Comportement in vitro du Sparassis crispa Wulf. ex Fr. et du Sparassis laminosa Fr

Behaviour in vitro of Sparassis crispa Wulf. ex. Fr. and Sparassis laminosa Fr . Sparassis crispa and S. laminosa are described in culture following the method used by Nobles. S. crispa is a very active wood destroying fungus in blocks of Douglas fir (sapwood and heartwood) in laboratory tests. The cauliflower-like fructifications are easily produced on malt-agar and could be produced on a large scale.     

Etude comparative in vitro de ľaptitude lignivore de quelques basidiomycetes agents de pourritures de coeur chez ľépicea

A comparative study of the wood destroying capacity in vitro of some butt-rot fungi . The wood destroying capacity of several butt-rot-fungi (Coriolus abietinus, Fomes annosus, Leptoporus adustus, Odontia bicolor, Sistotrema brinkmannii, Stereum areolatum, Stereum sanguinolentum) on Picea abies was studied comparatively in vitro. O. bicolor was more destructive than F. annosus. S. brinkmanni and S. areolatum caused only small weight losses.     

Détection par piégeage du Ceratocystis fimbriata f. platani

Application of the technique of trapping Ceratocystis fimbriata f. platani for the study of the persistance in affected trees . The study of the persistance of Ceratocystis fimbriata f. platani in affected trees is achieved by trapping of the fungus which is carried out on small branches of London plane, stripped of their bark. If C. fimbriata is present in samples of wood to be tested, it becomes visible after a few days when numerous perithecia form on the trap. Trapping the fungus by this method has been systematically achieved with young, artificially inoculated trees: in many cases, C. fimbriata persists in the wood after a period of about 19 to 22 months.     

Changes of decay and termite durabilities of Japanese larch (Larix leptolepis) wood due to high-temperature kiln drying processes

We investigated the effects of high-temperature drying schedules (120°–130°C) on decay and termite feeding of Japanese larch timbers. Thermogravimetric analysis was conducted to investigate changes of the wood components. Decay and termite feeding tests showed that specimens dried under high-temperature schedules were susceptible against a decaying fungus Fomitopsis palustris and attacks from termites Coptotermes formosanus and Reticulitermes speratus. These drying schedules changed chemical components, which were suggested by the thermal analytical result compared to the control sample. The results of this study indicated that the acceleration of termite feeding takes place even under temperatures that are comparatively lower than that used in our previous research in which 170°C steaming treatment was applied to Japanese larch wood. Decay durability against a brown rot fungus also decreased, possibly from production of low molecular weight fragments when hemicellulose decreased during the high-temperature drying processes.     

Stem-rot damage and the progress of causal fungi in old-aged Japanese larch trees at the foot of Mt. Fuji

Damage caused by stem-rot and the progress of the causal fungi in old-aged Japanese larch (Larix kaempferi (Lamb.) Carr.) was investigated at the foot of Mt. Fuji. Stem-rot was found in 75% of 108 trees investigated, and volume of rot was 6% of the total wood volume in the forest investigated. Stem-rot damage was much greater than the damage by butt-rot.Stereum sanguinolentum (Alb. and Schw. ex Fr.) Fr. infected larch trees at the greatest incidence (49.4%). However,Porodaedalea chrysoloma (Fr.) Imaz. caused the most volume loss to the trees.S. sanguinolentum infected larch stems mainly through stem wounds, and decay caused by the fungus progressed 9.75×10² cm³/year on average.P. chrysoloma infected larch stems mainly through dead branches and wounds, and the average rate of decay progress for the fungus was 2.74×10³ cm³/year.     

Growth of Phlebiopsis gigantea in wood of seven conifer species

Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.     

