Wood Mass Loss Research Articles

Changes in oak wood buried in waterlogged peat: shrinkage as a complementary indicator of the wood degradation rate

A study was made on the degradation of contemporary heartwood of oak (Quercus sp.) buried in waterlogged peat on the archaeological site at Biskupin (Poland). The state of wood preservation was evaluated after 2, 4, 6, 8 and 10 years of deposition of samples in conditions similar to anaerobic. The changes that occurred in the wood were assessed on the basis of microscopic examinations, chemical composition, mass loss and selected physical properties of the wood. Despite a distinct mass loss of the samples (7.4% after 10 years of the experiment), only the initial phase of cell wall degradation and almost unchanged contents of major chemical components were observed in the examined wood. Greater changes were recorded in the content of water-soluble extractives, maximum water content, basic density and wood porosity, as well as in the total tangential and the total radial shrinkage. Wood mass loss resulted mainly from the loss of substances soluble in water (up to 70.8% after 10 years of the experiment) and less from the biological degradation of cell walls (loss of major chemical components of wood). A close relationship was observed between content of substances soluble in water, mass loss, and wood shrinkage. It was concluded that tangential and radial shrinkage may serve as a simple complementary indicator of the state of preservation of wood decomposing in the conditions of a monitored archaeological site.

Modeling and prediction of devolatilization and elemental composition of wood during mild pyrolysis in a pilot-scale reactor

Mild pyrolysis, operated at 200–300 °C in an inert atmosphere, is a promising technology to produce sustainable materials (i.e., heat treated woods for construction and building) and solid fuels (i.e., torrefied woods or biochars for combustion and gasification). To aid in process and reactor design, the aim of this work is to conduct thermal degradation kinetics of wood. A two-step kinetics model is developed to predict the elemental composition (C, H, and O) and devolatilization dynamics of wood materials during heat treatment in a pilot-scale reactor by kinetic analysis. A hardwood poplar (Populus nigra) and a softwood fir (Abies pectinata) sever as feedstock, and the experiments are carried out at 200–230 °C with a heating rate of 0.2 °C min−1 in a low-pressure environment (200 hPa). The predictions in the weight losses of the woods are in a good agreement with the experimental data. The evolutions of solids, volatiles, elements (C, H, and O), and the heating values of treated woods are further analyzed. The predictions suggest that the intermediate solid is the main product, and almost all the woods are converted when the treatment temperature is as high as 230 °C. The devolatilization process, which is responsible for the mass loss of wood, can be clearly identified, and the volatile liberation amounts from poplar and fir at 230 °C are 17.05 and 12.44 wt%, respectively. The predicted HHVs of treated woods from the empirical formula are between 19.62 and 20.55 MJ kg−1, and the enhancement factors at the end of treatment are between 1.01 and 1.07 which is close to torrefied wood after light torrefaction. During the treatment, the extents of decarbonization, dehydrogenation, and deoxygenation in fir are all smaller than those in poplar, resulting from the lower intensity of devolatilization in the former.

Effect of the degree of decay on the electrical resistance of wood degraded by brown-rot fungi

There have been limited efforts to investigate the association between wood decay and electrical resistance; consequently, we have examined the change in the electrical resistance of wood progressively decayed by brown-rot fungi to elucidate the effect of the degree of decay. The rate of mass loss of wood was used as an indicator of the degree of fungal decay. The changes in the moisture content and ion concentrations were measured at various decay stages. The results showed a significant difference in the electrical resistances of sound wood and fungal-treated wood after 24 weeks. The electrical resistance significantly decreased with the exposure time. The degree of decay increased as the mass loss increased, resulting in the severe breakdown of cell walls and the accumulation of fungal mycelia. Empirical models related to the rate of mass loss and the percent decrease in the electrical resistance were established. The moisture content and cation concentrations increased to various degrees in decayed wood. This increase in the cation concentration was considered to play a dominant role in the decrease in the electrical resistance. The study results provide valuable information for developing an electrical resistance based method coupled with ion content measurements for incipient wood decay detection.

