Distribution of Myxomycetes on coarse woody debris of <Emphasis Type="Italic">Pinus densiflora</Emphasis> at different decay stages in secondary forests of western Japan

The relationship between myxomycete species and the decay stage of wood of Pinus densiflora coarse woody debris was investigated in warm temperate secondary forests of western Japan. The number of species and species diversity of the myxomycete community reached the maximum on moderately decayed wood. The 25 dominant species recorded from 8 or more samples of the total 1530 samples were arranged in order of the succession index corresponding to the stage of decay. Species on slightly decayed hard pine wood were characterized by Stemonitis splendens, Enerthenema papillatum, and Physarum viride, whereas species of Cribrariaceae were found on brittle decayed soft wood increasing abundance according to the decay stages. Most of the species occurred where there was sufficient moisture preserved in the environment of the decaying wood, although S. splendens specifically emerged in low-moisture environments. Because the myxomycete species had preference to different decay stages of wood, it appears that they change sequentially during myxomycete community succession on dead pine wood according to the progression of decay.     

A study of yeasts during the delignification and fungal transformation of wood into cattle feed in Chilean rain forest

In Chilean rain forest the presence and distribution of yeasts were studied during the fungal transformation of wood, producing a partially delignified material used as cattle feed (huempe). A total of 68 yeast species was reported, including a noticeable proportions of basidiomycetous and xylose-assimilating strains, the latter related to the increased availability of this sugar in the decayed wood. The results of the mathematic comparison of taxonomic data of 327 strains showed a delimitation of sharp clusters corresponding to different species, including several new species described from this substrate, and genera, as Rhodotorula and Cryptococcus.At the initial stages of wood decay, characterized by the presence of Candida species, yeast diversity was low. The highest values were found in the medium stage of decay, used as feed, with an important presence of the genera Apiotrichum, Rhodotorula, Cryptococcus and Schizoblastosporion. After establishing a non-linear ordination from Euclidean distances between samples, based on yeast abundances, a relationship was observed between the populations developing at the different stages of wood decay by Ganoderma applanatum. A succession of yeast species was demonstrated during wood degradation by this white-rot fungus.     

Topochemical investigation of early stages of lignin modification within individual cell wall layers of Scots pine (Pinus sylvestris L.) sapwood infected by the brown-rot fungus Antrodia vaillantii (DC.: Fr.) Ryv.

The initiation and progress of wood degradation of Pinus sylvestris sapwood exposed to the brown-rot fungus Antrodia vaillantii was studied on a cellular level by scanning UV microspectrophotometry (UMSP 80, Zeiss, MSP 800 Spectralytics). This improved analytical technique enables direct imaging of lignin modification within individual cell wall layers. The topochemical analyses were supplemented by light and transmission electron microscopy (TEM) studies in order to characterize morphological changes during the first days of degradation. Small wood blocks (1.5 × 1.5 × 5 mm) of Scots pine (P. sylvestris) were exposed to fungal decay by A. vaillantii for 3, 7, 11, 16, and 22 days. No significant weight loss was determined in the initial decay periods within three up to 7 days. After three days of decay the topochemical investigation revealed that the lignin modification starts at the outermost part of the secondary wall layer, especially in the region of the latewood tracheids. During advanced degradation after exposure of 22 days, lignin modification occurs non-homogeneously throughout the tissue. Even among the significantly damaged cells, some apparently unmodified cells still exist. Knowledge about lignin modification at initial stages of wood degradation is of fundamental importance to provide more information on the progress of brown-rot decay.     

