Heartwood Decay Research Articles

Occurrence and Characteristics of Serpula himantioides Fruiting Bodies on Living Trees in Japan.

Serpula himantioides is a globally distributed wood decay fungus that causes heartwood decay in several tree species. We investigated the occurrence of S. himantioides fruiting bodies in Japan for two years and six months to characterize their biology. The fruiting bodies matured in autumn and occurred on living Chamaecyparis pisifera, Chamaecyparis obtusa, Larix kaempferi, and Cryptomeria japonica trees, as well as on dead trees and soil. Assessing three circular plots, the incidence of living trees with S. himantioides fruiting bodies was lowest in the plot with the most advanced heartwood decay. Furthermore, fruiting bodies occurred more frequently in the lower slope direction of the trunk. Analysis using the pair correlation function suggested that the spatial distribution pattern of living trees with fruiting bodies may change from intensive to random with heartwood decay progress. Finally, according to generalized linear and generalized linear mixed models, which were used to investigate the factors affecting the development of fruiting bodies in C. pisifera, C. obtusa, and L. kaempferi, no clear relationship was found between the presence or absence of fruiting bodies and heartwood decay. Thus, we suggest that fruiting bodies can occur in healthy living trees as well as in living trees in the early stages of heartwood decay.

Heart Rot Disease of Walnut Caused by Nothophoma juglandis sp. nov. and Its Endophytic Biocontrol Agent.

English walnut (Juglans regia L.) is an economically important hardwood tree species cultivated worldwide. Walnut heart rot disease leading to heartwood decay of trees has been frequently observed in a number of plantations in China. To identify the causal agent, 29 diseased stem samples were collected from walnut plantations in Beijing, and 54 fungal isolates were obtained. Koch's postulates were developed, and the results showed that Nothophoma juglandis, a species new to science, was the causal agent of walnut heart rot disease. Granulobasidium vellereum, a notable biocontrol agent, was coisolated with N. juglandis. An antagonistic assay on dual culture and walnut stems (both in the field and detached branches) proved that G. vellereum acted as a potential biocontrol agent against N. juglandis, as it could significantly inhibit the expansion of N. juglandis. The optimal temperature for mycelial growth and pathogenicity of N. juglandis was 26.6 and 27.0°C, respectively, which frequently occur in the summer of the walnut-growing regions in China.

Assisted Migration of Sequoiadendron Genotypes for Conservation and Timber: Performance and Morphology in a Warmer Climate Outside of Their Range

Sequoiadendron giganteum (giant sequoia) has a fragmented distribution of 75 groves found along the western slope of the Sierra Nevada Mountains, California, USA. Outplanting and range expansion or assisted migration of this iconic species for the objectives of genetic conservation and timber production would be supported by information on growth and morphology to guide seed-collection decisions. We measured and assessed giant sequoia planted as seedlings and clonal stock originating from 22 groves in two common-garden experiments at Foresthill, California, north of the current species range, after 29 growing seasons. Traits examined were tree-size parameters, fluting and asymmetry of the lower stem, basal swelling, fullness of the live crown, epicormic sprouting, and heartwood decay resistance in cut stumps. Performance in terms of tree size after 29 years varied widely among genotypes with different grove origins. Morphology and decay resistance also exhibited some variation according to grove origins. The seedling stock outperformed the clonal stock of the same grove origins in terms of size and is therefore recommended when faster early growth is desired to outcompete other trees or for other management objectives. However, more fluting was exhibited by the larger fast-growing giant sequoia, while fewer seedlings had epicormic sprouts than the clonal stock of the same grove origins. At our warm low-elevation study site, giant sequoia from Mountain Home, Giant Forest, and Converse Basin consistently exhibited above-average growth among other giant sequoia in a pure planting and in an intimate mixture with five common conifer associates. Therefore, seed collected from these three groves should perform relatively well at other locations with a similar climate. When conservation of the species and its genetic diversity is the primary objective, we recommend collecting from a wide range of groves and undertaking assisted migration by planting at multiple locations inside and outside giant sequoia’s range as a hedge against the loss of native groves.

Fungal Degradation of Extractives Plays an Important Role in the Brown Rot Decay of Scots Pine Heartwood.