Thermo-treatment affects Quercus cerris L. wood properties and the antioxidant activity and chemical composition of its by-product extracts

Nowadays, there is an increasing interest on thermo-treatment and its effects on wood structure and extraction processes, connected to the wood use for industrial application and for its use as biorefinery. The present investigation aimed to provide the main changes on wood properties (mass loss, color variation and modulus of elasticity) and a comparative analysis of the antioxidant properties and GC–MS profile of the extracts from Turkey oak (Quercus cerris L.) wood. Untreated and thermo-treated wood (170 °C x 3 h) samples were compared. Thermo-treatment induced a mass loss (5.1%) in wood, a darkening of color surface (ΔE = 7.6) and a decrease of MOE (4.1%). Moreover samples were extracted using different techniques: maceration (ME), ultrasound assisted extraction (UAE) and accelerated solvent extraction (ASE). Extracts were tested to evaluate the content of polyphenols and flavonoids along with the in vitro antioxidant activity. Results showed that extracts obtained from thermo-treated wood reported the highest Relative Antioxidant Capacity Index and extraction techniques affected the value in the following rating: UAE > ME > ASE. Qualitative and quantitative measurements of chemical compounds were carried out by GC–MS system. Taking into account the thermo-treatment and extraction techniques, principal component analysis (PCA) was performed also in order to evaluate the relationships among principal chemical compounds. According to results obtained, thermo-treatment and extraction technique had a determinant role in the antioxidant efficiency and, consequently, on the potential application of extracts.

Suspended Dead Wood Decomposes Slowly in the Tropics, with Microbial Decay Greater than Termite Decay

Coarse woody debris (CWD) is an important pool of carbon in forest ecosystems and is present in all strata as fallen, standing or suspended CWD. However, there are relatively few decomposition studies of CWD in tropical forests compared with temperate forests, and research on suspended CWD in particular has largely not been attempted. Termites are important decomposers in tropical ecosystems yet their role relative to microbial decomposers and the importance of the vertical location of CWD has rarely been considered. For the first time, we examined the relative contribution of macro-invertebrates (predominantly termites) and microbes to the decay of suspended and ground-placed (fallen) CWD in lowland, tropical rainforest. We set up wood baits (Pinus radiata) with and without termite access, and measured wood mass loss after 1 year. Mass loss of ground-placed CWD assays was over four times greater than suspended CWD assays. Termite decomposition was vertically stratified with termites having a large relative contribution to the decomposition of ground-placed CWD and a negligible contribution to the decomposition of suspended CWD. In contrast, the effect of microbes on decomposition was low and not vertically stratified. Although our results support the findings of temperate studies in that decomposition of CWD is dependent on its physical location, we show that in tropical rainforests this is predominantly due to greater termite decomposition on the forest floor. Suspended CWD remains an important carbon sink due to slow microbial decay until it falls to the forest floor where it is more accessible to termites.

Wood decomposition in aquatic and terrestrial ecosystems in the tropics: contrasting biotic and abiotic processes.

Wood decomposition, a critical process in carbon and nutrient cycles, is influenced by environmental conditions, decomposer communities and substrate composition. While these factors differ between land and stream habitats, across-habitat comparisons of wood decay processes are rare, limiting our ability to evaluate the context- dependency of the drivers of decay. Here we tracked wood decomposition of three tree species placed in stream and terrestrial habitats in a lowland tropical forest in Panama. At 3 and 11 months we measured mass loss, wood nitrogen and wood polymer concentrations, and sampled wood-associated fungal and bacterial communities. After 11 months of decay we found that mass loss occurred 9% faster in streams than on land, but loss of cellulose, hemicellulose and lignin did not differ between habitats. We also observed large differences in microbial decomposer communities between habitats. Overall, we found faster mass loss of wood in water, but no differences in biotic decay processes between habitats despite distinct microbial communities in streams and on land. Our research challenges the assumption that wood decays relatively slowly in water reflecting unfavorable environmental conditions and a limited capacity of aquatic microbial communities to effectively degrade wood polymers.

Application of time–temperature–humidity superposition to the mass loss of wood through hygrothermally accelerated ageing at 95–140 °C and different relative humidity levels

Spruce wood specimens were hygrothermally treated at different temperatures (T, 95–140 °C) and relative humidity during heating (RHh, 0–92%) to measure the loss in dry mass (ML) due to the treatment. The ML was approximated by a power function of the heating duration t, and the plots of ML versus t were successfully superposed as a single master curve by shifting the plots along the t axis using the shift factors aT and aH, representing the effects of T and RHh, respectively. The apparent activation energies calculated from the linear correlation between ln(aT) and the reciprocal of absolute temperature were 109–116 kJ/mol, almost independent of RHh. Plots of aH versus RHh showed sigmoid shapes, suggesting that the aH value depended on the moisture content of the wood. The shift factors allowed the prediction of the ML of wood by hygrothermal treatment at arbitrary T and RHh. The predicted ML values showed good agreement with experimental ML values available in the literature.