Resistance of Scots pine wood to Brown-rot fungi after long-term forest fertilization

The susceptibility of Scots pine (Pinus sylvestris L.) sap- and heartwood against the wood decaying brown-rot fungus (Coniophora puteana) was investigated after long-term forest fertilization at three different sites in central Finland. Different wood properties: wood extractives, wood chemistry, and wood anatomy were used to explain sap- and heartwood decay. Scots pine sapwood was more susceptible to decay than its heartwood. In one site, sapwood seemed to be more resistant to wood decay after forest fertilization whereas the susceptibility of heartwood increased. Significant changes in the sapwood chemistry were found between treatment and sites, however, no relationship between wood chemistry and wood decay was observed in the factor analysis. The results of this study show that there was an inconsistent relationship between decay susceptibility and fertilization and the measured physical and chemical attributes of the wood were not consistently correlated with the decay rate.     

Biodeterioration of brazilwood Caesalpinia echinata Lam. (Leguminosae—Caesalpinioideae) by rot fungi and termites

The heartwood of Caesalpinia echinata Lam. (Leguminosae) (commonly called brazilwood) is used for violin bow manufacture due to the unique vibrational and physical properties found in the wood. In the present work, the effects of Pycnoporus sanguineus (white-rot fungus), Gloeophyllum trabeum (brown-rot fungus), Chaetomium globosum (soft-rot fungus), and Cryptotermes brevis (dry-wood termite) on weight losses and chemical composition of extractives and cell-wall polysaccharides of C. echinata wood were investigated under laboratory conditions and compared to those obtained for Anadenanthera macrocarpa, Eucalyptus grandis, and Pinus elliottii. The heartwood of C. echinata was found to be as resistant as A. macrocarpa to the decay fungi tested and to the attack of the dry-wood termite. Pinitol and galactopinitol A were the main sugar alcohols found in the extractives of wood of C. echinata, their presence, however, did not appear related to the resistance to fungal decay. Although only incipient stages of decay were found, the modifications in cell-wall polysaccharide composition of heartwood of C. echinata by rot fungi were related to decrease in polymers other than xylans. The high resistance of C. echinata to xylophages is probably due to the presence of toxic extractives in the wood.     

Wood durability of home-garden teak against brown-rot and white-rot fungi

Natural decay resistance of teak wood grown in home-garden forestry and the factors influencing decay resistance were determined in comparison with that of a typical forest plantation. Accelerated laboratory tests were conducted on 1800 wood samples drawn from 15 trees of three planted sites. Analysis of variance based on a univariate mixed model showed that planted site, fungal species, and their interaction terms were important sources of variation in decay resistance. With increasing decay resistance from centre to periphery of the heartwood, radial position was a critical factor and the interaction effect of fungal species × radial position was significant in influencing the durability. No significant differences were found in decay resistance either between the opposite radii or due to the various possible interaction terms of radii with the site, fungal species and radial position. There were significant differences in decay resistance against brown-rot fungi between wet and dry sites of home-garden teak although differences against white-rot fungi were non-significant among the three planted sites. Polyporus palustris was the more aggressive brown-rot fungus than Gloeophyllum trabeum. The higher susceptibility of wet site home-garden teak to brown-rot decay was associated with a paler colour of the wood and lower extractive content.     

Association between myxomycetes and the decay stage of coarse woody debris in an evergreen broadleaf forest in warm temperate Japan

Myxomycetes inhabit coarse woody debris in varying stages of decay; however, their ecology in the dead wood of evergreen broadleaf trees is not well known. In this study, we examined the relationships between myxomycete species and the decay stage of wood from fallen trees in an evergreen broadleaf forest in Japan. Myxomycete species richness and abundance were calculated for eight stages of decay in fallen logs, according to the appearance and wood hardness of log portions. A total of 70 myxomycete species (including varieties) were found on the logs. Moderately decayed wood was the preferred habitat of myxomycetes (57 species; 81% of the total) and most species inhabited moist decayed wood. Analysis by nonmetric multidimensional scaling enabled the differentiation of myxomycete assemblages, with five groupings recognized across the progression of decay. Forty-two species preferred a particular decay stage, represented by the decay index. Physarum viride and Stemonitis splendens particularly preferred the less-decayed wood and Stemonitopsis typhina var. similis especially inhabited the well-decayed wood. Species from the order Physarales dominated the less-decayed wood, whereas Trichiales and Liceales species dominated the softer well-decayed wood. Myxomycetes diversity was high in and varied among logs with various stages of decay in a typical Japanese evergreen forest.     

