FOYER SHOWING THE WOOD GRILLE. VIEW FACING NORTHWEST Camp ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

FOYER SHOWING THE WOOD GRILLE. VIEW FACING NORTHWEST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, U-Shaped Two-Bedroom Single-Family Type 6, Birch Circle, Elm Drive, Elm Circle, and Date Drive, Pearl City, Honolulu County, HI

49 CFR 178.603 - Drop test.

Code of Federal Regulations, 2010 CFR

2010-10-01

... drums, Plastic drums and Jerricans, Composite packagings which are in the shape of a drum Six—(three for... of natural wood, Plywood boxes, Reconstituted wood boxes, Fiberboard boxes, Plastic boxes, Steel or... Administrator. (c) Special preparation of test samples for the drop test. (1) Testing of plastic drums, plastic...

History of wood machining

Treesearch

Peter Koch

1967-01-01

The history of wood machining is closely tied to advanced in metallurgy and power sources. It has been strongly and continuously shaped by prevailing economic forces and the rise and decline of other contemporary industries. This paper sketches a few of the highlights, with emphasis on developments in North America.

Bacteria in decomposing wood and their interactions with wood-decay fungi.

PubMed

Johnston, Sarah R; Boddy, Lynne; Weightman, Andrew J

2016-11-01

The fungal community within dead wood has received considerable study, but far less attention has been paid to bacteria in the same habitat. Bacteria have long been known to inhabit decomposing wood, but much remains underexplored about their identity and ecology. Bacteria within the dead wood environment must interact with wood-decay fungi, but again, very little is known about the form this takes; there are indications of both antagonistic and beneficial interactions within this fungal microbiome. Fungi are hypothesised to play an important role in shaping bacterial communities in wood, and conversely, bacteria may affect wood-decay fungi in a variety of ways. This minireview considers what is currently known about bacteria in wood and their interactions with fungi, and proposes possible associations based on examples from other habitats. It aims to identify key knowledge gaps and pressing questions for future research. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Community assessment of tropical tree biomass: challenges and opportunities for REDD.

PubMed

Theilade, Ida; Rutishauser, Ervan; Poulsen, Michael K

2015-12-01

REDD+ programs rely on accurate forest carbon monitoring. Several REDD+ projects have recently shown that local communities can monitor above ground biomass as well as external professionals, but at lower costs. However, the precision and accuracy of carbon monitoring conducted by local communities have rarely been assessed in the tropics. The aim of this study was to investigate different sources of error in tree biomass measurements conducted by community monitors and determine the effect on biomass estimates. Furthermore, we explored the potential of local ecological knowledge to assess wood density and botanical identification of trees. Community monitors were able to measure tree DBH accurately, but some large errors were found in girth measurements of large and odd-shaped trees. Monitors with experience from the logging industry performed better than monitors without previous experience. Indeed, only experienced monitors were able to discriminate trees with low wood densities. Local ecological knowledge did not allow consistent tree identification across monitors. Future REDD+ programmes may benefit from the systematic training of local monitors in tree DBH measurement, with special attention given to large and odd-shaped trees. A better understanding of traditional classification systems and concepts is required for local tree identifications and wood density estimates to become useful in monitoring of biomass and tree diversity.

Comminution process to produce wood particles of uniform size and shape with disrupted grain structure from veneer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dooley, James H.; Lanning, David N.

Comminution process of wood veneer to produce wood particles, by feeding wood veneer in a direction of travel substantially normal to grain through a counter rotating pair of intermeshing arrays of cutting discs arrayed axially perpendicular to the direction of wood veneer travel, wherein the cutting discs have a uniform thickness (Td), to produce wood particles characterized by a length dimension (L) substantially equal to the Td and aligned substantially parallel to grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) aligned normal to W and L, wherein the W.times.H dimensions definemore » a pair of substantially parallel end surfaces with end checking between crosscut fibers.« less

Kickback risk of portable chainsaws while cutting wood of different properties: laboratory tests and deductions

PubMed Central

Dąbrowski, Andrzej

2015-01-01

Portable chainsaws are associated with substantial risk and can cause serious injury to operators, especially during kickback. This paper presents new results from research and analyses conducted regarding the impact between the different properties of wood on this occurrence. In an open area, such differences may include: wood species, humidity, temperature and the facing angle of the wood fibres in relation to the kerf and shape of the wood surface that comes in contact with the tip of the guide bar. This paper investigates chainsaw kickback including the research results on kickback and wood-cutting energy, saw chain speed and the efficiency of the chainsaw engine. It also presents conclusions drawn from the tests that can be useful for chainsaw users, showing the dependencies between the different properties of wood and the risk of injury. PMID:26694003

Multipass comminution process to produce precision wood particles of uniform size and shape with disrupted grain structure from wood chips

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dooley, James H; Lanning, David N

A process of comminution of wood chips (C) having a grain direction to produce a mixture of wood particles (P), wherein the wood chips are characterized by an average length dimension (L.sub.C) as measured substantially parallel to the grain, an average width dimension (W.sub.C) as measured normal to L.sub.C and aligned cross grain, and an average height dimension (H.sub.C) as measured normal to W.sub.C and L.sub.C, and wherein the comminution process comprises the step of feeding the wood chips in a direction of travel substantially randomly to the grain direction one or more times through a counter rotating pair ofmore » intermeshing arrays of cutting discs (D) arrayed axially perpendicular to the direction of wood chip travel.« less

77 FR 66662 - Generalized System of Preferences (GSP): Import Statistics Relating to Competitive Need Limitations

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-06

... exceeded will be effective July 1, 2013, unless the President grants a waiver before the exclusion goes... available in February 2013 on the Web site of the U.S. International Trade Commission at http://dataweb....10.05--Coniferous wood continuously shaped along any of its ends (Brazil) 7202.99.20--Calcium silicon...

Thinning effects on tree mortality and snag recruitment in western Oregon

Treesearch

Erich Kyle Dodson; Klaus J. Puettmann; Adrian Ares

2013-01-01

Tree mortality shapes forest structural development and the resulting dead wood provides habitat for many species. However, the eff ects of thinning on mortality and large snag recruitment have been variable and remain poorly understood. We examined thinning eff ects on tree mortality at eleven Density Management Study (DMS) sites in western Oregon. Th inning reduced...

Wotan’s Workshop: Military Experiments before World War II

DTIC Science & Technology

2013-06-27

photo: A column of mock tanks—with wood and canvas armor shapes mounted on light vehicles—participated in German military maneuvers in 1928. (Imperial...37mm antitank gun. The gunners called it a “ wood -o- meter” and claimed it could fire 400 splinters and 15 drops of turpentine per minute. Charles Gorry...ticipation in maneuvers. These surrogates, made of wood and canvas and mounted on cars or even on bicycles, were used in force-on-force maneuvers that

Comprehensive genetic dissection of wood properties in a widely-grown tropical tree: Eucalyptus

PubMed Central

2011-01-01

Background Eucalyptus is an important genus in industrial plantations throughout the world and is grown for use as timber, pulp, paper and charcoal. Several breeding programmes have been launched worldwide to concomitantly improve growth performance and wood properties (WPs). In this study, an interspecific cross between Eucalyptus urophylla and E. grandis was used to identify major genomic regions (Quantitative Trait Loci, QTL) controlling the variability of WPs. Results Linkage maps were generated for both parent species. A total of 117 QTLs were detected for a series of wood and end-use related traits, including chemical, technological, physical, mechanical and anatomical properties. The QTLs were mainly clustered into five linkage groups. In terms of distribution of QTL effects, our result agrees with the typical L-shape reported in most QTL studies, i.e. most WP QTLs had limited effects and only a few (13) had major effects (phenotypic variance explained > 15%). The co-locations of QTLs for different WPs as well as QTLs and candidate genes are discussed in terms of phenotypic correlations between traits, and of the function of the candidate genes. The major wood property QTL harbours a gene encoding a Cinnamoyl CoA reductase (CCR), a structural enzyme of the monolignol-specific biosynthesis pathway. Conclusions Given the number of traits analysed, this study provides a comprehensive understanding of the genetic architecture of wood properties in this Eucalyptus full-sib pedigree. At the dawn of Eucalyptus genome sequence, it will provide a framework to identify the nature of genes underlying these important quantitative traits. PMID:21651758

Juniper wood structure under the microscope.

PubMed

Bogolitsyn, Konstantin G; Zubov, Ivan N; Gusakova, Maria A; Chukhchin, Dmitry G; Krasikova, Anna A

2015-05-01

The investigations confirm the physicochemical nature of the structure and self-assembly of wood substance and endorse its application in plant species. The characteristic morphological features, ultra-microstructure, and submolecular structure of coniferous wood matrix using junipers as the representative tree were investigated by scanning electron (SEM) and atomic-force microscopy (AFM). Novel results on the specific composition and cell wall structure features of the common juniper (Juniperus Communis L.) were obtained. These data confirm the possibility of considering the wood substance as a nanobiocomposite. The cellulose nanofibrils (20-50 nm) and globular-shaped lignin-carbohydrate structures (diameter of 5-60 nm) form the base of such a nanobiocomposite.

Scene perception and the visual control of travel direction in navigating wood ants

PubMed Central

Collett, Thomas S.; Lent, David D.; Graham, Paul

2014-01-01

This review reflects a few of Mike Land's many and varied contributions to visual science. In it, we show for wood ants, as Mike has done for a variety of animals, including readers of this piece, what can be learnt from a detailed analysis of an animal's visually guided eye, head or body movements. In the case of wood ants, close examination of their body movements, as they follow visually guided routes, is starting to reveal how they perceive and respond to their visual world and negotiate a path within it. We describe first some of the mechanisms that underlie the visual control of their paths, emphasizing that vision is not the ant's only sense. In the second part, we discuss how remembered local shape-dependent and global shape-independent features of a visual scene may interact in guiding the ant's path. PMID:24395962

Dating furniture and coopered vessels without waney edge - Reconstructing historical wood-working in Austria with the help of dendrochronology.

PubMed

Klein, Andrea; Nemestothy, Sebastian; Kadnar, Julia; Grabner, Michael

In the present study, 208 furniture and 168 coopered vessels from three Austrian museums were examined. Dendrochronology was used to date objects and to extract further information such as the necessary time for seasoning, wood loss through wood-working and methods of construction. In most cases sampling was done by sanding the cross section and making digital photographs using a picture frame and measuring digitally. The dendrochronological dates of the sampled furniture range between 1524 and 1937. The group of furniture includes cupboards, chests, tables, benches, commodes and beds. In many cases furniture was artfully painted and sometimes even shows a painted year. With the help of dendrochronology it was proved that some objects had been painted for some time after construction, or had been over-painted. Most furniture, however, was painted immediately after completion. In this case, the seasoning and storage time of the boards and the wood loss due to shaping can be verified. As an average value, 14 years have passed between the dendrochronological date of the outermost ring and the painting. The time span includes time of seasoning and storage and the rings lost by wood-working. This leads, on the one hand to a short storage time of less than 10 years and on the other hand to very little wood loss due to manufacturing. Those boards being less shaped turned out to be back panels of cupboards, therefore they are recommended to be sampled for dating. Coopered vessels were dated between 1612 and 1940. There was evidence that staves were split and not sawn in many cases. The staves were often split out of the outermost part of the tree and hardly any wood was worked away which was proved by the close dendrochronological dates of the single staves of a vessel. Since there is a short time of storage and only little wood loss through wood-working, dating of objects without a waney edge becomes reasonable.

Evidence for biological shaping of hair ice

NASA Astrophysics Data System (ADS)

Hofmann, D.; Preuss, G.; Mätzler, C.

2015-07-01

An unusual ice type, called hair ice, grows on the surface of dead wood of broad-leaf trees at temperatures slightly below 0 °C. We describe this phenomenon and present physical, chemical, and biological investigations to gain insight in the properties and processes related to hair ice. Tests revealed that the biological activity of a winter-active fungus is required in the wood for enabling the growth of hair ice. We confirmed the fungus hypothesis originally suggested by Wegener (1918) by reproducing hair ice on wood samples. Treatment by heat and fungicide suppresses the formation of hair ice. Fruiting bodies of Asco- and Basidiomycota are identified on hair-ice-carrying wood. One species, Exidiopsis effusa (Ee), was present on all investigated samples. Both hair-ice-producing wood samples and those with killed fungus show essentially the same temperature variation, indicating that the heat produced by fungal metabolism is very small, that the freezing rate is not influenced by the fungus activity, and that ice segregation is the common mechanism of ice growth on the wood surface. The fungus plays the role of shaping the ice hairs and preventing them from recrystallisation. Melted hair ice indicates the presence of organic matter. Chemical analyses show a complex mixture of several thousand CHO(N,S) compounds similar to fulvic acids in dissolved organic matter (DOM). The evaluation reveals decomposed lignin as being the main constituent. Further work is needed to clarify its role in hair-ice growth and to identify the recrystallisation inhibitor.

Evidence for biological shaping of hair ice

NASA Astrophysics Data System (ADS)

Hofmann, D.; Preuss, G.; Mätzler, C.

2015-04-01

An unusual ice type, called hair ice, grows on the surface of dead wood of broad-leaf trees at temperatures slightly below 0 °C. We describe this phenomenon and present physical, chemical, and biological investigations to gain insight in the properties and processes related to hair ice. Tests revealed that the biological activity of a winter-active fungus is required in the wood for enabling the growth of hair ice. We confirmed the fungus hypothesis originally suggested by Wegener (1918) by reproducing hair ice on wood samples. Treatment by heat and fungicide, respectively, suppresses the formation of hair ice. Fruiting bodies of Asco- and Basidiomycota are identified on hair-ice carrying wood. One species, Exidiopsis effusa (Ee), has been present on all investigated samples. Both hair-ice producing wood samples and those with killed fungus show essentially the same temperature variation, indicating that the heat produced by fungal metabolism is very small, that the freezing rate is not influenced by the fungus activity and that ice segregation is the common mechanism of ice growth at the wood surface. The fungus plays the role of shaping the ice hairs and to prevent them from recrystallisation. Melted hair ice indicates the presence of organic matter. Chemical analyses show a complex mixture of several thousand CHO(N,S)-compounds similar to fulvic acids in dissolved organic matter (DOM). The evaluation reveals decomposed lignin as the main constituent. Further work is needed to clarify its role in hair-ice growth and to identify the recrystallisation inhibitor.

Recent advances in forest products research and development

Treesearch

Joseph E. Jakes

2016-01-01

Wood has always played an integral role in meeting our materials needs. The earliest evidence of woodworking dates back 1.5 million years to the modern human ancestor Homo erectus.1 Many characteristics that made wood a favorable material for our ancestors—relative abundance, ease of forming and shaping, exceptional strength-toweight ratio,...

Wood as inspiration for new stimuli-responsive structures and materials

Treesearch

Joseph E. Jakes; Nayomi Plaza-Rodriguez; Samuel L. Zelinka; Donald S. Stone; Sophie-Charlotte Gleber; Stefan Vogt

2014-01-01

Nature has often provided inspiration for new smart structures and materials. Recently, we showed a bundle of a few wood cells are moisture-activated torsional actuators that can reversibly twist multiple revolutions per centimeter of length. The bundles produce specific torque higher than that produced by electric motors and possess shape memory twist capabilities....

Stem Sinuosity of Loblolly Pine Seedlings as Influenced by Taproot Shape

Treesearch

Michael S. Murphy; Timothy B. Harrington

2004-01-01

Sinuous stem growth in loblolly pine (Pinus taeda L.) results in diminished potential for the utilization of wood products since these stems are difficult to mill and contain a higher percentage of compression wood. In this study, 90 full-sibling loblolly pine seedlings (30 seedlings from each of 3 families) were planted with 5 taproot configurations...

Taper of wood poles

Treesearch

Billy Bohannan; Hermann Habermann; Joan E. Lengel

1974-01-01

Round wood pole use has changed without accompanying advancement in engineering design data. Previous pole design was based on the assumption that maximum stress occurred at the groundline but, with the larger poles that are now being used, maximum stress may occur along the pole length. For accurate engineering analysis the shape or taper of a pole must be known. Both...

Plane stress analysis of wood members using isoparametric finite elements, a computer program

Treesearch

Gary D. Gerhardt

1983-01-01

A finite element program is presented which computes displacements, strains, and stresses in wood members of arbitrary shape which are subjected to plane strain/stressloading conditions. This report extends a program developed by R. L. Taylor in 1977, by adding both the cubic isoparametric finite element and the capability to analyze nonisotropic materials. The...

Comminution process to produce precision wood particles of uniform size and shape with disrupted grain structure from wood chips

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dooley, James H; Lanning, David N

A process of comminution of wood chips (C) having a grain direction to produce a mixture of wood particles (P), wherein the wood chips are characterized by an average length dimension (L.sub.C) as measured substantially parallel to the grain, an average width dimension (W.sub.C) as measured normal to L.sub.C and aligned cross grain, and an average height dimension (H.sub.C) as measured normal to W.sub.C and L.sub.C, and wherein the comminution process comprises the step of feeding the wood chips in a direction of travel substantially randomly to the grain direction through a counter rotating pair of intermeshing arrays of cuttingmore » discs (D) arrayed axially perpendicular to the direction of wood chip travel, wherein the cutting discs have a uniform thickness (T.sub.D), and wherein at least one of L.sub.C, W.sub.C, and H.sub.C is greater than T.sub.D.« less

When navigating wood ants use the centre of mass of a shape to extract directional information from a panoramic skyline.

PubMed

Woodgate, Joseph L; Buehlmann, Cornelia; Collett, Thomas S

2016-06-01

Bees and ants can control their direction of travel within a familiar landscape using the information available in the surrounding visual scene. To learn more about the visual cues that contribute to this directional control, we have examined how wood ants obtain direction from a single shape that is presented in an otherwise uniform panorama. Earlier experiments revealed that when an ant's goal is aligned with a point within a prominent shape, the ant is guided by a global property of the shape: it learns the relative areas of the shape that lie to its left and right when facing the goal and sets its path by keeping the proportions at the memorised value. This strategy cannot be applied when the direction of the goal lies outside the shape. To see whether a different global feature of the shape might guide ants under these conditions, we trained ants to follow a direction to a point outside a single shape and then analysed their direction of travel when they were presented with different shapes. The tests indicate that ants learn the retinal position of the centre of mass of the training shape when facing the goal and can then guide themselves by placing the centre of mass of training and test shapes in this learnt position. © 2016. Published by The Company of Biologists Ltd.

CosmoBon for studying wood formation under exotic gravitational environment for future space agriculture

NASA Astrophysics Data System (ADS)

Tomita-Yokotani, Kaori; Baba, Keiichi; Suzuki, Toshisada; Funada, Ryo; Nakamura, Teruko; Hashimoto, Hirofumi; Yamashita, Masamichi; Cosmobon, Jstwg

We are proposing to raise woody plants in space for several applications and plant science. Japanese flowering cherry tree is one of a candidate for these studies. Mechanism behind sensing gravity and controlling shape of tree has been studied quite extensively. Even molecular mechanism for the response of plant against gravity has been investigated quite intensively for various species, woody plants are left behind. Morphology of woody branch growth is different from that of stem growth in herbs. Morphology in tree is strongly dominated by the secondary xylem formation. Nobody knows the tree shape grown under the space environment. If whole tree could be brought up to space as research materials, it might provide important scientific knowledge. Furthermore, trees produce excess oxygen, wooden materials for living cabin, and provide biomass for cultivating mushroom and insect as for the space agriculture. Excellent tree shapes which would be deeply related to wood formation improve quality of life under stressful environment in outer space. The serious problem would be their size. Bonsai is one of the Japanese traditional arts. We can study secondly xylem formation, wood formation, under exotic gravitational environment using Bonsai. "CosmoBon" is the small tree Bonsai for our space experiment. It has been recognized that the reaction wood in CosmoBon is formed similar to natural trees. Our goal is to examine feasibility to grow various species of trees in space as bioresource for space agriculture.

Hygromorphic characterization of softwood under high resolution X-ray tomography for hygrothermal simulation

NASA Astrophysics Data System (ADS)

El Hachem, Chady; Abahri, Kamilia; Vicente, Jérôme; Bennacer, Rachid; Belarbi, Rafik

2018-03-01

Because of their complex hygromorphic shape, microstructural study of wooden materials behavior has recently been the point of interest of researchers. The purpose of this study, in a first part, consists in characterizing by high resolution X-ray tomography the microstructural properties of spruce wood. In a second part, the subresulting geometrical parameters will be incorporated when evaluating the wooden hygrothermal transfers behavior. To do so, volume reconstructions of 3 Dimensional images (3D), obtained with a voxel size of 0.5 μm were achieved. The post-treatment of the corresponding volumes has given access to averages and standard deviations of lumens' diameters and cell walls' thicknesses. These results were performed for both early wood and latewood. Further, a segmentation approach for individualizing wood lumens was developed, which presents an important challenge in understanding localized physical properties. In this context, 3D heat and mass transfers within the real reconstructed geometries took place in order to highlight the effect of wood directions on the equivalent conductivity and moisture diffusion coefficients. Results confirm that the softwood cellular structure has a critical impact on the reliability of the studied physical parameters.

Guidelines for estimating volume, biomass, and smoke production for piled slash.

Treesearch

Colin C. Hardy

1998-01-01

Guidelines in the form of a six-step approach are provided for estimating volumes, oven-dry mass, consumption, and particulate matter emissions for piled logging debris. Seven stylized pile shapes and their associated geometric volume formulae are used to estimate gross pile volumes. The gross volumes are then reduced to net wood volume by applying an appropriate wood-...

Comminution process to produce engineered wood particles of uniform size and shape with disrupted grain structure from veneer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dooley, James H; Lanning, David N

Comminution process of wood veneer to produce wood particles, by feeding wood veneer in a direction of travel substantially normal to grain through a counter rotating pair of intermeshing arrays of cutting discs arrayed axially perpendicular to the direction of veneer travel, wherein the cutting discs have a uniform thickness (Td), to produce wood particles characterized by a length dimension (L) substantially equal to the Td and aligned substantially parallel to grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) substantially equal to the veneer thickness (Tv) and aligned normal to Wmore » and L, wherein the W.times.H dimensions define a pair of substantially parallel end surfaces with end checking between crosscut fibers.« less

Delignified and Densified Cellulose Bulk Materials with Excellent Tensile Properties for Sustainable Engineering.

PubMed

Frey, Marion; Widner, Daniel; Segmehl, Jana S; Casdorff, Kirstin; Keplinger, Tobias; Burgert, Ingo

2018-02-07

Today's materials research aims at excellent mechanical performance in combination with advanced functionality. In this regard, great progress has been made in tailoring the materials by assembly processes in bottom-up approaches. In the field of wood-derived materials, nanocellulose research has gained increasing attention, and materials with advanced properties were developed. However, there are still unresolved issues concerning upscaling for large-scale applications. Alternatively, the sophisticated hierarchical scaffold of wood can be utilized in a top-down approach to upscale functionalization, and one can profit at the same time from its renewable nature, CO 2 storing capacity, light weight, and good mechanical performance. Nevertheless, for bulk wood materials, a wider multipurpose industrial use is so far impeded by concerns regarding durability, natural heterogeneity as well as limitations in terms of functionalization, processing, and shaping. Here, we present a novel cellulose bulk material concept based on delignification and densification of wood resulting in a high-performance material. A delignification process using hydrogen peroxide and acetic acid was optimized to delignify the entire bulk wooden blocks and to retain the highly beneficial structural directionality of wood. In a subsequent step, these cellulosic blocks were densified in a process combining compression and lateral shear to gain a very compact cellulosic material with entangled fibers while retaining unidirectional fiber orientation. The cellulose bulk materials obtained by different densification protocols were structurally, chemically, and mechanically characterized revealing superior tensile properties compared to native wood. Furthermore, after delignification, the cellulose bulk material can be easily formed into different shapes, and the delignification facilitates functionalization of the bioscaffold.

Cellulose-hemicellulose interaction in wood secondary cell-wall

NASA Astrophysics Data System (ADS)

Zhang, Ning; Li, Shi; Xiong, Liming; Hong, Yu; Chen, Youping

2015-12-01

The wood cell wall features a tough and relatively rigid fiber reinforced composite structure. It acts as a pressure vessel, offering protection against mechanical stress. Cellulose microfibrils, hemicellulose and amorphous lignin are the three major components of wood. The structure of secondary cell wall could be imagined as the same as reinforced concrete, in which cellulose microfibrils acts as reinforcing steel bar and hemicellulose-lignin matrices act as the concrete. Therefore, the interface between cellulose and hemicellulose/lignin plays a significant role in determine the mechanical behavior of wood secondary cell wall. To this end, we present a molecular dynamics (MD) simulation study attempting to quantify the strength of the interface between cellulose microfibrils and hemicellulose. Since hemicellulose binds with adjacent cellulose microfibrils in various patterns, the atomistic models of hemicellulose-cellulose composites with three typical binding modes, i.e. bridge, loop and random binding modes are constructed. The effect of the shape of hemicellulose chain on the strength of hemicellulose-cellulose composites under shear loadings is investigated. The contact area as well as hydrogen bonds between cellulose and hemicellulose, together with the covalent bonds in backbone of hemicellulose chain are found to be the controlling parameters which determine the strength of the interfaces in the composite system. For the bridge binding model, the effect of shear loading direction on the strength of the cellulose material is also studied. The obtained results suggest that the shear strength of wood-inspired engineering composites can be optimized through maximizing the formations of the contributing hydrogen bonds between cellulose and hemicellulose.

Desorption isotherms of heavy (AZOBE, EBONY) and light heavyweight tropical woods (IROKO, SAPELLI) of Cameroon

NASA Astrophysics Data System (ADS)

Nsouandélé, J. L.; Tamba, J. G.; Bonoma, B.

2018-04-01

This work is centered on the study of the desorption isotherms of heavy (Azobe, Ebony) and heavyweight (Iroko, Sapelli) tropical woods, which contribute in the determination of drying and storage of tropical plank woods. Desorption isotherms of tropical woods were experimentally determined under different temperatures in this study using the gravimetric method. The determination of Henderson's model isotherms parameters of desorption were obtained for temperatures of 20 °C, 30 °C, 40 °C, and 50 °C. The mean relative deviation between theoretical and experimental moisture contents was calculated and fitted well with the desorption models of tropical woods. We noticed that Henderson models fitted much better with experimental ones for 95% of relative humidity. The sigmoid shapes of results are satisfactory. Hysteresis phenomenon was observed for desorption isotherms of heavy (Azobe, Ebony) and heavyweight (Iroko, Sapelli) tropical woods. Results showed the difference between the stability and use of heavy and heavyweight tropical wood. These results help in the estimation of water content at equilibrium of tropical woods in relative humidity from experimented ones. Hygroscopic equilibrium humidity of heavy tropical woods varied between 0% and 50% while those of heavyweight varied between 0% and 25%. Therefore, these woods can be used in an opened environment; woodwork and decoration.

Energy and exergy analysis of cookstove by using Cedrus deodara (deodar wood) and saccharum officinarum (sugar cane) waste

NASA Astrophysics Data System (ADS)

Chouhan, A. P. Singh; Yaseen, S.; Pruthi, A.

2017-07-01

Deodar (Cedrus deodara) wood collected from the Kashmir region in India. This study is focused on energy and exergy analysis of cook stove by using deodar wood, demand of a cookstove is higher in rural areas. In ancient time U-shaped and three stone cook stove was used, but they emitted greenhouse gases CO and CO2 in the environment and these toxic emissions are also dangerous for human being and the environment. Sampada model cook stove used for the analysis of energy an exergy by using water boiling test with using deodar wood and bagasse samples and a mixture of wood and bagasse also used. Wood and bagasse characterized for the ultimate, proximate, calorific value before the water boiling test of the cookstove. Results carried out that the efficiency of cook stove with deodar wood was 33.33 % and exergy calculated 2.1 % and energy efficiency and energy efficiency by using bagasse were 23.23 % and 0.43 %, respectively, and wood and bagasse mixture ratio given energy and exergy efficiencies for ratios 75:25 is the best ratio of energy production. These results indicated that deodar wood is more stable because thermal stability of wood is greater than bagasse. Deodar is a suitable source for the combustion purposes of higher energy production.

Phylogeny and adaptation shape the teeth of insular mice

PubMed Central

Ledevin, Ronan; Chevret, Pascale; Ganem, Guila; Britton-Davidian, Janice; Hardouin, Emilie A.; Chapuis, Jean-Louis; Pisanu, Benoit; da Luz Mathias, Maria; Schlager, Stefan; Auffray, Jean-Christophe; Renaud, Sabrina

2016-01-01

By accompanying human travels since prehistorical times, the house mouse dispersed widely throughout the world, and colonized many islands. The origin of the travellers determined the phylogenetic source of the insular mice, which encountered diverse ecological and environmental conditions on the various islands. Insular mice are thus an exceptional model to disentangle the relative role of phylogeny, ecology and climate in evolution. Molar shape is known to vary according to phylogeny and to respond to adaptation. Using for the first time a three-dimensional geometric morphometric approach, compared with a classical two-dimensional quantification, the relative effects of size variation, phylogeny, climate and ecology were investigated on molar shape diversity across a variety of islands. Phylogeny emerged as the factor of prime importance in shaping the molar. Changes in competition level, mostly driven by the presence or absence of the wood mouse on the different islands, appeared as the second most important effect. Climate and size differences accounted for slight shape variation. This evidences a balanced role of random differentiation related to history of colonization, and of adaptation possibly related to resource exploitation. PMID:26842576

Phylogeny and adaptation shape the teeth of insular mice.

PubMed

Ledevin, Ronan; Chevret, Pascale; Ganem, Guila; Britton-Davidian, Janice; Hardouin, Emilie A; Chapuis, Jean-Louis; Pisanu, Benoit; da Luz Mathias, Maria; Schlager, Stefan; Auffray, Jean-Christophe; Renaud, Sabrina

2016-02-10

By accompanying human travels since prehistorical times, the house mouse dispersed widely throughout the world, and colonized many islands. The origin of the travellers determined the phylogenetic source of the insular mice, which encountered diverse ecological and environmental conditions on the various islands. Insular mice are thus an exceptional model to disentangle the relative role of phylogeny, ecology and climate in evolution. Molar shape is known to vary according to phylogeny and to respond to adaptation. Using for the first time a three-dimensional geometric morphometric approach, compared with a classical two-dimensional quantification, the relative effects of size variation, phylogeny, climate and ecology were investigated on molar shape diversity across a variety of islands. Phylogeny emerged as the factor of prime importance in shaping the molar. Changes in competition level, mostly driven by the presence or absence of the wood mouse on the different islands, appeared as the second most important effect. Climate and size differences accounted for slight shape variation. This evidences a balanced role of random differentiation related to history of colonization, and of adaptation possibly related to resource exploitation. © 2016 The Author(s).

The Piney Woods School: An Exploration of the Historically Black Boarding School Experience in Shaping Student Achievement, Cultural Esteem, and Collegiate Integration

ERIC Educational Resources Information Center

Alexander-Snow, Mia

2011-01-01

This qualitative case study explores the cultural impact the Piney Woods School, a historically Black independent boarding school, had on the social and academic experiences of four of its graduates in attendance at two traditionally White universities. The article discusses the collegiate experiences of four students: Samantha, Ira, Tony, and…

Estimates of downed woody debris decay class transitions for forests across the eastern United States

Treesearch

Matthew B. Russell; Christopher W. Woodall; Shawn Fraver; Anthony W. D' Amato

2013-01-01

Large-scale inventories of downed woody debris (DWD; downed dead wood of a minimum size) often record decay status by assigning pieces to classes of decay according to their visual/structural attributes (e.g., presence of branches, log shape, and texture and color of wood). DWD decay classes are not only essential for estimating current DWD biomass and carbon stocks,...

Comminution process to produce precision wood particles of uniform size and shape with disrupted grain structure from wood chips

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dooley, James H.; Lanning, David N.

A process of comminution of wood chips (C) having a grain direction to produce a mixture of wood particles (P), wherein the wood chips are characterized by an average length dimension (L.sub.C) as measured substantially parallel to the grain, an average width dimension (W.sub.C) as measured normal to L.sub.C and aligned cross grain, and an average height dimension (H.sub.C) as measured normal to W.sub.C and L.sub.C, wherein W.sub.C>L.sub.C, and wherein the comminution process comprises the step of feeding the wood chips in a direction of travel substantially randomly to the grain direction through a counter rotating pair of intermeshing arraysmore » of cutting discs (D) arrayed axially perpendicular to the direction of wood chip travel, wherein the cutting discs have a uniform thickness (T.sub.D), and wherein at least one of L.sub.C, W.sub.C, and H.sub.C is less than T.sub.D.« less

Exploitation of Full-Waveform LiDAR to Characterize / Exploit Under Canopy Targets - Foliage Penetration (FOPEN)

DTIC Science & Technology

2015-09-28

Figure 3 USACE ERDC mobile measurement system with Riegl VZ‐400  laser  scanner (a) and OSU GPSVan  with targets (b...five target  materials (red: retro reflective, blue: wood, cyan: fluffy plastic, yellow: cardboard, and black:  painted   wood...and black:  painted  wood) ........................ 28  Figure 21 Waveforms shapes of in the three classes

Wood crib fire free burning test in ISO room

NASA Astrophysics Data System (ADS)

Qiang, Xu; Griffin, Greg; Bradbury, Glenn; Dowling, Vince

2006-04-01

In the research of application potential of water mist fire suppression system for fire fighting in train luggage carriage, a series of experiments were conducted in ISO room on wood crib fire with and without water mist actuation. The results of free burn test without water mist suppression are used as reference in evaluating the efficiency of water mist suppression system. As part of the free burn test, several tests have been done under the hood of ISO room to calibrate the size of the crib fire and these tests can also be used in analyzing the wall effect in room fire hazard. In these free burning experiments, wood cribs of four sizes under the hood were tested. The temperature of crib fire, heat flux around the fire, gas concentration in hood of ISO room were measured in the experiments and two sets of thermal imaging system were used to get the temperature distribution and the typical shape of the free burning flames. From the experiments, the radiation intensity in specific positions around the fire, the effective heat of combustion, mass loss, oxygen consumption rate for different sizes of fire, typical structure of the flame and self extinguishment time was obtained for each crib size.