Une méthode d'inoculation pour l'évaluation précoce du comportement du Mélèze vis a vis du Lachnellula willkommii

An inoculation method for early assessment of Larch resistance to Lachnellula willkommii . Efficiency of inoculation with mycelium and ascospores was compared on 4–13-year-old Larix decidua. Only mycelium induced high infection rates. Mycelial inoculum was contained in colonized sorghum-straw pieces and was introduced in 1 mm diameter holes drilled through the bark in April/May. The main infection was detectable as early as 18 months after inoculation and infection rate increased only until the 28th month after inoculation. The susceptibility of the branches did not depend on their age, their position in the trees, the age of inoculated shoots or the management of the trees. Susceptibility was even for the 1–2-yr-old parts of the stems and branches but the oldest parts of the stems were less susceptible. The inoculation method was effective for detecting differences in susceptibility among trees. One seedling from the Alps, and clone 3001–00035, which is the mother of resistant hybrids, were the least susceptible.     

Enzymatic degradation of cellulose,cellulose derivatives and hemicelluloses in relation to the fungal decay of wood

Summary Cellulases and hemicellulases (mannanase and xylanase) from culture filtrates of various fungi, including a brown rot fungus, Polyporus schweinitzii and a soft rot fungus, Chaetomium globosum, have been isolated and characterized. Investigations of their molecular weights, pH- and temperature optima and stabilities indicate that hydrolases of the wood destroying fungi are very similar to one another and to hydrolases from various other plant organisms. Substrate specificities and the effect of substituents on the natural substrates have also been investigated. Routine tests for mannanase and xylanase were carried out with model substrates (mannan from Tubera salep, xylan from wheat straw), but preliminary tests with complex hemicelluloses isolated from wood showed that these too could be broken down to monoor oligosaccharides. The results presented are discussed in relation to possible roles of the various enzymes in vivo.Paper presented at the Int. Wood Chemistry Symposium, Seattle, 3. IX. 1969.With support of the Deutsche Forschungsgemeinschaft.     

Estimated amount of carbon accumulation of hybrid larch in three 31-year-old progeny test plantations

Hybrids generated by crossing Kuril larch (Larix gmelinii var. japonica) and Japanese larch (L. kaempferi) are expected to have high carbon accumulation ability because of fast growth and high wood density in Hokkaido, Japan. We estimated the amount of carbon accumulation of the hybrid larch in three progeny test plantations consisting of 21 full-sib families and compared the results to the carbon accumulation of open-pollinated progenies of Japanese larch plus-trees (improved Japanese larch). Gene-environment interactions were not observed for tree height and diameter at breast height but were seen for wood density (area-weighted density, AWD). The amount of carbon accumulated per unit area (C_stand) positively correlated with the stand volume. The AWD did not correlate with the C _stand; therefore, families with high wood density can be selected independent of the C _stand. The C _stand of the best full-sib family, female parent half-sib family, and male parent half-sib family at three sites were 106.1, 84.6, and 93.2 Cton·ha⁻¹, respectively. All these values exceed the mean for the improved Japanese larch, which has a C _stand value of 82.5 Cton·ha⁻¹.     

Blue stain fungi associated withIps cembrae (Coleoptera: Scolytidae) in Japanese larch in connection with their brood development

The association between blue stain fungi andIps cembrae Heer (Coleoptera: Scolytidae) was investigated in the Japanese larch,Larix leptolepis Gordon, in the Nagoya University Forest, Aichi Prefecture, central Japan.I. cembrae had one or two generation(s) in a year in this study area. Two blue stain fungi,Ophiostoma piceae andLeptographium sp., were isolated from the body surface of both male adults in mating chambers and female adults in parent galleries, suggesting that this beetle species was a vector of these fungi. Although no blue stain fungi were isolated from non-stained wood, both fungi were isolated from the mating chambers, the center and the uppermost end of the galleries throughout the season. The fact thatO. piceae was consistently isolated with high frequency from adults and from their galleries strongly suggested that this species would be the principal blue stain fungus infecting the beetle-attacked larch trees.     