Fungal decomposition of woody debris of Castanopsis sieboldii in a subtropical old-growth forest

Fungi, especially basidiomycetes, are the primary agents of woody debris decomposition in terrestrial forest ecosystems. However, quantitative data regarding the abundance and decay activity of wood-inhabiting fungi are lacking, especially for tropical and subtropical areas. This study demonstrates the dynamics of decay columns of wood-inhabiting fungi within decaying woody debris of Castanopsis sieboldii and the wood decay activities of those fungi in a subtropical natural forest. Among six basidiomycetes and two ascomycetes observed as sporocarps on fallen boles of C. sieboldii, Microporus affinis was most abundantly observed in terms of frequency of sporocarps and as percentage area of decay columns within cross-sections of boles, especially those in the early stages of decomposition. In decay columns of M. affinis, both acid-unhydrolyzable residue (AUR) and holocellulose decayed simultaneously, and wood relative density decreased to 45.8% of that of fresh C. sieboldii wood. A pure culture decay test under laboratory conditions showed that M. affinis was a strong decomposer of AUR and holocellulose. These results suggest that M. affinis has a central role in lignocellulose decomposition of wood of C. sieboldii in the early stages of decomposition.     

Small-scale variation in chemical property within logs of Japanese beech in relation to spatial distribution and decay ability of fungi

Fungal communities within a naturally fallen bough of Japanese beech (Fagus crenata) were investigated with reference to chemical properties of decay columns. Five logs were cut out from the fallen bough, which ranged from 10.7 to 20.5 cm in diameter. Nine fungal species and one sterile fungus were isolated from decay columns that elongated along a longitudinal axis and were delimited by black zone lines and wood discoloration. Lampteromyces japonicus and Trichoderma spp. were isolated from all five logs. Lampteromyces japonicus and Antrodiella albocinnamomea occupied the largest volume in the logs. Lignin and carbohydrate contents, lignocellulose index (LCI), nitrogen content, and water content were different among decay columns colonized by different fungal species in each log. In L. japonicus, LCI of decay column was correlated to that of wood blocks decayed under pure culture condition by the fungi isolated from the decay columns. These results suggest that the small-scale variation in chemical properties within fallen logs of Japanese beech reflects the distribution and the decay ability of colonized fungi.     

Soil organic matter dynamics under decaying wood in a subtropical wet forest: effect of tree species and decay stage

Decaying wood is an important structural and functional component of forests: it contributes to generate habitat diversity, acts as either sink or source of nutrients, and plays a preponderant role in soil formation. Thus, decaying wood might likely have measurable effects on chemical properties of the underlying soil. We hypothesized that decaying wood would have a stronger effect on soil as decomposition advances and that such effect would vary according to wood quality. Twenty logs from two species with contrasting wood properties (Dacryodes excelsa Vahl. and Swietenia macrophylla King) and at two different decay stages (6 and 15 years after falling) were selected, and soil under and 50 cm away from decaying logs was sampled for soil organic matter (SOM) fractions [NaOH-extractable and water-extractable organic matter -(WEOM)] and properties (WEOM aromaticity). NaOH-extractable C and WEOM were higher in the soil influenced by 15-year-old logs, while the degree of aromaticity of WEOM was higher in the soil influenced by the 6-year-old logs. Decaying logs did influence properties of the underlying soil with differing effects according to the species since there was more NaOH-extractable C in the soil associated to D. excelsa logs and more WEOM in the soil associated to S. macrophylla older logs. It is proposed that such effects occurred through changes in the relative quantity and quality of different SOM fractions, as influenced by species and advancement in decomposition. Through its effect on SOM and nutrient dynamics, decaying wood can contribute to the spatial heterogeneity of soil properties, and can affect process of soil formation and nutrient cycling. Responsible Editor: Barbara Wick.     