Explosive Loading of Metals and Related Topics

DTIC Science & Technology

1986-05-01

Griffiths, "A U. K. Note on the History of Shaped Charges,• Royal Armament Research and Development Establishment Report, August 1983, presented...1925. 20. R. W. Wood, •optical and Physical Effects of High Explosives,• Proceedings of .the Royal Society (London), Vol. 157A, 1936, pp. 249-261...correctly analyzes geometric configurations in this report such as the Jelly Roll, the Dagwood and similar explosive-metal multilayer arrangements. In

Spin singlet and spin triplet pairing correlations on shape evolution in s d -shell N =Z Nuclei

NASA Astrophysics Data System (ADS)

Ha, Eunja; Cheoun, Myung-Ki; Sagawa, H.

2018-02-01

We study the shape evolution of N =Z nuclei 24Mg,28Si, and 32S in the axially symmetric deformed Woods-Saxon model, taking into account both T =0 and T =1 pairing interactions. We find the coexistence of T =0 and T =1 superfluidity phases in the large deformation region | β2|>0.3 in these three nuclei. The interplay between the two pairing interactions has an important effect on determining the deformation of the ground states in these nuclei. The self-energy contributions from the pairing correlations to the single particle (s.p.) energies are also examined.

The Earliest Evidence of Holometabolan Insect Pupation in Conifer Wood

PubMed Central

Tapanila, Leif; Roberts, Eric M.

2012-01-01

Background The pre-Jurassic record of terrestrial wood borings is poorly resolved, despite body fossil evidence of insect diversification among xylophilic clades starting in the late Paleozoic. Detailed analysis of borings in petrified wood provides direct evidence of wood utilization by invertebrate animals, which typically comprises feeding behaviors. Methodology/Principal Findings We describe a U-shaped boring in petrified wood from the Late Triassic Chinle Formation of southern Utah that demonstrates a strong linkage between insect ontogeny and conifer wood resources. Xylokrypta durossi new ichnogenus and ichnospecies is a large excavation in wood that is backfilled with partially digested xylem, creating a secluded chamber. The tracemaker exited the chamber by way of a small vertical shaft. This sequence of behaviors is most consistent with the entrance of a larva followed by pupal quiescence and adult emergence — hallmarks of holometabolous insect ontogeny. Among the known body fossil record of Triassic insects, cupedid beetles (Coleoptera: Archostemata) are deemed the most plausible tracemakers of Xylokrypta, based on their body size and modern xylobiotic lifestyle. Conclusions/Significance This oldest record of pupation in fossil wood provides an alternative interpretation to borings once regarded as evidence for Triassic bees. Instead Xylokrypta suggests that early archostematan beetles were leaders in exploiting wood substrates well before modern clades of xylophages arose in the late Mesozoic. PMID:22355387

Detail of pier structure and wood fenders of Facility No. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Detail of pier structure and wood fenders of Facility No. B-1, showing floats in foreground and bollards on pier, view facing east - U.S. Naval Base, Pearl Harbor, South Quay Wall & Repair Wharf, L-shaped portion of quay walls starting at east side of mouth of Dry Dock No. 1, continuing along ocean side of Sixth Street, adjacent to Pier B-2, Pearl City, Honolulu County, HI

Drivers of Macrofungi Community Structure Differ between Soil and Rotten-Wood Substrates in a Temperate Mountain Forest in China

PubMed Central

Chen, Yun; Svenning, Jens-Christian; Wang, Xueying; Cao, Ruofan; Yuan, Zhiliang; Ye, Yongzhong

2018-01-01

The effects of environmental and dispersal processes on macrofungi community assembly remain unclear. Further, it is not well understood if community assembly differs for different functional guilds of macrofungi, e.g., soil and rotten-wood macrofungi. In this study, using 2433 macrofungi sporocarps belonging to 217 species located within a forest dynamics plot in temperate mountain forest (China), we examined the explanatory power of topography, spatial eigenvectors (representing unknown spatial processes, e.g., dispersal), plant community, and light availability for local spatial variation in the macrofungi community through variance partitioning and partial least squares path modeling. We found spatial eigenvectors and light as the most important factors for explaining species richness and composition of macrofungi. Light was negatively correlated with species richness of macrofungi. Furthermore, species richness and composition of soil macrofungi were best explained by light, and species richness and composition of rotten-wood macrofungi were best explained by spatial eigenvectors. Woody plant community structure was not an important factor for species richness and composition of macrofungi. Our findings suggest that spatial processes, perhaps dispersal limitation, and light availability were the most important factors affecting macrofungi community in temperate deciduous broad-leaved forest. Major differences in influencing factors between soil and rotten-wood macrofungi were observed, with light as the major driver for soil macrofungi and unknown spatial processes as the major driver for rotten-wood macrofungi. These findings shed new light to the processes shaping community assembly in macrofungi in temperate deciduous broad-leaved forest and point to the potential importance of both intrinsic dynamics, such as dispersal, and external forcing, such as forest dynamics, via its effect on light availability. PMID:29410660

Effect of Steam Activation on Development of Light Weight Biomorphic Porous SiC from Pine Wood Precursor

NASA Astrophysics Data System (ADS)

Manocha, Satish M.; Patel, Hemang; Manocha, L. M.

2013-02-01

Biomorphic SiC materials with tailor-made microstructure and properties similar to ceramic materials manufactured by conventional method are a new class of materials derived from natural biopolymeric cellulose templates (wood). Porous silicon carbide (SiC) ceramics with wood-like microstructure have been prepared by carbothermal reduction of charcoal/silica composites at 1300-1600 °C in inert Ar atmosphere. The C/SiO2 composites were fabricated by infiltrating silica sol into porous activated biocarbon template. Silica in the charcoal/silica composite, preferentially in the cellular pores, was found to get transformed in forms of fibers and rods due to shrinkage during drying. The changes in the morphology of resulting porous SiC ceramics after heat treatment to 1600 °C, as well as the conversion mechanism of wood to activated carbon and then to porous SiC ceramic have been investigated using scanning electron microscope, x-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry. Activation of carbon prior to silica infiltration has been found to enhance conversion of charcoal to SiC. The pore structure is found to be uniform in these materials than in those made from as-such charcoal/silica composites. This provides a low-cost and eco-friendly route to advanced ceramic materials, with near-net shape potential.

AFRL’s HP3 60mm Powder Gun

DTIC Science & Technology

2012-08-08

reminiscent of wood -grain. It is unknown what effect the different construction techniques will have on the material’s suitability as a projectile...large plastic bar and mounts on the rear of the target plate are the interferometry probe holder (and probe). 11 Distribution Statement A. Approval...required to extrude the tapered boot through the tapering cone of the orifice plate, the breech pressure pulse shape (how long the high pressures are

Filling behaviour of wood plastic composites

NASA Astrophysics Data System (ADS)

Duretek, I.; Lucyshyn, T.; Holzer, C.

2017-01-01

Wood plastic composites (WPC) are a young generation of composites with rapidly growing usage within the plastics industry. The advantages are the availability and low price of the wood particles, the possibility of partially substituting the polymer in the mixture and sustainable use of the earth’s resources. The current WPC products on the market are to a large extent limited to extruded products. Nowadays there is a great interest in the market for consumer products in more use of WPC as an alternative to pure thermoplastics in injection moulding processes. This work presents the results of numerical simulation and experimental visualisation of the mould filling process in injection moulding of WPC. The 3D injection moulding simulations were done with the commercial software package Autodesk® Moldflow® Insight 2016 (AMI). The mould filling experiments were conducted with a box-shaped test part. In contrast to unfilled polymers the WPC has reduced melt elasticity so that the fountain flow often does not develop. This results in irregular flow front shapes in the moulded part, especially at high filler content.

Bacteroidales ectosymbionts of gut flagellates shape the nitrogen-fixing community in dry-wood termites

PubMed Central

Desai, Mahesh S; Brune, Andreas

2012-01-01

Although it is well documented that the lack of nitrogen in the diet of wood-feeding termites is compensated by the nitrogen-fixing capacity of their gut microbiota, the bacteria responsible for this activity are largely unknown. Here, we analyzed the diversity and expression of nitrogenase genes (homologs of nifH) in four species of dry-wood termites (Kalotermitidae), which thrive on a particularly nitrogen-poor resource. Although each species harbored a highly diverse suite of termite-specific homologs in their microliter-sized hindgut, only a core set related to nifH genes of Treponema and Azoarcus spp., ‘Azobacteroides pseudotrichonymphae', the first member of the Bacteroidales identified as a diazotroph, and termite-gut-specific anfH genes of hitherto unknown origin were preferentially expressed. Transcription patterns corroborated that the populations of active diazotrophs differ fundamentally between termite genera. Capillary-picked suspensions of the flagellates Devescovina arta and Snyderella tabogae revealed that their bacterial ectosymbionts each possess two paralogs of nifH, which apparently have been acquired consecutively during evolution of Bacteroidales, but only one of them (anfH) is actively expressed. Transcription patterns correlated neither with the molybdenum content of the diet nor with intestinal hydrogen concentrations, measured with microsensors. We propose that the nitrogen-fixing community in different dry-wood termites is shaped by the symbionts of their specific flagellate populations. Our findings suggest that the diazotrophic nature of ‘Armantifilum devescovinae' has an important role in the nitrogen metabolism of dry-wood termites and is the driving force of co-evolution with its flagellate host. PMID:22189498

Profiles in Renewable Energy: Case Studies of Successful Utility-Sector

Science.gov Websites

Shape of Renewable Energy Technologies Today Biomass Wood-Burning Plant Reduces Air Pollution Kettle Economical Altamont Pass Windplants U.S. Windpower, Inc. For More Information The Shape of Renewable Energy temperatures >175 degrees C), which rely on flashing the hot water to steam, and binary plants (for resource

Shaping-lathe headrig will stretch shrinking timber supply

Treesearch

J. Gengler; J.D. Saul

1975-01-01

The first commercial version of the shaping lathe headrig, designed to machine short hardwood or softwood logs into cants and flakes, was introduced to forest industry executives in September during a working demonstration at Stetson-Ross Machine Co., Seattle. Based on a concept provided by Dr. Peter Koch, chief wood scientist at the Southern Forest Experiment Station...

Rehabilitating agricultural streams in Australia with wood: a review.

PubMed

Lester, Rebecca E; Boulton, Andrew J

2008-08-01

Worldwide, the ecological condition of streams and rivers has been impaired by agricultural practices such as broadscale modification of catchments, high nutrient and sediment inputs, loss of riparian vegetation, and altered hydrology. Typical responses include channel incision, excessive sedimentation, declining water quality, and loss of in-stream habitat complexity and biodiversity. We review these impacts, focusing on the potential benefits and limitations of wood reintroduction as a transitional rehabilitation technique in these agricultural landscapes using Australian examples. In streams, wood plays key roles in shaping velocity and sedimentation profiles, forming pools, and strengthening banks. In the simplified channels typical of many agricultural streams, wood provides habitat for fauna, substrate for biofilms, and refuge from predators and flow extremes, and enhances in-stream diversity of fish and macroinvertebrates.Most previous restoration studies involving wood reintroduction have been in forested landscapes, but some results might be extrapolated to agricultural streams. In these studies, wood enhanced diversity of fish and macroinvertebrates, increased storage of organic material and sediment, and improved bed and bank stability. Failure to meet restoration objectives appeared most likely where channel incision was severe and in highly degraded environments. Methods for wood reintroduction have logistical advantages over many other restoration techniques, being relatively low cost and low maintenance. Wood reintroduction is a viable transitional restoration technique for agricultural landscapes likely to rapidly improve stream condition if sources of colonists are viable and water quality is suitable.

Evaluation of morphological and chemical aspects of different wood species by spectroscopy and thermal methods

NASA Astrophysics Data System (ADS)

Popescu, Maria-Cristina; Popescu, Carmen-Mihaela; Lisa, Gabriela; Sakata, Yusaku

2011-03-01

The aim of this study is to find the most convenient procedure to make an easy differentiation between various kinds of wood. The wood samples used were: fir (Acer alba), poplar (Populus tremula), lime (Tillia cordata), sycamore (Acer pseudoplatanus), sweet cherry (Prunus avium), hornbeam (Carpinus betulus), walnut (Juglans regia), beech (Fagus sylvatica), oak (Quercus robur). The methods of investigation used were FT-IR spectroscopy, X-ray diffraction and thermogravimetry. By FT-IR spectroscopy, was observed that the ratio values of lignin/carbohydrate IR bands for wood decreases with increasing the average wood density, showing a decrease in lignin content. Also, the calculated values of lignin percentage from the FT-IR spectra are in very good correlation with the values from literature. Following the deconvolution process of the X-ray diffraction patterns, it was found that the degree of crystallinity, the apparent lateral crystallite size, the proportion of crystallite interior chains and cellulose fraction tend to increase with increasing of the wood density. Thermal analysis is able to give information about degradation temperatures for the principal components of different wood samples. The shape of DTG curves depends on the wood species that cause the enlargement of the peaks or the maxima of the decomposition step varies at larger or smaller temperatures ranges. The temperatures and weight loss percentage are particular for each kind of wood. This study showed that analytical methods used have the potential to be important sources of information for a quick evaluation of the chemical composition of wood samples.

Wood industrial application for quality control using image processing

NASA Astrophysics Data System (ADS)

Ferreira, M. J. O.; Neves, J. A. C.

1994-11-01

This paper describes an application of image processing for the furniture industry. It uses an input data, images acquired directly from wood planks where defects were previously marked by an operator. A set of image processing algorithms separates and codes each defect and detects a polygonal approach of the line representing them. For such a purpose we developed a pattern classification algorithm and a new technique of segmenting defects by carving the convex hull of the binary shape representing each isolated defect.

Patterns in hydraulic architecture from roots to branches in six tropical tree species from cacao agroforestry and their relation to wood density and stem growth.

PubMed

Kotowska, Martyna M; Hertel, Dietrich; Rajab, Yasmin Abou; Barus, Henry; Schuldt, Bernhard

2015-01-01

For decades it has been assumed that the largest vessels are generally found in roots and that vessel size and corresponding sapwood area-specific hydraulic conductivity are acropetally decreasing toward the distal twigs. However, recent studies from the perhumid tropics revealed a hump-shaped vessel size distribution. Worldwide tropical perhumid forests are extensively replaced by agroforestry systems often using introduced species of various biogeographical and climatic origins. Nonetheless, it is unknown so far what kind of hydraulic architectural patterns are developed in those agroforestry tree species and which impact this exerts regarding important tree functional traits, such as stem growth, hydraulic efficiency and wood density (WD). We investigated wood anatomical and hydraulic properties of the root, stem and branch wood in Theobroma cacao and five common shade tree species in agroforestry systems on Sulawesi (Indonesia); three of these were strictly perhumid tree species, and the other three tree species are tolerating seasonal drought. The overall goal of our study was to relate these properties to stem growth and other tree functional traits such as foliar nitrogen content and sapwood to leaf area ratio. Our results confirmed a hump-shaped vessel size distribution in nearly all species. Drought-adapted species showed divergent patterns of hydraulic conductivity, vessel density, and relative vessel lumen area between root, stem and branch wood compared to wet forest species. Confirming findings from natural old-growth forests in the same region, WD showed no relationship to specific conductivity. Overall, aboveground growth performance was better predicted by specific hydraulic conductivity than by foliar traits and WD. Our study results suggest that future research on conceptual trade-offs of tree hydraulic architecture should consider biogeographical patterns underlining the importance of anatomical adaptation mechanisms to environment.

F-16 Low Altitude Navigation and Targeting Infrared System for Night (LANTIRN) and the Night Close Air Support (CAS) Mission

DTIC Science & Technology

1989-06-02

physical reference can be a natural feature, river bend, distinctly shaped wooded area, or lake. Artificial references such as colored smoke or...fluorescent ground panels can also be placed instead of, or as an aid to recognition of the natural feature.ដ> But, artificial references that are effective...Government Printin-gOffice, 1959. Central Intelligence Agenc7. National Intellignece Survey, East Germany, Section 23, Weather and Climate. Washington

Effect of cement/wood ratios and wood storage conditions on hydration temperature, hydration time, and compressive strength of wood-cement mixtures

Treesearch

Andy W.C. Lee; Zhongli Hong; Douglas R. Phillips; Chung-Yun Hse

1987-01-01

This study investigated the effect of cement/wood ratios and wood storage conditions on hydration temperature, hydration time, and compressive strength of wood-cement mixtures made from six wood species: southern pine, white oak, southern red oak, yellow-poplar, sweetgum, and hickory. Cement/wood ratios varied from 13/1 to 4/1. Wood storage conditions consisted of air-...

Engineering specification and system design for CAD/CAM of custom shoes: UMC project effort

NASA Technical Reports Server (NTRS)

Bao, Han P.

1990-01-01

Further experimentations were made to improve the design and fabrication techniques of the integrated sole. The sole design is shown to be related to the foot position requirements and the actual shape of the foot including presence of neurotropic ulcers or other infections. Factors for consideration were: heel pitch, balance line, and rigidity conditions of the foot. Machining considerations were also part of the design problem. Among these considerations, widths of each contour, tool motion, tool feed rate, depths of cut, and slopes of cut at the boundary were the key elements. The essential fabrication techniques evolved around the idea of machining a mold then, using quick-firm latex material, casting the sole through the mold. Two main mold materials were experimented with: plaster and wood. Plaster was very easy to machine and shape but could barely support the pressure in the hydraulic press required by the casting process. Wood was found to be quite effective in terms of relative cost, strength, and surface smoothness except for the problem of cutting against the fibers which could generate ragged surfaces. The programming efforts to convert the original dBase programs into C programs so that they could be executed on the SUN Computer at North Carolina State University are discussed.

Shape Optimization for Navier-Stokes Equations with Algebraic Turbulence Model: Numerical Analysis and Computation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haslinger, Jaroslav, E-mail: hasling@karlin.mff.cuni.cz; Stebel, Jan, E-mail: stebel@math.cas.cz

2011-04-15

We study the shape optimization problem for the paper machine headbox which distributes a mixture of water and wood fibers in the paper making process. The aim is to find a shape which a priori ensures the given velocity profile on the outlet part. The mathematical formulation leads to the optimal control problem in which the control variable is the shape of the domain representing the header, the state problem is represented by the generalized Navier-Stokes system with nontrivial boundary conditions. This paper deals with numerical aspects of the problem.

Shaping-lathe headrig yields solid and molded-flake hardwood products.

Treesearch

P. Koch; R.A. Caughey

1978-01-01

A shaping-lathe headrig, operated one shift daily, can be used to manufacture hardwood cants to be resawed into pallet shook, one-piece and dowel-laminated crossties, posts and rail, and other solid wood products in lengths from 6 to 9 feet. Residual flakes machined by the headrig supply a three-shift operation in which molded pallets and 4- by 8-foot sheets of...

shaping-lathe headrig yields solid and molded-flake hardwood products

Treesearch

Peter Koch; R.A. Caughey

1978-01-01

A shaping-lathe headrig, operated one shift daily, can be used to manufacture hardwood cants to be resawed into pallet shook, one-piece and dowel-laminated crossties, posts and rails, and other solid wood products in lengths from 6 to 9 feet. Residual flakes machined by the headrig supply a three-shift operation in which molded pallets and 4- by 8-foot sheets of...

New views on antidiarrheal effect of wood creosote: is wood creosote really a gastrointestinal antiseptic?

PubMed

Ataka, Koji; Ito, Masafumi; Shibata, Takashi

2005-12-01

Wood creosote, the principal ingredient in Seirogan, has a long history as a known gastrointestinal microbicidal agent. When administered orally, the intraluminal concentration of wood creosote is not sufficiently high to achieve this microbicidal effect. Through further animal tests, we have shown that antimotility and antisecretory actions are the principal antidiarrheal effects of wood creosote. Wood creosote inhibits intestinal secretion induced by enterotoxins by blocking the Cl(-) channel on the intestinal epithelium. Wood creosote also decreases intestinal motility accelerated by mechanical, chemical, or electrical stimulus by the inhibition of the Ca(2+) influx into the smooth muscle cells. In this overview, the antimotility and antisecretory effects of wood creosote are compared with those of loperamide. Wood creosote was observed to inhibit stimulated colonic motility, but not normal jejunal motility. Loperamide inhibits normal jejunal motility, but not stimulated colonic motility. Both wood creosote and loperamide inhibit intestinal secretion accelerated by acetylcholine. Wood creosote was found to have greater antisecretory effects in the colon than loperamide. Based upon these findings, we conclude that the antidiarrheal effects of wood creosote are due to both antisecretory activity in the intestine and antimotility in the colon, but not due to the microbicidal activity as previously thought. Wood creosote was found to have no effects on normal intestinal activity. These conclusions are supported by the results of a recent clinical study comparing wood creosote and loperamide, which concluded that wood creosote was more efficacious in relieving abdominal pain and comparable to loperamide in relieving diarrhea.

Extensive survey of molecules related to wood formation and gravity for space agriculture.

NASA Astrophysics Data System (ADS)

Motohashi, Kyohei; Tomita-Yokotani, Kaori; Baba, Keiichi; Furukawa, Jun; Sato, Seigo; Suzuki, Toshisada; Hashimoto, Hirofumi; Yamashita, Masamichi; Japanese Space Tree Working Group

Most, if not all, terrestrial subjects are under the influence of gravity. Since the gravitational force is proportional to the mass of subject, gravity is dominant for larger masses. The response of a plant against gravity is not an exception in this respect even it shows rather complicated features. For the angiosperm tree, its shape is determined by the forming tension wood, which induces more tensile stress in the xylem than in the normal wood. The mechanism of tension wood formation and its relevance to gravity have been extensively studied. Gibberellin is known to be responsible for this phenomenon in angiosperm tree, for example, the Japanese cherry tree, Prunus jamasakura. However, full understanding of the mechanisms has not yet been clarified. For an extensive survey of molecules related to tension wood formation, we induced an artificial tension wood formation and examined the tension wood formation by microscopic observations with double-staining. This enables the screening of really functional molecules in the space environment for future space agriculture. We demonstrated that Prunus incise is suitable for this research as a test material based on several reasons. We focused our attention in the region of the branch, i.e., the CosmoTree in CosmoBon, and established an experimental system to analyze the real functional factors of the tension wood. This study might ensure wood formation in a space environment and use woody plants as a material for space development. ("CosmoBon" is the Bonsai small tree for our space experiments. "CosmoTree" is a small branch/tree.)

Large wood dynamics and biophysical consequences for riparian forests: A comparison of an unconfined alluvial river in a temperate rainforest and a bedrock confined river in a semi-arid South African savanna.

NASA Astrophysics Data System (ADS)

Latterell, J. J.; Pettit, N. E.; Naiman, R. J.

2005-05-01

Large wood shapes the geomorphology and ecology of rivers. We determined the origin, distribution, and fate of large wood in two rivers from contrasting environments. The Queets is an unstable temperate, rainforest river running from the Olympic Mountains (USA) through a glacial valley with colossal trees. In most years, the channel erodes a variety of forested landforms which forms jams that sculpt habitats. Many are displaced in a few years. Remaining jams initiate landform development and forest renewal. Thus, wood is stockpiled in the floodplain where it may become buried. Channel movements recapture most logs within 50 years. In contrast, the Sabie is a perennial river running through a confined bedrock channel in a fire-prone semi-arid South African savanna. Riparian trees are relatively small and many sink in water. A recent flood (February 2000) devastated the riparian forest, introducing wood to the channel. Jams formed on toppled trees, transported logs, and bedrock outcrops. Many trees survived and resprouted. Jams facilitated the establishment of woody plant seedlings and the intrusion of fire into riparian areas. Sunken wood formed unique depositional features. The Queets and Sabie rivers are strikingly different systems. However, large wood appears to promote the renewal and development of complex riparian forests in both rivers.

Genetic and environmental modification of the mechanical properties of wood

NASA Astrophysics Data System (ADS)

Sederoff, R.; Allona, I.; Whetten, R.

1996-02-01

Wood is one of the nation's leading raw materials and is used for a wide variety of products, either directly as wood, or as derived materials in pulp and paper. Wood is a biological material and evolved to provide mechanical support and water transport to the early plants that conquered the land. Wood is a tissue that results from the differentiation and programmed cell death of cells that derive from a tissue known as the vascular cambium. The vascular cambium is a thin cylinder of undifferentiated tissue in plant stems and roots that gives rise to several different cell types. Cells that differentiate on the internal side of the cambium form xylem, a tissue composed in major part, of long thin cells that die leaving a network of interconnected cell walls that serve to transport water and to provide mechanical support for the woody plant. The shape and chemical composition of the cells in xylem are well suited for these functions. The structure of cells in xylem determines the mechanical properties of the wood because of the strength derived from the reinforced matrix of the wall. The hydrophobic phenolic surface of the inside of the cell walls is essential to maintain surface tension upon which water transport is based and to resist decay caused by microorganisms. The properties of wood derived from the function of xylem also determine its structural and chemical properties as wood and paper products. Therefore, the physical and chemical properties of wood and paper products also depend on the morphology and composition of the cells from which they are derived. Wood (xylem cell walls) is an anisotropic material, a composite of lignocellulose. It is a matrix of cellulose microfibrils, complexed with hemicelluloses, (carbohydrate polymers which contain sugars other than glucose, both pentoses and hexoses), embedded together in a phenolic matrix of lignin. The high tensile strength of wood in the longitudinal direction, is due to the structure of cellulose and the orientation of the cellulose microfibrils. Lignin provides the embedding matrix that imparts compressive strength and flexibility. The water conducting cells in xylem, the tracheids, are long thin cells, which become the fibers of paper when the lignin is removed from wood during the papermaking process. The length of the tracheids and the thickness of the walls have important effects on the properties of paper that is produced. The past two decades have marked a revolutionary period in biological sciences due to the development of gene splicing techniques. These methods have led to the directed engineering of organisms to develop new industrial products. The technology has been used to produce a wide variety of new pharmaceuticals and transgenic plants and animals. This technology is now also being applied to forest trees.

Shape Optimization for Navier-Stokes Equations with Algebraic Turbulence Model: Existence Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bulicek, Miroslav; Haslinger, Jaroslav; Malek, Josef

2009-10-15

We study a shape optimization problem for the paper machine headbox which distributes a mixture of water and wood fibers in the paper making process. The aim is to find a shape which a priori ensures the given velocity profile on the outlet part. The mathematical formulation leads to an optimal control problem in which the control variable is the shape of the domain representing the header, the state problem is represented by a generalized stationary Navier-Stokes system with nontrivial mixed boundary conditions. In this paper we prove the existence of solutions both to the generalized Navier-Stokes system and tomore » the shape optimization problem.« less

Evaluation of Binding Effects in Wood Flour Board Containing Ligno-Cellulose Nanofibers

PubMed Central

Kojima, Yoichi; Isa, Akiko; Kobori, Hikaru; Suzuki, Shigehiko; Ito, Hirokazu; Makise, Rie; Okamoto, Masaki

2014-01-01

Wood-based materials are used extensively in residual construction worldwide. Most of the adhesives used in wood-based materials are derived from fossil resources, and some are not environmentally friendly. This study explores nanofiber technology as an alternative to such adhesives. Previous studies have shown that the three-dimensional binding effects of cellulose nanofiber (CNF), when mixed with wood flour, can significantly improve the physical and mechanical properties of wood flour board. In this study, ligno-cellulose nanofibers (LCNF) were fabricated by wet disk milling of wood flour. Composite boards of wood flour and LCNF were produced to investigate the binding effect(s) of LCNF. The fabrication of LCNF by disk milling was simple and effective, and its incorporation into wood flour board significantly enhanced the physical and mechanical properties of the board. PMID:28788217

Health effects of residential wood smoke particles: the importance of combustion conditions and physicochemical particle properties

PubMed Central

Kocbach Bølling, Anette; Pagels, Joakim; Yttri, Karl Espen; Barregard, Lars; Sallsten, Gerd; Schwarze, Per E; Boman, Christoffer

2009-01-01

Background Residential wood combustion is now recognized as a major particle source in many developed countries, and the number of studies investigating the negative health effects associated with wood smoke exposure is currently increasing. The combustion appliances in use today provide highly variable combustion conditions resulting in large variations in the physicochemical characteristics of the emitted particles. These differences in physicochemical properties are likely to influence the biological effects induced by the wood smoke particles. Outline The focus of this review is to discuss the present knowledge on physicochemical properties of wood smoke particles from different combustion conditions in relation to wood smoke-induced health effects. In addition, the human wood smoke exposure in developed countries is explored in order to identify the particle characteristics that are relevant for experimental studies of wood smoke-induced health effects. Finally, recent experimental studies regarding wood smoke exposure are discussed with respect to the applied combustion conditions and particle properties. Conclusion Overall, the reviewed literature regarding the physicochemical properties of wood smoke particles provides a relatively clear picture of how these properties vary with the combustion conditions, whereas particle emissions from specific classes of combustion appliances are less well characterised. The major gaps in knowledge concern; (i) characterisation of the atmospheric transformations of wood smoke particles, (ii) characterisation of the physicochemical properties of wood smoke particles in ambient and indoor environments, and (iii) identification of the physicochemical properties that influence the biological effects of wood smoke particles. PMID:19891791

Penetration and Effectiveness of Micronized Copper in Refractory Wood Species

PubMed Central

Civardi, Chiara; Van den Bulcke, Jan; Schubert, Mark; Michel, Elisabeth; Butron, Maria Isabel; Boone, Matthieu N.; Dierick, Manuel; Van Acker, Joris; Wick, Peter; Schwarze, Francis W. M. R.

2016-01-01

The North American wood decking market mostly relies on easily treatable Southern yellow pine (SYP), which is being impregnated with micronized copper (MC) wood preservatives since 2006. These formulations are composed of copper (Cu) carbonate particles (CuCO3·Cu(OH)2), with sizes ranging from 1 nm to 250 μm, according to manufacturers. MC-treated SYP wood is protected against decay by solubilized Cu2+ ions and unreacted CuCO3·Cu(OH)2 particles that successively release Cu2+ ions (reservoir effect). The wood species used for the European wood decking market differ from the North American SYP. One of the most common species is Norway spruce wood, which is poorly treatable i.e. refractory due to the anatomical properties, like pore size and structure, and chemical composition, like pit membrane components or presence of wood extractives. Therefore, MC formulations may not suitable for refractory wood species common in the European market, despite their good performance in SYP. We evaluated the penetration effectiveness of MC azole (MCA) in easily treatable Scots pine and in refractory Norway spruce wood. We assessed the effectiveness against the Cu-tolerant wood-destroying fungus Rhodonia placenta. Our findings show that MCA cannot easily penetrate refractory wood species and could not confirm the presence of a reservoir effect. PMID:27649315

Penetration and Effectiveness of Micronized Copper in Refractory Wood Species.

PubMed

Civardi, Chiara; Van den Bulcke, Jan; Schubert, Mark; Michel, Elisabeth; Butron, Maria Isabel; Boone, Matthieu N; Dierick, Manuel; Van Acker, Joris; Wick, Peter; Schwarze, Francis W M R

2016-01-01

The North American wood decking market mostly relies on easily treatable Southern yellow pine (SYP), which is being impregnated with micronized copper (MC) wood preservatives since 2006. These formulations are composed of copper (Cu) carbonate particles (CuCO3·Cu(OH)2), with sizes ranging from 1 nm to 250 μm, according to manufacturers. MC-treated SYP wood is protected against decay by solubilized Cu2+ ions and unreacted CuCO3·Cu(OH)2 particles that successively release Cu2+ ions (reservoir effect). The wood species used for the European wood decking market differ from the North American SYP. One of the most common species is Norway spruce wood, which is poorly treatable i.e. refractory due to the anatomical properties, like pore size and structure, and chemical composition, like pit membrane components or presence of wood extractives. Therefore, MC formulations may not suitable for refractory wood species common in the European market, despite their good performance in SYP. We evaluated the penetration effectiveness of MC azole (MCA) in easily treatable Scots pine and in refractory Norway spruce wood. We assessed the effectiveness against the Cu-tolerant wood-destroying fungus Rhodonia placenta. Our findings show that MCA cannot easily penetrate refractory wood species and could not confirm the presence of a reservoir effect.

Comparative study on liquefaction of creosote and chromated copper arsenate (CCA)-treated wood and untreated southern pine wood: effects of acid catalyst content, liquefaction time, temperature, and phenol to wood ratio

Treesearch

Hui Pan; Chung-Yun Hse; Todd F. Shupe

2009-01-01

Creosote- and chromated copper arsenate (CCA)-treated wood waste and untreated southern pine wood were liquefied with phenol and sulfuric acid. The effects of sulfuric acid content, liquefaction time, liquefaction temperature, and phenol to wood ratio on liquefaction rate (i.e., wood residue content) were investigated and analyzed by analysis of variance (...

Effects of wood fiber characteristics on mechanical properties of wood/polypropylene composites

Treesearch

Nicole M. Stark; Robert E. Rowlands

2003-01-01

Commercial wood flour, the most common wood-derived filler for thermoplastics, is produced in a mixture of particle sizes and generally has a lower aspect ratio than wood and other natural fibers. To understand how wood flour and fiber characteristics influence the mechanical properties of polypropylene composites, we first investigated the effect of different sizes of...

Establishing The Pasadena Seismological Laboratory: An Adventure in Scientific Collaboration

NASA Astrophysics Data System (ADS)

Hazen, M. H.