Scots pine heartwood is known to have resistance to wood decay due to the presence of extractives, namely stilbenes and resin acids. However, previous studies have indicated that these extractives are degradable by wood decaying fungi. This study aimed to investigate the relationship between extractive degradation and heartwood decay in detail and to gain insight into the mechanisms of extractive degradation. Mass losses recorded after a stacked-sample decay test with brown rot fungi showed that the heartwood had substantial decay resistance against Coniophora puteana but little resistance against Rhodonia placenta. Extracts obtained from the decayed heartwood samples revealed extensive degradation of stilbenes by R. placenta in the early stages of decay and a noticeable but statistically insignificant loss of resin acids. The extracts from R. placenta-degraded samples contained new compounds derived from the degraded extractives: hydroxylated stilbene derivatives appeared in the early decay stages and then disappeared, while compounds tentatively identified as hydroxylated derivatives of dehydroabietic acid accumulated in the later stages. The degradation of extractives was further analysed using simple degradation assays where an extract obtained from intact heartwood was incubated with fungal mycelium or extracellular culture fluid from liquid fungal cultures or with neat Fenton reagent. The assays showed that extractives can be eliminated by several fungal degradative systems and revealed differences between the degradative abilities of the two fungi. The results of the study indicate that extractive degradation plays an important role in heartwood decay and highlight the complexity of the fungal degradative systems.

Fungi Occurring in Norway Spruce Wood Decayed by Heterobasidion parviporum in Puszcza Borecka Stands (Northeastern Poland)

In many spruce stands, trees are frequently attacked by the pathogen Heterobasidion parviporum, albeit without visible symptoms in the crown. In the present work, the results of the presence of stem rot, assessed by PICUS Sonic Tomography, and the fungal biota on trees and stumps in eight plots in the Puszcza Borecka Forest are described. The plots were located in stands on original forest soil (4) and on post-agricultural soil (4), where around a stump with H. parviporum symptoms (signs of internal rot and basidiocarps), 30 trees were selected and examined for internal rot. Wood samples were collected from two selected trees for fungal molecular analysis. A total of 79 fungal taxa were found, including 57 taxa in plots on post-agricultural soil and 45 on forest soil. There were 395 fungal records on stumps and 22 records on trees, therein, from the inner parts of felled trunks. Significant differences in the Chao-1 diversity index indicate that the origin of the soil—post-agricultural or forest soil—influenced the alpha diversity of the fungal communities in the forests studied. The values of the Shannon and Simpson indices show that the two communities were similar in terms of species numbers. The presence of basidiomata of H. parviporum and two species of Armillaria (mainly A. cepistipes) in samples on all plots is striking, although Armillaria spp. was detected more frequently. Most of the species identified were typical saprotrophs, although rare species were also found, such as Entoloma byssisedum, Onnia tomentosa, Physisporinus vitreus, Postia ptychogaster, and Ramaria apiculata. The presence of H. parviporum in the inner woody parts was confirmed by PCR analysis, and decay was detected even up to a stem height of 6 m. Armillaria was the dominant genus in the studied stands and plays a significant and underestimated role in heartwood decay of old spruce trees in Puszcza Borecka Forest.

Fomes fomentarius . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Fomes fomentarius . Sporophores of this fungus are found on both living and dead trees, where the fungus causes a decay of heartwood. Some information on its associated organisms and substrata, dispersal and transmission, habitats and conservation status is given, along with details of its geographical distribution (Africa (São Tomé and Principe, Somalia, Tunisia), Asia (Azerbaijan, China (Hong Kong), Cyprus, Georgia, India (Himachal Pradesh, Jammu & Kashmir, Karnataka, Meghalaya, Sikkim, Tamil Nadu, Uttarakhand, Uttar Pradesh, West Bengal), Iran, Japan, Kazakhstan (Akmola, Aktobe, Almaty, East Kazakhstan, Kostanay, North Kazakhstan, Pavlodar, South Kazakhstan, West Kazakhstan), Kyrgyzstan, Mongolia, Nepal, North Korea, Pakistan, Russia (Altai Krai, Altai Republic, Buryatia, Chelyabinsk Oblast, Irkutsk Oblast, Khabarovsk Krai, Novosibirsk Oblast, Primorsky Krai, Sakha Republic, Sakhalin Oblast, Tyumen Oblast, Zabaykalsky Krai), South Korea, Tajikistan, Turkey, Uzbekistan), Central America (Panama), Atlantic Ocean (Portugal (Madeira)), Europe (Andorra, Austria, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Ireland, Italy, Kosovo, Latvia, Luxembourg, Moldova, Netherlands, Norway, Poland, Portugal, Romania, Russia (Komi Republic, Krasnodar Krai, Moscow Oblast, Nizhny Novgorod Oblast, Orenburg Oblast, Republic of Karelia, Saratov Oblast, Voronezh Oblast), Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Ukraine, UK), North America (Canada (Alberta, British Columbia, Manitoba, New Brunswick, Newfoundland and Labrador, Ontario, Quebec, Saskatchewan), USA (Alabama, Alaska, California, Connecticut, District of Columbia, Florida, Idaho, Iowa, Kentucky, Maine, Massachusetts, Michigan, Minnesota, Montana, Nebraska, New Hampshire, New Jersey, New York, North Carolina, Ohio, Oregon, Pennsylvania, Rhode Island, South Dakota, Tennessee, Vermont, Virginia, Washington, West Virginia, Wisconsin)), South America (Brazil (Minas Gerais, Santa Catarina), Chile)).