Beitrag zur Ätiologie des Triebsterbens junger Lärchen der subalpinen Stufe1

Etiologic of shoot dicback of young larches in the subalpine zone. I, Studies to possibles fungi-infections . Infection experiments with Ascocalyx laricina (Ettlinger) Schläpfer-Bernhard and research on endophytic fungi of old and young larch trees showed that infection by this particular fungus can be ruled out as the cause of shoot dieback.     

Characterization of host–fungus interactions among wood decay fungi associated with Khaya senegalensis (Desr.) A. Juss (Meliaceae) in Singapore

Tree pruning creates wounds that are amenable for wood decay fungi colonization. To characterize the dynamic host–fungus interactions at this location in Senegal mahogany (Khaya senegalensis), in vitro and in vivo pathogenicity tests were conducted with wood decay fungi associated with this tropical tree species. Fomitiporella caryophylii, Hymenochaete murina and Phellinus noxius isolates were included in this experiment following their frequent isolation from Senegal mahogany pruning wounds. The evaluated isolates demonstrated unique host interactions in laboratory tests that suggest equally divergent prognoses for living Senegal mahoganies affected by these fungi. Although all evaluated fungal isolates successfully breached naturally induced reaction zones, P. noxius alone caused significant mass loss to incubated wood blocks. In addition, P. noxius caused extensive wood decay after inoculation in living hosts, successfully illustrating Koch's postulates for this host–fungus relationship. The wood decay ability, invasiveness and facultative parasitism demonstrated by P. noxius suggest its dominant role in wood decay columns below pruning wounds on living Senegal mahoganies. These results highlight the importance of characterizing specific host–fungus interactions and their implications for wood decay severity below pruning wounds in living trees.     

Spectrophotometric assay of a wood preservative, <Emphasis Type="Italic">N,N</Emphasis>-didecyl-<Emphasis Type="Italic">N</Emphasis>-methylpoly(oxyethyl) ammonium propionate (DMPAP), in aqueous solution

A spectrophotometric assay based on the color reaction between N,N-didecyl-N-methyl-poly(oxyethyl) ammonium propionate (DMPAP) and 4-[4-(dipropylamino) phenylazo]-benzenesulfonic acid (propyl orange) was used to determine DMPAP concentrations as a wood preservative. The assay was carried out using a propyl orange solution at pH 2.9. The visible absorption spectrum of propyl orange showed an absorption maximum at 510 nm, which decreased linearly with increasing DMPAP concentration from 0 to 10 ppm. To apply this assay method to determine DMPAP retention in treated wood, the influence of wood extractives on the assay was investigated. Extractives from Japanese cedar, hinoki cypress, and Japanese larch were found to increase apparent DMPAP concentration. However, it was also found that measuring visible absorption at 477 nm prevented overestimation and gave precise values. This assay can be a viable alternative to the current methods for the determination of DMPAP concentrations.     

Early infection by Heterobasidion annosum in Larix x eurolepis seedlings planted on infested sites

The incidence of Heterobasidion annosum was examined in three young hybrid larch (Larix × eurolepis) plantations in southern Sweden that were established after felling Norway spruce (Picea abies) stands heavily infected by the fungus. The incidence of H. annosum was 7 %, 33 %, and 70 %, respectively, in the 2-, 3-, and 5-year-old plantations. In all plantations, H. annosum was the most frequent rot-causing fungus (81 %) and all isolates tested belonged to the P-intersterility group. No visible external differences between infected and healthy seedlings were found on any site. Both tap and lateral roots were infected by H. annosum. The results suggest that when hybrid larch is planted on sandy soils after clear felling of Norway spruce heavily infected by H. annosum, it is very susceptible to infection by H. annosum. Furthermore, transfer of H. annosum from infected stumps to hybrid larch occurs during the first few years after planting on scarified sites. In this study, scarification may have exacerbated the root disease situation and actually led to more early infections by distributing pieces inoculum across the sites.     

