Articles containing the keyword 'juurikääpä'

The purpose of the study was to find out whether Fomes annosus (now Heterobasidion annosum) growing in a Norway spruce (Picea abies (L.) H. Karst.) stump can, with its mycelium, take up the radioactive isotopes ³H, ³³P and ¹²⁵I in the heading, and whether it transfers them via the sporophores in situ to its basidiospores. Wood material in close proximity to active sporophores was injected with radioactive isotopes. All isotopes could be verified from the basidiospores. The production of viable basidiospores by sporophore was reduced by the isotope injections. This latter result may be of importance e.g. in meteorology for observation of the movements of air masses.

The PDF includes a summary in English.

• Kallio, E-mail: tk@mm.unknown
• Selander, E-mail: js@mm.unknown
• Uusi-Rauva, E-mail: au@mm.unknown

The study was carried out in a Norway spruce (Picea abies (L.) H. Karst.) stand in Southern Finland which was to be clear-cut due to decay. The species composition and incidence of decay fungi were investigated from the cut surfaces of the stumps. In addition, the colour and size of the decayed spot was observed.

About 28% of the total number of trees were decayed. Fomes annosus (Heterobasidion annosum) was the most common decay fungus. It was identified from 75% of the decayed trees, and was the sole agent in 43% of these trees. Armillaria mellea was the second commonest decay fungus. It decayed trees mostly in combination with Fomes annosus. The most common colours of the decay produced by F. annosus were reddish or yellowish brown. The decay caused by A. mellea was blackish brown. The causative agent cannot be reliably identified on the basis of the colour of the decayed part.

The PDF includes a summary in English.

• Kallio, E-mail: tk@mm.unknown
• Norokorpi, E-mail: yn@mm.unknown

Fomes annosus (Fr.) Cke. (now Heterobasidion annosum (s.str.)) has proved highly adaptable to varying conditions. Thus, the fungus is able to alter the pH as well as in alkalic as acid direction according to the original pH-grade. The fungus spreads mainly by basidiospores or by the sterile mycelium, but maybe also by the conidiospores. The fungus has spread through the temperate zone; in the tropical and sub-tropical zone it is found sporadically. There is a mention in the literature of at least 136 species in which it has been found. It is found in hardwoods but is most disastrous in conifers. The economic losses are considered biggest in England, Germany and Scandinavia.

The research has not been able to find a safe way to protect the trees growing on an infected site. The only way to limit the damage seems to be the use of mixed stands. Stump-protection has proved to be a relatively effective way to prevent the spread of the fungus to uninfected sites. The formerly used creosote has been mainly substituted by new chemicals, such as sodium nitrite. They act by altering the stump in a way that is favourable for antagonists to Fomes annosus, such as Trichoderma viride and Penicillium sp., or the recently presented Peniophora gigantea.

Although the fungus is found in many tree species, there is a difference in the relative resistance of different species. Among the conifers, the Abies-species (with exception of Abies grandis, A. alba and A. sachalienensis) are considered comparatively resistant. The species of Larix and Pseudotsuga are more resistant than those of Picea and Pinus.

The PDF includes a summary in English.

• Palmberg, E-mail: cp@mm.unknown

The aim of this investigation was to clarify aerial infection of Fomes annosus (now Heterbasision annosum) in the cross-sections of stumps of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) in Southern Finland. In addition, an attempt was made to study possibilities to reduce an eventual aerial infection by means of spreading various protecting substances on the cross-section of the stumps immediately after cutting. The stumps were treated withs creosote, ceruse (lead white) and a product named ”Ventti”, which active constituent is copper. The effect of prescribed burning of the site on the aerial spreading of the fungus was studied.

Five sample plots were located in spruce stands and one in a pine stand. One of the spruce stands was prescribed burned. Samples were taken from the stumps 14–17 and 24–29 months after cutting. To identify the fungi, the samples were cultivated on a nutrient substrate in laboratory conditions. The results show that Heterobasidion annosum had spread by air to cross-sections of stumps of spruce. 11.5% of the samples taken from the spruce stumps 14–17 months and 17% of samples taken 24–29 months after cutting were infected. Burning of the site reduced strongly the aerial infection of stumps by the fungus. The stumps of Scots pine were not infected by Heterobasidion annosum in this study. The infection could be limited by treating the cross-sections with substances that are used to prevent growth of mould.

The PDF includes a summary in English.

• Kallio, E-mail: tk@mm.unknown

Observatons of drying of Norway spruce (Picea abies (L.) Karst.) stands increased in 1930s in Southern Finland. The aim of the study was to analyse the advance and causes of drying. The work was begun in 1930s before the Second World War, and the damages caused to the forests by the war was used as supplemental observations in the study. A special method, drying analysis, was developed to study the process. It was used both in cases of insect and fungal diseases in the four research areas in Raivola and Ruotsinkylä. In addition, 7 observation areas were studied.

Several causes for drying of the trees were observed in the Norway spruce stands. These included European spruce bark beetle (Dendroctonus micans), root rot (Heterobasidion annosum), pine weevils (Pissodes sp.), bark beetles and honey fungus (Armillaria mellea).

The role of primary and secondary causes for drying, resistance of the trees and the drying process are discussed. Finally, the influence of forest management in drying process is analysed. Forests in natural state can be considered to be in an ideal balance. On the other hand, forest management can be used to maintain the vitality and resistance of the forests. Drying of Norway spruce stands can be taken into consideration when the stands are managed.

The PDF includes a summary in German.

• Kangas, E-mail: ek@mm.unknown

The aim of the study was to identify the microbes which reach the cut surface of Norway spruce (Picea abies (L.) Karst.) stumps during the first year after felling by means of air born spores, determine their occurrence frequency and the combinations in which they occur, investigate the colour changes in the wood caused by microbes and identify the microbial species isolated from the sap- and heart-wood.

The material consisted of 360 spruce stumps. 300 of the stumps were innoculated with five different fungi (Phlebia gigantea, Botrytis cinerea, Gliocladium deliquescens, Trichoderma viride, Verticicladiella procera) in order to inhibit air-born attack by Heterobasidion annosum. 60 stumps were left untreated as controls.

The cultural characteristics of the following fungi isolated from the stumps have been described e.g.: Ceraceomerulius serpens, Chondrostereum purpureum, Cylindrobasidium evolvens, Peniophora pithya, Phlebia gigantea (Phlebiopsis gigantea) , P. subserialis, Sistotrema brinhmannii, Bjerkandera adusta, Coriolellus serialis, Trametes zonata, Armillariella mellea, Panellus mitis, Nectria fucheliana (microconidial-stage), Ascocoryne cylichnium (conidial-stage), Leptographium lundbergii, Acremonium butyri, Gliocladium deliquescens, Verticicladiella procera.

The proportion of Basidiomycotina fungi out of the whole material was 53 %, Ascomycotina and Deuteromycotina fungi 37,6 % and bacteria 7,3 %.

The PDF includes a summary in English.

• Hallaksela, E-mail: ah@mm.unknown