Fomitopsis betulina . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Fomitopsis betulina . Sporophores of this fungus are found on both living and dead trees, where the fungus causes a brown-rot decay of heartwood, eventually reducing the substratum to a red-brown friable mass. Some information on its associated organisms and substrata, dispersal and transmission, habitats and conservation status is given, along with details of its geographical distribution (Asia (China (Gansu, Heilongjiang, Jilin, Nei Mongol Autonomous Region, Shaanxi, Sichuan, Xinjiang Autonomous Region, Yunnan), India (Meghalaya, Uttarakhand), Iran, Japan, Kazakhstan (Akmola, East Kazakhstan, Kostanay, North Kazakhstan), Nepal, Russia (Altai Krai, Altai Republic, Amur Oblast, Chelyabinsk Oblast, Irkutsk Oblast, Kamchatka Krai, Khabarovsk Krai, Khanty-Mansi Autonomous Okrug, Krasnoyarsk Krai, Novosibirsk Oblast, Omsk Oblast, Primorsky Krai, Sakha Republic, Sakhalin Oblast, Sverdlovsk Oblast, Tomsk Oblast, Tyumen Oblast, Yamalo-Nenets Autonomous Okrug, Zabaykalsky Krai), South Korea, Uzbekistan), Central America (Belize, Panama), Europe (Åland Islands, Andorra, Austria, Belarus, Belgium, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Isle of Man, Italy, Latvia, Lithuania, Luxembourg, Netherlands, Norway, Poland, Portugal, Romania, Russia (Bryansk Oblast, Chuvash Republic, Ivanovo Oblast, Kaliningrad Oblast, Kaluga Oblast, Kirov Oblast, Komi Republic, Kostroma Oblast, Krasnodar Krai, Kursk Oblast, Leningrad Oblast, Mari El Republic, Moscow Oblast, Murmansk Oblast, Nizhny Novgorod Oblast, Orenburg Oblast, Perm Krai, Pskov Oblast, Republic of Bashkortostan, Republic of Dagestan, Republic of Karelia, Republic of Mordovia, Republic of Tatarstan, Ryazan Oblast, Samara Oblast, Saratov Oblast, Smolensk Oblast, Tula Oblast, Tver Oblast, Udmurt Republic, Vladimir Oblast, Yaroslavl Oblast), Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Ukraine, UK), North America (Canada (Alberta, British Columbia, Manitoba, New Brunswick, Newfoundland and Labrador, Northwest Territories, Nova Scotia, Ontario, Prince Edward Island, Quebec, Yukon Territory), USA (Alabama, Alaska, Arkansas, California, Connecticut, District of Columbia, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Montana, Nebraska, New Hampshire, New Jersey, New York, North Carolina, North Dakota, Ohio, Oregon, Pennsylvania, Rhode Island, Tennessee, Texas, Vermont, Virginia, Washington, West Virginia, Wisconsin)), South America (Argentina, Colombia)).