Evaluation of Deterioration of Larix kaempferi Wood Heat-treated by Superheated Steam through Field Decay Test for 12 Months

In this study, the decay resistance of larch wood, which was heat treated by superheated steam, was evaluated by the field decay test. During the field decay test of 12 months, non-treated wood has been severely damaged by termite, however, no visible damage has occurred in the preservative-treated wood and superheated steam heat-treated wood. Results of field decay test showed approximately 5% mass loss of the non-treated wood and the preservative-treated wood, and approximately 1% mass loss of the superheated steam heat-treated wood. After the field decay test for 12 months, the residual amount of preservatives remaining in the preservative-treated wood was lower than that before the field decay test. It was considered that the preservative was partially eluted during the field decay test, and the mass loss of the preservative-treated wood was thought to be similar to that of the non-treated wood. Through this study and additional long-term monitoring test, superheated steam heat treatment can be considered to be an environmental-friendly method to enhance the decay resistance of wood against rot fungi and/or insect without chemical treatment such as preservative injection.

Swelling restraint of thermally modified ash wood perpendicular to the grain

The paper reports on creep of ash wood (Fraxinus excelsior L.) thermally modified at 180 and 200 °C, and subsequently subjected to compression in tangential and radial directions and simultaneously wetted, from the moisture content (MC) of 6% to above the fibre saturation point (FSP). The compressing load made 0.00, 0.25, 0.50 and 0.75 of impact stress at the proportional limit (Rc). The compression stress needed to restrain the swelling of wood, the so-called swelling pressure, was indirectly determined from isochrones of mechano-sorptive creep. The most important finding was that thermal modification reduces the strain of ash wood subjected to compression perpendicular to the grain to a degree proportional to the mass loss. The compression stress needed to restrain the swelling of thermally modified wood is ca. 10 and 20% smaller in the tangential and radial directions, respectively. This effect leads to a reduction in the anisotropy of swelling pressure of thermally modified wood perpendicular to the grain. Moreover, although upon thermal modification the mass loss of wood takes place, at the MC of 6% it shows practically the same modulus of elasticity (MOE) and Rc as the unmodified wood. After wetting to MC higher than the FSP, the thermally modified wood at 200 °C shows significantly higher MOE and Rc than the wood modified at 180 °C and untreated wood. Reduction of wood hygroscopicity, an inevitable effect of thermal modification, also reduces the range of changes in mechanical properties of wood caused by the increase in its MC to the FSP.

Встановлення ефективності вогнезахисту деревини органо-неорганічною композицією

Опис поведінки вогнезахисних засобів у момент формування теплоізоляційної структури є окремим і складним завданням, а просочення характеризується розкладом антипіренів під дією температури з поглинанням тепла та виділенням негорючих газів, гальмування окислення в газовій і конденсованій фазі та утворенням на поверхні деревини теплозахисного шару коксу. Наведено результати дослідження процесу термодеструкції деревини сосни і визначено термограми її розкладу та встановлено, що кінетика процесу розкладу деревини вогнезахисної композицією "Skela-i" зміщується у напрямку високих температур, із коксовим залишком у 4 рази більшого ніж для необробленої деревини. Експериментально встановлено, що під дією теплового потоку на вогнезахищені зразки відбувається інтенсивне виділення інертних газів та зменшення горючих, що доводить про ефективність вогнезахисту. Після випробувань виявлено, що інтенсивність утворення негорючих газів переміщується у сторону підвищеної температури з утворенням пінококсу. Газохроматографічними дослідженнями аналізу летких продуктів піролізу вогнезахищених зразків виявлено збільшення негорючих газів у 8 разів та зменшення вмісту горючих – понад 50 %. Здійснено дослідження з визначення групи горючості деревини та встановлено зменшення у 3 рази втрати маси зразків захищеної деревини, порівняно з необробленими, а температура димових газів становила менше 165°С.

