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Wood Rot Protection

P rotection focuses on fundamentals upon prevention of wood damage by fungi, and protection and preservation of wood (e.g., Willeitner and Liese 1992; Eaton and Hale 1993; Palfreyman et al. 1996; Murphy and Dickinson 1997; Zujest 2003; Goodell et al. 2003; Muller 2005).  Protection in the broader sense comprises non-chemical methods like organizational measures and measures by design, use of naturally durable woods, application of antagonisms, or wood modifications that do not affect the environment. Preservation predominantly stands for chemical measures.   The conditions for the development of wood fungi and protection principles that can be deduced from them. The principle of the wood protection consists of changing at least one of the three life prerequisites of fungi in wood in such a way that the development of fungi is impossible or at least inhibited. Fungal attack can be prevented   (Willeitner and Schwab 1981; Erler 2002; Willeitner 2000, 2003; Goodell et al. 2

Soft Rot

The term " soft rot " was originally used by Findlay and Savory (1954) to describe a specific type of wood decay caused by Ascomycetes and Deuteromycetes which typically produce chains of cavities within the S2 layer of soft- and hardwoods in terrestrial and aquatic environments (Liese 1955), for example when the wood-fill  in cooling towers became destroyed despite water saturation, and when poles broke, although they were protected against Basidiomvcetes.  About 300 species (Seehann et al. 1975) to some 1,600 examples of ascomvcete and deuteromvcete fungi (Eaton and Hale 1993) cause soft rot, e.g., Chaeromium globosurn (Takahashi 1978), Hurnicola spp., Lecythophora hoffrnannii, Monodictys putredinis, Paecilornyces spp., and Thielavia terrestris. Soft-rot fungi differ from brown-rot and white-rot Basidiomycetes by grow-ing mainly inside the woody cell wall trate, starting from the tracheidal lumina., by means of thin perforation hyphae of less than 0.5 pm thickne

White Rot

W hite-rot research has been reviewed by Ericksson et al. (1990) and Mess-ner et al. (2003). White rot means the degradation of cellulose, hemicellu-loses, and lignin usually by Basidiomycetes and rarely by Ascomycetes, e.g., Kretzschmaria deusta and Xylaria hypoxylon.  White rot has been classified by macroscopic characteristics into white-pocket, white-mottled, and white-stringy, the different types being affected by the fungal species, wood species, and ecological conditions. From microscopic and ultrastructural investiga-tions, two main types of white rot have been distinguished (Liese 1970).  In the simultaneous white rot ("corrosion rot"), carbohydrates and lignin are almost uniformly degraded at the same time and at a similar rate during all decay stages. Typical fungi with simultaneous white rot are Fomes fomentar-ws, Phellinus igniarius, Phellinus robustus, and Trametes versicolor in standing trees and stored hardwoods (Blanchette 1984a).  Wood decay

Brown Rot

B rown Ro t is caused by Basidiomvcetes, which metabolize the carbohydrates cellulose and hemicelluloses of the woody cell wall by non-enzymatic and enzymatic action and leave the lignin almost unaltered , whereby the brown color develops.  Brown-rot fungi do not produce lignin-degrading enzymes. There are how-ever reports of lignin peroxidase and manganese peroxidase in some brown-rot fungi, and lignin loss or metabolization by brown-rot fungi have been reported. Particularly in later stages of decay, the highly lignified middle lamella/primary walls were observed to undergo attack. Also, the penetration of the wood cell wall by bore holes removes lignin in the process, all suggesting that low molec-ular weight lignin degrading agents and potentially even lignin degrading enzymes max occur in some brown-rot fungi, at least with localized activity (Goodell 2003).  Laccase activity was also found in Coniophora puteana (Lee et. al. 2004), and in Glocophyllum trabeum and Olig

Wood Rot

There are three types of fungal wood rot: brown, white, and soft rot . Further terms are either older names (e.g., destruction rot = brown rot), specifications (red rot = white rot by Heterobasidion annosum) or terms used in practice ( marble rot = white rot with black demarcation lines) or false names (blue rot = blue stain).  According to the classical school of thought a fungal species causes only one type of decay, and species causing different rots shall not be grouped in the same genus [e.g.: Lentinus lepideus: brown rot ; Lentinula (in former times Lentinus) edodes: white rot].  Regarding the delineation between the three decay types, there are, however, exceptions: The brown-rot fungus Coniophora puteana produced cavities to be typical of soft-rot fungi and erosion and thinning of the cell wall to be charac-teristic of white-rot fungi (Kleist and Schmitt 2001; Lee et al. 2004).  Fistulina hepatica revealed the soft-rot mode in cell walls rich in syringyl lignin,

Protection

To avoid microbial wood discoloration, the generally suitable measures against fungi (e.g., Liese et al. 1973; Liese and Peek 1987; Grog et al. 1991; Yang and Beauregard 200 1) are listed in Table. Felling in the cold season and fast processing of the stems through well coordination between forestry and wood industry reduces microbial activity during storage of the stems in the forest. Cool, shady, and ventilated storage without ground contact and with unhurt bark to maintain high wood moisture content and to prevent lateral infections are favorable. Lumber discoloration can be prevented by prompt air-drying in well-ventilated stacks protected against rain by a roof, or by kiln-drying. Wet storage of stemwood by sprin-kling or ponding protects against fungi and insects. Currently, stem storage is performed in a N 2 /CO 2  atmosphere (Mahler 1992; Bues and Weber 1998; Maier at al. 1999). Table : reventive measures to avoid microbial wood discolorations and decay - fell