Ganoderma applanatum . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Ganoderma applanatum . Sporophores of this fungus are found on both living and dead trees, where the fungus causes a decay of heartwood resulting in a white soft spongy heart and butt rot. Some information on its associated organisms and substrata, dispersal and transmission, habitats and conservation status is given, along with details of its geographical distribution (Africa (Angola, Benin, Congo, Democratic Republic of the Congo, Equatorial Guinea, Ivory Coast, Kenya, Madagascar, Morocco, Mozambique, São Tomé and Principe, Sierra Leone, South Africa, Sudan, Tanzania, Togo), Asia (Azerbaijan, Brunei Darussalam, China (Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hainan, Hebei, Heilongjiang, Henan, Hong Kong, Hunan, Jiangsu, Jiangxi, Jilin, Nei Mongol Autonomous Region, Qinghai, Shaanxi, Shanxi, Sichuan, Xinjiang, Yunnan, Zhejiang), Christmas Island, Cyprus, Georgia, India (Assam, Chhattisgarh, Gujarat, Himachal Pradesh, Jammu & Kashmir, Karnataka, Kerala, Madhya Pradesh, Maharashtra, Meghalaya, Orissa, Punjab, Rajasthan, Uttarakhand, Uttar Pradesh, West Bengal), Indonesia, Iran, Israel, Japan, Kazakhstan (Almaty, East Kazakhstan, Kostanay, South Kazakhstan), Laos, Malaysia, Nepal, North Korea, Oman, Pakistan, Papua New Guinea, Philippines, Russia (Altai Krai, Altai Republic, Irkutsk Oblast, Kamchatka Krai, Kemerovo Oblast, Khanty-Mansi Autonomous Okrug, Krasnoyarsk Krai, Novosibirsk Oblast, Omsk Oblast, Primorsky Krai, Sakha Republic, Sverdlovsk Oblast, Tomsk Oblast, Tyumen Oblast, YamaloNenets Autonomous Okrug), Singapore, South Korea, Sri Lanka, Taiwan, Tajikistan, Thailand, Turkey, Uzbekistan, Vietnam), Australasia (Australia (Australian Capital Territory, New South Wales, Northern Territory, Queensland, South Australia, Tasmania, Victoria, Western Australia), New Zealand), Caribbean (American Virgin Islands, British Virgin Islands, Cuba, Dominican Republic, Guadeloupe, Haiti, Jamaica, Puerto Rico, Trinidad and Tobago), Central America (Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Panama. Europe: Austria, Belarus, Belgium, Bulgaria, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Ireland, Isle of Man, Italy, Latvia, Lithuania, Luxembourg, Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Russia (Arkhangelsk Oblast, Belgorod Oblast, Bryansk Oblast, Chuvash Republic, Ivanovo Oblast, Kaliningrad Oblast, Kaluga Oblast, Kirov Oblast, Kostroma Oblast, Krasnodar Krai, Kursk Oblast, Leningrad Oblast, Mari El Republic, Moscow Oblast, Nizhny Novgorod Oblast, Orenburg Oblast, Oryol Oblast, Penza Oblast, Perm Krai, Pskov Oblast, Republic of Bashkortostan, Republic of Tatarstan, Samara Oblast, Smolensk Oblast, Tula Oblast, Tver Oblast, Udmurt Republic, Vladimir Oblast, Vologda Oblast, Voronezh Oblast, Yaroslavl Oblast), Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Ukraine, UK), Indian Ocean (Seychelles. North America: Canada (Alberta, British Columbia, Manitoba, New Brunswick, Newfoundland and Labrador, Northwest Territories, Nova Scotia, Ontario, Prince Edward Island, Quebec, Saskatchewan), Mexico, USA (Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming)), Pacific Ocean (American Samoa, Cook Islands, Federated States of Micronesia, Fiji, French Polynesia, Guam, Marshall Islands, Samoa, Tuvalu, USA (Hawaii)), South America (Argentina, Bolivia, Brazil (Acre, Alagoas, Amapá, Amazonas, Bahia, Espírito Santo, Minas Gerais, Pará, Paraíba, Paraná, Pernambuco, Rio de Janeiro, Rio Grande do Sul, Rondônia, Roraima, Santa Catarina, São Paulo), Chile, Colombia, Ecuador, French Guiana, Peru, Suriname, Uruguay, Venezuela)).