2002-05-01

The 1906 San Francisco earthquake jolted Berkeley geologist Harry O. Wood (1879-1958) into a lifetime of seismological research that included the establishment of a seismic monitoring network in southern California, the co-invention of a seismograph capable of measuring short-period earthquakes, and the implementation of a public-safety campaign. None of these initiatives would have been possible without the support of the Carnegie Institution, a Washington DC-based research organization that supported not only exceptional individuals (as founder Andrew Carnegie had stipulated), but also large-scale, collaborative investigations. Wood published his plan for a "western United States" earthquake research program in 1916, but it was not until he moved to Washington during World War I that he made contacts that transformed his dream into a reality. While working at the National Research Council, Wood shared his vision with astronomer George Ellery Hale, geologist Arthur L. Day and, finally, Carnegie president John C. Merriam. Merriam was a Californian, a geologist, and a strong proponent of collaborative science. In 1921, the Carnegie Advisory Committee on Seismology - the first organization "of this magnitude" in American research - was formed. Initially, the program operated from an office at the Mount Wilson Observatory, where Wood was in charge of the daily operations. Then, in 1926, a joint venture with the California Institute of Technology was launched. Located in the mountains west of Pasadena, the Seismological Laboratory coordinated a range of scientific efforts. By 1930, thirteen American cities had Wood-Anderson seismographs in place, quantities of data had been acquired, new fault zones had been identified, and Beno Gutenberg and Charles F. Richter had been attracted to the program. Over the years, the U.S. Coast and Geodetic Survey and other government agencies also contributed to the effort. In the mid-1930s, the Carnegie Institution transferred the program to Caltech, but the Institution did not abandon seismology. Today, individual scientists like Harry Wood continue to shape the Institution's research agenda. And, like Gutenberg, they attempt to relate movements deep within the earth to the shaping of the earth's crust.

Laboratory evaluation of the particle size effect on the performance of an elastomeric half-mask respirator against ultrafine combustion particles.

PubMed

He, Xinjian; Grinshpun, Sergey A; Reponen, Tiina; Yermakov, Michael; McKay, Roy; Haruta, Hiroki; Kimura, Kazushi

2013-08-01

This study quantified the particle size effect on the performance of elastomeric half-mask respirators, which are widely used by firefighters and first responders exposed to combustion aerosols. One type of elastomeric half-mask respirator equipped with two P-100 filters was donned on a breathing manikin while challenged with three combustion aerosols (originated by burning wood, paper, and plastic). Testing was conducted with respirators that were fully sealed, partially sealed (nose area only), or unsealed to the face of a breathing manikin to simulate different faceseal leakages. Three cyclic flows with mean inspiratory flow (MIF) rates of 30, 85, and 135 L/min were tested for each combination of sealing condition and combustion material. Additional testing was performed with plastic combustion particles at other cyclic and constant flows. Particle penetration was determined by measuring particle number concentrations inside and outside the respirator with size ranges from 20 to 200 nm. Breathing flow rate, particle size, and combustion material all had significant effects on the performance of the respirator. For the partially sealed and unsealed respirators, the penetration through the faceseal leakage reached maximum at particle sizes >100 nm when challenged with plastic aerosol, whereas no clear peaks were observed for wood and paper aerosols. The particles aerosolized by burning plastic penetrated more readily into the unsealed half-mask than those aerosolized by the combustion of wood and paper. The difference may be attributed to the fact that plastic combustion particles differ from wood and paper particles by physical characteristics such as charge, shape, and density. For the partially sealed respirator, the highest penetration values were obtained at MIF = 85 L/min. The unsealed respirator had approximately 10-fold greater penetration than the one partially sealed around the bridge of the nose, which indicates that the nose area was the primary leak site.

Factors controlling large-wood transport in a mountain river

NASA Astrophysics Data System (ADS)

Ruiz-Villanueva, Virginia; Wyżga, Bartłomiej; Zawiejska, Joanna; Hajdukiewicz, Maciej; Stoffel, Markus

2016-11-01

As with bedload transport, wood transport in rivers is governed by several factors such as flow regime, geomorphic configuration of the channel and floodplain, or wood size and shape. Because large-wood tends to be transported during floods, safety and logistical constraints make field measurements difficult. As a result, direct observation and measurements of the conditions of wood transport are scarce. This lack of direct observations and the complexity of the processes involved in wood transport may result in an incomplete understanding of wood transport processes. Numerical modelling provides an alternative approach to addressing some of the unknowns in the dynamics of large-wood in rivers. The aim of this study is to improve the understanding of controls governing wood transport in mountain rivers, combining numerical modelling and direct field observations. By defining different scenarios, we illustrate relationships between the rate of wood transport and discharge, wood size, and river morphology. We test these relationships for a wide, multithread reach and a narrower, partially channelized single-thread reach of the Czarny Dunajec River in the Polish Carpathians. Results indicate that a wide range of quantitative information about wood transport can be obtained from a combination of numerical modelling and field observations and from document contrasting patterns of wood transport in single- and multithread river reaches. On the one hand, log diameter seems to have a greater importance for wood transport in the multithread channel because of shallower flow, lower flow velocity, and lower stream power. Hydrodynamic conditions in the single-thread channel allow transport of large-wood pieces, whereas in the multithread reach, logs with diameters similar to water depth are not being moved. On the other hand, log length also exerts strong control on wood transport, more so in the single-thread than in the multithread reach. In any case, wood transport strongly decreases with increasing piece volume, although this relation is not linear. We also document a nonlinear relationship between wood transport and flood magnitude. A threshold discharge was identified below which wood transport is negligible. This threshold is higher in the multithread reach, while in the single-thread reach floods of lower magnitude are able to transport wood downstream. Wood transport ratio increases with discharge until it reaches an upper threshold or tipping point, and then decreases or increases much more slowly. This threshold is clearly related to bankfull discharge, but it is much higher for the multithread reach than for the single-thread one. Although modelling input and field observations were taken from a specific river, our findings and conclusions are likely to be applicable to a much larger suite of (mountain) rivers.

Patterns in hydraulic architecture from roots to branches in six tropical tree species from cacao agroforestry and their relation to wood density and stem growth

PubMed Central

Kotowska, Martyna M.; Hertel, Dietrich; Rajab, Yasmin Abou; Barus, Henry; Schuldt, Bernhard

2015-01-01

For decades it has been assumed that the largest vessels are generally found in roots and that vessel size and corresponding sapwood area-specific hydraulic conductivity are acropetally decreasing toward the distal twigs. However, recent studies from the perhumid tropics revealed a hump-shaped vessel size distribution. Worldwide tropical perhumid forests are extensively replaced by agroforestry systems often using introduced species of various biogeographical and climatic origins. Nonetheless, it is unknown so far what kind of hydraulic architectural patterns are developed in those agroforestry tree species and which impact this exerts regarding important tree functional traits, such as stem growth, hydraulic efficiency and wood density (WD). We investigated wood anatomical and hydraulic properties of the root, stem and branch wood in Theobroma cacao and five common shade tree species in agroforestry systems on Sulawesi (Indonesia); three of these were strictly perhumid tree species, and the other three tree species are tolerating seasonal drought. The overall goal of our study was to relate these properties to stem growth and other tree functional traits such as foliar nitrogen content and sapwood to leaf area ratio. Our results confirmed a hump-shaped vessel size distribution in nearly all species. Drought-adapted species showed divergent patterns of hydraulic conductivity, vessel density, and relative vessel lumen area between root, stem and branch wood compared to wet forest species. Confirming findings from natural old-growth forests in the same region, WD showed no relationship to specific conductivity. Overall, aboveground growth performance was better predicted by specific hydraulic conductivity than by foliar traits and WD. Our study results suggest that future research on conceptual trade-offs of tree hydraulic architecture should consider biogeographical patterns underlining the importance of anatomical adaptation mechanisms to environment. PMID:25873922

Effects of swelling forces on the durability of wood adhesive bonds

Treesearch

Blake M. Hofferber; Edward Kolodka; Rishawn Brandon; Robert J. Moon; Charles R. Frihart

2006-01-01

The purpose of this study was to investigate the role of wood swelling on performance of wood-adhesive bonds (resorcinol formaldehyde, epoxy, emulsion polymerisocyanate), for untreated and acetylated wood. Effects of these treatments on measured strain anisotropy and swelling stress were measured and then related to compressive shear strength and percentage wood...

EFFECTS OF BURN RATE, WOOD SPECIES, MOISTURE CONTENT AND WEIGHT OF WOOD LOADED ON WOODSTOVE EMISSIONS

EPA Science Inventory

The report gives results of tests of four woodstove operating parameters (burn rate, wood moisture, wood load, and wood species) at two levels each using a half factorial experimental test design to determine statistically significant effects on the emission components CO, CO2, p...

First insights into macro- and meiofaunal colonisation patterns on paired wood/slate substrata at Atlantic deep-sea hydrothermal vents

NASA Astrophysics Data System (ADS)

Cuvelier, Daphne; Beesau, Julie; Ivanenko, Viatcheslav N.; Zeppilli, Daniela; Sarradin, Pierre-Marie; Sarrazin, Jozée

2014-05-01

In 2006, paired wood and slate panels, each equipped with a temperature probe, were deployed on three different localities on and around the Eiffel Tower edifice (Lucky Strike vent field, Mid-Atlantic Ridge) within close proximity of visible hydrothermal activity. Recovery of these panels took place in 2008. For this two-year deployment period, the composition of colonising organisms (both macro-and meiofauna) was assessed, along with image analyses of the deployment sites in 2006 and 2008. Very few significant differences in colonisation between organic (wood) and inorganic (slate) panels were revealed. Rather, the locality of deployment and the local environmental conditions and hydrothermal activity were found to influence taxonomic composition. Variability in microhabitat conditions and biological interactions were hypothesised to interact jointly in shaping new faunal communities on the colonisation substrata.

Inhibition and stimulation effects in communities of wood decay fungi: exudates from colonized wood influence growth by other species.

PubMed

Heilmann-Clausen, J; Boddy, L

2005-04-01

The effects of exudates from uncolonized and from partly decayed beech wood on the extension rates of 16 later stage decay fungi were investigated. The partly decayed wood had been colonized by the pyrenomycete Eutypa spinosa, or the basidiomycetes Fomes fomentarius, Stereum hirsutum, and Trametes versicolor, all known as common early decay agents in European beech forests. Sterilized wood pieces were placed onto 0.5% malt agar, opposite to small agar plugs containing the test fungi. The latter showed very variable and species-specific growth responses to the various wood types. The presence of uncolonized wood stimulated extension rates in many species, whereas the four previously decayed wood types had variable stimulatory or inhibitory effects. Wood decayed by S. hirsutum resulted in reduced extension rate, delayed growth, or total inhibition in the majority of species, thus it is suggested that this species uses secondary metabolites in a defensive strategy. A single species was, however, stimulated in the presence of S. hirsutum-decayed wood. In contrast, the presence of wood decayed by F. fomentarius was stimulatory to 45% of the species. The other previously decayed wood types generally resulted in more variable responses, depending upon species. The results are discussed in an ecological context and it is suggested that the exudates from the partly decayed wood that are responsible for the reported effects may function as infochemicals, structuring microbial communities in wood.

Analysis on the geometrical shape of T-honeycomb structure by finite element method (FEM)

NASA Astrophysics Data System (ADS)

Zain, Fitri; Rosli, Muhamad Farizuan; Effendi, M. S. M.; Abdullah, Mohamad Hariri

2017-09-01

Geometric in design is much related with our life. Each of the geometrical structure interacts with each other. The overall shape of an object contains other shape inside, and there shapes create a relationship between each other in space. Besides that, how geometry relates to the function of the object have to be considerate. In this project, the main purpose was to design the geometrical shape of modular furniture with the shrinking of Polyethylene Terephthalate (PET) jointing system that has good strength when applied load on it. But, the goal of this paper is focusing on the analysis of Static Cases by FEM of the hexagonal structure to obtain the strength when load apply on it. The review from the existing product has many information and very helpful to finish this paper. This project focuses on hexagonal shape that distributed to become a shelf inspired by honeycomb structure. It is very natural look and simple in shape and its modular structure more easily to separate and combine. The method discusses on chapter methodology are the method used to analysis the strength when the load applied to the structure. The software used to analysis the structure is Finite Element Method from CATIA V5R21 software. Bending test is done on the jointing part between the edges of the hexagonal shape by using Universal Tensile Machine (UTM). The data obtained have been calculate by bending test formulae and sketch the graph between flexural strains versus flexural stress. The material selection of the furniture is focused on wood. There are three different types of wood such as balsa, pine and oak, while the properties of jointing also be mentioned in this thesis. Hence, the design structural for honeycomb shape already have in the market but this design has main objective which has a good strength that can withstand maximum load and offers more potentials in the form of furniture.

Final Environmental Assessment for Beddown of the 610th Security Forces Squadron Regional Training Center at Fort Wolters, Texas

DTIC Science & Technology

2011-12-01

longitude 98° 02` 15.17`` W. The site is “7” shaped, is mostly cut grass with oak trees, and is wooded along the eastern boundary. The boundaries...1r 1r 1 Jll I .. Scot ! M. Horzen Ecologist Attachments by~~?L~ tor Mark WJhe State Htstoo p,.,.,.,,.. lor 1 f~ Data- o~. PI...record is actnched for your refet·ence. Based on a review of recent aeria l photography, the proposed project site is at !.east patti ally wooded

Effects of raw materials on the properties of wood fiber-polyethylene composites--part 3: effect of a compatibilizer and wood adhesive on the interfacial adhesion of wood/plastic composites

Treesearch

Chin-yin Hwang; Chung-yun Hse; Todd F. Shupe

2008-01-01

The objective of this study was to examine the effect of maleated polypropylene compatabilizer on the interfacial properties of wood and polyolefins. Birch wood dowels containing an adhesive applied on the surface were embedded in molten plastic matrices using specially designed jigs. The three plastics investigated included low density polyethylene (LFPE), linear low...

Woodland-to-forest transition during prolonged drought in Minnesota after ca. AD 1300.

PubMed

Shuman, Bryan; Henderson, Anna K; Plank, Colin; Stefanova, Ivanka; Ziegler, Susy S

2009-10-01

Interactions among multiple causes of ecological perturbation, such as climate change and disturbance, can produce "ecological surprises." Here, we examine whether climate-fire-vegetation interactions can produce ecological changes that differ in direction from those expected from the effects of climate change alone. To do so, we focus on the "Big Woods" of central Minnesota, USA, which was shaped both by climate and fire. The deciduous Big Woods forest replaced regional woodlands and savannas after the severity of regional fire regimes declined at ca. AD 1300. A trend toward wet conditions has long been assumed to explain the forest expansion, but we show that water levels at two lakes within the region (Wolsfeld Lake and Bufflehead Pond) were low when open woodlands were transformed into the Big Woods. Water levels were high instead at ca. 2240-795 BC when regional fire regimes were most severe. Based on the correlation between water levels and fire-regime severity, we infer that prolonged or repeated droughts after ca. AD 1265 reduced the biomass and connectivity of fine fuels (grasses) within the woodlands. As a result, regional fire severity declined and allowed tree populations to expand. Tree-ring data from the region show a peak in the recruitment of key Big Woods tree species during the AD 1930s drought and suggest that low regional moisture balance need not have been a limiting factor for forest expansion. The regional history, thus, demonstrates the types of counterintuitive ecosystem changes that may arise as climate changes in the future.

Modelling and simulation of wood chip combustion in a hot air generator system.

PubMed

Rajika, J K A T; Narayana, Mahinsasa

2016-01-01

This study focuses on modelling and simulation of horizontal moving bed/grate wood chip combustor. A standalone finite volume based 2-D steady state Euler-Euler Computational Fluid Dynamics (CFD) model was developed for packed bed combustion. Packed bed combustion of a medium scale biomass combustor, which was retrofitted from wood log to wood chip feeding for Tea drying in Sri Lanka, was evaluated by a CFD simulation study. The model was validated by the experimental results of an industrial biomass combustor for a hot air generation system in tea industry. Open-source CFD tool; OpenFOAM was used to generate CFD model source code for the packed bed combustion and simulated along with an available solver for free board region modelling in the CFD tool. Height of the packed bed is about 20 cm and biomass particles are assumed to be spherical shape with constant surface area to volume ratio. Temperature measurements of the combustor are well agreed with simulation results while gas phase compositions have discrepancies. Combustion efficiency of the validated hot air generator is around 52.2 %.

Fossil woods of Detarioideae subfamily (Fabaceae) from El Palmar Formation (Late Pleistocene) in South America

NASA Astrophysics Data System (ADS)

Ramos, R. Soledad; Brea, Mariana; Kröhling, Daniela M.

2017-11-01

The main aim of the present paper is to describe the first Detarioideae fossil woods from El Palmar Formation (Late Pleistocene) in the Uruguay River Basin (Entre Ríos, Argentina). This study is based on five silicified wood specimens preserved in fluvial deposits, which were transported from their growth site. Two new genera and species are described: Paraoxystigma concordiensis gen. nov and sp. nov. has medium-sized vessels, paratracheal axial parenchyma, heterocellular and multiseriate rays, and diffuse axial canals similar in size and shape to vessels, and Gossweilerodendroxylon palmariensis gen. nov and sp. nov. has medium-sized vessels, alternate intervessel pits, paratracheal and apotracheal axial parenchyma, homocellular and uni to-multiseriate rays, and small diffuse axial canals. These Detarioideae fossil records in south-eastern South America support the existence of a very old relationship with the extant West African forests. Eco-anatomical features observed in these fossil woods, along with the climatic information available from the Nearest Living Relatives (NLRs) comparison, suggest warm and humid climatic conditions for the upper-middle basin of the Uruguay River during some periods of the Late Pleistocene.

The Mechanical Properties of Wood of Different Moisture Content Within -200 Degrees to +200 Degrees C Temperature Range

NASA Technical Reports Server (NTRS)

Kollmann, Franz

1941-01-01

Systematic experiments were undertaken with special reference to the effect of gross specific weight (specific weight inclusive of pores) and the moisture content of wood. It was found that the modules of elasticity of wood at room temperature and frozen at -8 degrees is practically the same. The effect of moisture on the compression strength of frozen wood was explored as well as the flexural and impact strength of frozen wood and frozen laminated wood.

Statistical analysis of influence of soil source on leaching of arsenic and copper from CCA-C treated wood

Treesearch

Patricia Lebow; Richard Ziobro; Linda Sites; Tor Schultz; David Pettry; Darrel Nicholas; Stan Lebow; Pascal Kamdem; Roger Fox; Douglas Crawford

2006-01-01

Leaching of wood preservatives affects the long-term efficacy and environmental impact of treated wood. Soil properties and wood characteristicscan affectleaching of woad preservatives, but these effects are not well understood. This paper reports a statistical analysis of the effects of soil and wood properties on leaching of arsenic (As) and copper (Cu) from southern...

Visibility of Different Intraorbital Foreign Bodies Using Plain Radiography, Computed Tomography, Magnetic Resonance Imaging, and Cone-Beam Computed Tomography: An In Vitro Study.

PubMed

Javadrashid, Reza; Golamian, Masoud; Shahrzad, Maryam; Hajalioghli, Parisa; Shahmorady, Zahra; Fouladi, Daniel F; Sadrarhami, Shohreh; Akhoundzadeh, Leila

2017-05-01

The study sought to compare the usefulness of 4 imaging modalities in visualizing various intraorbital foreign bodies (IOFBs) in different sizes. Six different materials including metal, wood, plastic, stone, glass. and graphite were cut in cylindrical shapes in 4 sizes (dimensions: 0.5, 1, 2, and 3 mm) and placed intraorbitally in the extraocular space of fresh sheep's head. Four skilled radiologists rated the visibility of the objects individually using plain radiography, spiral computed tomography (CT), magnetic resonance imaging (MRI), and cone-beam computed tomography (CBCT) in accordance with a previously described grading system. Excluding wood, all embedded foreign bodies were best visualized in CT and CBCT images with almost equal accuracies. Wood could only be detected using MRI, and then only when fragments were more than 2 mm in size. There were 3 false-positive MRI reports, suggesting air bubbles as wood IOFBs. Because of lower cost and using less radiation in comparison with conventional CT, CBCT can be used as the initial imaging technique in cases with suspected IOFBs. Optimal imaging technique for wood IOFBs is yet to be defined. Copyright © 2016 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

The use of image analysis in evaluation of the fibers orientation in Wood-polymer composites (WPC)

NASA Astrophysics Data System (ADS)

Bednarz, Arkadiusz; Frącz, Wiesław; Janowski, Grzegorz

2016-12-01

In this paper a novel way of a digital analysis of fibers orientation with a five-step algorithmwas presented. In the study, a molded piece with a dumbbell shape prepared from wood-polymer composite was used. The injection molding process was examined in experimental and numerical way. Based on the developed mathematical algorithm, a significant compliance of fiber orientation in different areas of the molded piece was obtained. The main aim of thisworkwas fiber orientation analysis of wood-polymer composites. An additional goal of thiswork was the comparison of the results reached in numerical analysis with results obtained from an experiment. The results of this research were important for the scientific and also from the practical point of view. In future works the prepared algorithm could be used to reach optimal parameters of the injection molding process.

CosmoBon, tree research team, for studying utilization of woody plant in space environment

NASA Astrophysics Data System (ADS)

Tomita-Yokotani, Kaori; Yamashita, Masamichi; Hashimoto, Hirofumi; Sato, Seigo; Baba, Keiichi; Chida, Yukari

2012-07-01

We are proposing to raise woody plants in space for several applications and plant science, as Tree research team, TRT. Trees produce excess oxygen, wooden materials for living cabin, and provide biomass for cultivating mushroom and insect as for the space agriculture. Excellent tree shapes which would be deeply related to wood formation improve quality of life under stressful environment in outer space. We have the serious problem about their size. Bonsai is one of the Japanese traditional arts. We have been investigating the tension wood formation under exotic gravitational environment using Bonsai. CosmoBon is the small tree Bonsai for our space experiment. The tension wood formation in CosmoBon was confirmed as the same as that in the natural trees. Our goal is to examine feasibility to grow various species of trees in space as bioresource for space agriculture.

Integrated control of wood destroying basidiomycetes combining Cu-based wood preservatives and Trichoderma spp.

PubMed Central

2017-01-01

The production of new generation of wood preservatives (without addition of a co-biocide) in combination with an exchange of wood poles on identical sites with high fungal inoculum, has resulted in an increase of premature failures of wood utility poles in the last decades. Wood destroying basidiomycetes inhabiting sites where poles have been installed, have developed resistance against wood preservatives. The objective of the in vitro studies was to identify a Trichoderma spp. with a highly antagonistic potential against wood destroying basidiomycetes that is capable of colonizing Cu-rich environments. For this purpose, the activity of five Trichoderma spp. on Cu-rich medium was evaluated according to its growth and sporulation rates. The influence of the selected Trichoderma spp. on wood colonization and degradation by five wood destroying basidiomycetes was quantitatively analyzed by means of dry weight loss of wood specimens. Furthermore, the preventative effect of the selected Trichoderma spp. in combination with four Cu-based preservatives was also examined by mass loss and histological changes in the wood specimens. Trichoderma harzianum (T-720) was considered the biocontrol agent with higher antagonistic potential to colonize Cu-rich environments (up to 0.1% CuSO4 amended medium). T. harzianum demonstrated significant preventative effect on wood specimens against four wood destroying basidiomycetes. The combined effect of T. harzianum and Cu-based wood preservatives demonstrated that after 9 months incubation with two wood destroying basidiomycetes, wood specimens treated with 3.8 kg m-3 copper-chromium had weight losses between 55–65%, whereas containers previously treated with T. harzianum had significantly lower weight losses (0–25%). Histological studies on one of the wood destroying basidiomycetes revealed typical decomposition of wood cells by brown-rot fungi in Cu-impregnated samples, that were notably absent in wood specimens previously exposed to T. harzianum. It is concluded that carefully selected Trichoderma isolates can be used for integrated wood protection against a range of wood destroying basidiomycetes and may have potential for integrated wood protection in the field. PMID:28379978

Integrated control of wood destroying basidiomycetes combining Cu-based wood preservatives and Trichoderma spp.

PubMed

Ribera, Javier; Fink, Siegfried; Bas, Maria Del Carmen; Schwarze, Francis W M R

2017-01-01

The production of new generation of wood preservatives (without addition of a co-biocide) in combination with an exchange of wood poles on identical sites with high fungal inoculum, has resulted in an increase of premature failures of wood utility poles in the last decades. Wood destroying basidiomycetes inhabiting sites where poles have been installed, have developed resistance against wood preservatives. The objective of the in vitro studies was to identify a Trichoderma spp. with a highly antagonistic potential against wood destroying basidiomycetes that is capable of colonizing Cu-rich environments. For this purpose, the activity of five Trichoderma spp. on Cu-rich medium was evaluated according to its growth and sporulation rates. The influence of the selected Trichoderma spp. on wood colonization and degradation by five wood destroying basidiomycetes was quantitatively analyzed by means of dry weight loss of wood specimens. Furthermore, the preventative effect of the selected Trichoderma spp. in combination with four Cu-based preservatives was also examined by mass loss and histological changes in the wood specimens. Trichoderma harzianum (T-720) was considered the biocontrol agent with higher antagonistic potential to colonize Cu-rich environments (up to 0.1% CuSO4 amended medium). T. harzianum demonstrated significant preventative effect on wood specimens against four wood destroying basidiomycetes. The combined effect of T. harzianum and Cu-based wood preservatives demonstrated that after 9 months incubation with two wood destroying basidiomycetes, wood specimens treated with 3.8 kg m-3 copper-chromium had weight losses between 55-65%, whereas containers previously treated with T. harzianum had significantly lower weight losses (0-25%). Histological studies on one of the wood destroying basidiomycetes revealed typical decomposition of wood cells by brown-rot fungi in Cu-impregnated samples, that were notably absent in wood specimens previously exposed to T. harzianum. It is concluded that carefully selected Trichoderma isolates can be used for integrated wood protection against a range of wood destroying basidiomycetes and may have potential for integrated wood protection in the field.

Acoustic vibration analysis for utilization of woody plant in space environment

NASA Astrophysics Data System (ADS)

Chida, Yukari; Yamashita, Masamichi; Hashimoto, Hirofumi; Sato, Seigo; Tomita-Yokotani, Kaori; Baba, Keiichi; Suzuki, Toshisada; Motohashi, Kyohei; Sakurai, Naoki; Nakagawa-izumi, Akiko

2012-07-01

We are proposing to raise woody plants for space agriculture in Mars. Space agriculture has the utilization of wood in their ecosystem. Nobody knows the real tree shape grown under space environment under the low or micro gravitational conditions such as outer environment. Angiosperm tree forms tension wood for keeping their shape. Tension wood formation is deeply related to gravity, but the details of the mechanism of its formation has not yet been clarified. For clarifying the mechanism, the space experiment in international space station, ISS is the best way to investigate about them as the first step. It is necessary to establish the easy method for crews who examine the experiments at ISS. Here, we are proposing to investigate the possibility of the acoustic vibration analysis for the experiment at ISS. Two types of Japanese cherry tree, weeping and upright types in Prunus sp., were analyzed by the acoustic vibration method. Coefficient-of-variation (CV) of sound speed was calculated by the acoustic vibration analysis. The amount of lignin and decomposed lignin were estimated by both Klason and Py-GC/MS method, respectively. The relationships of the results of acoustic vibration analysis and the inner components in tested woody materials were investigated. After the experiments, we confirm the correlation about them. Our results indicated that the acoustic vibration analysis would be useful for determining the inside composition as a nondestructive method in outer space environment.

Amount of leachant and water absorption levels of wood treated with borates and water repellents.

PubMed

Baysal, Ergun; Sonmez, Abdullah; Colak, Mehmet; Toker, Hilmi

2006-12-01

Wood protection efficacy of borates against biological agents, flame retardancy, and suitability to the environment is well known. Since borates can be applied to timber as water based solutions, they are preferred economically as well. Even though they are highly mobile in wood, boron compounds are widely used in timber preservation. Borates migrate in liquid and increase the hygroscopicity of wood in damp conditions. This study deals with the physical restriction of water access in wood by impregnating water repellent agents into wood to limit amount of leachant and water absorption levels of wood after boron treatment. Borates were incorporated with polyethylene glycol-400 (PEG-400) their bulking effect in wood was considered. Results indicated that the amount of leachates from wood treated with borates in PEG-400 was remarkably higher compared to those of wood treated with the aqueous solutions of borates. Water absorption (WA) levels of wood treated with aqueous solutions of borates were higher than those of their treated samples with the solutions in PEG-400. Secondary treatments of wood with the water repellent (WR) chemicals following borate impregnation reduced the leaching of chemicals from wood in water and also WA of the specimens were less than those of the wood treated with only borates from aqueous and PEG solutions. Styrene (St) was the most effective monomer among the other agents used in terms of immobility effect on borates and WA.

Bending efficiency through property gradients in bamboo, palm, and wood-based composites.

PubMed

Wegst, Ulrike G K

2011-07-01

Nature, to a greater extent than engineering, takes advantage of hierarchical structures. These allow for optimization at each structural level to achieve mechanical efficiency, meaning mechanical performance per unit mass. Palms and bamboos do this exceptionally well; both are fibre-reinforced cellular materials in which the fibres are aligned parallel to the stem or culm, respectively. The distribution of these fibres is, however, not uniform: there is a density and modulus gradient across the section. This property gradient increases the flexural rigidity of the plants per unit mass, mass being a measure of metabolic investment made into an organism's construction. An analytical model is presented with which a 'gradient shape factor' can be calculated that describes by how much a plant's bending efficiency is increased through gradient structures. Combining the 'gradient shape factor' with a 'microstructural shape factor' that captures the efficiency gained through the cellular nature of the fibre composite's matrix, and a 'macroscopical shape factor' with which the tubular shape of bamboo can be described, for example, it is possible to explore how much each of these three structural levels of the hierarchy contributes to the overall bending performance of the stem or culm. In analogy, the bending efficiency of the commonly used wood-based composite medium-density fibreboard can be analysed; its property gradient is due to its manufacture by hot pressing. A few other engineered materials exist that emulate property gradients; new manufacturing routes to prepare them are currently being explored. It appears worthwhile to pursue these further. Copyright © 2011. Published by Elsevier Ltd.

Chapter 6: Wood energy and competing wood product markers

Treesearch

Kenneth E. Skog; Robert C. Abt; Karen Abt

2014-01-01

Understanding the effect of expanding wood energy markets is important to all wood-dependent industries and to policymakers debating the implementation of public programs to support the expansion of wood energy generation. A key factor in determining the feasibility of wood energy projects (e.g. wood boiler or pellet plant) is the long-term (i.e. 20-30year) supply...

River logjams cause frequent large-scale forest die-off events in southwestern Amazonia

NASA Astrophysics Data System (ADS)

Lombardo, Umberto

2017-07-01

This paper investigates the dynamics of logjam-induced floods and alluvial deposition in the Bolivian Amazon and the effects these have on forest disturbance and recovery cycles. It expands on previous work by Gullison et al. (1996) who reported a case of catastrophic floods triggered by logjams in the Chimane Forest in the Bolivian Amazon. No further studies have followed up on this observation and no research has been published on the effects of large wood in tropical lowland rivers. The study is based on the analysis of a time series of Landsat imagery (1984-2016) and field evidence. Results show that logjam-induced floods are a major driver of forest disturbance along the Andean piedmont in the Bolivian Amazon. New logjams form on an almost yearly basis, always further upriver, until an avulsion takes place. Logjam-induced floods are characterized here by the sudden deposition of a thick sand layer and the death of forest in a V-shaped area. The Bolivian Amazon offers a unique opportunity for further research on how large wood affects river behavior in lowland tropical settings and how large and frequent forest disturbance events resulting from river logjams affect forest biodiversity and community successions.

Characterization of Unexplored Deadwood Mycobiome in Highly Diverse Subtropical Forests Using Culture-independent Molecular Technique.

PubMed

Purahong, Witoon; Pietsch, Katherina A; Lentendu, Guillaume; Schöps, Ricardo; Bruelheide, Helge; Wirth, Christian; Buscot, François; Wubet, Tesfaye

2017-01-01

The deadwood mycobiome, also known as wood-inhabiting fungi (WIF), are among the key players in wood decomposition, having a large impact on nutrient cycling in forest soils. However, our knowledge of WIF richness and distribution patterns in different forest biomes is limited. Here, we used pyrotag sequencing of the fungal internal transcribed spacer (ITS2) region to characterize the deadwood mycobiome of two tree species with greatly different wood characteristics ( Schima superba and Pinus massoniana ) in a Chinese subtropical forest ecosystem. Specifically, we tested (i) the effects of tree species and wood quality properties on WIF OTU richness and community composition; (ii) the role of biotic and abiotic factors in shaping the WIF communities; and (iii) the relationship between WIF OTU richness, community composition and decomposition rates. Due to different wood chemical properties, we hypothesized that the WIF communities derived from the two tree species would be correlated differently with biotic and abiotic factors. Our results show that deadwood in subtropical forests harbors diverse fungal communities comprising six ecological functional groups. We found interesting colonization patterns for this subtropical biome, where Resinicium spp. were highly detected in both broadleaved and coniferous deadwood. In addition, the members of Xylariales were frequently found in Schima . The two deadwood species differed significantly in WIF OTU richness ( Pinus > Schima ) and community composition ( P < 0.001). Variations in WIF community composition of both tree species were significantly explained by wood pH and ecological factors (biotic: deadwood species, basal area and abiotic: soil pH), but the WIF communities derived from each tree species correlated differently with abiotic factors. Interestingly, we found that deadwood decomposition rate significantly correlated with WIF communities and negatively correlated with WIF OTU richness. We conclude that the pattern of WIF OTU richness and community composition are controlled by multiple interacting biotic and abiotic factors. Overall, our study provides an in-depth picture of the deadwood mycobiome in this subtropical forest. Furthermore, by comparing our results to results from temperate and boreal forests we contribute to a better understanding of patterns of WIF communities across different biomes and geographic locations.