Changes in the Contribution of Termites to Mass Loss of Dead Wood among Three Tree Species during 23 Months in a Lowland Tropical Rainforest

This study investigated the contribution of termites to mass loss of dead wood (Macaranga bancana, Elateriospermum tapos, and Dillenia beccariana) in a lowland tropical rainforest, Brunei Darussalam. Mesh bag method was used to exclude termites, and the mass remaining was monitored after 3, 7, 13, and 23 months. C/N ratio of the samples was analyzed after 13 and 23 months. Initial wood density was 0.63, 0.92, and 1.02 g/cm3 for M. bancana, E. tapos, and D. beccariana, respectively, and the termite contribution to mass loss was an average (range) of 13.05±5.68 (4.17-29.59%), 3.48±1.13 (2.20-6.49), and 3.40±1.92% (0.74-10.78), respectively. Until 7 months, termites contributed highly to mass loss, given the low initial wood density, and interaction effect of species and treatment was significant. After 7 months, the contribution decreased in M. bancana and E. tapos, whereas it increased consistently in D. beccariana. The interaction effect was not significant, whereas differences in C/N ratio among the species were significant, with a lower C/N ratio in M. bancana and E. tapos than in D. beccariana. After 23 months, the differences in C/N ratio were not significant, and ants were present at 40% of control samples in M. bancana and E. tapos. Our results suggest that the contribution of termites to mass loss varies by dead wood species and is temporally variable. Initial wood traits could affect the termite feeding in the beginning, however, termites thereafter could forage in response to the varying C/N ratio among species and predators.

Hexadecyl ammonium chloride amylose inclusion complex to emulsify cedarwood oil and treat wood against termites and wood-decay fungi

Cedarwood oil (CWO) has a wide range of bioactivities, including insect repellency and toxicity, as well as conferring resistance against termites and wood-decay fungi. In previous work examining pressure treatment of wood, ethanol was used as the diluent/carrier for CWO. However, it is preferable to use a water-based carrier for environmental, safety and cost considerations. In this research, we describe the use of a hexadecyl ammonium chloride amylose inclusion complex/polyvinyl alcohol (AIC/PVOH) as an emulsifier for CWO to pressure treat wood. Wood samples were subsequently tested for resistance to termites and four species of wood-decay fungi. Wood was also compared for water absorption and swelling. In the termite test, the lowest wood mass losses were for the AIC/PVOH/CWO (5.4%) and EtOH/CWO (5.4%) treatments, which also had the highest termite mortalities (i.e., 100% and 97.6%, respectively). In general, for wood-decay fungi, wood mass losses were lowest for the EtOH/CWO and AIC/PVOH/CWO treatments and were highest for the Water, EtOH, and AIC/PVOH treatments. Wood blocks treated with AIC/PVOH repelled water as evidenced by higher contact angle, lower mass gain (both by submersion and water saturation) and lower swelling. The results indicated that the amylose inclusion complex makes an excellent emulsifier and the AIC/PVOH/CWO mixture inhibits both termites and wood-decay fungi. The amylose inclusion complex alone was as inhibitory as CWO against termites and also inhibits both water absorption and swelling in treated wood.

Thermal degradation and compositional changes of wood treated in a semi-industrial scale reactor in vacuum

Heat treatment is an eco-friendly and efficient way to improve the defective properties of woods, such as hygroscopic nature, lack of dimensional stability, and low resistance against biological degradation, and to produce a green and sustainable wood material for construction and buildings. The aim of this study is to investigate the thermal degradation of a hardwood (poplar, Populus nigra) and a softwood (fir, Abies pectinata) in a semi-industrial scale reactor in which a vacuum environment is adopted to intensify the thermal degradation process. Four different stages of thermal degradation during wood heat treatment are defined, based on the intensity of differential mass loss (DML). Meanwhile, a number of analyses on untreated and treated woods are performed to evaluate their thermal degradation characteristics and compositional change during treatment. The FTIR analysis clearly demonstrates the thermal degradation through dehydration, deacetylation, depolymerization, and condensation reactions during the heat treatment. In addition, the XRD analysis indicates an increase in relative crystallinity of cellulose. The correlation of devolatilization index (DI) with respect to mass loss of the two wood species is strongly characterized by linear distribution, which is able to provide a simple and useful tool in predicting mass loss of wood treated in wood industry.

Wood carbonization as a protective treatment on resistance to wood destroying fungi

Wood, as a typical natural material, is crucial to extend its service lifetime through preservative treatments against both biological and abiotic processes. Conventional wood protective treatment methods have major disadvantages by utilization of toxic chemicals. In this study, a physical treatment approach against wood biodeterioration was tested via the carbonization treatment technique. Both Pinus sylvestris and poplar were systematically prepared under different conditions of carbonization treatments to analyze the mechanism of carbonization protective treatment and then the performance against biodeterioration. Variations of nitrogen contents, thiamine (Vitamin B1), inorganic salts, pH, moisture content and the mass loss of wood were investigated after the different carbonization treatments. Indigenous wood decay fungi were destroyed by the carbonization treatments to decrease the opportunity for initiation of destruction from inside the wood. The results also illustrated that significant change of pH and moisture content in wood were also remarkable, but the wood nitrogen contents, thiamine (Vitamin B1) and inorganic salt were not influenced much after carbonization treatments. Since the indigenous microflora and also their favourable conditions for growth were eliminated or further restricted, further protection can be extended for the service life of wood against fungal colonization and biodeterioration under selective conditions.