A century old regeneration problem of Shorea robusta Gaertn. F. in south Asia: SWOT analysis (Review)

Shorea robusta (Sal) Gaertn. F. a commercially and ecologically important forestry species of south Asia, is facing serious regeneration problem since last century. The continuously diminishing natural regeneration is associated with numerous abiotic and biotic factors, like edaphic, micro-climatic, physiological, genetic, anthropogenic, pathogens, insect-pests, etc. Following a good seed year and timely commencement of monsoon, Sal seeds germinate readily, and thousands of seedlings cover the forest floor. Subsequently, these get afflicted with die-back syndrome impeding shoot growth. Regular fire incidences during hot and dry season further aggravates the problem. Among biotic factors, Hoplocerambyx spinicornis , Cylindrocladium floridanum and Inonotus shoreae causes severe heartwood decay, blight and dieback leading to mortality. Moreover, over-exploitation, illegal felling, grazing, etc., have severely depleted the Sal forest. This review systematically explores the factors contributing to regeneration problem in S. robusta and opines appropriate silvicultural operations and management strategies for the conservation of Sal forests through SWOT (Strengths, Weaknesses, Opportunities and Threats) analysis. We emphasized on the ecological aspects, soil characteristics, micro-climatic factors and importance of associated species to develop sustainable management regimes. Highlighting all facets of Sal regeneration problem and SWOT assessment, we suggest comprehensive weaknesses and threat perceptions to formulate strategies to seal the gaps.

Stem Decay in Live Trees: Heartwood Hollows and Termites in Five Timber Species in Eastern Amazonia

Research Highlights: Tree size and wood characteristics influenced the susceptibility of five Amazonian timber tree species to heartwood decay and colonization by termites. Termites occurred in the heartwoods of 43% of the trees, with Coptotermes testaceus the most abundant species. Background and Objectives: Hollows and rotten cores in the stems of living trees have ecological and economic impacts in forests managed for timber. The decision on whether to cut or maintain hollow trees in such forests must account for the susceptibility of different tree species to decay. We investigated tree and wood characteristics of living trees of five commercial timber species in the eastern Amazon that influenced the likelihood of heartwood decay and the occurrence of termite nests inside the rotten cores. Materials and Methods: We used Pearson’s correlations and one-way analysis of variance (ANOVA) to explore relationships among tree basal area and hollow area. We used principal components analysis (PCA) to analyze the variation of wood anatomical traits, followed by a linear regression to explore the relationships between PCA scores, and heartwood hollow area. We used a logistic model to investigate if the probability the occurrence of colonies of C. testaceus inside tree cores varied with tree and species characteristics. Results: Heartwood hollow areas increased with stem basal area. Larger hollows were more likely to occur in species with higher vessel and ray densities, and smaller diameter vessels. Termites occurred in the hollows of 43% of the trees sampled, with C. testaceus the most common (76%). The probability of encountering termite nests of C. testaceus varied among tree species and was positively related to wood density. Conclusions: This study shows that given the increased likelihood of stem hollows and rotten cores in large trees, tree selection criteria in managed tropical forests should include maximum cutting sizes that vary with the susceptibility of different tree species to stem decay.

Tissue type and location within forest together regulate decay trajectories of Abies faxoniana logs at early and mid-decay stage

Deadwood decomposition plays a crucial role in global carbon and nutrient cycles. Factors controlling deadwood decomposition at local scales could also have strong effects at broader scales. We tested how trait variation within stems (i.e. tissue types) and forest habitat heterogeneity (i.e. location within forest) together influence the deadwood decay trajectory and decay rate. We conducted an in situ decomposition experiment of Abies faxoniana logs in an alpine forest on the eastern Qinghai-Tibetan Plateau, decomposing logs from a series of decay classes I-III (on a 5-class scale) for five years on the forest floor in canopy gap, gap edge and under closed canopy (each sized 25 ± 3 × 25 ± 3 m). We found strong differences in density and chemical composition between tissue types at least across decay classes I-III, which revealed the distinct contribution of each tissue type to carbon and nutrient cycling. There were remarkable interactions of tissue types and locations within forest. We found bark always decomposed faster than wood, while heartwood can decompose faster than sapwood in canopy edge and canopy gap. Locations within forest influenced the best fit decay model and decay rate of bark and sapwood in the same way, while it had no corresponding effects for heartwood decay dynamics. The largest difference in T0.25 and T0.4 (time to 25% and 40% mass loss) between locations were 1.52 and 3.21 (bark), 19.41 and 37.61 (wood overall), 31.82 and 60.15 (sapwood), and 12.86 and 22.84 (heartwood), respectively. We also found that pH was significantly negatively related with sapwood and heartwood mass loss, demonstrating that pH can potentially be applied to evaluate sapwood and heartwood mass loss when density correction is difficult to achieve at least at early to mid-decay stages. However, whether pH is a powerful predictor of decomposition trajectory across more species and biomes remains to be tested. We strongly recommend that further model predictions of coarse log decay include radial positions within stem and locations within forest as factors to increase the reliability of carbon budget estimates.

