hornbeam or closely related forests (of the alliance Carpinion betuli). Field research revealed a clear dominance of U. laevis, a species which in the past was predominantly located out of woodland and rarely cultivated. Data analysis indicated that all trees greater than 70 cm in diameter belonged to this species. Data from plots surveyed directly also suggest that the three elm species have slightly different habitat preferences. U. laevis prefers riparian habitats, although the major part of its resources is now on potential sites of oak-hornbeam or closely related forests. U. minor even more often than U. laevis occurs at less humid sites (mostly potential sites of oak-hornbeam or closely related forests), while U. glabra prefers moist slopes. In general, it appears that the impact of DED in the last 20-30 years has been smaller than in the preceding period, however, the disappearance of the disease has not been established. Undoubtedly, U. laevis is the elm species that is least impacted by DED

Communities of fungi in decomposed wood of oak and pine

The abundance and diversity of wood decomposing fungi were investigated by isolating and cultivating filamentous fungi from wood and by detection of fruit bodies of ascomycetous and basidiomycetous fungi. The objective was to study the impact of forest management on fungi in 100-year-old oak and 87-year-old Scots pine forests in Northern Poland. Fungi were found on coarse woody debris of decayed stumps and fallen logs, boughs and branches in each of the three (managed and unmanaged) examined stands. In total, 226 species of Oomycota and fungi were recorded. Oak wood was colonized by one species of Oomycota and 141 species of fungi including Zygomycota (19 species), Ascomycota (103 species) and Basidiomycota (19 species). Scots pine wood was also colonized by one species of Oomycota and 138 species of fungi including Zygomycota (19 species), Ascomycota (90 species) and Basidiomycota (29 species). In the first, second and third stages of decomposition, the oak wood was colonized by 101, 89 and 56 species of fungi respectively and pine wood was colonized by 82, 103 and 47 species respectively. Eighty three of the observed species (37%) occurred on both types of wood, while the other species displayed nutritional preferences. A decrease in the number of species with advancing decay indicates the necessity for a continuous supply of dead wood to the forest ecosystem. This supply would secure the continuity of fauna and flora and guarantee a stable forest development. The nutritional and ecological preferences of many fungal species furthermore indicate the necessity of supplying the forests with wood of different species. In commercially managed forests the results obtained here will aid in: (i) the development of strategies for effective dead wood management in the context of forest productivity and future wood stock growth, as well as (ii) finding a compromise between forest management requirements and environmental protection

Effect of pre-planting soil preparation on biological activity of soil towards root rot pathogens in 40-year-old Scots pine stand

Effects of pre−planting soil preparation on the clear−cut on the community structure of soil fungi and bacteria, their possible biological activity towards Armillaria and Heterobasidion, and mortality of Scots pine trees were studied in 40−year−old Scots pine plantation in Międzychód Forest District (W Poland). Pre−planting soil preparation included: (i) deep ploughing, (ii) shallow furrowing, (iii) making holes for planting, and (iv) shallow turning of the topsoil. The soil−dilution method was used for detection of fungi and bacteria in soil. Morphotyping was used for identification of fungi. Phenotypic traits and biochemical properties were used for identification of bacteria. Molecular method, MID−66 or BIOLOG® systems were additionally applied for identification of the most common bacteria. Deep furrowing, making holes for planting or shallow turning of the topsoil before planting increased abundance of fungi and bacteria in soil 40 years after treatment. Increased abundance of fungi and bacteria was associated with increased presence of taxa considered as antagonistic to Armillaria and Heterobasidion. The highest mortality of Scots pines was observed on sites with deep ploughing or shallow furrowing before planting, while the lowest mortality was found on sites with making holes for planting or shallow turning of the topsoil. The majority of dead trees were infected by H. annosum. Moderate intervention into the soil habitat on the clear−cut site before planting of Scots pine seedlings seems to create the habitat beneficial for the future growth of trees