Characterization of Unexplored Deadwood Mycobiome in Highly Diverse Subtropical Forests Using Culture-independent Molecular Technique

PubMed Central

Purahong, Witoon; Pietsch, Katherina A.; Lentendu, Guillaume; Schöps, Ricardo; Bruelheide, Helge; Wirth, Christian; Buscot, François; Wubet, Tesfaye

2017-01-01

The deadwood mycobiome, also known as wood-inhabiting fungi (WIF), are among the key players in wood decomposition, having a large impact on nutrient cycling in forest soils. However, our knowledge of WIF richness and distribution patterns in different forest biomes is limited. Here, we used pyrotag sequencing of the fungal internal transcribed spacer (ITS2) region to characterize the deadwood mycobiome of two tree species with greatly different wood characteristics (Schima superba and Pinus massoniana) in a Chinese subtropical forest ecosystem. Specifically, we tested (i) the effects of tree species and wood quality properties on WIF OTU richness and community composition; (ii) the role of biotic and abiotic factors in shaping the WIF communities; and (iii) the relationship between WIF OTU richness, community composition and decomposition rates. Due to different wood chemical properties, we hypothesized that the WIF communities derived from the two tree species would be correlated differently with biotic and abiotic factors. Our results show that deadwood in subtropical forests harbors diverse fungal communities comprising six ecological functional groups. We found interesting colonization patterns for this subtropical biome, where Resinicium spp. were highly detected in both broadleaved and coniferous deadwood. In addition, the members of Xylariales were frequently found in Schima. The two deadwood species differed significantly in WIF OTU richness (Pinus > Schima) and community composition (P < 0.001). Variations in WIF community composition of both tree species were significantly explained by wood pH and ecological factors (biotic: deadwood species, basal area and abiotic: soil pH), but the WIF communities derived from each tree species correlated differently with abiotic factors. Interestingly, we found that deadwood decomposition rate significantly correlated with WIF communities and negatively correlated with WIF OTU richness. We conclude that the pattern of WIF OTU richness and community composition are controlled by multiple interacting biotic and abiotic factors. Overall, our study provides an in-depth picture of the deadwood mycobiome in this subtropical forest. Furthermore, by comparing our results to results from temperate and boreal forests we contribute to a better understanding of patterns of WIF communities across different biomes and geographic locations. PMID:28469600

Species composition and forest structure explain the temperature sensitivity patterns of productivity in temperate forests

NASA Astrophysics Data System (ADS)

Bohn, Friedrich J.; May, Felix; Huth, Andreas

2018-03-01

Rising temperatures due to climate change influence the wood production of forests. Observations show that some temperate forests increase their productivity, whereas others reduce their productivity. This study focuses on how species composition and forest structure properties influence the temperature sensitivity of aboveground wood production (AWP). It further investigates which forests will increase their productivity the most with rising temperatures. We described forest structure by leaf area index, forest height and tree height heterogeneity. Species composition was described by a functional diversity index (Rao's Q) and a species distribution index (ΩAWP). ΩAWP quantified how well species are distributed over the different forest layers with regard to AWP. We analysed 370 170 forest stands generated with a forest gap model. These forest stands covered a wide range of possible forest types. For each stand, we estimated annual aboveground wood production and performed a climate sensitivity analysis based on 320 different climate time series (of 1-year length). The scenarios differed in mean annual temperature and annual temperature amplitude. Temperature sensitivity of wood production was quantified as the relative change in productivity resulting from a 1 °C rise in mean annual temperature or annual temperature amplitude. Increasing ΩAWP positively influenced both temperature sensitivity indices of forest, whereas forest height showed a bell-shaped relationship with both indices. Further, we found forests in each successional stage that are positively affected by temperature rise. For such forests, large ΩAWP values were important. In the case of young forests, low functional diversity and small tree height heterogeneity were associated with a positive effect of temperature on wood production. During later successional stages, higher species diversity and larger tree height heterogeneity were an advantage. To achieve such a development, one could plant below the closed canopy of even-aged, pioneer trees a climax-species-rich understorey that will build the canopy of the mature forest. This study highlights that forest structure and species composition are both relevant for understanding the temperature sensitivity of wood production.

Effects of copper amine treatments on mechanical, biological and surface/interphase properties of poly (vinyl chloride)/wood composites

NASA Astrophysics Data System (ADS)

Jiang, Haihong

2005-11-01

The copper ethanolamine (CuEA) complex was used as a wood surface modifier and a coupling agent for wood-PVC composites. Mechanical properties of composites, such as unnotched impact strength, flexural strength and flexural toughness, were significantly increased, and fungal decay weight loss was dramatically decreased by wood surface copper amine treatments. It is evident that copper amine was a very effective coupling agent and decay inhibitor for PVC/wood flour composites, especially in high wood flour loading level. A DSC study showed that the heat capacity differences (DeltaCp) of composites before and after PVC glass transition were reduced by adding wood particles. A DMA study revealed that the movements of PVC chain segments during glass transition were limited and obstructed by the presence of wood molecule chains. This restriction effect became stronger by increasing wood flour content and by using Cu-treated wood flour. Wood flour particles acted as "physical cross-linking points" inside the PVC matrix, resulting in the absence of the rubbery plateau of PVC and higher E', E'' above Tg, and smaller tan delta peaks. Enhanced mechanical performances were attributed to the improved wetting condition between PVC melts and wood surfaces, and the formation of a stronger interphase strengthened by chemical interactions between Cu-treated wood flour and the PVC matrix. Contact angles of PVC solution drops on Cu-treated wood surfaces were decreased dramatically compared to those on the untreated surfaces. Acid-base (polar), gammaAB, electron-acceptor (acid) (gamma +), electron-donor (base) (gamma-) surface energy components and the total surface energies increased after wood surface Cu-treatments, indicating a strong tendency toward acid-base or polar interactions. Improved interphase and interfacial adhesion were further confirmed by measuring interfacial shear strength between wood and the PVC matrix.

The Area of a Circle

ERIC Educational Resources Information Center

Greenslade, Thomas B., Jr.

2011-01-01

The geometrical shapes in Fig. 1 recently came into the Greenslade Collection. The semi-triangular pieces of wood looked like slices from a pie, each 22.5 degrees in angular width. They were tied together with a thin leather band tacked around their curved surfaces. What is this apparatus?

Field building: lessons from the Robert Wood Johnson Foundation's anthology series.

PubMed

Isaacs, Stephen L; Knickman, James R

2005-01-01

As editors of the Robert Wood Johnson Foundation's (RWJF's) anthology series, we have examined the entire range of the foundation's grant making since 1972. We found that the RWJF has enjoyed considerable success in building fields--from nurse practitioners to tobacco control to end-of-life care. The RWJF has done this by shaping fields as they were emerging, by adopting a wide-ranging "bear hug" approach, and by staying the course. The lessons from the RWJF's field-building efforts are relevant for both large and small foundations: Small funders can develop strategic plans aimed at building fields in their home state or locality.

Effect of wood flour content on the optical color, surface chemistry, mechanical and morphological properties of wood flour/recycled high density polyethylene (rHDPE) composite

NASA Astrophysics Data System (ADS)

Sheng, Chan Kok; Amin, Khairul Anuar Mat; Kee, Kwa Bee; Hassan, Mohd Faiz; Ali, E. Ghapur E.

2018-05-01

In this study, effect of wood flour content on the color, surface chemistry, mechanical properties and surface morphology of wood-plastic composite (WPC) on different mixture ratios of recycled high density polyethylene (rHDPE) and wood flour were investigated in detail. The presence of wood flour in the composite indicates a significant total color change and a decrease of lightness. Functional groups of wood flour in WPC can be seen clearer from the Fourier transform infrared (FTIR) spectra as the wood flour content increases. The mechanical tensile testing shows that the tensile strength of Young's modulus is improved, whereas the strain and elongation at break were reduced by the addition of wood flour. The gap between the wood flour microvoid fibre and rHDPE matrix becomes closer when the wood flour content is increased as observed by scanning electron microscope (SEM) image. This finding implies a significant improvement on the interaction of interfacial adhesion between the rHDPE matrix and wood flour filler in the present WPC.

[The influence of oil heat treatment on wood decay resistance by Fourier infrared spectrum analysis].

PubMed

Wang, Ya-Mei; Ma, Shu-Ling; Feng, Li-Qun

2014-03-01

Wood preservative treatment can improve defects of plantation wood such as easy to corrupt and moth eaten. Among them heat-treatment is not only environmental and no pollution, also can improve the corrosion resistance and dimension stability of wood. In this test Poplar and Mongolian Seoteh Pine was treated by soybean oil as heat-conducting medium, and the heat treatment wood was studied for indoor decay resistance; wood chemical components before and after treatment, the effect of heat treatment on wood decay resistance performance and main mechanism of action were analysed by Fourier infrared spectrometric. Results showed that the mass loss rate of poplar fell from 19.37% to 5% and Mongolian Seoteh Pine's fell from 8.23% to 3.15%, so oil heat treatment can effectively improve the decay resistance. Infrared spectrum analysis shows that the heat treatment made wood's hydrophilic groups such as hydroxyl groups in largely reduced, absorbing capacity decreased and the moisture of wood rotting fungi necessary was reduced; during the heat treatment wood chemical components such as cellulose, hemicellu lose were degraded, and the nutrient source of wood rotting fungi growth necessary was reduced. Wood decay fungi can grow in the wood to discredit wood is because of that wood can provide better living conditions for wood decay fungi, such as nutrients, water, oxygen, and so on. The cellulose and hemicellulose in wood is the main nutrition source of wood decay fungi. So the oil heat-treatment can reduce the cellulose, hemicellulose nutrition source of wood decay fungi so as to improve the decay resistance of wood.

Impacts of adding different components of wood vinegar on rape (Brassica napus L.) seed germiantion

NASA Astrophysics Data System (ADS)

Shan, Xue; Liu, Xia; Zhang, Qian

2018-03-01

In recent years, wood vinegar has been widely used in the agricultural production. It can be used as the soil amendment, antibacterial agent and organic fertilizer. This study investigated the effect of wood vinegar on rape (Brassica napus L.) seed germination. The results in this study showed that 1% (v/v) wood vinegar had the greatest inhibition effect on the seed germination of rape (Brassica napus L.). The wood vinegar (WV) and the distilled wood vinegar at 98 - 130 °C (D2) significantly inhibited seed germination by 100%, compared to the control treatment. However, the distilled wood vinegar (D1) had significantly increased the shoot length and root length by 58.4% and 31.7%, respectively. These positive effects could be attributed to the improved soil fertility, increased nutrient supply, and further stimulated plant growth. Overall, the D1 could be a promising soil amendment to promote plants growth and enhance crop yields. Effect of adding different components of distilled wood vinegar on the seed germination of rape

Eco-friendly materials for large area piezoelectronics: self-oriented Rochelle salt in wood

NASA Astrophysics Data System (ADS)

Lemaire, E.; Ayela, C.; Atli, A.

2018-02-01

Upgraded biodegradable piezoelectric composite materials elaborated by incorporation of Rochelle salt (RS, Sodium potassium tartrate tetrahydrate) in wood were reported. RS crystals, known as the first discovered piezoelectric material, were grown in the micro-cavities of wood, having naturally a tubular structure, by soaking the wood into RS saturated water. Since most of the cavities in wood are oriented in the same direction, the piezoelectric effect was improved when the cavities were filled by RS crystals. The mechanical, structural and piezoelectric properties of RS incorporated wood composite samples were characterized. Both direct and converse piezoelectric effects are illustrated. The wood-base composite exhibits an effective piezoelectric constant d 33 of 11 pC N-1. Also, the flexural strength and modulus of elasticity were enhanced by inserting RS into the wood, nevertheless the samples became more brittle. The wood-based piezoelectric samples prepared in this work can be used as actuators, sensors or energy harvesters. The process developed here permits us to manufacture large area piezoelectric devices which are environmentally and economically unsurpassed.

Effect of stacking sequence on mechanical properties neem wood veneer plastic composites

NASA Astrophysics Data System (ADS)

Nagamadhu, M.; Kumar, G. C. Mohan; Jeyaraj, P.

2018-04-01

This study investigates the effect of wood veneer stacking sequence on mechanical properties of neem wood polymer composite (WPC) experimentally. Wood laminated samples were fabricated by conventional hand layup technique in a mold and cured under pressure at room temperature and then post cured at elevated temperature. Initially, the tensile, flexural, and impact test were conducted to understand the effect of weight fraction of fiber on mechanical properties. The mechanical properties have increased with the weight fraction of fiber. Moreover the stacking sequence of neem wood plays an important role. As it has a significant impact on the mechanical properties. The results indicated that 0°/0° WPC shows highest mechanical properties as compared to other sequences (90°/90°, 0°/90°, 45°/90°, 45°/45°). The Fourier Transform Infrared Spectroscopy (FTIR) Analysis were carried out to identify chemical compounds both in raw neem wood and neem wood epoxy composite. The microstructure raw/neat neem wood and the interfacial bonding characteristics of neem wood composite investigated using Scanning electron microscopy images.

Biological effects of wood ash application to forest and aquatic ecosystems.

PubMed

Aronsson, K Andreas; Ekelund, Nils G A

2004-01-01

The present review aims to summarize current knowledge in the topic of wood ash application to boreal forest and aquatic ecosystems, and the different effects derived from these actions. Much research has been conducted regarding the effects of wood ash application on forest growth. Present studies show that, generally speaking, forest growth can be increased on wood ash-ameliorated peatland rich in nitrogen. On mineral soils, however, no change or even decreased growth have been reported. The effects on ground vegetation are not very clear, as well as the effects on fungi, soil microbes, and soil-decomposing animals. The discrepancies between different studies are for the most part explained by abiotic factors such as variation in fertility among sites, different degrees of stabilization, and wood ash dosage used, and different time scales among different studies. The lack of knowledge in the field of aquatic ecosystems and their response to ash application is an important issue for future research. The few studies conducted have mainly considered changes in water chemistry. The biotoxic effects of ash application can roughly be divided into two categories: primary and secondary. Among the primary effects is toxicity deriving from compounds in the wood ash and cadmium is probably the worst among these. The secondary effects of wood ash are generally due to its alkaline capacity and a release of ions into the soil and soil water, and finally, watercourses and lakes. Given current knowledge, we would recommend site- and wood ash-specific application practices, rather than broad and general guidelines for wood ash application to forests.

Visual cues for the retrieval of landmark memories by navigating wood ants.

PubMed

Harris, Robert A; Graham, Paul; Collett, Thomas S

2007-01-23

Even on short routes, ants can be guided by multiple visual memories. We investigate here the cues controlling memory retrieval as wood ants approach a one- or two-edged landmark to collect sucrose at a point along its base. In such tasks, ants store the desired retinal position of landmark edges at several points along their route. They guide subsequent trips by retrieving the appropriate memory and moving to bring the edges in the scene toward the stored positions. The apparent width of the landmark turns out to be a powerful cue for retrieving the desired retinal position of a landmark edge. Two other potential cues, the landmark's apparent height and the distance that the ant walks, have little effect on memory retrieval. A simple model encapsulates these conclusions and reproduces the ants' routes in several conditions. According to this model, the ant stores a look-up table. Each entry contains the apparent width of the landmark and the desired retinal position of vertical edges. The currently perceived width provides an index for retrieving the associated stored edge positions. The model accounts for the population behavior of ants and the idiosyncratic training routes of individual ants. Our results imply binding between the edge of a shape and its width and, further, imply that assessing the width of a shape does not depend on the presence of any particular local feature, such as a landmark edge. This property makes the ant's retrieval and guidance system relatively robust to edge occlusions.

Two Tools Shaping NCDA's Place

ERIC Educational Resources Information Center

Feller, Rich, Ed.; Furbish, Dale, Ed.

2013-01-01

The authors are pleased to introduce the second pair of articles in the National Career Development Association (NCDA) Centennial Special Series celebrating the 100th anniversary of NCDA. In this issue, JoAnn Harris-Bowlsbey reviews the development and use of computer-assisted career guidance systems, and Juliette N. Lester, James Woods, and…

Increasing the Presence of Underrepresented Minorities in the Geosciences: The Woods Hole Partnership Education Program Model and Outcomes

NASA Astrophysics Data System (ADS)

George, A.; Gutierrez, B.; Jearld, A.; Liles, G.; Scott, O.; Harden, B.

2017-12-01

Launched in 2009, the Partnership Education Program (PEP) is supported by six scientific institutions in Woods Hole, Massachusetts through the Woods Hole Diversity Initiative. PEP, which was shaped by experience with other diversity programs as well as input from scientists in Woods Hole, is designed to promote a diverse scientific community by recruiting talent from minority groups that are under-represented in marine and environmental sciences. Focused on college juniors and seniors with course work in marine and/or environmental sciences, PEP is comprised of a four-week course, "Ocean and Environmental Sciences: Global Climate Change," and a six to eight week individual research project under the guidance of a research mentor. Investigators from the six science institutions serve as course faculty and research mentors. Course credit is through PEP's academic partner, the University of Maryland Eastern Shore. PEP students also participate in seminars, workshops, field trips, at-sea experiences, career development activities, and attend lectures at participating science institutions throughout the summer. Students present their research results at the end of the summer with a 15-minute public presentation. A number of PEP participants then presented their work at professional and scientific meetings, such as AGU, using the program as a gateway to graduate education and career opportunities in the marine and environmental sciences. From 2009 through 2017, 138 students from 86 colleges and universities, including many that previously had sent few or no students or faculty to Woods Hole, have participated in the program. Participating organizations are: Northeast Fisheries Science Center (NOAA Fisheries), Marine Biological Laboratory (MBL), Sea Education Association (SEA), U.S. Geological Survey (USGS), Woods Hole Oceanographic Institution (WHOI), Woods Hole Research Center (WHRC), and University of Maryland Eastern Shore (UMES) - academic partner.

Effects of humidity on the magnetic and woody characteristics of powder-type magnetic wood

NASA Astrophysics Data System (ADS)

Oka, H.; Tokuta, H.; Namizaki, Y.; Sekino, N.

2004-05-01

Among three types of proposed magnetic wood, powder-type magnetic wood can be made of recycled magnetic materials from IT devices, consumer electronics and waste wood. Because of its wood powder content, powder-type magnetic wood shows special characteristics different from those of typical magnetic materials. We focused on the relationship between humidity and magnetic characteristics of powder-type magnetic wood. The magnetic powder ratio, wood powder density and magnetic binder density were all examined as parameters for AC permeability.

Wood chip mulch thickness effects on soil water, soil temperature, weed growth, and landscape plant growth

USDA-ARS?s Scientific Manuscript database

Wood chip mulches are used in landscapes to reduce soil water evaporation and competition from weeds. A study was conducted over a three-year period to determine soil water content at various depths under four wood chip mulch treatments and to evaluate the effects of wood chip thickness on growth of...

UV resistance and dimensional stability of wood modified with isopropenyl acetate.

PubMed

Nagarajappa, Giridhar B; Pandey, Krishna K

2016-02-01

Chemical modification of Rubberwood (Hevea brasiliensis Müll.Arg) with isopropenyl acetate (IPA) in the presence of anhydrous aluminum chloride as a catalyst has been carried out under solvent free conditions. The level of modification was estimated by determining the weight percent gain and modified wood was characterized by FTIR-ATR and CP/MAS (13)C NMR spectroscopy. The effect of catalyst concentration on WPG was studied. UV resistance, moisture adsorption and dimensional stability of modified wood were evaluated. UV resistance of modified wood was evaluated by exposing unmodified and modified wood to UV irradiation in a QUV accelerated weathering tester. Unmodified wood showed rapid color changes and degradation of lignin upon exposure to UV light. Chemical modification of wood polymers with IPA was effective in reducing light induced color changes (photo-yellowing) at wood surfaces. In contrast to unmodified wood, modified wood exhibited bleaching. FTIR analysis of modified wood exposed to UV light indicated stabilization of wood polymers against UV degradation. Modified wood showed good dimensional stability and hydrophobicity. Thermogravimetric analysis showed that modification with IPA improved thermal stability of wood. Improved dimensional stability and UV resistance of modified wood indicates IPA as a promising reagent since there is no acid byproduct of reaction as observed in case of other esterification reactions. Copyright © 2015 Elsevier B.V. All rights reserved.

Microscopic characterization of tension wood cell walls of Japanese beech (Fagus crenata) treated with ionic liquids.

PubMed

Kanbayashi, Toru; Miyafuji, Hisashi

2016-09-01

Tension wood that is an abnormal part formed in angiosperms has been barely used for wood industry. In this study, to utilize the tension wood effectively by means of liquefaction using ionic liquid, we performed morphological and topochemical determination of the changes in tension wood of Japanese beech (Fagus crenata) during ionic liquid treatment at the cellular level using light microscopy, scanning electron microscopy and confocal Raman microscopy. Ionic liquid treatment induced cell wall swelling in tension wood. Changes in the tissue morphology treated with ionic liquids were different between normal wood and tension wood, moreover the types of ionic liquids. The ionic liquid 1-ethyl-3-methylimidazolium chloride liquefied gelatinous layers rapidly, whereas 1-ethylpyridinium bromide liquefied slowly but delignified selectively. These novel insights into the deconstruction behavior of tension wood cell walls during ionic liquid treatment provide better understanding of the liquefaction mechanism. The obtained knowledge will contribute to development of an effective chemical processing of tension wood using ionic liquids and lead to efficient use of wood resources. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of Trichoderma-enriched organic charcoal in the integrated wood protection strategy

PubMed Central

Gandía, Mónica; Marcos, Jose F.; Bas, Maria del Carmen; Fink, Siegfried

2017-01-01

The gradual elimination of chromium from wood preservative formulations results in higher Cu leaching and increased susceptibility to wood decay fungi. Finding a sustainable strategy in wood protection has become of great interest among researchers. The objective of these in vitro studies was to demonstrate the effect of T-720-enriched organic charcoal (biochar) against five wood decay basidiomycetes isolated from strongly damaged poles. For this purpose, the antagonistic potential of Trichoderma harzianum (strain T-720) was confirmed among other four Trichoderma spp. against five brown-rot basidiomycetes in dual culture tests. T-720 was genetically transformed and tagged with the green fluorescent protein (GFP) in order to study its antagonistic mechanism against wood decay basidiomycetes. It was also demonstrated that T-720 inhibits the oxalic acid production by basidiomycetes, a well-known mechanism used by brown-rot fungi to detoxify Cu from impregnated wood. Additionally, this study evaluated the effect of biochar, alone or in combination with T-720, on Cu leaching by different preservatives, pH stabilization and prevention of wood decay caused by five basidiomycetes. Addition of biochar resulted in a significant Cu binding released from impregnated wood specimens. T-720-enriched biochar showed a significant reduction of wood decay caused by four basidiomycetes. The addition of T-720-enriched biochar to the soil into which utility poles are placed may improve the efficiency of Cr-free wood preservatives. PMID:28797118

Effect of Trichoderma-enriched organic charcoal in the integrated wood protection strategy.

PubMed

Ribera, Javier; Gandía, Mónica; Marcos, Jose F; Bas, Maria Del Carmen; Fink, Siegfried; Schwarze, Francis W M R

2017-01-01

The gradual elimination of chromium from wood preservative formulations results in higher Cu leaching and increased susceptibility to wood decay fungi. Finding a sustainable strategy in wood protection has become of great interest among researchers. The objective of these in vitro studies was to demonstrate the effect of T-720-enriched organic charcoal (biochar) against five wood decay basidiomycetes isolated from strongly damaged poles. For this purpose, the antagonistic potential of Trichoderma harzianum (strain T-720) was confirmed among other four Trichoderma spp. against five brown-rot basidiomycetes in dual culture tests. T-720 was genetically transformed and tagged with the green fluorescent protein (GFP) in order to study its antagonistic mechanism against wood decay basidiomycetes. It was also demonstrated that T-720 inhibits the oxalic acid production by basidiomycetes, a well-known mechanism used by brown-rot fungi to detoxify Cu from impregnated wood. Additionally, this study evaluated the effect of biochar, alone or in combination with T-720, on Cu leaching by different preservatives, pH stabilization and prevention of wood decay caused by five basidiomycetes. Addition of biochar resulted in a significant Cu binding released from impregnated wood specimens. T-720-enriched biochar showed a significant reduction of wood decay caused by four basidiomycetes. The addition of T-720-enriched biochar to the soil into which utility poles are placed may improve the efficiency of Cr-free wood preservatives.

First insight into dead wood protistan diversity: a molecular sampling of bright-spored Myxomycetes (Amoebozoa, slime-moulds) in decaying beech logs.

PubMed

Clissmann, Fionn; Fiore-Donno, Anna Maria; Hoppe, Björn; Krüger, Dirk; Kahl, Tiemo; Unterseher, Martin; Schnittler, Martin

2015-06-01

Decaying wood hosts a large diversity of seldom investigated protists. Environmental sequencing offers novel insights into communities, but has rarely been applied to saproxylic protists. We investigated the diversity of bright-spored wood-inhabiting Myxomycetes by environmental sequencing. Myxomycetes have a complex life cycle culminating in the formation of mainly macroscopic fruiting bodies, highly variable in shape and colour that are often found on decaying logs. Our hypothesis was that diversity of bright-spored Myxomycetes would increase with decay. DNA was extracted from wood chips collected from 17 beech logs of varying decay stages from the Hainich-Dün region in Central Germany. We obtained 260 partial small subunit ribosomal RNA gene sequences of bright-spored Myxomycetes that were assembled into 29 OTUs, of which 65% were less than 98% similar to those in the existing database. The OTU richness revealed by molecular analysis surpassed that of a parallel inventory of fruiting bodies. We tested several environmental variables and identified pH, rather than decay stage, as the main structuring factor of myxomycete distribution. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Instream wood loads in montane forest streams of the Colorado Front Range, USA

NASA Astrophysics Data System (ADS)

Jackson, Karen J.; Wohl, Ellen

2015-04-01

Although several studies examine instream wood loads and associated geomorphic effects in streams of subalpine forests in the U.S. Southern Rocky Mountains, little is known of instream wood loads in lower elevation, montane forests of the region. We compare instream wood loads and geomorphic effects between streams draining montane forest stands of differing age (old growth versus younger) and disturbance history (healthy versus infested by mountain pine beetles). We examined forest stand characteristics, instream wood load, channel geometry, pool volume, and sediment storage in 33 pool-riffle or plane-bed stream reaches with objectives of determining whether (i) instream wood and geomorphic effects differed significantly among old-growth, younger, healthy, and beetle-infested forest stands and (ii) wood loads correlated with valley and channel characteristics. Wood loads were standardized to drainage area, stream gradient, reach length, bankfull width, and floodplain area. Streams flowing through old-growth forests had significantly larger wood loads and logjam volumes (pairwise t-tests), as well as logjam frequencies (Kruskal-Wallis test), residual pool volume, and fine sediment storage around wood than streams flowing through younger forests. Wood loads in streams draining beetle-infested forest did not differ significantly from those in healthy forest stands, but best subset regression models indicated that elevation, stand age, and beetle infestation were the best predictors of wood loads in channels and on floodplains, suggesting that beetle infestation is affecting instream wood characteristics. Wood loads are larger than values from subalpine streams in the same region and jams are larger and more closely spaced. We interpret these differences to reflect greater wood piece mobility in subalpine zone streams. Stand age appears to exert the dominant influence on instream wood characteristics within pool-riffle streams in the study area rather than beetle infestation, although this may reflect the relatively recent nature (< 10 years) of the infestation.

Effects of material parameters on the diffusion and sorption properties of wood-flour/polypropylene composites

Treesearch

Vera Steckel; Craig Merrill Clemons; Heiko Thoemen

2007-01-01

Composites of wood in a thermoplastic matrix (wood–plastic composites) are considered a low maintenance solution to using wood in outdoor applications. Knowledge of moisture uptake and transport properties would be useful in estimating moisture-related effects such as fungal attack and loss of mechanical strength. Our objectives were to determine how material...

Thinning and riparian buffer configuration effects on down wood abundance in headwater streams in coniferous forests

Treesearch

Adrian Ares; Deanna H. Olson; Klaus J. Puettmann

2013-01-01

Down wood is associated with the function, structure, and diversity of riparian systems. Considerable knowledge has been generated regarding down wood stocks and dynamics in temperate forests, but there are few studies on effects of silvicultural practices and riparian buffer design on down wood, particularly in headwater streams. We analyzed interactive eff ects of...

The fungus that came in from the cold: dry rot's pre-adapted ability to invade buildings.

PubMed

Balasundaram, S V; Hess, J; Durling, M B; Moody, S C; Thorbek, L; Progida, C; LaButti, K; Aerts, A; Barry, K; Grigoriev, I V; Boddy, L; Högberg, N; Kauserud, H; Eastwood, D C; Skrede, I

2018-03-01

Many organisms benefit from being pre-adapted to niches shaped by human activity, and have successfully invaded man-made habitats. One such species is the dry rot fungus Serpula lacrymans, which has a wide distribution in buildings in temperate and boreal regions, where it decomposes coniferous construction wood. Comparative genomic analyses and growth experiments using this species and its wild relatives revealed that S. lacrymans evolved a very effective brown rot decay compared to its wild relatives, enabling an extremely rapid decay in buildings under suitable conditions. Adaptations in intracellular transport machineries promoting hyphal growth, and nutrient and water transport may explain why it is has become a successful invader of timber in houses. Further, we demonstrate that S. lacrymans has poor combative ability in our experimental setup, compared to other brown rot fungi. In sheltered indoor conditions, the dry rot fungus may have limited encounters with other wood decay fungi compared to its wild relatives. Overall, our analyses indicate that the dry rot fungus is an ecological specialist with poor combative ability against other fungi.

Aging and the Haptic Perception of Material Properties.

PubMed

Norman, J Farley; Adkins, Olivia C; Hoyng, Stevie C; Dowell, Catherine J; Pedersen, Lauren E; Gilliam, Ashley N

2016-12-01

The ability of 26 younger (mean age was 22.5 years) and older adults (mean age was 72.6 years) to haptically perceive material properties was evaluated. The participants manually explored (for 5 seconds) 42 surfaces twice and placed each of these 84 experimental stimuli into one of seven categories: paper, plastic, metal, wood, stone, fabric, and fur/leather. In general, the participants were best able to identify fur/leather and wood materials; in contrast, recognition performance was worst for stone and paper. Despite similar overall patterns of performance for younger and older participants, the younger adults' recognition accuracies were 26.5% higher. The participants' tactile acuities (assessed by tactile grating orientation discrimination) affected their ability to identify surface material. In particular, the Pearson r correlation coefficient relating the participants' grating orientation thresholds and their material identification performance was -0.8: The higher the participants' thresholds, the lower the material recognition ability. While older adults are able to effectively perceive the solid shape of environmental objects using the sense of touch, their ability to perceive surface materials is significantly compromised.

Does reintroducing large wood influence the hydraulic landscape of a lowland river system?

NASA Astrophysics Data System (ADS)

Matheson, Adrian; Thoms, Martin; Reid, Michael

2017-09-01

Our understanding of the effectiveness of reintroduced large wood for restoration is largely based on studies from high energy river systems. By contrast, few studies of the effectiveness of reintroducing large wood have been undertaken on large, low energy, lowland river systems: river systems where large wood is a significant physical feature on the in-channel environment. This study investigated the effect of reintroduced large wood on the hydraulic landscape of the Barwon-Darling River, Australia, at low flows. To achieve this, the study compared three hydraulic landscapes of replicated reference (naturally wooded), control (unwooded,) and managed (wood reintroduced) treatments on three low flow periods. These time periods were prior to the reintroduction of large wood to managed reaches; several months after the reintroduction of large wood into the managed reaches; and then more than four years after wood reintroduction following several large flood events. Hydraulic landscapes of reaches were characterised using a range of spatial measures calculated from velocity measurements taken with a boat-mounted Acoustic Doppler Profiler. We hypothesised that reintroduced large wood would increase the diversity of the hydraulic landscape at low flows and that managed reaches would be more similar to the reference reaches. Our results suggest that the reintroduction of large wood did not significantly change the character of the hydraulic landscape at the reach scale after several months (p = 0.16) or several years (p = 0.29). Overall, the character of the hydraulic landscape in the managed reaches was more similar to the hydraulic landscape of the control reaches than the hydraulic landscape of the reference reaches, at low flows. Some variability in the hydraulic landscapes was detected over time, and this may reflect reworking of riverbed sediments and sensitivity to variation in discharge. The lack of a response in the low flow hydraulic landscape to the reintroduction of large wood is inferred because the character (the size and complexity of individual pieces) and positioning of large wood in managed reaches did not mimic that of reference reaches effectively despite the abundance of wood pieces being similar in the reference and managed reaches. The results of this study highlight the importance of understanding the natural character and distribution of large wood on hydraulic landscapes in large low energy lowland river systems, especially when reintroducing large wood for river management purposes.

Effect of citric acid modification of aspen wood on sorption of copper ion

Treesearch

James D. McSweeny; Roger M. Rowell; Soo Hong Min

2006-01-01

Milled aspen wood was thermochemically modified with citric acid for the purpose of improving the copper (Cu2+) ion sorption capacity of the wood when tested in 24-hour equilibrium batch tests. The wood-citric acid adducts provided additional carboxyl groups to those in the native wood and substantially increased Cu2+ ion uptake of the modified wood compared with that...

Water repellents and water-repellent preservatives for wood

Treesearch

R. Sam Williams; William C. Feist

1999-01-01

Water repellents and water-repellent preservatives increase the durability of wood by enabling the wood to repel liquid water. This report focuses on water-repellent finishes for wood exposed outdoors above ground. The report includes a discussion of the effects of outdoor exposure on wood, the characteristics of water repellent and water-repellent preservative...

The effect on biological and moisture resistance of epichlorohydrin chemically modified wood

Treesearch

Rebecca E. Ibach; Beom-Goo Lee

2002-01-01

Southern pine solid wood and fiber were chemically modified with epichlorohydrin to help in understanding the role of moisture in the mechanism of biological effectiveness of chemically modified wood. The solid wood had weight gains from 11% to 34%, while the fiber had weight gains from 9% to 75%. After modification, part of the specimens were water leached for 2 weeks...

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

Treesearch

Marcela Zalamea; Grizelle Gonzalez; Chien-Lu Ping; Gary Michaelson

2007-01-01

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...

Effects of Heat-Treated Wood Particles on the Physico-Mechanical Properties and Extended Creep Behavior of Wood/Recycled-HDPE Composites Using the Time-Temperature Superposition Principle.