An approach to quantify natural durability of Eucalyptus bosistoana by near infrared spectroscopy for genetic selection

Natural durability within a timber species can be variable. Hence efficient assessments of natural durability are required to ensure quality either through tree breeding or segregation during production. In this study, first the relationship between extractive content and mass loss of Eucalyptus bosistoana heartwood caused by a white and a brown-rot fungus was validated. Then the ability of NIR spectroscopy as a high-throughput method to evaluate heartwood decay resistance was examined. Finally the NIR method was applied to a tree breeding trial. A correlation between extractive content and mass loss against the white-rot fungus (Perenniporia tephropora) and the brown-rot fungus (Coniophora olivacea) were found. Analysis of NIR spectra indicated that this relationship is causal with shared bands for mass loss and extractive content models at 6650, 6017, 5265 and 4659 cm−1. Partial least squares regression (PLSR), supplemented with spectra normalisation and variable selection, allowed prediction of mass loss with a residual mean square error (RMSE) of 7.48 % and 5.76 % for the white-rot and brown-rot, respectively. This level of precision allowed the characterisation of a E. bosistoana resource which showed a range of mass loss from 0 to 60 %. Genetic control was found for mass loss by the white-rot ( h2 = 0.70 and 0.24) and the brown-rot ( h2 = 0.15 and 0.13) at two sites in New Zealand. The rankings were correlated between sites, with genetic correlations (Rg2) of 0.69 and 0.63 for white-rot and brown-rot, respectively, as well as to the predicted extractive content (0.82 to 0.92). However, the study indicated a significant site effect on the decay resistance of the E. bosistoana heartwood. In summary, this study has shown that the decay resistance could be assessed rapidly and efficiently using NIR technology for genetic selection.

Cellular level chemical changes in Scots pine heartwood during incipient brown rot decay

The heartwoods of many wood species have natural resistance to wood decay due to the accumulation of antifungal heartwood extractives. The natural durability of heartwoods has been extensively investigated, yet very little information is available on the initiation of heartwood decay. This experiment examined the onset of Rhodonia placenta brown rot decay in Scots pine heartwood in order to identify the key changes leading to heartwood decay. An imaging approach based on Raman imaging and multivariate image analysis revealed that the degradation of heartwood began in the innermost cell wall layers and then spread into the remaining cell walls and the middle lamella. Pinosylvins were extensively degraded in the cell walls, middle lamella and extractive deposits, while unidentified material most likely consisting of hemicelluloses and/or lipophilic extractives was removed from the inner cell wall layers. Changes similar to inner cell wall degradation were seen in the remaining cell walls in more advanced decay. The results indicate that the key change in incipient heartwood decay is the degradation of antifungal heartwood extractives. The inner cell wall degradation seen in this experiment may serve a nutritive purpose or facilitate the penetration of degradative agents into the cell walls and middle lamella.

The presence of heartwood decay, a precursor to hollow formation, within Eucalyptus camaldulensis in relation to stem size

SummaryRiver Red Gums (Eucalyptus camaldulensis Dehnh.) are large trees that dominated many of continental Australia's riparian areas, providing abundant hollows for nesting and denning fauna. Land clearing and forestry have reduced the availability of large trees, and much of the remaining forest is dominated by small regrowth trees that lack visible hollow entrances. Inspection of recently felled River Red Gums revealed that heartwood decay, a precursor of hollow formation, can be common in relatively small trees. Internal decay and voids remain inaccessible until stochastic damage exposes them, which may not occur until the tree is old, and hence probably large. This discrepancy indicates that there is likely to be a size range of trees into which artificial entrances can be added to quickly increase hollow availability in landscapes undergoing active restoration as fauna habitat.