Community structure of polypores (Basidiomycota) in Andean alder wood in Argentina: Functional groups among wood‐decay fungi?

Abstract The polypores (Aphyllophorales s.l., Basidiomycota) are very effective wood decayers. Different species differ in their capacity to decay wood; therefore, many functionally different species can be found decaying different substrate conditions (decay stages and log diameter). This study aimed to describe the structure of the wood‐decay polypore communities that occur on different states of wood of the Andean alder (Alnus acuminata) within Argentina and to identify groups of polypore species that share the same substrate condition, and thus might have a similar functional role in the decay processes. We found 16 polypore species, among which Trametes versicolor, Bjerkandera adusta and Trametes cubensis were dominant species, showing the highest relative frequency in alder wood. Species richness was lower on trunks of living trees and higher on dead branches. Based on preferential occurrence on different wood conditions, a cluster analysis distinguished three groups, each of them containing one of the three dominant species. This corresponds to the situation of other groups of organisms, where each functional type consists of a dominant species that accounts for most of the ‘function’ and several subordinate species with similar functions. Albeit preliminary, our results provide a formal classification of wood‐decay fungi into functional types.     

When does dead wood turn into a substrate for spruce replacement?

Question: How many years must elapse for freshly fallen Picea abies stems to be transformed into a substrate for P. abies recruitment? Location: Natural sub‐alpine spruce forest, 1200–1300 m a.s.l., western Carpathians, Poland. Methods: Coarse woody debris (CWD) was measured on nine plots with a total area of 4.3 ha. All individuals of P. abies regeneration growing on dead wood were counted and their age was estimated. Decay rate of logs was determined using dendrochronological cross‐dating of samples from logs in different decay stages. Results: Although CWD covered only 4% of the forest floor, 43% of the saplings were growing on decaying logs and stumps. The highest abundance of P. abies recruitment occurs on logs 30–60 years after tree death, when wood is in decay stages no. 4–7 (on an 8 degree decay scale). However, much earlier colonization is possible. The first seedlings may germinate on a log during the second decade after tree death and survive for decades. Their slow growth is possibly due to the gradual progressive decomposition of wood. Conclusions: This study confirms the importance of decaying wood for P. abies recruitment. The decaying logs exhibit continuous and favourable conditions for the germination of P. abies seeds throughout their decay process. Logs, irrespective of their decay stage and age, are colonized by young seedlings. This recruitment bank is constantly renewed.     

Investigation on catechin as a beech wood decay biomarker

A high-performance liquid chromatography (HPLC) method based on the evolution of wood extractives was developed to follow the first stages of fungal degradation of beech wood exposed to Coriolus versicolor. The nature and the quantity of the extracts initially present in wood depended on the extraction conditions and also on the wood-drying conditions (time and temperature). The most interesting fraction was soxhlet extracted with acetone at 56 °C for 6 h. The best conditions to avoid extractives degradation consisted of a moderate drying at 55 °C for 48 h allowing identification of catechin as potential tracer. After 2 weeks of wood blocks exposure to C. versicolor, analysis of their acetonic extractives showed that catechin signal initially detected in beech wood, had totally disappeared. Treatment of wood with an appropriate fungicide such as propiconazole before exposure to C. versicolor, prevents the catechin amount from any variation. The comparison of these results with the classical weight loss (WL) measurements obtained after long-time experiments on treated and untreated wood blocks shows that the catechin amount evolution, monitored during 2 weeks, correlates with the wood resistance evaluated during 16 weeks, allowing the use of this flavonoid as a valuable biomarker of wood decay.     