Effects of accelerated aging treatment on the microstructure and mechanics of wood-resin interphase

AbstractPlywood panels prepared from loblolly pine with cured phenol resin (PF) and urea-formaldehyde resin (UF) were submitted to accelerated aging and the microstructures and mechanics of wood-resin interphase were studied by nanoindentation (NI) and nanoscale dynamic mechanical analysis (Nano-DMA). The mass loss (ML) of wood, PF and UF resins were 3.4, 5.0 and 4.6% after aging treatment, respectively, and a large amount of microcracks were observed on the surface of wood and resins after aging treatment, which also affected the static mechanics of the cell walls far from the interphase region and the resins in the interphase region. The elastic modulus (Er) and hardness (H) values of the cell wall decreased by 7.2 and 9.5%, respectively, against the untreated control. The storage and loss modulus of the resins decreased significantly after aging treatment. The significant inconsistency in the mechanics, shrinkage and swelling properties of wood cell wall and resin in the interphase region after aging treatment resulted in a decrease of about 47 and 51% on the average bonding strength of the plywood made of PF and UF resins, respectively.

Study of thermal decomposition process and the reaction mechanism of the eucalyptus wood

The mass loss of eucalyptus wood was measured against time and temperature at four different heating rates (5, 10, 15, 20 °C/min), in nitrogen environment, through thermogravimetry analysis technique. These measurements revealed that the decomposition of wood samples occurred in three stages (dehydration stage, active stage and passive stage), and the maximum decomposition peak in DTG curve shifted towards higher temperature range with increase in heating rate. In addition, the decomposition kinetic parameters were determined by adopting two thermal kinetic methods viz. Flynn–Wall–Ozawa and modified Coats and Redfern. Further, from the master curves (generated through different values of g(α) and f(α)) and experimental curve obtained using the Criado method, the kinetic mechanism involved in the pyrolysis of the eucalyptus wood was commented.

Resistance of thermally modified ash (Fraxinus excelsior L.) wood under steam pressure against rot fungi, soil-inhabiting micro-organisms and termites

Thermal modification processes have been developed to increase the biological durability and dimensional stability of wood. The aim of this paper was to study the influence of ThermoWood® treatment intensity on improvement of wood decay resistance against soil-inhabiting micro-organisms, brown/white rots and termite exposures. All of the tests were carried out in the laboratory with two different complementary research materials. The main research material consisted of ash (Fraxinus excelsior L.) wood thermally modified at temperatures of 170, 200, 215 and 228 °C. The reference materials were untreated ash and beech wood for decay resistance tests, untreated ash wood for soil bed tests and untreated ash, beech and pine wood for termite resistance tests. An agar block test was used to determine the resistance to two brown-rot and two white-rot fungi according to CEN/TS 15083-1 directives. Durability against soil-inhabiting micro-organisms was determined following the CEN/TS 15083-2 directives, by measuring the weight loss, modulus of elasticity (MOE) and modulus of rupture (MOR) after incubation periods of 24, 32 and 90 weeks. Finally, Reticulitermes santonensis species was used for determining the termite attack resistance by non-choice screening tests, with a size sample adjustment according to EN 117 standard directives on control samples and on samples which have previously been exposed to soil bed test. Thermal modification increased the biological durability of all samples. However, high thermal modification temperature above 215 °C, represented by a wood mass loss (ML%) due to thermal degradation of 20%, was needed to reach resistance against decay comparable with the durability classes of ‘‘durable’’ or ‘‘very durable’’ in the soil bed test. The brown-rot and white-rot tests gave slightly better durability classes than the soil bed test. Whatever the heat treatment conditions are, thermally modified ash wood was not efficient against termite attack neither before nor after soft rot degradation.