Susceptibility of Pericopsis elata (Assamela) to heartwood decay and identification of micro and macro fungi associated with the disease in Cameroon

Heartwood decay is one of the major pathological constraints affecting the quality and marketable volume of tropical timber. A study on its behavior was conducted on Pericopsis elata in order to contribute to its sustainable management in Cameroon. Tree susceptibility to heartwood decay was evaluated using three diameter classes, based on allometric equations between decayed and healthy trees. Wood samples and visible macromycetes were taken from living and felled trees with an auger. Isolation of microfungi was performed on potato dextrose agar medium and their identification was based on the morphological and microscopic characteristics of the mycelium and conidia with reference to identification keys of mycology. Identification of macromycetes was based on their morphological characteristics as described in reference books on macromycetes identification. Results show that diameter class ]110, 120[ presented highly significant (P<0.05) volume loss (3755.96 cm3), followed by diameter class ]100, 110[. Microfungi frequently associated with heartwood decay of P. elata were Cercospora sp (24.57%), Fusarium oxysporum (12.64%) and Penicillium sp (12.58%) in living decay trees and Aspergillus niger (25.19%), Cercospora sp (22.21%), Penicillium sp (17.69%) and Phoma sp (15.05%) in felled decay trees. Macrofungi associated with living trees were Inonotus sp and Ganoderma sp. This is the first time that these fungal species are reported on P. elata wood. This study provides baseline information for the study of heartwood decay and management of P. elata in Cameroon.

Fungi inhabiting knotwood ofPinus sylvestrisinfected byPorodaedalea pini

AbstractAbundance and diversity of fungi in naturally formed knots ofPinus sylvestrisaffected byPorodaedalea piniwere investigated. Samples were taken from trees that were (i) affected, with internal heartwood decay and no conks, (ii) affected, with internal heartwood decay and conks and (iii) controls. The Illumina sequencing technology was used for amplification ofDNA, sequencing and analysis. In total, 566,279 raw sequences were obtained from six samples. Sequences included 74% of culturable and 8.4% of non‐culturable fungi and 17.6% of organisms with no reference sequences inNCBI. Abundance of organisms in knotwood, measured as number ofOTUs, ranged from 36,272 (29,506 for fungi) to 178,535 (177,484 for fungi) and differed significantly between two trees in a stand and between stands. The highest and lowest average number of fungalOTUs occurred in infected trees with no conks and in trees with conks, respectively. Number of taxa ranged from 171 to 415 and often differed significantly between two trees in one stand and between stands. Greatest diversity occurred in control trees. The number of fungal taxa shared by two trees in one stand was 67–152 and that shared by two stands was 51–141. The majority of fungi were Ascomycota. Those most common in pines affected byP. piniwereConiochaeta hoffmanniiandC. fodinicola(19.65%–59.92%).Infundichalara microchona,Leotiomycetes spp. andRhinocladiella atrovirenswere also present. Another common species,Lecanora conizaeoides,occurred most often in control trees (0.30%–8.82%).Porodaedalea piniwas detected only sporadically. Non‐culturable fungi were most frequent in the control trees. The greater average abundance and smaller average diversity of fungi in knots of trees infected byP. pinisuggest that the pathogen successfully competes with some fungal species and does not inhibit the growth of survivors. Some fungi detected may contribute to production of natural biocides.

Evaluation of Sapwood and Heartwood Decay Resistance after Immersion-Treatment with Pyroligneous Liquor

To evaluate the resistance of wood to decay caused by fungi, sapwood and heartwood of red pine (Pinus densiflora) and sapwood and heartwood of larch (Larix kaempferi) were conducted. Wood samples were immersed for 96 h in pyroligneous liquor. Then, the brown-rot fungus, Fomitopsis palustris, was used to examine the decay resistance of red pine and larch. Weight and density of wood from the all conditions increased after immersion treatment. Weight loss after decay resistance test was also dropped with a immersion treatment. The lowest weight loss indicated at immersion-treated heartwood of larch. Immersion treatment using pyroligneous liquor effectively increased the resistance of wood to decay caused by fungi.