Diffuse competition for heterogeneous substrate in soil among six species of wood-decomposing basidiomycetes

Competition among six wood decay fungi was studied using 15×15 mm wood blocks placed in 250×250 mm plastic trays filled with unsterilized sand or clay. The wood blocks were preinoculated with Heterobasidion annosum (Fr.) Bref., Resinicium bicolor (Alb. & Schw. ex Fr.) Parm., Phanerochaete sanguinea (Fr.) Hjortstam, Coniophora sp. DC. ex Me"rat, Armillaria borealis Marxmuller and Korhonen and Hypholoma capnoides (Fr.) Kummer before they were combined in all possible combinations in the trays. Two methods were used, one with all wood blocks inoculated, and one with sterilized non-inoculated wood blocks distributed between the inoculated ones. Wood blocks preinoculated with the six species were also used in a pairwise competition test. Following incubation for 9 months in darkness at 21°C, mycelia were reisolated and identified. R. bicolor was most successful at invading through the soil and replacing other species in the wood blocks. P. sanguinea, Coniophora sp. and H. capnoides also had some success.     

Decomposition of Japanese beech wood by diverse fungi isolated from a cool temperate deciduous forest

We assessed 62 fungal strains in 31 species of wood decay fungi in the ability to decompose wood blocks of Japanese beech (Fagus crenata) under a pure culture condition. Fungi were collected in a cool temperate beech forest in Japan and isolated from the inside of beech logs and from sporocarps fruiting on logs and snags of beech that were different in diameter and decay class. Fungi in Holobasidiomycetidae showed marked decomposition of lignin and carbohydrate. These fungi were divided into three groups according to the pattern of lignin and carbohydrate utilization. Phanerochaete filamentosa decomposed lignin selectively. Lampteromyces japonicus, Steccherinum rhois, Trichaptum biforme, Stereum ostrea, Mycena haematopoda, Antrodiella albocinnamomea, Daedalea dickinsii, Daedaleopsis tricolor, Ganoderma tsunodae, and Trametes versicolor decomposed lignin and carbohydrates simultaneously. Psathyrella candolleana, Lenzites betulinus, and Trametes hirsuta decomposed carbohydrates selectively. Species in the Phragmobasidiomycetidae and in the Ascomycota caused low mass loss of wood.     

Biodegradation of Pinus radiata softwood by white- and brown-rot fungi

The weight and component losses of Pinus radiata wood after decay by six species of white-rot and two species of brown-rot fungi for periods varying from 30 to 360 days were evaluated. Three groups of decayed wood samples were identified based on the principal component analysis (PCA) of the data on their weight and component losses. Selective lignin degradation was produced by Ceriporiopsis subvermispora and Punctularia atropurpurascens within different periods, the longest one lasting 90 days, and also by Merulius tremellosus after 90 days of biodegradation. Comparing the data on biodegradation of P. radiata by Trametes versicolor with the ones reported for biodegradation of Eucalyptus globulus and E. grandis indicated that P. radiata is as susceptible to wood decay by this white-rot fungus as the two types of hardwood.     

Seed size,establishment sites and species coexistence in a Chilean rain forest

Abstract. Seedling densities on the forest floor and on elevated microsites (logs and stumps) were compared for eight woody species in a temperate rain forest in southern Chile. Degree of association with elevated microsites varied significantly between species, showed no systematic relationship with reported shade tolerance, but was significantly negatively correlated with seed mass. Large-seeded Podocarpus nubigena established preferentially on undisturbed forest floor sites, whereas seedlings of small-seeded species such as Nothofagus nitida and Laurelia philippiana were found mainly on fallen logs and stumps. The abundance of large seedlings and saplings of N. nitida on logs/stumps, and the growth forms of canopy trees, confirm that recruitment of this species occurs mainly on decaying wood. The relationship between seed size and microsite preferences may be caused by effects of seed size on (1) ability to establish in forest floor litter and (2) retention of seeds on logs. Seedling occupancy of logs and stumps varied with state of decay. Few seedlings of any species were present on logs in the early stages of decay. N. nitida established earlier than the other species, attaining maximum abundance on wood in the middle decay classes. Species richness and overall seedling abundance were highest on wood in advanced stages of decay. Seed size differences are suggested as a determinant of differential utilization of forest floor heterogeneity, and hence of plant species coexistence.     