Necrophylactic periderm formation in the roots of western larch and Douglas‐fir trees infected with Armillaria ostoyae. II. The response to the pathogen

Periderm formation was studied in bark samples collected from the roots of western larch (Larix occidentalis) and Douglas‐fir (Pseudotsuga menziesii) trees infected with Armillaria ostoyae. Necrophylactic periderms were formed in advance of infection and successfully restricted continued fungal spread in 68 and 45% of the samples collected from 10‐ and 27‐year‐old western larch, respectively. However, all periderms formed in 11‐ and 25‐year‐old Douglas‐fir had been breached by the advancing fungus. In both species, necrophylactic periderms were commonly breached at the junction of the periderm with the vascular cambium. In western larch, stone phellem often comprised the external phellem layer of necrophylactic periderms with multiple bands of phellem. In 27‐year‐old western larch, infection was often confined to discrete lesions bounded by multiple periderms with multiple bands of phellem. In both tree species, phellem production was greater in response to infection than in response to abiotic wounding.     

Pine canker fungus,Lachnellula pini,and L. flavovirens in Finland

The distribution of Lachnellula pini, cause of pine canker and Lacbnellula flavovirens, occurring on pine needles and branches killed by snow blight, was studied in Finland.     

Dependence of shear strength on wood properties in cultivated Larix sibirica

Abstract

Mechanical properties are very important in structural uses of wood. In the case of larch wood, shear strength (SS) may be a limiting property, because the wood is brittle and it splinters easily. In this study, SS of Siberian larch (Larix sibirica) wood was studied in relation to its axial and radial location and to some other wood properties in the part of the trunk that produces logs of good carpentry quality. SS increased by 21–23% from the pith to the outer heartwood at each studied height (butt, 4.5 and 9 m), and it was at its most approximately 7% higher at the butt than at the other studied heights. The main reason for the radial increase in SS was the increase in density caused by wood maturation, but other factors also affected SS, depending on the grouping mode (combined material, radial/axial location). An exception was sapwood, for which no factors affecting SS could be identified. Thus, sapwood may behave differently from heartwood regarding use, even unexpectedly. The results suggest that mature heartwood, but not juvenile wood and sapwood, of Larix sibirica should primarily be used in products that require high SS.     

Wundfäule in Fichtenwaldungen mit alten Schälschäden

Wound decays in spruce stands following bark stripping . 2083 trees in 91 sample plots on four trial areas (24 ha) were examined for bark stripping and decay. Only 25% of trees showed no injury. Of the injured trees, 73% showed some degree of decay, 10% discoloration. and 17% neither decay nor discoloration. Of the wood destroying fungi isolated Fomes annosus was dominant and appeared to be the most important and widespread of the wound inhabiting fungi in the test area. Besides the Basidiomycetes a considerable number of other fungi was isolated. The most frequent was Cylindrocarpon cylindroides var. tenue.     

Variation in the decay resistance of larch to fungi

? Decay resistance of larch (Larix sp.) to fungi was evaluated on heartwood samples belonging to 3 species (L. decidua, L. kaempferi and their hybrid), 3 races of European larch (polonica, sudetica and alpine), 13 wood lots (populations) and 313 trees.

? Larch wood appeared, on average, as moderately durable although a high variability was observed. At the sample level as well as at the mean individual tree level, durability ranged from class 1 to 5 according to EN 350-1 standard. At the population level, larch wood varied from ‘durable’ to ‘slightly durable’. Genetics played a major role in decay resistance at the species, provenance and tree levels. Environmental factors such as the position of heartwood samples and the age of trees were also identified as a source of variability.

? The most durable wood was not necessarily from old native alpine stands of European larch: some young larches from faster growing lowland origins also produced durable wood.

? Genetic improvement of larch wood durability appeared therefore likely by the selection of the best populations for decay resistance as well as from the selection of individuals.