Red Streaking

Red Streaking Red-streaking discoloration (known as "Rotstreifigkeit" in Germany) is one of the most common and important damage in seasoning logs and sawn lumber, occurring only in conifers (spruce, pine, fir) and recognized as a distinct con-dition in continental Europe.  The stripe-shaped to spotted yellow to reddish-brown discoloration extends in logs from both their bark-covered faces and from their cut ends (Butin 1995; Baum and Bariska 2002) . Stems that are not debarked show a rather flat discoloration and debarked stems exhibit a streakier staining (v. Pechmann et al. 1967). Causal agents are several white-rot Basidiomycetes, in spruce particularly Stereum sanguinolentum (Kleist and Seehann 1997) and Amylostereum areola-turn. In south Germany, Amylostereum chailettii is common (Zycha and Knopf 1963; v. Pechmann et al. 1967).  In pine, red streaking is mainly due to Trichap-turn abietinum (Butin 1995). According to Kreisel (1961), S. sanguinolentum and T

Classification

           Approximately 120,000 fungal species are described. If the numerical ratio between vascular plants and fungi of 1:6 in botanically well-examined regions, like Great Britain, however, is transferred to a global scale of 270,000 vascular plants, 1.6 million fungi might exist. That is, so far only about 10°A) of the actual fungal species are described (Anonymous 1992b).              Robson (1999) even estimated 3 million fungal species. Nomenclature regulates the constitution of names, their validity, legitimacy andpriority or synonymy, and maintains a single correct name for each taxon (International Code of Botanical Nomenclature, St. Louis Code 2000). In view of the author names for fungi, these have to be only abbreviated when more than two letters are saved. Names are always abbreviated between a consonant and a vowel. The abbreviation should not cause confusion with other names. Contractions by omission of letters are avoided. Sanctioned names are indicated with

Sexual Reproduction

A specific feature of the sexual reproduction of Ascomycetes and Basid-iomycetes is that plasmogamy of haploid cells and karyogamy of two nuclei (n) to form a diploid nucleus (2n) are separated from each other temporally as well spatially by the dikaryophase (two-nuclei phase, dikaryon, n + n, ===) (Fig.1). A dikaryotic hypha is one with two nuclei that derive from two haploid hyphae, but in which the nuclei are not yet fused by karyogamy. Particularly in Basidiomycetes, the dikaryotic phase is considerably ex-tended. By conjugated division of the two nuclei (conjugated mitosis), by division of the dikaryotic hypha, and by means of a special nucleus migration connested with camp formation both daughter cells become again dikaryotic.  Ascomycetes  The life cycle of a typical ascomycete is shown in Fig.1 (also Muller and Loeffler 1992; Eaton and Hale 1993; Schwantes 1996; Jennings and Lysek 1999). Haploid (n) spores (A, ascospores or conidia from an anamorph) germi-nate

Reproduction of Deuteromycetes

    F ungi that reproduce asexually (anamorphic fungi ) are either yeasts or Deu-teromycetes. The term "yeast" is descriptive and stands for any fungus that reproduces by budding. Deuteromycetes (Fungi imperfecti, colloquially: molds) is an artificial as-semblage of fungi that reproduce asexually by conidia (conidiospores), either as the only form for propagation (imperfect fungi) or additionally (anamorph) to a sexual reproduction (teleomorph). When both the anamorph and the teleo-morph are known, the fungus is called a holomorph (the whole fungus). The teleomorph may have one (mono-anamorphic) or many (pleo-anamorphic) asexual stages. In other words: Deuteromycetes are the conidia-producing forms of a fungus and may or may not be associated with a teleomorph. Many Deuteromycetes are supposed to have a teleomorph in the Ascomycetes, but they may also have basidiomycetous affinity. Also in the wood-inhabiting Deuteromycetes, the teleomorph often is of ascomycetous a

Growth and Spreading

 Vegetative Growth Simplistically, wood fungi live through two functionally different phases: the vegetative stage for mycelial spread and the reproductive stage for the elab-oration of spore-producing structures. Rayner et al. (1985) extended the development of a fungus in arrival, establishment, exploitation, and exit. The vegetative, asexual stage consists in wood fungi of vegetative hyphae with some specialized forms. The reproductive stage can both occur asexually or sexually (Schwantes 1996). Functional specialization of the mycelium occurs during the vegetative stage: germination, infection, spread, and survival. These functions are correlated with different "fungal organs". Spores (conidia, chlamydospores, also the sex-ually derived asco- and basidiospores) germinate under suitable conditions (moisture, temperature). The young germ hypha first shows some nuclei be-fore the young mycelium grows with septation in the monokaryotic condi( ion. N1ycelial growth takes

Cytology and Morphology

            " Wood fungi " are eukaryotic and carbon-heterotrophic (free from chlorophyll) organisms with chitin in the cell wall, reproduce asexually and/or sexually by non-flagellate spores, filamentous, immovable and mostly land inhabiting. Damage to wood in water by fungi is described by Jones and Irvine , Jones  and Kim and Singh . Soft-rot fungi belonging to the Ascomycetes and Deuteromycetes  destroy wood with high moisture content in water or soil (e.g., Findlay and Savory 1954; Liese 1955). Fungi associated with leaf litter in a woodland stream were treated by Suberkropp .  In this book, a fungal cell, the hypha, is defined as one individual cell of mostly tubular shape that consists of a cell wall, contains a protoplasm with a nucleus and other organelles, and is in the "higher fungi" separated from its one or two neighbors by a transverse wall, the septum . In analogy to the "higher plants", where nearly every living cell is connected t