PubMed

Yang, Teng-Chun; Chien, Yi-Chi; Wu, Tung-Lin; Hung, Ke-Chang; Wu, Jyh-Horng

2017-03-30

This study investigated the effectiveness of heat-treated wood particles for improving the physico-mechanical properties and creep performance of wood/recycled-HDPE composites. The results reveal that the composites with heat-treated wood particles had significantly decreased moisture content, water absorption, and thickness swelling, while no improvements of the flexural properties or the wood screw holding strength were observed, except for the internal bond strength. Additionally, creep tests were conducted at a series of elevated temperatures using the time-temperature superposition principle (TTSP), and the TTSP-predicted creep compliance curves fit well with the experimental data. The creep resistance values of composites with heat-treated wood particles were greater than those having untreated wood particles due to the hydrophobic character of the treated wood particles and improved interfacial compatibility between the wood particles and polymer matrix. At a reference temperature of 20 °C, the improvement of creep resistance ( ICR ) of composites with heat-treated wood particles reached approximately 30% over a 30-year period, and it increased significantly with increasing reference temperature.

Effects of Heat-Treated Wood Particles on the Physico-Mechanical Properties and Extended Creep Behavior of Wood/Recycled-HDPE Composites Using the Time–Temperature Superposition Principle

PubMed Central

Yang, Teng-Chun; Chien, Yi-Chi; Wu, Tung-Lin; Hung, Ke-Chang; Wu, Jyh-Horng

2017-01-01

This study investigated the effectiveness of heat-treated wood particles for improving the physico-mechanical properties and creep performance of wood/recycled-HDPE composites. The results reveal that the composites with heat-treated wood particles had significantly decreased moisture content, water absorption, and thickness swelling, while no improvements of the flexural properties or the wood screw holding strength were observed, except for the internal bond strength. Additionally, creep tests were conducted at a series of elevated temperatures using the time–temperature superposition principle (TTSP), and the TTSP-predicted creep compliance curves fit well with the experimental data. The creep resistance values of composites with heat-treated wood particles were greater than those having untreated wood particles due to the hydrophobic character of the treated wood particles and improved interfacial compatibility between the wood particles and polymer matrix. At a reference temperature of 20 °C, the improvement of creep resistance (ICR) of composites with heat-treated wood particles reached approximately 30% over a 30-year period, and it increased significantly with increasing reference temperature. PMID:28772726

The Influence of Tip Shape on the Wing Load Distribution as Determined by Flight Tests

NASA Technical Reports Server (NTRS)

Rhode, Richard V

1935-01-01

Pressure measurements were made in flight on the right upper wing of an M-3 airplane. The effects of tip plan form, washout, and transverse camber were investigated with eight tip forms in unyawed conditions through the range of positive lift coefficients from zero lift to the stall. The conclusion is that the tip plan form does not influence the span distribution of the coefficients of normal force and moment. It is shown inferentially that temperature, humidity, and the aging of the wood and fabric wing structure used on the M-3 airplane have an appreciable influence on the load distribution.

Chapter 2: Manufacturing Cross-laminated timber manufacturing

Treesearch

Borjen Yeh; Dave Kretschmann; Brad (Jianhe) Wang

2013-01-01

Cross-laminated timber ( CLT) is defined as a prefabricated solid engineered wood product made of at least three orthogonally bonded layers of solid-sawn lumber or structural composite lumber (SCL) that are laminated by gluing oflongitudinal and transverse layers with structural adhesives to form a solid rectangular-shaped, straight, and plane timber intended for roof...

Effect of heat treatment of wood on the morphology, surface roughness and penetration of simulated and human blood.

PubMed

Rekola, J; Lassila, L V J; Nganga, S; Ylä-Soininmäki, A; Fleming, G J P; Grenman, R; Aho, A J; Vallittu, P K

2014-01-01

Wood has been used as a model material for the development of novel fiber-reinforced composite bone substitute biomaterials. In previous studies heat treatment of wood was perceived to significantly increase the osteoconductivity of implanted wood material. The objective of this study was to examine some of the changing attributes of wood materials that may contribute to improved biological responses gained with heat treatment. Untreated and 140°C and 200°C heat-treated downy birch (Betula pubescens Ehrh.) were used as the wood materials. Surface roughness and the effect of pre-measurement grinding were measured with contact and non-contact profilometry. Liquid interaction was assessed with a dipping test using two manufactured liquids (simulated blood) as well as human blood. SEM was used to visualize possible heat treatment-induced changes in the hierarchical structure of wood. The surface roughness was observed to significantly decrease with heat treatment. Grinding methods had more influence on the surface contour and roughness than heat treatment. The penetration of the human blood in the 200°C heat-treated exceeded that in the untreated and 140°C heat-treated materials. SEM showed no significant change due to heat treatment in the dry-state morphology of the wood. The results of the liquid penetration test support previous findings in literature concerning the effects of heat treatment on the biological response to implanted wood. Heat-treatment has only a marginal effect on the surface contour of wood. The highly specialized liquid conveyance system of wood may serve as a biomimetic model for the further development of tailored fiber-composite materials.

Micronized Copper Wood Preservatives: Efficacy of Ion, Nano, and Bulk Copper against the Brown Rot Fungus Rhodonia placenta

PubMed Central

Civardi, Chiara; Schubert, Mark; Fey, Angelika; Wick, Peter; Schwarze, Francis W. M. R.

2015-01-01

Recently introduced micronized copper (MC) formulations, consisting of a nanosized fraction of basic copper (Cu) carbonate (CuCO3·Cu(OH)2) nanoparticles (NPs), were introduced to the market for wood protection. Cu NPs may presumably be more effective against wood-destroying fungi than bulk or ionic Cu compounds. In particular, Cu- tolerant wood-destroying fungi may not recognize NPs, which may penetrate into fungal cell walls and membranes and exert their impact. The objective of this study was to assess if MC wood preservative formulations have a superior efficacy against Cu-tolerant wood-destroying fungi due to nano effects than conventional Cu biocides. After screening a range of wood-destroying fungi for their resistance to Cu, we investigated fungal growth of the Cu-tolerant fungus Rhodonia placenta in solid and liquid media and on wood treated with MC azole (MCA). In liquid cultures we evaluated the fungal response to ion, nano and bulk Cu distinguishing the ionic and particle effects by means of the Cu2+ chelator ammonium tetrathiomolybdate (TTM) and measuring fungal biomass, oxalic acid production and laccase activity of R. placenta. Our results do not support the presence of particular nano effects of MCA against R. placenta that would account for an increased antifungal efficacy, but provide evidence that attribute the main effectiveness of MCA to azoles. PMID:26554706

Micronized Copper Wood Preservatives: Efficacy of Ion, Nano, and Bulk Copper against the Brown Rot Fungus Rhodonia placenta.

PubMed

Civardi, Chiara; Schubert, Mark; Fey, Angelika; Wick, Peter; Schwarze, Francis W M R

2015-01-01

Recently introduced micronized copper (MC) formulations, consisting of a nanosized fraction of basic copper (Cu) carbonate (CuCO3·Cu(OH)2) nanoparticles (NPs), were introduced to the market for wood protection. Cu NPs may presumably be more effective against wood-destroying fungi than bulk or ionic Cu compounds. In particular, Cu- tolerant wood-destroying fungi may not recognize NPs, which may penetrate into fungal cell walls and membranes and exert their impact. The objective of this study was to assess if MC wood preservative formulations have a superior efficacy against Cu-tolerant wood-destroying fungi due to nano effects than conventional Cu biocides. After screening a range of wood-destroying fungi for their resistance to Cu, we investigated fungal growth of the Cu-tolerant fungus Rhodonia placenta in solid and liquid media and on wood treated with MC azole (MCA). In liquid cultures we evaluated the fungal response to ion, nano and bulk Cu distinguishing the ionic and particle effects by means of the Cu2+ chelator ammonium tetrathiomolybdate (TTM) and measuring fungal biomass, oxalic acid production and laccase activity of R. placenta. Our results do not support the presence of particular nano effects of MCA against R. placenta that would account for an increased antifungal efficacy, but provide evidence that attribute the main effectiveness of MCA to azoles.

Bioprocessing preservative-treated waste wood

Treesearch

Barbara L. Illman; Vina W. Yang; Les Ferge

2000-01-01

Disposal of preservative-treated waste wood is a growing problem worldwide. Bioprocessing the treated wood offers one approach to waste management under certain conditions. One goal is to use wood decay fungi to reduce the volume of waste with an easily managed system in a cost-effective manner. Wood decay fungi were obtained from culture collections in the Mycology...

Effects of chemically modified wood on bond durability

Treesearch

Rishawn Brandon; Rebecca E. Ibach; Charles R. Frihart

2005-01-01

Chemical modification of wood can improve its dimensional stability and resistance to biological degradation and moisture, but modification can also create a new surface for bonding. Acetylation of wood results in the loss of hydroxyl groups, making the wood more hydrophobic and reduces its ability to hydrogen-bond with the adhesive. In contrast, reacting wood with...

Juvenile wood effect in red alder : analysis of physical and mechanical data to delineate juvenile and mature wood zones

Treesearch

Joel W. Evans; John F. Senft; David W. Green

2000-01-01

The objective of this study was to investigate the influence of juvenile wood on the mechanical and physical properties of red alder. Tree growth in the first 10 to 20 years, usually referred to as juvenile wood, often influences wood quality by adversely affecting mechanical strength properties. Strength can be reduced up to 50 percent by the presence of juvenile wood...

Modeling the CO2-effects of forest management and wood usage on a regional basis.

PubMed

Knauf, Marcus; Köhl, Michael; Mues, Volker; Olschofsky, Konstantin; Frühwald, Arno

2015-12-01

At the 15 th Conference of Parties of the UN Framework Convention on Climate Change, Copenhagen, 2009, harvested wood products were identified as an additional carbon pool. This modification eliminates inconsistencies in greenhouse gas reporting by recognizing the role of the forest and timber sector in the global carbon cycle. Any additional CO 2 -effects related to wood usage are not considered by this modification. This results in a downward bias when the contribution of the forest and timber sector to climate change mitigation is assessed. The following article analyses the overall contribution to climate protection made by the forest management and wood utilization through CO 2 -emissions reduction using an example from the German state of North Rhine-Westphalia. Based on long term study periods (2011 to 2050 and 2100, respectively). Various alternative scenarios for forest management and wood usage are presented. In the mid- to long-term (2050 and 2100, respectively) the net climate protection function of scenarios with varying levels of wood usage is higher than in scenarios without any wood usage. This is not observed for all scenarios on short and mid term evaluations. The advantages of wood usage are evident although the simulations resulted in high values for forest storage in the C pools. Even the carbon sink effect due to temporal accumulation of deadwood during the period from 2011 to 2100 is outbalanced by the potential of wood usage effects. A full assessment of the CO 2 -effects of the forest management requires an assessment of the forest supplemented with an assessment of the effects of wood usage. CO 2 -emission reductions through both fuel and material substitution as well as CO 2 sink in wood products need to be considered. An integrated assessment of the climate protection function based on the analysis of the study's scenarios provides decision parameters for a strategic approach to climate protection with regard to forest management and wood use at regional and national levels. The short-term evaluation of subsystems can be misleading, rendering long-term evaluations (until 2100, or even longer) more effective. This is also consistent with the inherently long-term perspective of forest management decisions and measures.

Wood fuel consumption and mortality rates in Sub-Saharan Africa: Evidence from a dynamic panel study.

PubMed

Sulaiman, Chindo; Abdul-Rahim, A S; Chin, Lee; Mohd-Shahwahid, H O

2017-06-01

This study examined the impact of wood fuel consumption on health outcomes, specifically under-five and adult mortality in Sub-Saharan Africa, where wood usage for cooking and heating is on the increase. Generalized method of moment (GMM) estimators were used to estimate the impact of wood fuel consumption on under-five and adult mortality (and also male and female mortality) in the region. The findings revealed that wood fuel consumption had significant positive impact on under-five and adult mortality. It suggests that over the studied period, an increase in wood fuel consumption has increased the mortality of under-five and adult. Importantly, it indicated that the magnitude of the effect of wood fuel consumption was more on the under-five than the adults. Similarly, assessing the effect on a gender basis, it was revealed that the effect was more on female than male adults. This finding suggests that the resultant mortality from wood smoke related infections is more on under-five children than adults, and also are more on female adults than male adults. We, therefore, recommended that an alternative affordable, clean energy source for cooking and heating should be provided to reduce the wood fuel consumption. Copyright © 2017 Elsevier Ltd. All rights reserved.

Intense laser field effects on a Woods-Saxon potential quantum well

NASA Astrophysics Data System (ADS)

Restrepo, R. L.; Morales, A. L.; Akimov, V.; Tulupenko, V.; Kasapoglu, E.; Ungan, F.; Duque, C. A.

2015-11-01

This paper presents the results of the theoretical study of the effects of non-resonant intense laser field and electric and magnetic fields on the optical properties in an quantum well (QW) make with Woods-Saxon potential profile. The electric field and intense laser field are applied along the growth direction of the Woods-Saxon quantum well and the magnetic field is oriented perpendicularly. To calculate the energy and the wave functions of the electron in the Woods-Saxon quantum well, the effective mass approximation and the method of envelope wave function are used. The confinement in the Woods-Saxon quantum well is changed drastically by the application of intense laser field or either the effect of electric and magnetic fields. The optical properties are calculated using the compact density matrix.

Characterization of carbonaceous aerosols emitted from outdoor wood boilers

EPA Science Inventory

This study examines the chemical properties of carbonaceous aerosols emitted from different outdoor wood-fired boiler (OWB) technologies including two cord-wood heaters, a pellet heater, and a multistage gasifier/combustor. The effect of fuel type [red oak wood (Quercus rubra), w...

Compact vacuum insulation

DOEpatents

Benson, D.K.; Potter, T.F.

1992-10-27

Improved compact insulation panel is provided which is comprised of two adjacent metal sheets spaced close together with a plurality of spherical, or other discretely shaped, glass or ceramic beads optimally positioned between the sheets to provide support and maintain the spacing between the metal sheets when the gases there between are evacuated to form a vacuum. These spherical glass beads provide the maximum support while minimizing thermal conductance. In its preferred embodiment; these two metal sheets are textured with ribs or concave protrusions in conjunction with the glass beads to maximize the structural integrity of the panels while increasing the spacing between beads, thereby reducing the number of beads and the number of thermal conduction paths. Glass or porcelain-enameled liners in combination with the glass spacers and metal sidewalls effectively decrease thermal conductivity, and various laminates, including wood, porcelain-enameled metal, and others effectively increase the strength and insulation capabilities of the panels. Also, a metal web is provided to hold the spacers in place, and strategic grooves are shown to accommodate expansion and contraction or shaping of the panels. 35 figs.

Compact vacuum insulation

DOEpatents

Benson, David K.; Potter, Thomas F.

1992-01-01

Improved compact insulation panel is provided which is comprised of two adjacent metal sheets spaced close together with a plurality of spherical, or other discretely shaped, glass or ceramic beads optimally positioned between the sheets to provide support and maintain the spacing between the metal sheets when the gases therebetween are evacuated to form a vacuum. These spherical glass beads provide the maximum support while minimizing thermal conductance. In its preferred embodiment; these two metal sheets are textured with ribs or concave protrusions in conjunction with the glass beads to maximize the structural integrity of the panels while increasing the spacing between beads, thereby reducing the number of beads and the number of thermal conduction paths. Glass or porcelain-enameled liners in combination with the glass spacers and metal sidewalls effectively decrease thermal conductivity, and variious laminates, including wood, porcelain-enameled metal, and others effectively increase the strength and insulation capabilities of the panels. Also, a metal web is provided to hold the spacers in place, and strategic grooves are shown to accommodate expansion and contraction or shaping of the panels.

Increased anthropogenic disturbance and aridity reduce phylogenetic and functional diversity of ant communities in Caatinga dry forest.

PubMed

Arnan, Xavier; Arcoverde, Gabriela B; Pie, Marcio R; Ribeiro-Neto, José D; Leal, Inara R

2018-08-01

Anthropogenic disturbance and climate change are major threats to biodiversity. The Brazilian Caatinga is the world's largest and most diverse type of seasonally dry tropical forest. It is also one of the most threatened, but remains poorly studied. Here, we analyzed the individual and combined effects of anthropogenic disturbance (three types: livestock grazing, wood extraction, and miscellaneous use of forest resources) and increasing aridity on taxonomic, phylogenetic and functional ant diversity in the Caatinga. We found no aridity and disturbance effects on taxonomic diversity. In spite of this, functional diversity, and to a lesser extent phylogenetic diversity, decreased with increased levels of disturbance and aridity. These effects depended on disturbance type: livestock grazing and miscellaneous resource use, but not wood extraction, deterministically filtered both components of diversity. Interestingly, disturbance and aridity interacted to shape biodiversity responses. While aridity sometimes intensified the negative effects of disturbance, the greatest declines in biodiversity were in the wettest areas. Our results imply that anthropogenic disturbance and aridity interact in complex ways to endanger biodiversity in seasonally dry tropical forests. Given global climate change, neotropical semi-arid areas are habitats of concern, and our findings suggest Caatinga conservation policies must prioritize protection of the wettest areas, where biodiversity loss stands to be the greatest. Given the major ecological relevance of ants, declines in both ant phylogenetic and functional diversity might have downstream effects on ecosystem processes, insect populations, and plant populations. Copyright © 2018 Elsevier B.V. All rights reserved.

The central role of wood biology in understanding the durability of wood-coating interactions

Treesearch

Alex C. Wiedenhoeft

2007-01-01

To design effectively for durability, one must actively and honestly assess the material properties and limitations of each of the components in the design system; wood or wood composite, and the coating. Inasmuch as wood coatings are manufactured to specified tolerances from known materials, we have control of that component of the system. Compared to manmade...

Moisture Performance of wood-plastic composites reinforced with extracted and delignified wood flour

Treesearch

Yao Chen; Nicole M. Stark; Mandla A. Tshabalala; Jianmin Gao; Yongming Fan

2014-01-01

This study investigated the effect of using extracted and delignified wood flour on water sorption properties of wood–plastic composites. Wood flour (WF) extraction was performed with three solvent systems: toluene/ethanol (TE), acetone/water (AW), and hot water (HW); delignification was conducted using sodium chlorite/acetic acid solution. A 24 full-factorial...

Allowable bending stresses of wood for use in portable wood ladders

Treesearch

Fred Werren

1975-01-01

A standard for portable wood ladders has been in effect since 1923, and has been revised several times since then. The most recent publication is "American National Standard Safety Standard for Portable Wood Ladders," A14.1-1975, from American National Standards Institute, Inc. Methods of arriving at allowable stresses for wood ladder parts have never been...

Factors influencing wood mobilization in Minnesota streams

USGS Publications Warehouse

Merten, Eric; Finlay, Jacques; Johnson, Lucinda; Newman, Raymond; Stefan, Heinz; Vondracek, Bruce C.

2010-01-01

Natural pieces of wood provide a variety of ecosystem functions in streams including habitat, organic matter retention, increased hyporheic exchange and transient storage, and enhanced hydraulic and geomorphic heterogeneity. Wood mobilization is a critical process in determining the residence time of wood. We documented the characteristics and locations of 865 natural wood pieces (>0.05 m in diameter for a portion >1 m in length) in nine streams along the north shore of Lake Superior in Minnesota. We determined the locations of the pieces again after an overbank stormflow event to determine the factors that influenced mobilization of stationary wood pieces in natural streams. Seven of 11 potential predictor variables were identified with multiple logistic regression as significant to mobilization: burial, effective depth, ratio of piece length to effective stream width (length ratio), bracing, rootwad presence, downstream force ratio, and draft ratio. The final model (P< 0.001, r2 = 0.39) indicated that wood mobilization under natural conditions is a complex function of both mechanical factors (burial, length ratio, bracing, rootwad presence, draft ratio) and hydraulic factors (effective depth, downstream force ratio). If stable pieces are a goal for stream management then features such as partial burial, low effective depth, high length relative to channel width, bracing against other objects (e.g., stream banks, trees, rocks, or larger wood pieces), and rootwads are desirable. Using the model equation from this study, stewards of natural resources can better manage in-stream wood for the benefit of stream ecosystems.

Dynamic aspects of large woody debris in river channels

NASA Astrophysics Data System (ADS)

Vergaro, Alexandra; Caporali, Enrica; Becchi, Ignazio

2015-04-01

Large Woody Debris (LWD) are an integral component of the fluvial environment. They represent an environmental resource, but without doubt they represent also a risk factor for the amplification that could give to the destructive power of a flood event. While countless intervention in river channels have reintroduced wood in rivers with restoration and banks protection aims, during several flash flood events LWD have had a great part in catastrophic consequences, pointing out the urgency of an adequate risk assessment procedure. At present wood dynamics in rivers is not systematically considered within the procedures for the elaboration of hazard maps resulting in loss of prediction accuracy and underestimation of hazard impacts. The assessment inconsistency comes from the complexity of the question: several aspects in wood processes are not yet well known and the superposition of different physical phenomena results in great difficulty to predict critical scenarios. The presented research activity has been aimed to improve management skills for the assessment of the hydrologic risk associated to the presence of large woody debris in rivers, improving knowledge about LWD dynamic processes and proposing effective tools for monitoring and mapping river catchments vulnerability. Utilizing critical review of the published works, field surveys and experimental investigations LWD damaging potential has been analysed to support the identification of the exposed sites and the redaction of hazard maps, taking into account that a comprehensive procedure has to involve: a) Identification of the critical cross sections; b) Evaluation of wood availability in the river catchment; c) Prediction of hazard scenarios through the estimation of water discharge, wood recruitment and entrainment, wood transport and destination. Particularly, a survey sheets form for direct measurements has been implemented and tested in field to provide an investigation instruments for wood and river reach monitoring. The sheets have been settled down to answer to several information requests involved in all steps of a risk assessment procedure, and to provide useful indications for a better comprehension of the dynamics of wood in rivers. Based on a critical analysis of the current state of the art an improved theoretical mechanistic model of LWD entrainment has been proposed and tested with flume experiments, considering this feature a crucial aspect in wood dynamics. The entrainment condition is traditionally physically based on the stationary equilibrium of gravity, buoyancy, friction and hydrodynamic forces acting on the body partially submerged in a flow field. In this work no any force has been neglected a priori and an original interpretation of some aspects of the problem has been adduced taking cues from different disciplines The proposed approach is able to provide a threshold parameter, showing relative small experimental scatter, and to discriminate between entrainment modes (sliding, rolling, floating). The provided correlation, for each particular configuration of the debris (shape and orientation), establish the threshold value for the proposed entrainment criterion that allows determining, for a discharge with a certain recurrence interval, the probability of motion and the relative entrainment mode.

Experiences of Earned Success: Community College Students' Shifts in College Confidence

ERIC Educational Resources Information Center

Bickerstaff, Susan; Barragan, Melissa; Rucks-Ahidiana, Zawadi

2017-01-01

Confidence and related constructs such as self-efficacy have been previously identified as important to college student persistence and performance (e.g., Cox, 2009; Wood & Turner, 2011), but existing research gives little indication of how confidence is shaped by students' day-to-day interactions in class and on campus. Using data from nearly…

Balancing Eggs

ERIC Educational Resources Information Center

Mills, Allan

2014-01-01

Theory predicts that an egg-shaped body should rest in stable equilibrium when on its side, balance vertically in metastable equilibrium on its broad end and be completely unstable on its narrow end. A homogeneous solid egg made from wood, clay or plastic behaves in this way, but a real egg will not stand on either end. It is shown that this…

Thermal conductivity of some common forest fuels

Treesearch

G.M. Byram; W.L. Fons

1952-01-01

This study was designed to obtain thermal conductivity of som common forest fuels which hitherto had defied such efforts because of their shape, size, or structure. Dry leaves and decayed. wood (punk) were modified so that conductivity measurements could be made by a thin plate uni-directional heat flow calibration stand, Resultss of these measurements are compatible...

Water content measurement in forest soils and decayed wood using time domain reflectometry

Treesearch

Andrew Gray; Thomas Spies

1995-01-01

The use of time domain reflectometry to measure moisture content in forest soils and woody debris was evaluated. Calibrations were developed on undisturbed soil cores from four forest stands and on point samples from decayed logs. An algorithm for interpreting irregularly shaped traces generated by the reflectometer was also developed. Two different calibration...

The North American Product Standard for Cross-Laminated Timber

Treesearch

Borjen Yeh; Sylvain Gagnon; Tom Williamson; Ciprian Pirvu; Conroy Lum; Dave Kretschmann

2012-01-01

Cross-laminated timber (CLT) is a prefabricated solid engineered wood product made of at least three orthogonally bonded layers of solid-sawn lumber or structural composite lumber that are laminated by gluing of longitudinal and transverse layers with structural adhesives to form a solid rectangular-shaped, straight, and plane timber intended for roof, floor, or wall...

Analysis of the semi-permanent house in Merauke city in terms of aesthetic value in architecture

NASA Astrophysics Data System (ADS)

Topan, Anton; Octavia, Sari; Soleman, Henry

2018-05-01

Semi permanent houses are also used called “Rumah Kancingan” is the houses that generally exist in the Merauke city. Called semi permanent because the main structure use is woods even if the walls uses bricks. This research tries to analyze more about Semi permanent house in terms of aesthethics value. This research is a qualitative research with data collection techniques using questionnaire method and direct observation field and study of literature. The result of questionnaire data collection then processed using SPSS to get the influence of independent variable against the dependent variable and found that color, ornament, shape of the door-window and shape of roof (independent) gives 97,1% influence to the aesthetics of the Semi permanent house and based on the output coefficient SPSS obtained that the dependent variable has p-value < 0.05 which means independent variables have an effect on significant to aesthetic variable. For variables of semi permanent and wooden structure gives an effect of 98,6% to aesthetics and based on the result of SPSS coefficient it is found that free variable has p-value < 0.05 which means independent variables have an effect on significant to aesthetic variable.

The effect of tannins and pH on the corrosion of metals in wood extracts

Treesearch

Samuel Zelinka; D.S. Stone

2011-01-01

Tannins and pH are often cited as factors that affect the corrosiveness of wood yet there are few data to confirm these statements. The purpose of this paper is to systematically investigate the effect of tannins and pH on corrosion of metals in wood. Four wood species known to vary in both their pH and extractives were chosen and extracted with water. The pH, tannin...

Effects of permethrin treated wood on the subterranean termite Reticulitermes flavipes (Kollar) and comparison of solvent extraction for HPLC analysis of permethrin in wood

Treesearch

Mark Mankowski; Blossie Boyd; Geoffrey Webb

2016-01-01

Permethrin is a common insecticide used in wood preservation. It is an effective synthetic pyrethroid that is considered to be less toxic to higher organisms than organochlorine insecticides. In wood preservation, it can be used in combination with fungicides such as 3-iodo-2-propynyl butyl carbamate (IPBC). Permethrin has a dual mode of action as it is a repellent and...

Bridging the gaps: An overview of wood across time and space in diverse rivers

NASA Astrophysics Data System (ADS)

Wohl, Ellen

2017-02-01

Nearly 50 years of research focused on large wood (LW) in rivers provide a basis for understanding how wood enters rivers; how wood decays, breaks, and is transported downstream; and how at least temporarily stable wood influences channel geometry, fluxes of water, sediment, and organic matter, and the abundance and diversity of aquatic and riparian organisms. Field-based studies have led to qualitative conceptual models and to numerical stimulations of river processes involving wood. Numerous important gaps remain, however, in our understanding of wood dynamics. The majority of research on wood in rivers focuses on small- to medium-sized rivers, defined using the ratio of wood piece size to channel width as channels narrower than the locally typical wood-piece length (small) and slightly narrower than the longer wood pieces present (medium). Although diverse geographic regions and biomes are represented by one or a few studies in each region, the majority of research comes from perennial rivers draining temperate conifer forests. Regional syntheses most commonly focus on the Pacific Northwest region of North America where most of these studies originate. Consequently, significant gaps in our understanding include lack of knowledge of wood-related processes in large rivers, dryland rivers, and rivers of the high and low latitudes. Using a wood budget as an organizing framework, this paper identifies other gaps related to wood recruitment, transport, storage, and how beavers influence LW dynamics. With respect to wood recruitment, we lack information on the relative importance of mass tree mortality and transport of buried or surficial downed wood from the floodplain into the channel in diverse settings. Knowledge gaps related to wood transport include transport distances of LW and thresholds for LW mobility in small to medium rivers. With respect to wood storage, we have limited data on longitudinal trends in LW loads within unaltered large and great rivers and on fluctuations in LW load over time intervals greater than a few years. Other knowledge gaps relate to physical and ecological effects of wood, including the magnitude of flow resistance caused by LW; patterns of wood-related sediment storage for diverse river sizes and channel geometry; quantification of channel-floodplain-LW interactions; and potential threshold effects of LW in relation to physical processes and biotic communities. Finally, knowledge gaps are related to management of large wood and river corridors, including understanding the consequences of enormous historical reductions in LW load in rivers through the forested portions of the temperate zone; and how to effectively reintroduce and manage existing LW in river corridors, which includes enhancing public understanding of the importance of LW. Addressing these knowledge gaps requires more case studies from diverse rivers, as well as more syntheses and metadata analyses.

Effects of wood on debris flow runout in small mountain watersheds.

Treesearch

Stephen T. Lancaster; Shannon K. Hayes

2003-01-01

Debris flows have typically been viewed as two-phase mixtures of sediment and water, but in forested mountain landscapes, wood can represent a sizable fraction of total flow volume. The effects of this third phase on flow behavior are poorly understood. To evaluate whether wood can have a significant effect on debris flow runout in small mountainous watersheds, we used...

Japanese flowering cherry tree as a woody plant candidate grown in space

NASA Astrophysics Data System (ADS)

Tomita-Yokotani, K.; Yoshida, S.; Hashimoto, H.; Nyunoya, H.; Funada, R.; Katayama, T.; Suzuki, T.; Honma, T.; Nagatomo, M.; Nakamura, T.

We are proposing to raise woody plant in space for several applications Japanese flowering cherry tree is a candidate to do wood science in space Mechanism of sensing gravity and controlling shape of tree has been studied quite extensively Cherry mutants associated with gravity are telling responsible plant hormones and molecular machinery for plant adaptation against action of gravity Space experiment using our wood model contribute to understand molecular and cellular process of gravitropism in plant Tree is considered to be an important member in space agriculture to produce excess oxygen wooden materials for constructing living environment and provide biomass for cultivating mushrooms and insects Furthermore trees and their flowers improve quality of life under stressful environment in outer space

Microscopic few-body and Gaussian-shaped density distributions for the analysis of the 6He exotic nucleus with different target nuclei

NASA Astrophysics Data System (ADS)

Aygun, M.; Kucuk, Y.; Boztosun, I.; Ibraheem, Awad A.

2010-12-01

The elastic scattering angular distributions of 6He projectile on different medium and heavy mass target nuclei including 12C, 27Al, 58Ni, 64Zn, 65Cu, 197Au, 208Pb and 209Bi have been examined by using the few-body and Gaussian-shaped density distributions at various energies. The microscopic real parts of the complex nuclear optical potential have been obtained by using the double-folding model for each of the density distributions and the phenomenological imaginary potentials have been taken as the Woods-Saxon type. Comparative results of the few-body and Gaussian-shaped density distributions together with the experimental data are presented within the framework of the optical model.

Long-term priority effects among insects and fungi colonizing decaying wood.

PubMed

Weslien, Jan; Djupström, Line B; Schroeder, Martin; Widenfalk, Olof

2011-11-01

1. Priority effects have been hypothesized to have long-lasting impact on community structure in natural ecosystems. Long-term studies of priority effects in natural ecosystems are however sparse, especially in terrestrial ecosystems. 2. Wood decay is a slow process involving a high diversity of insect and fungus species. Species interactions that drive change in communities of insects and fungi during wood decay are poorly understood because of a lack of sufficient long-term studies. 3. In this paper, we followed the colonization and succession of wood-living insects and fungi on cut trees during 15 years, from tree death and onwards, in a boreal forest landscape. We test the long-term priority effects hypothesis that the identity and abundance of species that colonize first affect the colonization success of later-arriving species. We also hypothesize that species interact in both facilitative and inhibitory ways, which ultimately affect habitat quality for a red-listed late-succession beetle species. 4. Possible causal associations between species were explored by path analysis. The results indicate that one bark beetle species, Hylurgops palliatus, and one wood-borer species, Monochamus sutor, which colonized the wood during the first year after cutting, influenced the occurrence of a rare, wood-living beetle, Peltis grossa, that started to emerge from the stumps about 10 years later. The positive effects of Hylurgops palliatus and negative effects of M. sutor were largely mediated through the wood-decaying fungus species Fomitopsis pinicola. 5. The study shows that variable priority effects may have long-lasting impact on community assembly in decaying wood. The study also exemplifies new possibilities for managing populations of threatened species by exploring links between early, well-understood species guilds and late, more poorly understood species guilds. © 2011 The Authors. Journal of Animal Ecology © 2011 British Ecological Society.

21 CFR 178.3800 - Preservatives for wood.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Preservatives for wood. 178.3800 Section 178.3800... Certain Adjuvants and Production Aids § 178.3800 Preservatives for wood. Preservatives may be safely used... to accomplish the technical effect of protecting the wood from decay, mildew, and water absorption...

21 CFR 178.3800 - Preservatives for wood.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Preservatives for wood. 178.3800 Section 178.3800... Certain Adjuvants and Production Aids § 178.3800 Preservatives for wood. Preservatives may be safely used... to accomplish the technical effect of protecting the wood from decay, mildew, and water absorption...

21 CFR 178.3800 - Preservatives for wood.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Preservatives for wood. 178.3800 Section 178.3800... Certain Adjuvants and Production Aids § 178.3800 Preservatives for wood. Preservatives may be safely used... to accomplish the technical effect of protecting the wood from decay, mildew, and water absorption...

21 CFR 178.3800 - Preservatives for wood.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Preservatives for wood. 178.3800 Section 178.3800... Certain Adjuvants and Production Aids § 178.3800 Preservatives for wood. Preservatives may be safely used... to accomplish the technical effect of protecting the wood from decay, mildew, and water absorption...

Evolution of wood anatomical characters in Nepenthes and close relatives of Caryophyllales.