Clostridial ADP-ribosylating toxins: effects on ATP and GTP-binding proteins

The actin cytoskeleton appears to be as the cellular target of various clostridial ADP-ribosyltransferases which have been described during recent years.Clostridium botulinum C2 toxin,Clostridium perfringens iota toxin andClostridium spiroforme toxin ADP-ribosylate actin monomers and inhibit actin polymerization.Clostridium botulium exoenzyme C3 andClostridium limosum exoenzyme ADP-ribosylate the low-molecular-mass GTP-binding proteins of the Rho family, which participate in the regulation of the actin cytoskeleton. ADP-ribosylation inactivates the regulatory Rho proteins and disturbs the organization of the actin cytoskeleton.     

Succession in myxomycete communities on dead <Emphasis Type="Italic">Pinus densiflora</Emphasis> wood in a secondary forest in southwestern Japan

Changes in myxomycete communities and species were investigated over an 8-year period in relation to the decay state of dead Pinus densiflora Siebold & Zucc. wood on which myxomycete fruiting bodies occurred. The study was carried out during three different seasons in a pine forest in southwestern Japan. A total of 44 species and seven varieties of myxomycetes were recorded. The species richness and diversity of the annual myxomycete communities did not clearly change in relation to the series of years, but the percent similarity of the myxomycete community from the beginning of the survey through the following years tended to decrease every season. The ordination of the annual communities, analyzed using non-metric multidimensional scaling (NMDS), indicated that seasonal factors on the first axis and the decay state of the wood on the second axis were significantly related. Species colonization patterns were arranged using succession indices and the distribution of certain species at particular times of the year: Arcyria ferruginea, A. obvelata, Lamproderma arcyrionema, and Physarum viride early in the year and Stemonitopsis hyperopta, Cribraria intricata, Lindbladia cribrarioides, Lamproderma columbinum, Tubifera ferruginosa, and Trichia verrucosa later on. Changes in the relative abundance of colony sizes of several species showed annual trends. Species using slightly decayed wood at the beginning were replaced by those using more brittle wood as the years progressed. Myxomycete succession on dead wood changed through time as the wood decayed, based on species preferences for particular decay stages.     

Evaluation of the white-rot fungi Ganoderma australe and Ceriporiopsis subvermispora in biotechnological applications

Ganoderma australe is a white-rot fungus that causes a selective wood biodelignification in some hardwoods found in the Chilean rainforest. Ceriporiopsis subvermispora is also a lignin-degrading fungus used in several biopulping studies. The enzymatic system responsible for lignin degradation in wood can also be used to degrade recalcitrant organic pollutants in liquid effluents. In this work, two strains of G. australe and one strain of C. subvermipora were comparatively evaluated in the biodegradation of ABTS and the dye Poly R-478 in liquid medium, and in the pretreatment of Eucalyptus globulus wood chips for further kraft biopulping. Laccase was detected in liquid and wood cultures with G. australe. Ceriporiopsis subvermispora produce laccase and manganese peroxidase when grown in liquid medium and only manganese peroxidase was detected during wood decay. ABTS was totally depleted by all strains after 8 days of incubation while Poly R-478 was degraded up to 40% with G. australe strains and up to 62% by C. subvermispora after 22 days of incubation. Eucalyptus globulus wood chips decayed for 15 days presented 1–6% of lignin loss and less than 2% of glucan loss. Kraft pulps with kappa number 15 were produced from biotreated wood chips with 2% less active alkali, with up to 3% increase in pulp yield and up to 20% less hexenuronic acids than pulps from undecayed control. Results showed that G. australe strains evaluated were not as efficient as C. subvermispora for dye and wood biodegradation, but could be used as a feasible alternative in biotechnological processes such as bioremediation and biopulping.