Evaluation of stem rot in 339 Bornean tree species: implications of size, taxonomy, and soil-related variation for aboveground biomass estimates

Abstract. Fungal decay of heart wood creates hollows and areas of reduced wood density within the stems of living trees known as stem rot. Although stem rot is acknowledged as a source of error in forest aboveground biomass (AGB) estimates, there are few data sets available to evaluate the controls over stem rot infection and severity in tropical forests. Using legacy and recent data from 3180 drilled, felled, and cored stems in mixed dipterocarp forests in Sarawak, Malaysian Borneo, we quantified the frequency and severity of stem rot in a total of 339 tree species, and related variation in stem rot with tree size, wood density, taxonomy, and species' soil association, as well as edaphic conditions. Predicted stem rot frequency for a 50 cm tree was 53 % of felled, 39 % of drilled, and 28 % of cored stems, demonstrating differences among methods in rot detection ability. The percent stem volume infected by rot, or stem rot severity, ranged widely among trees with stem rot infection (0.1–82.8 %) and averaged 9 % across all trees felled. Tree taxonomy explained the greatest proportion of variance in both stem rot frequency and severity among the predictors evaluated in our models. Stem rot frequency, but not severity, increased sharply with tree diameter, ranging from 13 % in trees 10–30 cm DBH to 54 % in stems ≥ 50 cm DBH across all data sets. The frequency of stem rot increased significantly in soils with low pH and cation concentrations in topsoil, and stem rot was more common in tree species associated with dystrophic sandy soils than with nutrient-rich clays. When scaled to forest stands, the maximum percent of stem biomass lost to stem rot varied significantly with soil properties, and we estimate that stem rot reduces total forest AGB estimates by up to 7 % relative to what would be predicted assuming all stems are composed strictly of intact wood. This study demonstrates not only that stem rot is likely to be a significant source of error in forest AGB estimation, but also that it strongly covaries with tree size, taxonomy, habitat association, and soil resources, underscoring the need to account for tree community composition and edaphic variation in estimating carbon storage in tropical forests.

Carbon Dioxide and Methane Formation in Norway Spruce Stems Infected by White-Rot Fungi

Globally, billions of tons of carbon sequestered in trees are annually recycled back to the atmosphere through wood decomposition by microbes. In Norway, every fifth Norway spruce shows at final harvest infection by pathogenic white-rot fungi in the genera Heterobasidion and Armillaria. As these fungi can mineralize all components of wood, we predicted that they have a significant carbon footprint. Gas samples taken from infected stems were analyzed for CO2 and CH4 concentrations, and wood samples from different parts of the decay columns were incubated under hypoxic (4% O2) and anoxic laboratory conditions. In spring and summer the stem concentrations of CO2 were generally two times higher in trees with heartwood decay than in healthy trees. For most of the healthy trees and trees with heartwood decay, mean stem concentrations of CH4 were comparable to ambient air, and only some Armillaria infected trees showed moderately elevated CH4. Consistently, low CH4 production potentials were recorded in the laboratory experiment. Up-scaling of CO2 efflux due to wood decay in living trees suggests that the balance between carbon sequestration and emission may be substantially influenced in stands with high frequency of advanced root and stem heartwood decay.

Prediction of the Decay and Termite Resistance of Western Red Cedar Heartwood

Abstract Western red cedar (WRC; Thuja plicata) is highly valued for its natural durability. Rapid methods to assess heartwood durability are needed to identify breeding stock that will ultimately yield trees with durable wood when harvested. Chromatographic methods to detect heartwood extractives have been developed, but these still require significant time and laboratory resources and rely upon an understanding of the relationship between extractives and durability that is still incomplete. Visible/near-infrared (VIS/NIR) spectroscopy combined with multivariate statistical analysis has been used to rapidly predict a wide range of wood properties, including extractive content and decay resistance. The present work investigates the ability of VIS/NIR spectroscopy to predict extractive content, decay resistance, and termite resistance of WRC heartwood and explores the association between extractive content and durability. Partial least squares (PLS) models based on VIS/NIR spectra had moderate predictive ability for lignans, plicatic acid, beta-thujaplicinol, and total extractives. Other extractives were poorly predicted. Developed PLS models were not predictive for decay resistance but were moderately predictive of termite resistance. Decay and termite resistance were not strongly associated with any measured extractive. A moderately strong correlation was observed between termite resistance and red coloration (a*). Some of the models developed may be suitable for screening, but none are accurate enough for phenotyping.