PubMed

Schwallier, Rachel; Gravendeel, Barbara; de Boer, Hugo; Nylinder, Stephan; van Heuven, Bertie Joan; Sieder, Anton; Sumail, Sukaibin; van Vugt, Rogier; Lens, Frederic

2017-05-01

Nepenthes attracts wide attention with its spectacularly shaped carnivorous pitchers, cultural value and horticultural curiosity. Despite the plant's iconic fascination, surprisingly little anatomical detail is known about the genus beyond its modified leaf tip traps. Here, the wood anatomical diversity of Nepenthes is explored. This diversity is further assessed with a phylogenetic framework to investigate whether the wood characters within the genus are relevant from an evolutionary or ecological perspective, or rather depend on differences in developmental stages, growth habits, substrates or precipitation. Observations were performed using light microscopy and scanning electron microscopy. Ancestral states of selected wood and pith characters were reconstructed using an existing molecular phylogeny for Nepenthes and a broader Caryophyllales framework. Pairwise comparisons were assessed for possible relationships between wood anatomy and developmental stages, growth habits, substrates and ecology. Wood anatomy of Nepenthes is diffuse porous, with mainly solitary vessels showing simple, bordered perforation plates and alternate intervessel pits, fibres with distinctly bordered pits (occasionally septate), apotracheal axial parenchyma and co-occurring uni- and multiseriate rays often including silica bodies. Precipitation and growth habit (stem length) are linked with vessel density and multiseriate ray height, while soil type correlates with vessel diameter, vessel element length and maximum ray width. For Caryophyllales as a whole, silica grains, successive cambia and bordered perforation plates are the result of convergent evolution. Peculiar helical sculpturing patterns within various cell types occur uniquely within the insectivorous clade of non-core Caryophyllales. The wood anatomical variation in Nepenthes displays variation for some characters dependent on soil type, precipitation and stem length, but is largely conservative. The helical-banded fibre-sclereids that mainly occur idioblastically in pith and cortex are synapomorphic for Nepenthes , while other typical Nepenthes characters evolved convergently in different Caryophyllales lineages. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Evolution of wood anatomical characters in Nepenthes and close relatives of Caryophyllales

PubMed Central

Gravendeel, Barbara; de Boer, Hugo; Nylinder, Stephan; van Heuven, Bertie Joan; Sieder, Anton; Sumail, Sukaibin; van Vugt, Rogier; Lens, Frederic

2017-01-01

Abstract Background and Aims Nepenthes attracts wide attention with its spectacularly shaped carnivorous pitchers, cultural value and horticultural curiosity. Despite the plant’s iconic fascination, surprisingly little anatomical detail is known about the genus beyond its modified leaf tip traps. Here, the wood anatomical diversity of Nepenthes is explored. This diversity is further assessed with a phylogenetic framework to investigate whether the wood characters within the genus are relevant from an evolutionary or ecological perspective, or rather depend on differences in developmental stages, growth habits, substrates or precipitation. Methods Observations were performed using light microscopy and scanning electron microscopy. Ancestral states of selected wood and pith characters were reconstructed using an existing molecular phylogeny for Nepenthes and a broader Caryophyllales framework. Pairwise comparisons were assessed for possible relationships between wood anatomy and developmental stages, growth habits, substrates and ecology. Key Results Wood anatomy of Nepenthes is diffuse porous, with mainly solitary vessels showing simple, bordered perforation plates and alternate intervessel pits, fibres with distinctly bordered pits (occasionally septate), apotracheal axial parenchyma and co-occurring uni- and multiseriate rays often including silica bodies. Precipitation and growth habit (stem length) are linked with vessel density and multiseriate ray height, while soil type correlates with vessel diameter, vessel element length and maximum ray width. For Caryophyllales as a whole, silica grains, successive cambia and bordered perforation plates are the result of convergent evolution. Peculiar helical sculpturing patterns within various cell types occur uniquely within the insectivorous clade of non-core Caryophyllales. Conclusions The wood anatomical variation in Nepenthes displays variation for some characters dependent on soil type, precipitation and stem length, but is largely conservative. The helical-banded fibre-sclereids that mainly occur idioblastically in pith and cortex are synapomorphic for Nepenthes, while other typical Nepenthes characters evolved convergently in different Caryophyllales lineages. PMID:28387789

Classification of CITES-listed and other neotropical Meliaceae wood images using convolutional neural networks.

PubMed

Ravindran, Prabu; Costa, Adriana; Soares, Richard; Wiedenhoeft, Alex C

2018-01-01

The current state-of-the-art for field wood identification to combat illegal logging relies on experienced practitioners using hand lenses, specialized identification keys, atlases of woods, and field manuals. Accumulation of this expertise is time-consuming and access to training is relatively rare compared to the international demand for field wood identification. A reliable, consistent and cost effective field screening method is necessary for effective global scale enforcement of international treaties such as the Convention on the International Trade in Endagered Species (CITES) or national laws (e.g. the US Lacey Act) governing timber trade and imports. We present highly effective computer vision classification models, based on deep convolutional neural networks, trained via transfer learning, to identify the woods of 10 neotropical species in the family Meliaceae, including CITES-listed Swietenia macrophylla , Swietenia mahagoni , Cedrela fissilis , and Cedrela odorata . We build and evaluate models to classify the 10 woods at the species and genus levels, with image-level model accuracy ranging from 87.4 to 97.5%, with the strongest performance by the genus-level model. Misclassified images are attributed to classes consistent with traditional wood anatomical results, and our species-level accuracy greatly exceeds the resolution of traditional wood identification. The end-to-end trained image classifiers that we present discriminate the woods based on digital images of the transverse surface of solid wood blocks, which are surfaces and images that can be prepared and captured in the field. Hence this work represents a strong proof-of-concept for using computer vision and convolutional neural networks to develop practical models for field screening timber and wood products to combat illegal logging.

Effectiveness of the International Phytosanitary Standard ISPM No. 15 on reducing wood borer infestation rates in wood packaging material entering the United States

Treesearch

Robert A. Haack; Kerry O. Britton; Eckelhard G. Brockerhoff; Joseph F. Cavey; Lynn J. Garrett; Mark Kimberley; Frank Lowenstein; Amelia Nuding; Lars J. Olson; James Tumer; Kathryn N. Vasilaky

2014-01-01

Numerous bark- and wood-infesting insects have been introduced to new countries by international trade where some have caused severe environmental and economic damage. Wood packaging material (WPM), such as pallets, is one of the high risk pathways for the introduction of wood pests. International recognition of this risk resulted in adoption of International Standards...

Assemblage composition of fungal wood-decay species has a major influence on how climate and wood quality modify decomposition.

PubMed

Venugopal, Parvathy; Junninen, Kaisa; Edman, Mattias; Kouki, Jari

2017-03-01

The interactions among saprotrophic fungal species, as well as their interactions with environmental factors, may have a major influence on wood decay and carbon release in ecosystems. We studied the effect that decomposer diversity (species richness and assemblage composition) has on wood decomposition when the climatic variables and substrate quality vary simultaneously. We used two temperatures (16 and 21°C) and two humidity levels (70% and 90%) with two wood qualities (wood from managed and old-growth forests) of Pinus sylvestris. In a 9-month experiment, the effects of fungal diversity were tested using four wood-decaying fungi (Antrodia xantha, Dichomitus squalens, Fomitopsis pinicola and Gloeophyllum protractum) at assemblage levels of one, two and four species. Wood quality and assemblage composition affected the influence of climatic factors on decomposition rates. Fungal assemblage composition was found to be more important than fungal species richness, indicating that species-specific fungal traits are of paramount importance in driving decomposition. We conclude that models containing fungal wood-decay species (and wood-based carbon) need to take into account species-specific and assemblage composition-specific properties to improve predictive capacity in regard to decomposition-related carbon dynamics. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

LCA-based optimization of wood utilization under special consideration of a cascading use of wood.

PubMed

Höglmeier, Karin; Steubing, Bernhard; Weber-Blaschke, Gabriele; Richter, Klaus

2015-04-01

Cascading, the use of the same unit of a resource in multiple successional applications, is considered as a viable means to improve the efficiency of resource utilization and to decrease environmental impacts. Wood, as a regrowing but nevertheless limited and increasingly in demand resource, can be used in cascades, thereby increasing the potential efficiency per unit of wood. This study aims to assess the influence of cascading wood utilization on optimizing the overall environmental impact of wood utilization. By combining a material flow model of existing wood applications - both for materials provision and energy production - with an algebraic optimization tool, the effects of the use of wood in cascades can be modelled and quantified based on life cycle impact assessment results for all production processes. To identify the most efficient wood allocation, the effects of a potential substitution of non-wood products were taken into account in a part of the model runs. The considered environmental indicators were global warming potential, particulate matter formation, land occupation and an aggregated single score indicator. We found that optimizing either the overall global warming potential or the value of the single score indicator of the system leads to a simultaneous relative decrease of all other considered environmental impacts. The relative differences between the impacts of the model run with and without the possibility of a cascading use of wood were 7% for global warming potential and the single score indicator, despite cascading only influencing a small part of the overall system, namely wood panel production. Cascading led to savings of up to 14% of the annual primary wood supply of the study area. We conclude that cascading can improve the overall performance of a wood utilization system. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of compression wood on leaching of chromium, copper, and arsenic from CCA-C treated red pine (Pinus resinosa Ait.)

Treesearch

S. Nami. Kartal; Stan. Lebow

2000-01-01

In this study, the effect of compression wood formation on the release rate of chromium, copper, and arsenic elements from red pine (Pinus resinosa Ait) was investigated. Wood blocks from red pine containing compression and normal wood portions were treated with a 1.0% CCA-C solution and were then allowed to fix at 23 * 2*C (74 * 4*F) for 0, 6, 24, 48, 96, 192, and 336...

Feasibility of white-rot fungi for biodegradation of PCP-treated ammunition boxes. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scholze, R.J.; Lamar, R.T.; Bolduc, J.

1995-01-01

Millions of pounds of wood ammunition boxes treated with the wood preservative pentachiorophenol (PCP) are being stockpiled at military installations, primarily depots, because cost-effective disposal is not readily available. The Army needs cost-effective and environmentally benign treatment methods for destruction and disposal of PCP-treated wood products. This research investigated the use of white-rot fungi to biodegrade PCP-treated wood. Results showed that white-rot fungi effectively decreased the PCP concentration in contaminated hardwood and softwood chips. Under ideal laboratory conditions the fungi reduced the PCP concentration by 80 percent; a field study showed only a 30 percent decrease in PCP concentration. Despitemore » this disparity, this study demonstrated the feasibility of using white-rot fungi to reduce PCP in treated wood.« less

Factors controlling bark decomposition and its role in wood decomposition in five tropical tree species

PubMed Central

Dossa, Gbadamassi G. O.; Paudel, Ekananda; Cao, Kunfang; Schaefer, Douglas; Harrison, Rhett D.

2016-01-01

Organic matter decomposition represents a vital ecosystem process by which nutrients are made available for plant uptake and is a major flux in the global carbon cycle. Previous studies have investigated decomposition of different plant parts, but few considered bark decomposition or its role in decomposition of wood. However, bark can comprise a large fraction of tree biomass. We used a common litter-bed approach to investigate factors affecting bark decomposition and its role in wood decomposition for five tree species in a secondary seasonal tropical rain forest in SW China. For bark, we implemented a litter bag experiment over 12 mo, using different mesh sizes to investigate effects of litter meso- and macro-fauna. For wood, we compared the decomposition of branches with and without bark over 24 mo. Bark in coarse mesh bags decomposed 1.11–1.76 times faster than bark in fine mesh bags. For wood decomposition, responses to bark removal were species dependent. Three species with slow wood decomposition rates showed significant negative effects of bark-removal, but there was no significant effect in the other two species. Future research should also separately examine bark and wood decomposition, and consider bark-removal experiments to better understand roles of bark in wood decomposition. PMID:27698461

Factors controlling bark decomposition and its role in wood decomposition in five tropical tree species.

PubMed

Dossa, Gbadamassi G O; Paudel, Ekananda; Cao, Kunfang; Schaefer, Douglas; Harrison, Rhett D

2016-10-04

Organic matter decomposition represents a vital ecosystem process by which nutrients are made available for plant uptake and is a major flux in the global carbon cycle. Previous studies have investigated decomposition of different plant parts, but few considered bark decomposition or its role in decomposition of wood. However, bark can comprise a large fraction of tree biomass. We used a common litter-bed approach to investigate factors affecting bark decomposition and its role in wood decomposition for five tree species in a secondary seasonal tropical rain forest in SW China. For bark, we implemented a litter bag experiment over 12 mo, using different mesh sizes to investigate effects of litter meso- and macro-fauna. For wood, we compared the decomposition of branches with and without bark over 24 mo. Bark in coarse mesh bags decomposed 1.11-1.76 times faster than bark in fine mesh bags. For wood decomposition, responses to bark removal were species dependent. Three species with slow wood decomposition rates showed significant negative effects of bark-removal, but there was no significant effect in the other two species. Future research should also separately examine bark and wood decomposition, and consider bark-removal experiments to better understand roles of bark in wood decomposition.

Comparative Performance of Three Magnesium Compounds on Thermal Degradation Behavior of Red Gum Wood.

PubMed

Wu, Yiqiang; Yao, Chunhua; Hu, Yunchu; Zhu, Xiaodan; Qing, Yan; Wu, Qinglin

2014-01-24

The effect of basic magnesium carbonate (BMC), magnesium hydroxide (MH), and magnesium chloride hydrate (MCH) on thermal degradation of red gum wood was studied using cone calorimetry, Thermogravimetric-differential scanning calorimetry (TG-DSC) analysis, and X-ray diffraction (XRD) characterization. The results showed common fire retardation actions of the three compounds by releasing incombustible gas and/or water vapor to dilute combustible gas in the flaming zone, and by converting to MgO, which had a satisfactory protective wall effect on the wood. Individually, BMC absorbed heat from the wood at the pre-decomposition stage and, thus, slowed down wood pyrolysis process. It slightly increased the char yield by charring in both the charring stage and the char calcination stage. MH lost water at about 270 °C, close to the temperature at which wood thermally degraded. MH rendered wood char quickly, and the compact char layer impeded further carbonization and burning of inner wood. MCH promoted charring with Mg 2+ as a Lewis acid, and increased wood char yield. MCH also released Cl· free radical and HCl at 167 °C, which easily coordinated with combustion reaction radical, and slowed down, even inhibited, the combustion chain reaction.

Comparative Performance of Three Magnesium Compounds on Thermal Degradation Behavior of Red Gum Wood

PubMed Central

Wu, Yiqiang; Yao, Chunhua; Hu, Yunchu; Zhu, Xiaodan; Qing, Yan; Wu, Qinglin

2014-01-01

The effect of basic magnesium carbonate (BMC), magnesium hydroxide (MH), and magnesium chloride hydrate (MCH) on thermal degradation of red gum wood was studied using cone calorimetry, Thermogravimetric-differential scanning calorimetry (TG-DSC) analysis, and X-ray diffraction (XRD) characterization. The results showed common fire retardation actions of the three compounds by releasing incombustible gas and/or water vapor to dilute combustible gas in the flaming zone, and by converting to MgO, which had a satisfactory protective wall effect on the wood. Individually, BMC absorbed heat from the wood at the pre-decomposition stage and, thus, slowed down wood pyrolysis process. It slightly increased the char yield by charring in both the charring stage and the char calcination stage. MH lost water at about 270°C, close to the temperature at which wood thermally degraded. MH rendered wood char quickly, and the compact char layer impeded further carbonization and burning of inner wood. MCH promoted charring with Mg2+ as a Lewis acid, and increased wood char yield. MCH also released Cl· free radical and HCl at 167°C, which easily coordinated with combustion reaction radical, and slowed down, even inhibited, the combustion chain reaction. PMID:28788480

Disentangling the drivers of coarse woody debris behavior and carbon gas emissions during fire

NASA Astrophysics Data System (ADS)

Zhao, Weiwei; van der Werf, Guido R.; van Logtestijn, Richard S. P.; van Hal, Jurgen R.; Cornelissen, Johannes H. C.

2016-04-01

The turnover of coarse woody debris, a key terrestrial carbon pool, plays fundamental roles in global carbon cycling. Biological decomposition and fire are two main fates for dead wood turnover. Compared to slow decomposition, fire rapidly transfers organic carbon from the earth surface to the atmosphere. Both a-biotic environmental factors and biotic wood properties determine coarse wood combustion and thereby its carbon gas emissions during fire. Moisture is a key inhibitory environmental factor for fire. The properties of dead wood strongly affect how it burns either directly or indirectly through interacting with moisture. Coarse wood properties vary between plant species and between various decay stages. Moreover, if we put a piece of dead wood in the context of a forest fuel bed, the soil and wood contact might also greatly affect their fire behavior. Using controlled laboratory burns, we disentangled the effects of all these driving factors: tree species (one gymnosperms needle-leaf species, three angiosperms broad-leaf species), wood decay stages (freshly dead, middle decayed, very strongly decayed), moisture content (air-dried, 30% moisture content in mass), and soil-wood contact (on versus 3cm above the ground surface) on dead wood flammability and carbon gas efflux (CO2 and CO released in grams) during fire. Wood density was measured for all coarse wood samples used in our experiment. We found that compared to other drivers, wood decay stages have predominant positive effects on coarse wood combustion (for wood mass burned, R2=0.72 when air-dried and R2=0.52 at 30% moisture content) and associated carbon gas emissions (for CO2andCO (g) released, R2=0.55 when air-dried and R2=0.42 at 30% moisture content) during fire. Thus, wood decay accelerates wood combustion and its CO2 and CO emissions during fire, which can be mainly attributed to the decreasing wood density (for wood mass burned, R2=0.91 when air-dried and R2=0.63 at 30% moisture content) as wood becomes more decomposed. Our results provide quantitative experimental evidence for how several key abiotic and biotic factors, especially moisture content and the key underlying trait wood density, as well as their interactions, together drive coarse wood carbon turnover through fire. Our experimental data on coarse wood behavior and gas efflux during fire will help to improve the predictive power of global vegetation climate models on dead wood turnover and its feedback to climate.

EVALUATION OF THE EFFECTIVENESS OF COATINGS IN REDUCING DISLODGEABLE ARSENIC, CHROMIUM, AND COPPER FROM CCA TREATED WOOD; FINAL REPORT

EPA Science Inventory

EPA conducted a study to evaluate the effect of coatings on dislodgeable arsenic, chromium, and copper residues on the surfaces of chromated copper arsenate (CAA) treated wood. Dislodgeable CCA, determined by wipe sampling the wood surfaces, was the primary evaluation criterion f...

Protection of Historical Wood against Microbial Degradation-Selection and Application of Microbiocides.

PubMed

Koziróg, Anna; Rajkowska, Katarzyna; Otlewska, Anna; Piotrowska, Małgorzata; Kunicka-Styczyńska, Alina; Brycki, Bogumił; Nowicka-Krawczyk, Paulina; Kościelniak, Marta; Gutarowska, Beata

2016-08-22

The aim of this study was to select effective and safe microbiocides for the disinfection and protection of historical wooden surfaces at the former Auschwitz II-Birkenau concentration and extermination camp. We tested seven active compounds against bacteria and moulds, of which didecyldimethylammonium chloride and N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine were effective even at 0.02%-2%. Subsequently, eight microbiocides containing the selected active ingredients were chosen and applied three times on the surface of wood samples colonized by bacteria and moulds. ABM-1 and ABM-2-6% solution; Rocima 101-8%; Preventol R 80-12%; Acticide 706 LV-15% and Boramon-30% were the most effective disinfectants. Under laboratory conditions, ABM-1, Boramon and Rocima 101 ensured antimicrobial protection of new wood samples for six months. In situ, 30% Boramon and 8% Rocima 101 applied by spraying effectively protected the historical wood from bacterial and mould growth for 12 and 3 months, respectively. Colour and luminance of the new wood were not altered after exposure to the biocides. Boramon and Rocima 101, applied by the spraying method, caused no significant change in the colour of the historical wood. Results from this study were used to develop a procedure for the protection of wood in historical buildings against biodeterioration.

Protection of Historical Wood against Microbial Degradation—Selection and Application of Microbiocides

PubMed Central

Koziróg, Anna; Rajkowska, Katarzyna; Otlewska, Anna; Piotrowska, Małgorzata; Kunicka-Styczyńska, Alina; Brycki, Bogumił; Nowicka-Krawczyk, Paulina; Kościelniak, Marta; Gutarowska, Beata

2016-01-01

The aim of this study was to select effective and safe microbiocides for the disinfection and protection of historical wooden surfaces at the former Auschwitz II-Birkenau concentration and extermination camp. We tested seven active compounds against bacteria and moulds, of which didecyldimethylammonium chloride and N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine were effective even at 0.02%–2%. Subsequently, eight microbiocides containing the selected active ingredients were chosen and applied three times on the surface of wood samples colonized by bacteria and moulds. ABM-1 and ABM-2—6% solution; Rocima 101—8%; Preventol R 80—12%; Acticide 706 LV—15% and Boramon—30% were the most effective disinfectants. Under laboratory conditions, ABM-1, Boramon and Rocima 101 ensured antimicrobial protection of new wood samples for six months. In situ, 30% Boramon and 8% Rocima 101 applied by spraying effectively protected the historical wood from bacterial and mould growth for 12 and 3 months, respectively. Colour and luminance of the new wood were not altered after exposure to the biocides. Boramon and Rocima 101, applied by the spraying method, caused no significant change in the colour of the historical wood. Results from this study were used to develop a procedure for the protection of wood in historical buildings against biodeterioration. PMID:27556450

Water repellency and dimensional stability of wood

Treesearch

Roger M. Rowell; W. Bart Banks

1985-01-01

A discussion of the interaction between wood and water makes clear the distinction between water repellency of wood (a rate of change) and dimensional stability (a level of equilibrium). A review of methods of treating wood follows, leading to comparison of their effectiveness, description of test procedures to evaluate treatments, and discussion of deficiencies of the...

Effects of phosphoramides on wood dimensional stability

Treesearch

Hong-Lin Lee; George C. Chen; Roger M. Rowell

2000-01-01

To evaluate the dimensional stability of phosphoramide-reacted wood, wood was reacted with a mixture which was derived from compounding phosphorus pentoxide and each of 12 amines including alkyl, halophenyl, and phenyl amines in N,N-dimethylformamide. Dimensional stability of such reacted wood was analyzed by antishrink efficiency (ASE) using the water-soak method....

Impacts of fiber orientation and milling on observed crystallinity in jack pine

Treesearch

Umesh P. Agarwal; Sally A. Ralph; Richard S. Reiner; Roderquita K. Moore; Carlos Baez

2014-01-01

Influences of fiber orientation and milling on wood cellulose crystallinity were studied using jack pine wood. The fiber orientation effects were measured by sampling rectangular wood blocks in radial, tangential, and cross-sectional orientations. The influence of milling was studied by analyzing the unsieved and sieved milled wood fractions (all

Nondestructive testing methods to predict effect of degradation on wood : a critical assessment

Treesearch

J. Kaiserlik

1978-01-01

Results are reported for an assessment of methods for predicting strength of wood, wood-based, or related material. Research directly applicable to nondestructive strength prediction was very limited. In wood, strength prediction research is limited to vibration decay, wave attenuation, and multiparameter "degradation models." Nonwood methods with potential...

Surface characterization of weathered wood-plastic composites produced from modified wood flour

Treesearch

James S. Fabiyi; Armando G. McDonald; Nicole M. Stark

2007-01-01

The effects of weathering on the surface properties of wood-plastic composites (WPC) were examined. High-density polyethylene (HDPE) based WPCs made from modified wood flour (untreated, extractives free, and holocellulose (delignified) fibers) were subjected to accelerated (xenon-arc) weathering. Colorimetry and Fourier-transform infrared spectroscopy were employed to...

Fatty acid-based formulations for wood protection against mold and sapstain

Treesearch

Carol A. Clausen; Robert D. Coleman; Vina W. Yang

2010-01-01

Safer, highly effective biocides providing long-term protection of mold growth on wood-based materials is of interest to the wood protection industry. Moldicide formulations containing synergistic combinations of ingredients derived from natural sources are commonly recognized as a promising approach for the next generation of wood protectants. Although fatty acid (FA...

DNA Damage among Wood Workers Assessed with the Comet Assay

PubMed Central

Bruschweiler, Evin Danisman; Wild, Pascal; Huynh, Cong Khanh; Savova-Bianchi, Dessislava; Danuser, Brigitta; Hopf, Nancy B.

2016-01-01

Exposure to wood dust, a human carcinogen, is common in wood-related industries, and millions of workers are occupationally exposed to wood dust worldwide. The comet assay is a rapid, simple, and sensitive method for determining DNA damage. The objective of this study was to investigate the DNA damage associated with occupational exposure to wood dust using the comet assay (peripheral blood samples) among nonsmoking wood workers (n = 31, furniture and construction workers) and controls (n = 19). DNA damage was greater in the group exposed to composite wood products compared to the group exposed to natural woods and controls (P < 0.001). No difference in DNA damage was observed between workers exposed to natural woods and controls (P = 0.13). Duration of exposure and current dust concentrations had no effect on DNA damage. In future studies, workers’ exposures should include cumulative dust concentrations and exposures originating from the binders used in composite wood products. PMID:27398027

Hyperspectral imaging as a technique for investigating the effect of consolidating materials on wood

NASA Astrophysics Data System (ADS)

Bonifazi, Giuseppe; Serranti, Silvia; Capobianco, Giuseppe; Agresti, Giorgia; Calienno, Luca; Picchio, Rodolfo; Lo Monaco, Angela; Santamaria, Ulderico; Pelosi, Claudia

2017-01-01

The focus of this study was to investigate the potential of hyperspectral imaging (HSI) in the monitoring of commercial consolidant products applied on wood samples. Poplar (Populus spp.) and walnut (Juglans Regia L.) were chosen for the consolidant application. Both traditional and innovative products were selected, based on acrylic, epoxy, and aliphatic compounds. Wood samples were stressed by freeze/thaw cycles in order to cause material degradation without the loss of wood components. Then the consolidant was applied under vacuum. The samples were finally artificially aged for 168 h in a solar box chamber. The samples were acquired in the short wave infrared (1000 to 2500 nm) range by SISUChema XL™ device (Specim, Finland) after 168 h of irradiation. As comparison, color measurement was also used as an economic, simple, and noninvasive technique to evaluate the deterioration and consolidation effects on wood. All data were then processed adopting a chemometric approach finalized to define correlation models, HSI based, between consolidating materials, wood species, and short-time aging effects.

Effects of wood biochar addition on growth of cherry radish (Raphanus sativus L. var. radculus pers)

NASA Astrophysics Data System (ADS)

Ke, Huadan; Zhang, Qian; Liu, Guocheng

2018-03-01

Extensive cultivation and unreasonable management of the farmland result in severe soil degradation such as compaction, acidification, and salinization. Our results showed that the biochar amendment increased the cherry radish germination rate, while barely influenced the fresh biomass of shoot and root. Moreover, both 1.5% and 3% biochar addition showed no significant difference in the fruit shape index of cherry radish compared to the control treatment. These results suggested that the biochar application alone could not improve the cherry radish growth in this tested soil. Thus, application of biochar combined with fertilizer or composted with organic wastes should be taken into account for this soil.

Wood Ash Induced pH Changes Strongly Affect Soil Bacterial Numbers and Community Composition

PubMed Central

Bang-Andreasen, Toke; Nielsen, Jeppe T.; Voriskova, Jana; Heise, Janine; Rønn, Regin; Kjøller, Rasmus; Hansen, Hans C. B.; Jacobsen, Carsten S.

2017-01-01

Recirculation of wood ash from energy production to forest soil improves the sustainability of this energy production form as recycled wood ash contains nutrients that otherwise would be lost at harvest. In addition, wood-ash is beneficial to many soils due to its inherent acid-neutralizing capabilities. However, wood ash has several ecosystem-perturbing effects like increased soil pH and pore water electrical conductivity both known to strongly impact soil bacterial numbers and community composition. Studies investigating soil bacterial community responses to wood ash application remain sparse and the available results are ambiguous and remain at a general taxonomic level. Here we investigate the response of bacterial communities in a spruce forest soil to wood ash addition corresponding to 0, 5, 22, and 167 t wood ash ha-1. We used culture-based enumerations of general bacteria, Pseudomonas and sporeforming bacteria combined with 16S rRNA gene amplicon sequencing to valuate soil bacterial responses to wood ash application. Results showed that wood ash addition strongly increased soil pH and electrical conductivity. Soil pH increased from acidic through neutral at 22 t ha-1 to alkaline at 167 t ha-1. Bacterial numbers significantly increased up to a wood ash dose of 22 t ha-1 followed by significant decrease at 167 t ha-1 wood ash. The soil bacterial community composition changed after wood ash application with copiotrophic bacteria responding positively up to a wood ash dose of 22 t ha-1 while the adverse effect was seen for oligotrophic bacteria. Marked changes in bacterial community composition occurred at a wood ash dose of 167 t ha-1 with a single alkaliphilic genus dominating. Additionally, spore-formers became abundant at an ash dose of 167 t ha-1 whereas this was not the case at lower ash doses. Lastly, bacterial richness and diversity strongly decreased with increasing amount of wood ash applied. All of the observed bacterial responses can be directly explained by the wood ash induced changes in pH, electrical conductivity and the addition of wood ash inherent nutrients. PMID:28804476

Wood Ash Induced pH Changes Strongly Affect Soil Bacterial Numbers and Community Composition.

PubMed

Bang-Andreasen, Toke; Nielsen, Jeppe T; Voriskova, Jana; Heise, Janine; Rønn, Regin; Kjøller, Rasmus; Hansen, Hans C B; Jacobsen, Carsten S

2017-01-01

Recirculation of wood ash from energy production to forest soil improves the sustainability of this energy production form as recycled wood ash contains nutrients that otherwise would be lost at harvest. In addition, wood-ash is beneficial to many soils due to its inherent acid-neutralizing capabilities. However, wood ash has several ecosystem-perturbing effects like increased soil pH and pore water electrical conductivity both known to strongly impact soil bacterial numbers and community composition. Studies investigating soil bacterial community responses to wood ash application remain sparse and the available results are ambiguous and remain at a general taxonomic level. Here we investigate the response of bacterial communities in a spruce forest soil to wood ash addition corresponding to 0, 5, 22, and 167 t wood ash ha -1 . We used culture-based enumerations of general bacteria, Pseudomonas and sporeforming bacteria combined with 16S rRNA gene amplicon sequencing to valuate soil bacterial responses to wood ash application. Results showed that wood ash addition strongly increased soil pH and electrical conductivity. Soil pH increased from acidic through neutral at 22 t ha -1 to alkaline at 167 t ha -1 . Bacterial numbers significantly increased up to a wood ash dose of 22 t ha -1 followed by significant decrease at 167 t ha -1 wood ash. The soil bacterial community composition changed after wood ash application with copiotrophic bacteria responding positively up to a wood ash dose of 22 t ha -1 while the adverse effect was seen for oligotrophic bacteria. Marked changes in bacterial community composition occurred at a wood ash dose of 167 t ha -1 with a single alkaliphilic genus dominating. Additionally, spore-formers became abundant at an ash dose of 167 t ha -1 whereas this was not the case at lower ash doses. Lastly, bacterial richness and diversity strongly decreased with increasing amount of wood ash applied. All of the observed bacterial responses can be directly explained by the wood ash induced changes in pH, electrical conductivity and the addition of wood ash inherent nutrients.

Effect of autohydrolysis on the wettability, absorbility and further alkali impregnation of poplar wood chips.

PubMed

Xu, Ningpan; Liu, Wei; Hou, Qingxi; Wang, Peiyun; Yao, Zhirong

2016-09-01

Autohydrolysis with different severity factors was performed on poplar wood chips prior to pulping, and the wettability, absorbility and the following impregnation of NaOH solution for the poplar wood chips were then investigated. The results showed that after autohydrolysis pretreatment the porosity, shrinkage and fiber saturation point (FSP) of the poplar wood chips were increased, while the surface contact angle decreased as the severity factor was increased. The autohydrolyzed chips absorbed more NaOH in impregnation that resulted in a low NaOH concentration in the bulk impregnation liquor (i.e., the impregnation liquor outside wood chips), while the concentration in the entrapped liquor (i.e., the impregnation liquor inside wood chips) was increased. Autohydrolysis substantially improved the effectiveness of alkali impregnation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Simulated nitrogen deposition affects wood decomposition by cord-forming fungi.

PubMed

Bebber, Daniel P; Watkinson, Sarah C; Boddy, Lynne; Darrah, Peter R

2011-12-01

Anthropogenic nitrogen (N) deposition affects many natural processes, including forest litter decomposition. Saprotrophic fungi are the only organisms capable of completely decomposing lignocellulosic (woody) litter in temperate ecosystems, and therefore the responses of fungi to N deposition are critical in understanding the effects of global change on the forest carbon cycle. Plant litter decomposition under elevated N has been intensively studied, with varying results. The complexity of forest floor biota and variability in litter quality have obscured N-elevation effects on decomposers. Field experiments often utilize standardized substrates and N-levels, but few studies have controlled the decay organisms. Decomposition of beech (Fagus sylvatica) blocks inoculated with two cord-forming basidiomycete fungi, Hypholoma fasciculare and Phanerochaete velutina, was compared experimentally under realistic levels of simulated N deposition at Wytham Wood, Oxfordshire, UK. Mass loss was greater with P. velutina than with H. fasciculare, and with N treatment than in the control. Decomposition was accompanied by growth of the fungal mycelium and increasing N concentration in the remaining wood. We attribute the N effect on wood decay to the response of cord-forming wood decay fungi to N availability. Previous studies demonstrated the capacity of these fungi to scavenge and import N to decaying wood via a translocating network of mycelium. This study shows that small increases in N availability can increase wood decomposition by these organisms. Dead wood is an important carbon store and habitat. The responses of wood decomposers to anthropogenic N deposition should be considered in models of forest carbon dynamics.

Functional lignocellulosic materials prepared by ATRP from a wood scaffold.