Study on chemical oxidation of heat treated lignocellulosic biomass under oxygen exposure by STA-DSC-FTIR analysis

Heat treatment helps enhance some properties of raw biomass by improving its decay resistance, its dimensional stability, increasing energy density and reducing transport costs of biomass. During storage period, many industrial sites undergo fires caused by self-ignition of torrefied or carbonized biomass. The main objective of this work was to study the chemical behavior of heat treated wood under oxygen exposure. Softwood and hardwood species have been thermally treated under a nitrogen atmosphere at different treatment conditions intensities. Sample mass and heat flow have been measured during the process to observe the temperature, time and air flow influence on reaction mechanisms of heat treated wood. The oxidation process and heat flux have been evaluated in addition. Results showed that reaction heat flows used for the treatment were correlated with temperature and time of thermal degradation of both examined wood species, as well as wood mass loss, respectively. However, hardwood (beech) seems to be more sensitive to thermal degradation and oxidation than softwood (silver fir) species. In addition, differential scanning calorimetry exothermic peak and wood mass gain were observed during oxygen exposure. In fact, this phenomenon was more pronounced for degradation carried out at high temperatures and times and it tends to be correlated with the elemental composition of wood. The main evolved products of heat treated wood were identified as water (H2O), carbon monoxide (CO) and carbon dioxide (CO2).

Wood decomposition by microbes and macroinvertebrates, and soil CO2 efflux vary in response to throughfall reduction and fertilization in a loblolly pine (Pinus taeda L.) plantation

Climate and nutrient availability modify the rate of carbon loss from soil and detrital pools in forest ecosystems. In a managed loblolly pine (Pinus taeda L.) plantation, we examined how reduced throughfall and fertilization affected wood decomposition and soil CO2 efflux. For ∼1.5years, soil CO2 efflux and the mass loss of Pinus wood sticks were examined in relation to soil temperature and moisture and the accumulation of soil NH4+ and NO3− for a factorial combination of two treatments: a 30% throughfall reduction (TR) treatment, fertilization with nutrient additions typical for this plantation type (224kg/ha N, 64kg/ha P and 67kg/ha K), and a combined treatment. Wood mass loss was estimated separately for substrates affected by only microbes and those with visual signs (e.g. tunnels) of macroinvertebrate consumption. For the 426days of the experiment, wood sticks decomposed only by microbes lost 3–6% of their mass while those also tunneled by macroinvertebrates lost 35–45% of their mass. By the end of the study macroinvertebrates had tunneled into 54% of all sticks across treatments. Because of macroinvertebrates, fertilization increased wood decomposition overall, despite significantly lower decomposition occurring in fertilized plots for sticks only decomposed by microbes. The TR treatment decreased wood decomposition but there was an interaction with location, where inhibition occurred near trees and under throughfall excluders but not at the midpoint between two planted rows. Wood sticks placed inside a collar used to measure soil CO2 efflux also decomposed significantly slower than all other locations. Soil CO2 efflux was inhibited by fertilization, primarily in August when temperatures were at the annual maximum. The depressed soil CO2 efflux from fertilization may have been the result of increased N availability, as fertilization stimulated NO3− production. The main effect of TR on soil CO2 efflux or N availability was not significant, but the TR effect on soil CO2 efflux interacted with time, reflecting generally lower efflux on different dates relative to non-TR treatments. These results suggest ecosystem C loss from soil CO2 efflux was relatively insensitive to throughfall reduction, but wood decomposition was sensitive to both fertilization and lowered moisture availability. However for wood decomposition, the positive fertilization effect was dependent on macroinvertebrates, whose response to fertilization was the opposite to that of both microbes and soil CO2 efflux. Predicting the fate of woody detritus in loblolly pine plantations may require models that include the response of macroinvertebrates to climate and management.

Impact of a low pulsed electric field on the fungal degradation of wood in laboratory trials

Wood protection against fungal decay is mainly based on chemical protection. Nontoxic protection methods have become more important in Europe due to environmental concerns. A method using electric fields to inhibit wood decay by fungi has been investigated in laboratory trials and wood mass loss and moisture content after exposure to fungal attack were determined.The results show significantly reduced mass loss for wood samples exposed to a low pulsed electric field (LPEF), while wood samples connected to alternating and direct current displayed higher mass loss compared to LPEF. Changing the electrode material reduced the mass increase due to metal ion transfer into the wood samples for LPEF-exposed samples. The use of conductive polymer instead of metal electrodes and carbon fibers was preferable as no ions were transferred and the integrity of the material persisted. Decay of pre-exposed wood samples to white rot could be stopped or slowed down by means of LPEF.