PubMed

Cabane, Etienne; Keplinger, Tobias; Künniger, Tina; Merk, Vivian; Burgert, Ingo

2016-08-10

Wood, a natural and abundant source of organic polymers, has been used as a scaffold to develop novel wood-polymer hybrid materials. Through a two-step surface-initiated Atom Transfer Radical Polymerization (ATRP), the porous wood structure can be effectively modified with polymer chains of various nature. In the present study, polystyrene and poly(N-isopropylacrylamide) were used. As shown with various characterization techniques including confocal Raman microscopy, FTIR, and SEM/EDX, the native wood ultrastructure and features are retained and the polymer chains can be introduced deep within the wood, i.e. inside the wood cell walls. The physical properties of the new materials have been studied, and results indicate that the insertion of polymer chains inside the wood cell wall alters the intrinsic properties of wood to yield a hybrid composite material with new functionalities. This approach to the functionalization of wood could lead to the fabrication of a new class of interesting functional materials and promote innovative utilizations of the renewable resource wood.

Functional lignocellulosic materials prepared by ATRP from a wood scaffold

PubMed Central

Cabane, Etienne; Keplinger, Tobias; Künniger, Tina; Merk, Vivian; Burgert, Ingo

2016-01-01

Wood, a natural and abundant source of organic polymers, has been used as a scaffold to develop novel wood-polymer hybrid materials. Through a two-step surface-initiated Atom Transfer Radical Polymerization (ATRP), the porous wood structure can be effectively modified with polymer chains of various nature. In the present study, polystyrene and poly(N-isopropylacrylamide) were used. As shown with various characterization techniques including confocal Raman microscopy, FTIR, and SEM/EDX, the native wood ultrastructure and features are retained and the polymer chains can be introduced deep within the wood, i.e. inside the wood cell walls. The physical properties of the new materials have been studied, and results indicate that the insertion of polymer chains inside the wood cell wall alters the intrinsic properties of wood to yield a hybrid composite material with new functionalities. This approach to the functionalization of wood could lead to the fabrication of a new class of interesting functional materials and promote innovative utilizations of the renewable resource wood. PMID:27506369

Functional symbiosis and communication in microbial ecosystems. The case of wood-eating termites and cockroaches.

PubMed

Berlanga, Mercedes

2015-09-01

Animal hosts typically have strong specificity for microbial symbionts and their functions. The symbiotic relationships have enhanced the limited metabolic networks of most eukaryotes by contributing several prokaryotic metabolic capabilities, such as methanogenesis, chemolithoautotrophy, nitrogen assimilation, etc. This review will examine the characteristics that determine bacterial "fidelity" to certain groups of animals (e.g., xylophagous insects, such as termites and cockroaches) over generations and throughout evolution. The hindgut bacteria of wood-feeding termites and cockroaches belong to several phyla, including Proteobacteria, especially Deltaproteobacteria, Bacteroidetes, Firmicutes, Actinomycetes, Spirochetes, Verrucomicrobia, and Actinobacteria, as detected by 16S rRNA. Termites effectively feed on many types of lignocelluloses assisted by their gut microbial symbionts. Although the community structures differ between the hosts (termites and cockroaches), with changes in the relative abundances of particular bacterial taxa, the composition of the bacterial community could reflect at least in part the host evolution in that the microbiota may derive from the microbiota of a common ancestor. Therefore, factors other than host phylogeny, such as diet could have had strong influence in shaping the bacterial community structure. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.

Experimental analysis and simulation modeling of forest management impacts on wood thrushes, Hylocichla mustelina

USGS Publications Warehouse

Banks, R.C.

1998-01-01

North American Breeding Bird Survey data show that wood thrush (Hylocichla mustelina) populations in eastern U.S. forests have declined 1.8% per year during 1966-95. The declining quality of breeding forest tracts in North America is one possible cause for the apparent decline of some neotropical migratory birds, such as the wood thrush. In Georgia, however, wood thrush populations have declined during a period of increasing pine forest area and larger patch sizes. We hypothesized that forest management practices such as thinning and prescribed burning might create unsuitable habitat for wood thrushes. We conducted a four-year before/after, treatment/control experiment at the Piedmont National Wildlife Refuge in central Georgia to study to the effects of a treatment of thinning and prescribed burning on wood thrush demographic parameters. We simultaneously monitored wood thrush adults and juveniles with mark-recapture, radio-telemetry, nest searches, and plot-map surveys. Our analyses showed that wood thrushes were less likely to emigrate from the study compartments after the treatment, and wood thrushes exhibited some tendency to increase preference for hardwood habitats and decrease preference for pine habitats following the treatment. However, we observed no effects of treatment on nest success, adult survival, and adult and juvenile dispersal distances. We also found that female wood thrushes had lower survival rates than males during the breeding season, and we documented large-scale, within-year dispersal movements of adult (up to 17 km) and juvenile (up to 7 km) wood thrushes. We conclude that landscape level habitat quantity and quality must be considered during songbird management decisions. The documentation of sex- and age-specific wood thrush survival and movement rates was critical for construction of a set of population models. We used three stochastic models to learn more about wood thrush population dynamics and make predictions about population growth rates, reproductive success, and the effect of habitat changes on wood thrush populations. The simplest source/sink population model suggests that the Piedmont National Wildlife Refuge's wood thrush population is probably stable or increasing, and wood thrush populations in treated areas had higher growth rates than birds in untreated areas. We were able to use the individual-based model of wood thrush productivity to predict fecundity, a parameter that we could not measure directly in the field. Again, females on treated areas had higher fecundity than birds on untreated areas. Our spatially-based model predicted that wood thrush populations should respond positively to predicted changes in the age/size class structure of the Refuge's pine forests. Our model also showed that most wood thrushes leave the Refuge's forest compartments during the breeding season, and these dispersal movements are extremely important to understanding and managing wood thrush populations. The use of prescribed burning and retention shelterwood silviculture at the Piedmont National Wildlife Refuge does not appear to negatively affect the local wood thrush population. Continued use of the current management regime should result in adequate nesting, foraging, and escape habitats for wood thrushes. However, landscape-level habitat availability and quality, including lands outside the Refuge, must be considered when making management decisions that may affect wood thrushes.

Analysis of Cutmarks on Bone: Can Light Microscopy Be of Any Help?

PubMed

Cerutti, Elisa; Spagnoli, Laura; Araujo, Nadezhda; Gibelli, Daniele; Mazzarelli, Debora; Cattaneo, Cristina

2016-12-01

One of the main issues in forensic anthropology consists of the identification of signs of trauma in skeletal remains, including sharp-force injuries. So far, several studies have been performed to assess differences between injuries caused by different instruments, not, however, through light microscopy.In this study, 152 sharp-force injuries were performed by 5 different tools through 2 different orientations on 2 humeral diaphyses and were analyzed by stereo and light microscopy to assess possible morphological differences.This study showed that although W-shaped injuries are frequently reported in cases of wood-cutting saws, other shapes are often observed; lesions due to metal-cutting saws are almost always U shaped, whereas injuries caused by knives are V shaped. Although cut marks may represent a variable range of features, the present study was able to highlight typical profiles that may be of some help for the diagnosis of weapon and the intentionality of the action.

Surface shape analysis of rough lumber for wane detection

Treesearch

Sang-Mook Lee; A. Lynn Abbott; Daniel L. Schmoldt

2003-01-01

The initial breakdown of hardwood logs into lumber produces boards with rough surfaces. These boards contain wane (missing wood that emanates from the log exterior, often containing residual bark) that is removed by edge and trim cuts prior to sale. Because hardwood lumber value is determined based on board size and quality, knowledge of wane position and defects is...

An 800-year fire history

Treesearch

Stanley G. Kitchen

2010-01-01

"Fire in the woods!" The words are a real heart stopper. Yet in spite of its capacity to destroy, fire plays an essential role in shaping plant communities. Knowledge of the patterns of fire over long time periods is critical for understanding this role. Trees often retain evidence of nonlethal fires in the form of injuries or scars in the annual growth rings...

Long term human impacts on genetic structure of Italian walnut inferred by SSR markers

Treesearch

Paola Pollegioni; Keith Woeste; Irene Olimpieri; Danilo Marandola; Francesco Cannata; Maria E Malvolti

2011-01-01

Life history traits, historic factors, and human activities can all shape the genetic diversity of a species. In Italy, walnut (Juglans regia L.) has a long history of cultivation both for wood and edible nuts. To better understand the genetic variability of current Italian walnut resources, we analyzed the relationships among the genetic structure...

Characterization of Defects in Lumber Using Color, Shape, and Density Information

Treesearch

B.H. Bond; D. Earl Kline; Philip A. Araman

1998-01-01

To help guide the development of multi-sensor machine vision systems for defect detection in lumber, a fundamental understanding of wood defects is needed. The purpose of this research was to advance the basic understanding of defects in lumber by describing them in terms of parameters that can be derived from color and x-ray scanning technologies and to demonstrate...

Estimation of a Ramsay-Curve Item Response Theory Model by the Metropolis-Hastings Robbins-Monro Algorithm. CRESST Report 834

ERIC Educational Resources Information Center

Monroe, Scott; Cai, Li

2013-01-01

In Ramsay curve item response theory (RC-IRT, Woods & Thissen, 2006) modeling, the shape of the latent trait distribution is estimated simultaneously with the item parameters. In its original implementation, RC-IRT is estimated via Bock and Aitkin's (1981) EM algorithm, which yields maximum marginal likelihood estimates. This method, however,…

Effect of Moisture Cycling on Mechanical Response of Metal-Plate Connector Joints With and Without an Adhesive Interface

Treesearch

Leslie H. Groom

1995-01-01

Wood trusses are frequently located in light-frame structures where they are subjected to significant shifts in moisture conditions. However, little is known about the effects of moisture cycling of the wood members on the mechanical behavior of metal-plate connector (MPC) joints. Thus, the primary objective of this study was to quantify the effect of wood moisture...

3D Molding of Veneers by Mechanical and Pneumatic Methods

PubMed Central

Gaff, Milan; Gašparík, Miroslav

2017-01-01

This paper deals with the influence of selected methods (mechanical and pneumatic) as well as various factors (wood species, moisture content, veneer shape, punch diameter, laminating foil thickness, holding method, plasticizing) on 3D molding of veneers. 3D molding was evaluated on the basis of maximum deflection of birch and beech veneers. Cracks and warping edges were also evaluated in selected groups of mechanical molding. Mechanical methods tested veneers with various treatments (steaming, water and ammonia plasticizing and lamination). The pneumatic method was based on veneer shaping using air pressure. The results indicate that birch veneers are more suitable for 3D molding. The differences between the mechanical and pneumatic methods were not considerable. The most suitable method for mechanical 3D molding was the veneer lamination by polyethylene foils with thicknesses of 80 and 125 μm, inasmuch as these achieved better results than veneer plasticized by steam. The occurrence of cracks was more frequent in beech veneers, whereas, edge warping occurred at similar rates for both wood species and depends rather on holding method during 3D molding. Use of the ammonia solution is more suitable and there occurs no marked increase in moisture as happens when soaking in water. PMID:28772684

Short-term chamber exposure to low doses of two kinds of wood smoke does not induce systemic inflammation, coagulation or oxidative stress in healthy humans

PubMed Central

Sallsten, Gerd; Almerud, Pernilla; Basu, Samar; Barregard, Lars

2013-01-01

Introduction: Air pollution increases the risk of cardiovascular diseases. A proposed mechanism is that local airway inflammation leads to systemic inflammation, affecting coagulation and the long-term risk of atherosclerosis. One major source of air pollution is wood burning. Here we investigate whether exposure to two kinds of wood smoke, previously shown to cause airway effects, affects biomarkers of systemic inflammation, coagulation and lipid peroxidation. Methods: Thirteen healthy adults were exposed to filtered air followed by two sessions of wood smoke for three hours, one week apart. One session used smoke from the start-up phase of the wood-burning cycle, and the other smoke from the burn-out phase. Mean particle mass concentrations were 295 µg/m3 and 146 µg/m3, and number concentrations were 140 000/cm3 and 100 000/cm3, respectively. Biomarkers were analyzed in samples of blood and urine taken before and several times after exposure. Results after wood smoke exposure were adjusted for exposure to filtered air. Results: Markers of systemic inflammation and soluble adhesion molecules did not increase after wood smoke exposure. Effects on markers of coagulation were ambiguous, with minor decreases in fibrinogen and platelet counts and mixed results concerning the coagulation factors VII and VIII. Urinary F2-isoprostane, a consistent marker of in vivo lipid peroxidation, unexpectedly decreased after wood smoke exposure. Conclusions: The effects on biomarkers of inflammation, coagulation and lipid peroxidation do not indicate an increased risk of cardiovascular diseases in healthy adults by short-term exposure to wood smoke at these moderate doses, previously shown to cause airway effects. PMID:23808634

Ecology of coarse wood decomposition by the saprotrophic fungus Fomes fomentarius.

PubMed

Větrovský, Tomáš; Voříšková, Jana; Snajdr, Jaroslav; Gabriel, Jiří; Baldrian, Petr

2011-07-01

Saprotrophic wood-inhabiting basidiomycetes are the most important decomposers of lignin and cellulose in dead wood and as such they attracted considerable attention. The aims of this work were to quantify the activity and spatial distribution of extracellular enzymes in coarse wood colonised by the white-rot basidiomycete Fomes fomentarius and in adjacent fruitbodies of the fungus and to analyse the diversity of the fungal and bacterial community in a fungus-colonised wood and its potential effect on enzyme production by F. fomentarius. Fungus-colonised wood and fruitbodies were collected in low management intensity forests in the Czech Republic. There were significant differences in enzyme production by F. fomentarius between Betula pendula and Fagus sylvatica wood, the activity of cellulose and xylan-degrading enzymes was significantly higher in beech wood than in birch wood. Spatial analysis of a sample B. pendula log segment proved that F. fomentarius was the single fungal representative found in the log. There was a high level of spatial variability in the amount of fungal biomass detected, but no effects on enzyme activities were observed. Samples from the fruiting body showed high β-glucosidase and chitinase activities compared to wood samples. Significantly higher levels of xylanase and cellobiohydrolase were found in samples located near the fruitbody (proximal), and higher laccase and Mn-peroxidase activities were found in the distal ones. The microbial community in wood was dominated by the fungus (fungal to bacterial DNA ratio of 62-111). Bacterial abundance composition was lower in proximal than distal parts of wood by a factor of 24. These results show a significant level of spatial heterogeneity in coarse wood. One of the explanations may be the successive colonization of wood by the fungus: due to differential enzyme production, the rates of biodegradation of coarse wood are also spatially inhomogeneous.

Environmental controls of wood entrapment in upper Midwestern streams

USGS Publications Warehouse

Merten, Eric C.; Finlay, Jacques; Johnson, Lucinda; Newman, Raymond; Stefan, Heinz; Vondracek, Bruce C.

2011-01-01

Wood deposited in streams provides a wide variety of ecosystem functions, including enhancing habitat for key species in stream food webs, increasing geomorphic and hydraulic heterogeneity and retaining organic matter. Given the strong role that wood plays in streams, factors that influence wood inputs, retention and transport are critical to stream ecology. Wood entrapment, the process of wood coming to rest after being swept downstream at least 10 m, is poorly understood, yet important for predicting stream function and success of restoration efforts. Data on entrapment were collected for a wide range of natural wood pieces (n = 344), stream geomorphology and hydraulic conditions in nine streams along the north shore of Lake Superior in Minnesota. Locations of pieces were determined in summer 2007 and again following an overbank stormflow event in fall 2007. The ratio of piece length to effective stream width (length ratio) and the weight of the piece were important in a multiple logistic regression model that explained 25% of the variance in wood entrapment. Entrapment remains difficult to predict in natural streams, and often may simply occur wherever wood pieces are located when high water recedes. However, this study can inform stream modifications to discourage entrapment at road crossings or other infrastructure by applying the model formula to estimate the effective width required to pass particular wood pieces. Conversely, these results could also be used to determine conditions (e.g. pre-existing large, stable pieces) that encourage entrapment where wood is valued for ecological functions.

Analysis of Architectural Building Design Influences on Fire Spread in Densely Urban Settlement using Cellular Automata

NASA Astrophysics Data System (ADS)

Tambunan, L.; Salamah, H.; Asriana, N.

2017-03-01

This study aims to determine the influence of architectural design on the risk of fire spread in densely urban settlement area. Cellular Automata (CA) is used to analyse the fire spread pattern, speed, and the extent of damage. Four cells represent buildings, streets, and fields characteristic in the simulated area, as well as their flammability level and fire spread capabilities. Two fire scenarios are used to model the spread of fire: (1) fire origin in a building with concrete and wood material majority, and (2) fire origin in building with wood material majority. Building shape, building distance, road width, and total area of wall openings are considered constant, while wind is ignored. The result shows that fire spread faster in the building area with wood majority than with concrete majority. Significant amount of combustible building material, absence of distance between buildings, narrow streets and limited fields are factors which influence fire spread speed and pattern as well as extent of damage when fire occurs in the densely urban settlement area.

EVALUATION OF THE EFFECTIVENESS OF COATINGS IN REDUCING DISLODGEABLE ARSENIC, CHROMIUM, AND COPPER FROM CCA TREATED WOOD, INTERIM DATA REPORT

EPA Science Inventory

EPA is approximately 20 months into a project to evaluate the performance of wood coatings as a way to prevent arsenic, chromium and copper exposure from the surfaces of CCA treated wood. Potential dermal exposure, as measured by wipe sampling dislodgeable CCA chemical from wood ...

Contemporary wood utilization research needs in the Western United States.

Treesearch

Robert A. Monserud; Eini C. Lowell; Dennis R. Becker; Susan Stevens Hummel; Ellen M. Donoghue; R. James Barbour; Kenneth A. Kilborn; David L. Nicholls; Joe Roos; Randall A. Cantrell

2004-01-01

Contemporary wood utilization research needs in the Western United States are examined in this problem analysis. Key focal areas include: A. Changes in forest management actions and policies affect forest conditions and people, which in turn affect wood quality and wood utilization opportunities. B. Effects of natural disturbances (e.g., wildfire, insect outbreaks) on...

GC-MS Characterizations of Termiticidal Heartwood Extractives from Wood Species Utilized in Pakistan

Treesearch

Mark Mankowski; Blossie Boyd; Barbar Hassan; Grant T. Kirker

2016-01-01

Wood species that exhibit innate tolerance to wood destroying organisms such as termites are considered to be naturally durable. This durability can, in part, be due to the complex chemical compounds in the heartwood of naturally durable wood species. We examined the effects of varying concentrations of heartwood extractives on the subterranean termite, ...

Effect of processing method on surface and weathering characteristics of wood-flour/HDPE composites

Treesearch

Nicole M. Stark; Laurent M. Matuana; Craig M. Clemons

2004-01-01

Wood-plastic lumber is promoted as a low maintenance high-durability product. When exposed to accelerated weathering, however, wood-plastic composites may experience a color change and/or loss in mechanical properties. Different methods of manufacturing wood-plastic composites lead to different surface characteristics, which can influence weathering, In this study, 50...

Effect of processing method on accelerated weathering of wood-flour/HDPE composites

Treesearch

Nicole M. Stark; Laurent M. Matuana; Craig M. Clemons

2003-01-01

Wood-plastic lumber is promoted as a low maintenance high-durability product. When exposed to accelerated weathering, however, wood-plastic composites may experience a color change and/or loss in mechanical properties. Different methods of manufacturing wood-plastic composites lead to different surface characteristics, which can influence weathering, In this study, 50...

Theoretical thermal conductivity equation for uniform density wood cells

Treesearch

John F. Hunt; Hongmei Gu; Patricia Lebow

2008-01-01

The anisotropy of wood creates a complex problem requiring that analyses be based on fundamental material properties and characteristics of the wood structure to solve heat transfer problems. A two-dimensional finite element model that evaluates the effective thermal conductivity of a wood cell over the full range of moisture contents and porosities was previously...

CCA retention and its effects on the bonding performance of decommissioned treated wood: a preliminary study

Treesearch

Cheng Piao; Todd F. Shupe; Mark Gibson; Chung Y. Hse

2009-01-01

Chromated copper arsenate (CCA) continues to be widely used as a wood preservative for industrial uses in the U.S. Disposal of treated wood is a potential long-term environmental liability. Current practices for disposing of decommissioned preservative-treated wood include landfilling and incineration, which are increasingly impractical due to environmental...

Environmental impact of preservative-treated wood in a wetland boardwalk.

Treesearch

Stan T. Lebow; Patricia K. Lebow; Daniel O. Foster; Kenneth M. Brooks

Forest Service, Bureau of Land Management, and industry partners are cooperating in a study of the leaching and environmental effects of a wetland boardwalk. The construction project is considered bworst casec because the site has high rainfall and large volumes of treated wood were used. Separate boardwalk test sections were constructed using untreated wood or wood...

Effects of Acid Deposition on Wood

Treesearch

Mark Knaebe

2013-01-01

Since acid deposition increases the rate of deterioration of unpainted wood, it can also affect the performance of paint applied to this weathered wood. In tests conducted near Madison, Wisconsin, smooth-planed wood was allowed to weather before painting. Exposure for as little as 2 weeks shortened the service life of the subsequently applied paint. The paint bond was...

The effect of mid-rotation fertilization on the wood properties of loblolly pine (Pinus taeda)

Treesearch

Finto Antony; Lewis Jordan; Laurence R. Schimleck; Richard F. Daniels; Alexander Clark III

2009-01-01

Mid-rotation fertilization is a common practice in the management of loblolly pine (Pinus taeda L.) plantations, typically providing large improvements in growth. However, concerns exist about the quality of wood produced following fertilization. The objective of this study was to develop an understanding of wood property changes following fertilization. Wood...

Effect of size on bending strength of wood members

Treesearch

Billy Bohannan

1966-01-01

This paper discusses the assumptions used in the statistical theory of strength, shows the application of the theory to wood bending members, and gives a comparison between theory and actual data for wood beams.

Representation of Glossy Material Surface in Ventral Superior Temporal Sulcal Area of Common Marmosets

PubMed Central

Miyakawa, Naohisa; Banno, Taku; Abe, Hiroshi; Tani, Toshiki; Suzuki, Wataru; Ichinohe, Noritaka

2017-01-01

The common marmoset (Callithrix jacchus) is one of the smallest species of primates, with high visual recognition abilities that allow them to judge the identity and quality of food and objects in their environment. To address the cortical processing of visual information related to material surface features in marmosets, we presented a set of stimuli that have identical three-dimensional shapes (bone, torus or amorphous) but different material appearances (ceramic, glass, fur, leather, metal, stone, wood, or matte) to anesthetized marmoset, and recorded multiunit activities from an area ventral to the superior temporal sulcus (STS) using multi-shanked, and depth resolved multi-electrode array. Out of 143 visually responsive multiunits recorded from four animals, 29% had significant main effect only of the material, 3% only of the shape and 43% of both the material and the shape. Furthermore, we found neuronal cluster(s), in which most cells: (1) showed a significant main effect in material appearance; (2) the best stimulus was a glossy material (glass or metal); and (3) had reduced response to the pixel-shuffled version of the glossy material images. The location of the gloss-selective area was in agreement with previous macaque studies, showing activation in the ventral bank of STS. Our results suggest that perception of gloss is an important ability preserved across wide range of primate species. PMID:28367117

Representation of Glossy Material Surface in Ventral Superior Temporal Sulcal Area of Common Marmosets.

PubMed

Miyakawa, Naohisa; Banno, Taku; Abe, Hiroshi; Tani, Toshiki; Suzuki, Wataru; Ichinohe, Noritaka

2017-01-01

The common marmoset ( Callithrix jacchus ) is one of the smallest species of primates, with high visual recognition abilities that allow them to judge the identity and quality of food and objects in their environment. To address the cortical processing of visual information related to material surface features in marmosets, we presented a set of stimuli that have identical three-dimensional shapes (bone, torus or amorphous) but different material appearances (ceramic, glass, fur, leather, metal, stone, wood, or matte) to anesthetized marmoset, and recorded multiunit activities from an area ventral to the superior temporal sulcus (STS) using multi-shanked, and depth resolved multi-electrode array. Out of 143 visually responsive multiunits recorded from four animals, 29% had significant main effect only of the material, 3% only of the shape and 43% of both the material and the shape. Furthermore, we found neuronal cluster(s), in which most cells: (1) showed a significant main effect in material appearance; (2) the best stimulus was a glossy material (glass or metal); and (3) had reduced response to the pixel-shuffled version of the glossy material images. The location of the gloss-selective area was in agreement with previous macaque studies, showing activation in the ventral bank of STS. Our results suggest that perception of gloss is an important ability preserved across wide range of primate species.

Proceedings of the Ship Control Systems Symposium (6th) Held in Ottawa, Canada on 26-30 October 1981. Volume 2.

DTIC Science & Technology

1981-10-30

cumulative effects of wooding on visibility, as shown in Fig. 3b, it is clear that no more than five windows should lie in the same plane. Two principles...012000/ / 25300 0 / 3000 n3% 20 25 30 WOODING AS PERCENT Of IONIZONTAL FIELD OF VIEW FIG. 3a. Percent of Wooding in Forward 1800 Field of View for...Effect of Wooding on Horizontal Field of View with Increasing Distance from Window. El 2-11 voice communication among bridge personnel at expected levels

Scots pine responses to elevated temperature and carbon dioxide concentration: growth and wood properties.

PubMed

Kilpeläinen, Antti; Peltola, Heli; Ryyppö, Aija; Kellomäki, Seppo

2005-01-01

Growth and wood properties of 20-year-old Scots pine (Pinus sylvestris L.) trees were studied for 6 years in 16 closed chambers providing a factorial combination of two temperature regimes (ambient and elevated) and two carbon dioxide concentrations ([CO2]) (ambient and twice ambient). The elevation of temperature corresponded to the predicted effect at the site of a doubling in atmospheric [CO2]. Annual height and radial growth and wood properties were analyzed during 1997-2002. Physical wood properties analyzed included early- and latewood widths and their proportions, intra-ring wood densities, early- and latewood density and mean fiber length. Chemical wood properties analyzed included concentrations of acetone-soluble extractives, lignin, cellulose and hemicellulose. There were no significant treatment effects on height growth during the 6-year study. Elevated [CO2] increased ring width by 66 and 47% at ambient and elevated temperatures, respectively. At ambient [CO2], elevated temperature increased ring width by 19%. Increased ring width in response to elevated [CO2] resulted from increases in both early- and latewood width; however, there was no effect of the treatments on early- and latewood proportions. Mean wood density, earlywood density and fiber length increased in response to elevated temperature. The chemical composition of wood was affected by elevated [CO2], which reduced the cellulose concentration, and by elevated temperature, which reduced the concentration of acetone-soluble extractives. Thus, over the 6-year period, radial growth was significantly increased by elevated [CO2], and some wood properties were significantly affected by elevated temperature or elevated [CO2], or both, indicating that climate change may affect the material properties of wood.

A mathematical framework for modelling cambial surface evolution using a level set method

PubMed Central

Sellier, Damien; Plank, Michael J.; Harrington, Jonathan J.

2011-01-01

Background and Aims During their lifetime, tree stems take a series of successive nested shapes. Individual tree growth models traditionally focus on apical growth and architecture. However, cambial growth, which is distributed over a surface layer wrapping the whole organism, equally contributes to plant form and function. This study aims at providing a framework to simulate how organism shape evolves as a result of a secondary growth process that occurs at the cellular scale. Methods The development of the vascular cambium is modelled as an expanding surface using the level set method. The surface consists of multiple compartments following distinct expansion rules. Growth behaviour can be formulated as a mathematical function of surface state variables and independent variables to describe biological processes. Key Results The model was coupled to an architectural model and to a forest stand model to simulate cambium dynamics and wood formation at the scale of the organism. The model is able to simulate competition between cambia, surface irregularities and local features. Predicting the shapes associated with arbitrarily complex growth functions does not add complexity to the numerical method itself. Conclusions Despite their slenderness, it is sometimes useful to conceive of trees as expanding surfaces. The proposed mathematical framework provides a way to integrate through time and space the biological and physical mechanisms underlying cambium activity. It can be used either to test growth hypotheses or to generate detailed maps of wood internal structure. PMID:21470972

Wood combustion particles induce adverse effects to normal and diseased airway epithelia.

PubMed

Krapf, Manuel; Künzi, Lisa; Allenbach, Sandrine; Bruns, Emily A; Gavarini, Ilaria; El-Haddad, Imad; Slowik, Jay G; Prévôt, André S H; Drinovec, Luka; Močnik, Griša; Dümbgen, Lutz; Salathe, Matthias; Baumlin, Nathalie; Sioutas, Constantinos; Baltensperger, Urs; Dommen, Josef; Geiser, Marianne

2017-04-19

Residential wood burning is a major source of poorly characterized, deleterious particulate matter, whose composition and toxicity may vary with wood type, burning condition and photochemical age. The causative link between ambient wood particle constituents and observed adverse health effects is currently lacking. Here we investigate the relationship between chemical properties of primary and atmospherically aged wood combustion particles and acute toxicity in human airway epithelial cells. Emissions from a log wood burner were diluted and injected into a smog chamber for photochemical aging. After concentration-enrichment and removal of oxidizing gases, directly emitted and atmospherically aged particles were deposited on cell cultures at the air-liquid interface for 2 hours in an aerosol deposition chamber mimicking physiological conditions in lungs. Cell models were fully differentiated normal and diseased (cystic fibrosis and asthma) human bronchial epithelia (HBE) and the bronchial epithelial cell line BEAS-2B. Cell responses were assessed at 24 hours after aerosol exposure. Atmospherically relevant doses of wood combustion particles significantly increased cell death in all but the asthma cell model. Expression of oxidative stress markers increased in HBE from all donors. Increased cell death and inflammatory responses could not be assigned to a single chemical fraction of the particles. Exposure to primary and aged wood combustion particles caused adverse effects to airway epithelia, apparently induced by several interacting components.

The Role of Dead Wood in Maintaining Arthropod Diversity on the Forest Floor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanula, James L.; Horn, Scott; Wade, Dale D.

2006-08-01

Dead wood is a major component of forests and contributes to overall diversity, primarily by supporting insects that feed directly on or in it. Further, a variety of organisms benefit by feeding on those insects. What is not well known is how or whether dead wood influences the composition of the arthropod community that is not solely dependent on it as a food resource, or whether woody debris influences prey available to generalist predators. One group likely to be affected by dead wood is ground-dwelling arthropods. We studied the effect of adding large dead wood to unburned and frequently burnedmore » pine stands to determine if dead wood was used more when the litter and understory plant community are removed. We also studied the effect of annual removal of dead wood from large (10-ha) plots over a 5-year period on ground-dwelling arthropods. In related studies, we examined the relationships among an endangered woodpecker that forages for prey on live trees, its prey, and dead wood in the forest. Finally, the results of these and other studies show that dead wood can influence the abundance and diversity of the ground-dwelling arthropod community and of prey available to generalist predators not foraging directly on dead trees.« less

Effect of wood ash application on soil solution chemistry of tropical acid soils: incubation study.

PubMed

Nkana, J C Voundi; Demeyer, A; Verloo, M G

2002-12-01

The objective of this study was to determine the effect of wood ash application on soil solution composition of three tropical acid soils. Calcium carbonate was used as a reference amendment. Amended soils and control were incubated for 60 days. To assess soluble nutrients, saturation extracts were analysed at 15 days intervals. Wood ash application affects the soil solution chemistry in two ways, as a liming agent and as a supplier of nutrients. As a liming agent, wood ash application induced increases in soil solution pH, Ca, Mg, inorganic C, SO4 and DOC. As a supplier of elements, the increase in the soil solution pH was partly due to ligand exchange between wood ash SO4 and OH- ions. Large increases in concentrations of inorganic C, SO4, Ca and Mg with wood ash relative to lime and especially increases in K reflected the supply of these elements by wood ash. Wood ash application could represent increased availability of nutrients for the plant. However, large concentrations of basic cations, SO4 and NO3 obtained with higher application rates could be a concern because of potential solute transport to surface waters and groundwater. Wood ash must be applied at reasonable rates to avoid any risk for the environment.

Calculating broad neutron resonances in a cut-off Woods-Saxon potential

NASA Astrophysics Data System (ADS)

Baran, Á.; Noszály, Cs.; Salamon, P.; Vertse, T.

2015-07-01

In a cut-off Woods-Saxon (CWS) potential with realistic depth S -matrix poles being far from the imaginary wave number axis form a sequence where the distances of the consecutive resonances are inversely proportional with the cut-off radius value, which is an unphysical parameter. Other poles lying closer to the imaginary wave number axis might have trajectories with irregular shapes as the depth of the potential increases. Poles being close repel each other, and their repulsion is responsible for the changes of the directions of the corresponding trajectories. The repulsion might cause that certain resonances become antibound and later resonances again when they collide on the imaginary axis. The interaction is extremely sensitive to the cut-off radius value, which is an apparent handicap of the CWS potential.

Geology of the Woods Hole area, Massachusetts; the story behind the landscape

USGS Publications Warehouse

Hutchinson, D.R.; Schwarzman, Beth

2001-01-01

The geologic story of the Woods Hole area, Cape Cod, Mass., was written by glacial ice during the last ice age and edited by the ocean waves. If you learn to read today's landscape, you can see the fascinating history it records. The features of Cape Cod, from the ponds and cranberry bogs to the gently sloping sandy uplands and rocky, irregular hills to the beaches, result from the glacial processes that built the cape and the marine processes that still shape it. Many geologists since the late 19th century have contributed to telling this story. The U.S. Geological Survey has studied the geology of Cape Cod in order to provide people with objective scientific data that can be applied to wise stewardship of the land and coasts.

Effect of carbon fiber addition on the electromagnetic shielding properties of carbon fiber/polyacrylamide/wood based fiberboards

NASA Astrophysics Data System (ADS)

Dang, Baokang; Chen, Yipeng; Yang, Ning; Chen, Bo; Sun, Qingfeng

2018-05-01

Carbon fiber (CF) reinforced polyacrylamide/wood fiber composite boards are fabricated by mechanical grind-assisted hot-pressing, and are used for electromagnetic interference (EMI) shielding. CF with an average diameter of 150 nm is distributed on wood fiber, which is then encased by polyacrylamide. The CF/polyacrylamide/wood fiber (CPW) composite exhibits an optimal EMI shielding effectiveness (SE) of 41.03 dB compared to that of polyacrylamide/wood fiber composite (0.41 dB), which meets the requirements of commercial merchandise. Meanwhile, the CPW composite also shows high mechanical strength. The maximum modulus of rupture (MOR) and modulus of elasticity (MOE) of CPW composites are 39.52 MPa and 5823.15 MPa, respectively. The MOR and MOE of CPW composites increased by 38% and 96%, respectively, compared to that of polyacrylamide/wood fiber composite (28.64 and 2967.35 MPa).

Effect of carbon fiber addition on the electromagnetic shielding properties of carbon fiber/polyacrylamide/wood based fiberboards.

PubMed

Dang, Baokang; Chen, Yipeng; Yang, Ning; Chen, Bo; Sun, Qingfeng

2018-05-11

Carbon fiber (CF) reinforced polyacrylamide/wood fiber composite boards are fabricated by mechanical grind-assisted hot-pressing, and are used for electromagnetic interference (EMI) shielding. CF with an average diameter of 150 nm is distributed on wood fiber, which is then encased by polyacrylamide. The CF/polyacrylamide/wood fiber (CPW) composite exhibits an optimal EMI shielding effectiveness (SE) of 41.03 dB compared to that of polyacrylamide/wood fiber composite (0.41 dB), which meets the requirements of commercial merchandise. Meanwhile, the CPW composite also shows high mechanical strength. The maximum modulus of rupture (MOR) and modulus of elasticity (MOE) of CPW composites are 39.52 MPa and 5823.15 MPa, respectively. The MOR and MOE of CPW composites increased by 38% and 96%, respectively, compared to that of polyacrylamide/wood fiber composite (28.64 and 2967.35 MPa).

Effect of adding wood vinegar on cucumber (Cucumis sativus L) seed germination

NASA Astrophysics Data System (ADS)

Lei, Ming; Liu, Bingjie; Wang, Xiao

2018-03-01

Wood vinegar, a liquid by-product that was obtained from the condensed vapor generated during the biomass pyrolysis, had been reported as plant growth promotor, but the impact on the plant seeds was still not clear. Thus, we investigated the effects of wood vinegar on the germination and seedling growth of cucumber seeds through the germination experiments. The results showed that the different diluted wood vinegar addition showed no significant difference in the germination rates of cucumber seeds compared to those of the CK treatment (P > 0.05). However, the added wood vinegar at the 10000-time dilution significantly increased the root length and dry biomass of cucumber by 20.9 % and 5.92 %, respectively (P < 0.05). Therefore, the wood vinegar at an optimal time of dilution could be used a promising soaking agent for the seeds germination, and further enhance crop yields.

Effect of precipitation pattern on leaching of preservative from treated wood and implications for accelerated testing

Treesearch

Stan Lebow

2014-01-01

There is a need to develop improved accelerated test methods for evaluating the leaching of wood preservatives from treated wood exposed to precipitation. In this study the effects of rate of rainfall and length of intervals between rainfall events on leaching was evaluated by exposing specimens to varying patterns of simulated rainfall under controlled laboratory...

"Effect of Anxiety Reduction on Children's School Performance and Social Adjustment": Correction to Wood (2006)

ERIC Educational Resources Information Center

Wood, Jeffrey J.

2007-01-01

Reports an error in "Effect of anxiety reduction on children's school performance and social adjustment" by Jeffrey Wood (Developmental Psychology, 2006[Mar], Vol 42[2], 345-349). The byline and author note should have included the author's middle initial, J. Thus, the byline and author note should refer to "Jeffrey J. Wood." The correction is…

The effect of wind on burning rate of wood cribs

Treesearch

Sara McAllister; Mark Finney

2016-01-01

Wood cribs are often used as ignition sources for room fire tests. A wood crib may also apply to studies of burning rate in wildland fires, because wildland fuel beds are porous and three dimensional. A unique aspect of wildland fires is the ubiquitous presence of wind. However, very little is known about what effect the increased ventilation has on the...

Use of wood-based materials in beef bedded manure packs: 1. Effect on ammonia, total reduced sulfide, and greenhouse gas concentrations

USDA-ARS?s Scientific Manuscript database

The objectives of this study were to determine the effect of using corn stover or three different wood-based bedding materials (kiln-dried pine wood chips, dry cedar chips, or green cedar chips) on airborne concentrations of ammonia (NH3), total reduced sulfur (TRS), carbon dioxide (CO2), methane (C...

Effect of Fungal Competition on Decay Rates in Bicultured Soil Bottle Assays

Treesearch

Grant T. Kirker; Amy Blodgett; Patricia K. Lebow; Carol A. Clausen

2016-01-01

For decades, wood scientists and preservative formulators have employed the monocultured soil bottle assay to test efficacy of wood treatment in the laboratory as a rapid predictor of field performance. This study examines the effects of bicultured soil bottle assays on the decay by common wood decay fungi. Mycelial interactions were noted in early stages of...

Sol-gel modification of wood substrates to retard weathering

Treesearch

Mandla A Tshabalala; Sam Williams

2008-01-01

Wood specimens were treated with sol-gel systems based on metalorganic precursors of silicon (Si), iron (Fe), zirconium (Zr), and titanium (Ti). The effect of these sol-gel systems on weathering properties of wood was investigated. These sol-gel systems were found to have a positive effect on surface color stability and water vapor resistance of the specimens. Under...

Effects of shear coupling on shear properties of wood

Treesearch

Jen Y. Liu

2000-01-01

Under pure shear loading, an off-axis element of orthotropic material such as pure wood undergoes both shear and normal deformations. The ratio of the shear strain to a normal strain is defined as the shear coupling coefficient associated with the direction of the normal strain. The effects of shear coupling on shear properties of wood as predicted by the orthotropic...

Effects of plantation density on wood density and anatomical properties of red pine (Pinus resinosa Ait.)

Treesearch

J. Y. Zhu; C. Tim Scott; Karen L. Scallon; Gary C. Myers

2007-01-01

This study demonstrated that average ring width (or average annual radial growth rate) is a reliable parameter to quantify the effects of tree plantation density (growth suppression) on wood density and tracheid anatomical properties. The average ring width successfully correlated wood density and tracheid anatomical properties of red pines (Pinus resinosa Ait.) from a...

Effect of initial planting spacing on wood properties of unthinned loblolly pine at age 21

Treesearch

Alexander III Clark; Lewis Jordan; Laurie Schimleck; Richard F. Daniels

2008-01-01

Young, fast growing, intensively managed plantation loblolly pine (Pinus taeda L.) contains a large proportion of juvenile wood that may not have the stiffness required to meet the design requirements for southern pine dimension lumber. An unthinned loblolly pine spacing study was sampled to determine the effect of initial spacing on wood stiffness,...

The Effect of Soil Warming on Decomposition of Biochar, Wood, and Bulk Soil Organic Carbon in Contrasting Temperate and Tropical Soils

NASA Astrophysics Data System (ADS)

Torn, Margaret; Tas, Neslihan; Reichl, Ken; Castanha, Cristina; Fischer, Marc; Abiven, Samuel; Schmidt, Michael; Brodie, Eoin; Jansson, Janet

2013-04-01

Biochar and wood are known to decay at different rates in soil, but the longterm effect of char versus unaltered wood inputs on soil carbon dynamics may vary by soil ecosystem and by their sensitivity to warming. We conducted an incubation experiment to explore three questions: (1) How do decomposition rates of char and wood vary with soil type and depth? (2) How vulnerable to warming are these slowly decomposing inputs? And (3) Do char or wood additions increase loss of native soil organic carbon (priming)? Soils from a Mediterranean grassland (Hopland Experimental Research Station, California) and a moist tropical forest (Tabunoco Forest, Puerto Rico) were collected from two soil depths and incubated at ambient temperature (14°C, 20°C for Hopland and Tabonuco respectively) and ambient +6°C. We added 13C-labeled wood and char (made from the wood at 450oC) to the soils and quantified CO2 and 13CO2 fluxes with continuous online carbon isotope measurements using a Cavity Ringdown Spectrometer (Picarro, Inc) for one year. As expected, in all treatments the wood decomposed much (about 50 times) more quickly than did the char amendment. With few exceptions, amendments placed in the surface soil decomposed more quickly than those in deeper soil, and in forest soil faster than that placed in grassland soil, at the same temperature. The two substrates were not very temperature sensitive. Both had Q10 less than 2 and char decomposition in particular was relatively insensitive to warming. Finally, the addition of wood caused a significant increase of roughly 30% in decomposition losses of the native soil organic carbon in the grassland and slightly less in forest. Char had only a slight positive priming effect but had a significant effect on microbial community. These results show that conversion of wood inputs to char through wildfire or intentional management will alter not only the persistence of the carbon in soil but also its temperature response and effect on microbial communities.

Adhesive groups and how they relate to the durability of bonded wood

Treesearch

Charles R. Frihart

2009-01-01

There is a need to develop models that evaluate the interaction of wood adhesives at the macroscopic level to explain observations on the durability of bonded wood laminate products with changing moisture conditions. This paper emphasizes a model that relates durability to strain on the bondline caused by wood swelling. The effect of this strain is discussed in...

Effect of acetylated wood flour or coupling agent on moisture, UV, and biological resistance of extruded woodfiber-plastic composites

Treesearch

Rebecca E. Ibach; Craig M. Clemons

2006-01-01

Although moisture sorption in woodfiber-thermoplastic composites (WPCs) is slower than in unmodified solid wood, it still affects strength and ultimately results in decay of the material in moist outdoor exposure conditions. Chemical modification of the hydroxyl groups of wood with acetic anhydride esterifies the hydroxyl making the wood more hydrophobic and...

Wood and Wood-Based Materials as Sensors—A Review of the Piezoelectric Effect in Wood

Treesearch

Robert J. Ross; Jiangming Kan; Xiping Wang; Julie Blankenburg; Janet I. Stockhausen; Roy F. Pellerin

2012-01-01

A variety of techniques have been investigated for use in assessing the physical and mechanical properties of wood products and structures. Ultrasound, transverse vibration, and stress-wave based methods are all techniques that have shown promise for many nondestructive evaluation applications. These techniques and others rely on the use of measurement systems to...

Adhesive Penetration of Wood and Its Effect on Bond Strength

Treesearch

Charles R. Frihart

2016-01-01

Woodworkers know that wood is porous in that adhesive flows into lumens for a mechanical interlock (1) and that wood absorbs water, allowing the use of water-borne adhesives. However, the anatomical aspects of wood that lend to its porosity are much more complicated and have a greater influence on adhesive performance than is normallyrealized or discussed. This...

Improvements in decay resistance based on moisture exclusion

Treesearch

Roger M. Rowell; Rebecca E. Ibach

2000-01-01

Moisture content has an effect on the biological decay of wood. The literature states that serious decay occurs when the moisture content of wood is above the fiber saturation point (FSP), which is the measurement of the moisture content of wood when the cell walls are saturated and the cell cavities free from water (average 30%). We can chemically modify wood...

Disturbance legacies of historic tie-drives persistently alter geomorphology and large wood characteristics in headwater streams, southeast Wyoming

Treesearch

Claire M. Ruffing; Melinda D. Daniels; Kathleen A. Dwire

2015-01-01

Instream wood is recognized as an integral component of stream morphology in forested areas. However, few studies have evaluated the legacy effects of historic wood removal activities and associated impacts on channel morphology, contemporary wood loading, and recruitment. This study investigates the role of historic tie-driving, a widespread channel disturbance legacy...

Enhanced understanding of the relationship between chemical modification and mechanical properties of wood

Treesearch

Charles R. Frihart; Daniel J. Yelle; John Ralph; Robert J. Moon; Donald S. Stone; Joseph E. Jakes

2008-01-01

Chemical additions to wood often change its bulk properties, which can be determined using conventional macroscopic mechanical tests. However, the controlling interactions between chemicals and wood take place at and below the scale of individual cells and cell walls. To better understand the effects of chemical additions to wood, we have adapted and extended two...

Harvesting Duke FACE: improving estimates of productivity and biomass under elevated CO2

NASA Astrophysics Data System (ADS)

McCarthy, H. R.; Oren, R.; Kim, D.; Tor-ngern, P.; Johnsen, K. H.; Maier, C. A.

2013-12-01

Free air CO2 enrichment experiments (FACE) have greatly advanced our knowledge on the impacts of increasing atmospheric CO2 concentrations in developing and mature ecosystems. These experiments have provided years of data on changes in physiology and ecosystem functions, such as photosynthesis, water use, net primary productivity (NPP), ecosystem carbon storage, and nutrient cycling. As these experiments come to a close, there has also been the opportunity to add critically lacking biometric data, which can be obtained only through destructive measurements. After 15 years of CO2 elevation at the Duke Forest FACE, a 28 year old pine plantation with a hardwood understory, a vast array of biometric data was obtained through harvesting of >1150 trees in both elevated and ambient CO2 plots. Harvested trees included pines and hardwoods, understory and overstory trees. The harvest provided direct assessments of leaf, stem and branch biomass, as well as the vertical distribution of these masses. In combination with leaf and wood level properties (e.g. specific leaf area, wood density), it was possible to explore potential CO2 effects on allometric relationships between plant parts, and stem and canopy shape and distribution. Although stimulatory effects of elevated CO2 on NPP are well established in this forest (averaging 27%), harvest results thus far indicate few changes in basic allometric relationships, such as height-diameter relationships, proportion of mass contained in different plant parts (stems vs. leaves vs. branches), distribution of leaves within the canopy and stem shape. The coupling of site-specific biometric relationships with long-term data on tree growth and mortality will reduce current sources of uncertainty in estimates of NPP and carbon storage under future increased CO2 conditions. Recent efforts in data-model synthesis have demonstrated the critical need for such data as constraints and initial values in ecosystem and earth system models; these outcomes suggest that we are well positioned to represent future forest growth and function.

X-RAY DENSITOMETRY OF NORWAY SPRUCE SUBFOSSIL WOOD FROM THE AUSTRIAN ALPS

PubMed Central

KŁUSEK, MARZENA; GRABNER, MICHAEL

2016-01-01

The processing of subfossil wood poses some difficulties in densitometric research. Problems arise because of the physio-chemical changes of wood occurring in the sedimentation environment. Subfossil wood modification can result from the uptake of mineral and organic substances into the wood tissue. It can also occur as the effect of microbiological degradation of wood. The goal of this study was to identify the appropriate method of subfossil wood preparation for the densitometric research. For this purpose the wood of Norway spruce from Lake Schwarzensee was subjected to extraction in deionized water, acetone and diluted acetic acid. The application of acetic acid did not significantly influence the density of the wood and acetone seemed to be too aggressive. The best result was obtained by rinsing the samples in cold de-ionized water. This extraction procedure allowed removal of unwanted water-soluble, organic and inorganic compounds from wood and simultaneously did not lead to the degradation of subfossil samples. PMID:27158247

Response of Microtermes mycophagus (Isoptera: Termitidae) to twenty one wood species

PubMed Central

Saeed, Shafqat

2015-01-01

The responses of termite species to bait depend upon the quality of the food used in the stations. Woods are the most common food sources for termites but different termite species behave differently to different wood species and types. The knowledge of the preference status of different wood species to a termite species helps in effective monitoring and baiting program. The current study was carried out to evaluate the preference of 21 wood species to the termite, Microtermes mycophagus in the field by no-choice and choice feeding tests. The results indicated silk cotton tree and sacred fig woods as the most preferred wood species with mean mass losses of 71.21 ± 5.09% and 68.38 ± 7.27% in no-choice test and 95.02 ± 1.65% and 91.69 ± 2.07% in choice tests, respectively. White cedar was the least preferred wood species with mean mass losses of 7.49 ± 1.64% and 13.92 ± 1.89% in no choice and choice feeding tests, respectively. Based on present studies, sapwood of silk cotton tree and sacred fig may be used in effective monitoring and baiting program against M. mycophagus. PMID:26312171

Review of environmental effects and treatment of runoff from storage and handling of wood.

PubMed

Hedmark, Asa; Scholz, Miklas

2008-09-01

This review paper summarises the environmental effects of runoff from wood handling sites including log yards. The characteristics of site runoff and the corresponding effects on the receiving watercourses are presented for worldwide case studies, highlighting the urgent need to address the water pollution problem associated with the wood industry. The methods used to reduce the negative environmental impact of the runoff, such as constructed wetlands, soil infiltration and chemical oxidation, are evaluated. The principal environmental problem of runoff is usually the high concentration of organic substances originating from the wood and bark, some of which are toxic to aquatic life. Phosphorus is also a problem according to some studies. The toxicity of the runoff varies greatly, and depends on the species of tree stored, the amount of water the wood has been in contact with and the degree of runoff treatment.

Study of processes influencing bioavailability of pesticides in wood-soil systems: Effect of different factors.

PubMed

Marín-Benito, J M; Herrero-Hernández, E; Rodríguez-Cruz, M S; Arienzo, M; Sánchez-Martín, M J

2017-05-01

Lignocellulosic wastes and by-products containing lignin are now available in large amounts from forestry and industrial activities, and could be promising organic materials for the biosorption of pesticides by soils in order to reduce point-source pollution. Adding these materials to soil requires understanding the process of pesticide sorption-desorption by wood-soils, as sorption capacity could increase, with changes in pesticide bioavailability and final fate. The objective of this work was to study the effect that pine and oak wood added to soils had on the sorption/desorption of the pesticides linuron, alachlor, and metalaxyl. Experiments were conducted with two sandy loam and sandy clay soils each amended with two wood doses (5% and 50%) after different incubation times (0, 5 and 12 months). A low wood dose (5%) had no significant impact on the sorption (K f ) of alachlor, but K f increased for linuron (up to 5.4-1.7 times) and metalaxyl (up to 4.4 and 8.6 times) in all wood-soil systems. The results were not significantly different after different incubation times. The desorption results indicated that wood decreases the sorption irreversibility of alachlor, and increases that of linuron and metalaxyl, with a varying effect of the wood-soil incubation time. The addition of a high wood dose to soil (50%) was more significant for increasing the sorption of all the pesticides, and the sorbed amounts remaining after desorption (>49% for linuron, >33% for alachlor and >6% for metalaxyl), although there was no apparent discrimination between the two types of woods. The role of the nature of the organic carbón (K oc values) for sorption was evidenced for alachlor and metalaxyl, but not for linuron. These outcomes are of interest for extending wood application to soil as a barrier for avoiding environmental risk by point-source pollution due to the use and management of pesticides in farming systems. Copyright © 2017 Elsevier Inc. All rights reserved.

Respiratory symptoms and lung function in relation to wood dust and monoterpene exposure in the wood pellet industry.

PubMed

Löfstedt, Håkan; Hagström, Katja; Bryngelsson, Ing-Liss; Holmström, Mats; Rask-Andersen, Anna

2017-06-01

Wood pellets are used as a source of renewable energy for heating purposes. Common exposures are wood dust and monoterpenes, which are known to be hazardous for the airways. The purpose of this study was to study the effect of occupational exposure on respiratory health in wood pellet workers. Thirty-nine men working with wood pellet production at six plants were investigated with a questionnaire, medical examination, allergy screening, spirometry, and nasal peak expiratory flow (nasal PEF). Exposure to wood dust and monoterpenes was measured. The wood pellet workers reported a higher frequency of nasal symptoms, dry cough, and asthma medication compared to controls from the general population. There were no differences in nasal PEF between work and leisure time. A lower lung function than expected (vital capacity [VC], 95%; forced vital capacity in 1 second [FEV 1 ], 96% of predicted) was noted, but no changes were noted during shifts. There was no correlation between lung function and years working in pellet production. Personal measurements of wood dust at work showed high concentrations (0.16-19 mg/m 3 ), and exposure peaks when performing certain work tasks. Levels of monoterpenes were low (0.64-28 mg/m 3 ). There was no association between exposure and acute lung function effects. In this study of wood pellet workers, high levels of wood dust were observed, and that may have influenced the airways negatively as the study group reported upper airway symptoms and dry cough more frequently than expected. The wood pellet workers had both a lower VC and FEV 1 than expected. No cross-shift changes were found.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richard F. Daniels; Alexander Clark III

The forest industry will increasingly rely on fast-growing intensively managed southern pine plantations to furnish wood and fiber. Intensive silvicultural practices, including competition control, stand density control, fertilization, and genetic improvement are yielding tremendous gains in the quantity of wood production from commercial forest land. How these technologies affect wood properties was heretofore unknown, although there is concern about the suitability of fast-grown wood for traditional forest products. A four year study was undertaken to examine the effects of these intensive practices on the properties of loblolly and slash pine wood by applying a common sampling method over 10 existingmore » field experiments. Early weed control gets young pines off to a rapid start, often with dramatically increased growth rates. This response is all in juvenile wood however, which is low in density and strength. Similar results are found with early Nitrogen fertilization at the time of planting. These treatments increase the proportion of juvenile wood in the tree. Later, mid-rotation fertilization with Nitrogen and Phosphorus can have long term (4-8 year) growth gains. Slight reductions in wood density are short-lived (1-2 years) and occur while the tree is producing dense, stiff mature wood. Impacts of mid-rotation fertilization on wood properties for manufacturing are estimated to be minimal. Genetic differences are evident in wood density and other properties. Single family plantings showed somewhat more uniform properties than bulk improved or unimproved seedlots. Selection of genetic sources with optimal wood properties may counter some of the negative impacts of intensive weed control and fertilization. This work will allow forest managers to better predict the effects of their practices on the quality of their final product.« less

Respiratory symptoms and lung function in relation to wood dust and monoterpene exposure in the wood pellet industry

PubMed Central

Löfstedt, Håkan; Hagström, Katja; Bryngelsson, Ing-Liss; Holmström, Mats; Rask-Andersen, Anna

2017-01-01

Introduction Wood pellets are used as a source of renewable energy for heating purposes. Common exposures are wood dust and monoterpenes, which are known to be hazardous for the airways. The purpose of this study was to study the effect of occupational exposure on respiratory health in wood pellet workers. Materials and methods Thirty-nine men working with wood pellet production at six plants were investigated with a questionnaire, medical examination, allergy screening, spirometry, and nasal peak expiratory flow (nasal PEF). Exposure to wood dust and monoterpenes was measured. Results The wood pellet workers reported a higher frequency of nasal symptoms, dry cough, and asthma medication compared to controls from the general population. There were no differences in nasal PEF between work and leisure time. A lower lung function than expected (vital capacity [VC], 95%; forced vital capacity in 1 second [FEV1], 96% of predicted) was noted, but no changes were noted during shifts. There was no correlation between lung function and years working in pellet production. Personal measurements of wood dust at work showed high concentrations (0.16–19 mg/m3), and exposure peaks when performing certain work tasks. Levels of monoterpenes were low (0.64–28 mg/m3). There was no association between exposure and acute lung function effects. Conclusions In this study of wood pellet workers, high levels of wood dust were observed, and that may have influenced the airways negatively as the study group reported upper airway symptoms and dry cough more frequently than expected. The wood pellet workers had both a lower VC and FEV1 than expected. No cross-shift changes were found. PMID:28276782

X-ray computed tomography of wood-adhesive bondlines: Attenuation and phase-contrast effects

DOE PAGES

Paris, Jesse L.; Kamke, Frederick A.; Xiao, Xianghui

2015-07-29

Microscale X-ray computed tomography (XCT) is discussed as a technique for identifying 3D adhesive distribution in wood-adhesive bondlines. Visualization and material segmentation of the adhesives from the surrounding cellular structures require sufficient gray-scale contrast in the reconstructed XCT data. Commercial wood-adhesive polymers have similar chemical characteristics and density to wood cell wall polymers and therefore do not provide good XCT attenuation contrast in their native form. Here, three different adhesive types, namely phenol formaldehyde, polymeric diphenylmethane diisocyanate, and a hybrid polyvinyl acetate, are tagged with iodine such that they yield sufficient X-ray attenuation contrast. However, phase-contrast effects at material edgesmore » complicate image quality and segmentation in XCT data reconstructed with conventional filtered backprojection absorption contrast algorithms. A quantitative phase retrieval algorithm, which isolates and removes the phase-contrast effect, was demonstrated. The paper discusses and illustrates the balance between material X-ray attenuation and phase-contrast effects in all quantitative XCT analyses of wood-adhesive bondlines.« less

X-ray computed tomography of wood-adhesive bondlines: Attenuation and phase-contrast effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paris, Jesse L.; Kamke, Frederick A.; Xiao, Xianghui

Microscale X-ray computed tomography (XCT) is discussed as a technique for identifying 3D adhesive distribution in wood-adhesive bondlines. Visualization and material segmentation of the adhesives from the surrounding cellular structures require sufficient gray-scale contrast in the reconstructed XCT data. Commercial wood-adhesive polymers have similar chemical characteristics and density to wood cell wall polymers and therefore do not provide good XCT attenuation contrast in their native form. Here, three different adhesive types, namely phenol formaldehyde, polymeric diphenylmethane diisocyanate, and a hybrid polyvinyl acetate, are tagged with iodine such that they yield sufficient X-ray attenuation contrast. However, phase-contrast effects at material edgesmore » complicate image quality and segmentation in XCT data reconstructed with conventional filtered backprojection absorption contrast algorithms. A quantitative phase retrieval algorithm, which isolates and removes the phase-contrast effect, was demonstrated. The paper discusses and illustrates the balance between material X-ray attenuation and phase-contrast effects in all quantitative XCT analyses of wood-adhesive bondlines.« less

The Effect of Kiln Drying on the Strength of Airplane Woods

NASA Technical Reports Server (NTRS)

Wilson, T R C

1920-01-01

This report is a very complete treatise on the comparative strength of air and kiln dried wood. The series of tests includes 26 species of wood, approximately 100 kiln runs, and over 10,000 mechanical tests.

Particulate matter emissions from combustion of wood in district heating applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghafghazi, S.; Sowlati, T.; Sokhansanj, Shahabaddine

2011-01-01

The utilization of wood biomass to generate district heat and power in communities that have access to this energy source is increasing. In this paper the effect of wood fuel properties, combustion condition, and flue gas cleaning system on variation in the amount and formation of particles in the flue gas of typical district heating wood boilers are discussed based on the literature survey. Direct measurements of particulate matter (PM) emissions from wood boilers with district heating applications are reviewed and presented. Finally, recommendations are given regarding the selection of wood fuel, combustion system condition, and flue gas cleaning systemmore » in district heating systems in order to meet stringent air quality standards. It is concluded that utilization of high quality wood fuel, such as wood pellets produced from natural, uncontaminated stem wood, would generate the least PM emissions compared to other wood fuel types. Particulate matter emissions from grate burners equipped with electrostatic precipitators when using wood pellets can be well below stringent regulatory emission limit such as particulate emission limit of Metro Vancouver, Canada.« less

Both a frameshift and a missense mutation of the STRA6 gene observed in an infant with the Matthew-Wood syndrome.

PubMed

Sadowski, Samantha; Chassaing, Nicolas; Gaj, Zuzanna; Czichos, Ewa; Wilczynski, Jan; Nowakowska, Dorota

2017-03-01

The Matthew-Wood syndrome is associated with mutations of the STRA6 gene. It combines a pulmonary agenesis/hypoplasia; microphthalmia/anophthalmia; congenital cardiac, digestive, and urogenital malformations; and diaphragmatic defects. A 23-year-old nulliparous woman was referred to our center after a fetal ultrasound examination at 26 weeks of pregnancy revealed an abnormal head shape, a heart malformation, multiple cysts in both kidneys, and dilated ureters. A male baby (46, XY; 3600g; Apgar score 1) was delivered at 38 weeks of gestation and died 1 hr later due to respiratory failure. The diagnosis of Matthew-Wood syndrome was suspected given the association of bilateral anophthalmia, agenesis of the left lung, and heart and kidney defects. It was confirmed by the identification of two deleterious mutations of the STRA6 gene. The child was a compound heterozygote for two previously reported mutations, a paternally inherited missense mutation (c.878C>T [p.Pro293Leu] and a maternally inherited frameshift mutation (c.50_52delACTinsCC [p. Asp17Alafs*55]), producing a premature stop codon. The diagnosis of Matthew-Wood syndrome should be considered in all fetuses with microphthalmia/anophthalmia. It requires an extensive ultrasound/MRI examination of the lung, heart, and diaphragm. Birth Defects Research 109:251-253, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Co-culturing Effects of Coexisting Bacteria on Wood Degradation by Trametes versicolor.

PubMed

Kamei, Ichiro

2017-01-01

White-rot fungi are the main decomposers of wood cell-wall polymer in forest ecosystems. Little is known, however, about the interactions between white-rot fungi and other coexisting microorganisms in decayed wood. A white-rot fungus, Trametes versicolor strain TN6F, was isolated from a fruit body, and 44 strains of coexisting cultivable bacteria were isolated from its substrate, natural white rot-decayed wood. The effects of these bacteria on fungal growth were examined by an in vitro confrontation growth assay. Among the isolates, nine bacterial strains inhibited the growth of strain TN6F, while 35 strains did not affect the growth of TN6F. However, when co-cultured with strain TN6F on wood powder, many bacterial strains promoted the weight loss of the substrate. A subsequent chemical composition analysis showed that co-culturing accelerated delignification. Higher laccase activity was detected when strain TN6F was co-cultured on wood powder medium with bacterial strains TN6W-26 or TN6W-27. These results indicate that some bacterial strains might promote wood degradation.

Synchrotron-based X-ray Fluorescence Microscopy in Conjunction with Nanoindentation to Study Molecular-Scale Interactions of Phenol-Formaldehyde in Wood Cell Walls

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jakes, Joseph E.; Hunt, Chris G.; Yelle, Daniel J.

Understanding and controlling molecular-scale interactions between adhesives and wood polymers are critical to accelerate the development of improved adhesives for advanced wood-based materials. The submicrometer resolution of synchrotron-based X-ray fluorescence microscopy (XFM) was found capable of mapping and quantifying infiltration of Br-labeled phenolformaldehyde (BrPF) into wood cell walls. Cell wall infiltration of five BrPF adhesives with different average molecular weights (MWs) was mapped. Nanoindentation on the same cell walls was performed to assess the effects of BrPF infiltration on cell wall hygromechanical properties. For the same amount of weight uptake, lower MW BrPF adhesives were found to be more effectivemore » at decreasing moisture-induced mechanical softening. This greater effectiveness of lower MW phenolic adhesives likely resulted from their ability to more intimately associate with water sorption sites in the wood polymers. Evidence also suggests that a BrPF interpenetrating polymer network (IPN) formed within the wood polymers, which might also decrease moisture sorption by mechanically restraining wood polymers during swelling.« less

Five new machines and six products can triple commodity recovery from southern forests

Treesearch

Peter Koch

1978-01-01

Mixed southern pine-hardwood stands now yield 20 to 22 percent of their biomass in wood products. A new energy self-sufficient system using tree pullers, wet-fuel burners, mobile chippers, shaping-lathe headrigs, and continuous kilns can convert 67 percent of the biomass (above- and below-ground parts of trees of all species) into products worth about $150 per dry ton...

Temperature changes in an initially frozen wood chip pile.

Treesearch

George R. Sampson; Jenifer H. McBeath

1987-01-01

White spruce trees and tops were chipped and placed in a pile near Fairbanks, Alaska, in February 1983. The pile was 6 meters in diameter and 6 meters high in a cylindrical shape. Thermocouples were placed at 25 locations within the pile so that temperatures could be tracked over time. Gypsum blocks were placed at 10 locations to determine changes in moisture content....

Potential Effects of Wood Chip Mill Harvests on Economic Returns and Forest Management Practices of Nonindustrial Private Forest Landowners in North Carolina

Treesearch

Anthony Snider; Frederick Cubbage; Robert Moulton

2001-01-01

Four approaches were used to estimate the market effects of wood chip mills for nonindustrial private forest (NIPF) landowners. First, we used economic welfare analyses to estimate potential changes in consumer and producer surplus that might be attributed to increased stumpage demand created by wood chip mills. Better markets would consistently increase economic...

Effects of introduced small wood in a degraded stream on fish community and functional diversity

Treesearch

Ken A. Sterling; Melvin L.  Warren Jr.

2018-01-01

Abstract - Though the effects of introduced wood on fishes is widely studied for salmonids in upland coldwater streams, there are few studies on this topic conducted in the Coastal Plain of the southeastern US. This research gap is problematic because the introduction of wood is a critical component of efforts aimed at conserving the threatened fish diversity of the...

Effect of simulated rainfall and weathering on release of preservative elements from CCA treated wood

Treesearch

Stan Lebow; R. Sam Williams; Patricia Lebow

2003-01-01

The release of arsenic from wood pressure-treated with chromated copper arsenate (CCA) can be decreased by application of wood finishes, but little is known about the types of finishes that are best suited for this purpose. This study evaluated the effects of finish water repellent content and ultraviolet (UV) radiation on the release of arsenic, copper, and chromium...

Use of wood-based materials in beef bedded manure packs: 2. Effect on odorous volatile organic compounds, odor activity value, Escherichia coli, and nutrient concentrations

USDA-ARS?s Scientific Manuscript database

The objectives of this study were to determine the effects of three types of wood-based bedding materials (kiln-dried pine wood chips, dry cedar chips, and green cedar chips) and corn stover on concentration of odorous volatile organic compounds (VOC) and total Escherichia coli in bedded pack materi...

Effects of processing method and moisture history on laboratory fungal resistance of wood-HDPE composites.

Treesearch

Craig M. Clemons; Rebecca E. Ibach

2004-01-01

The purpose of this study was to clarify the effects of composite processing and moisture sorption on laboratory fungal resistance of wood-plastic composites. A 2-week water soaking or cyclic boiling-drying procedure was used to infuse moisture into composites made from high-density polyethylene filled with 50 percent wood flour and processed by extrusion, compression...

Untreated and copper-treated wood soaked in sodium oxalate: effects of decay by copper-tolerant and copper-sensitive fungi

Treesearch

Katie M. Ohno; Grant T. Kirker; Amy B. Bishell; Carol A. Clausen

2017-01-01

Copper is widely used as the primary component in wood protectants because it demonstrates a broad range of biocidal properties. However, a key concern with using copper in wood preservative formulations is the possibility for brown-rot basidiomycetes to resist the toxic effect. Many brown-rot basidiomycetes have evolved mechanisms, like the production and accumulation...

Dead-wood addition promotes non-saproxylic epigeal arthropods but effects are mediated by canopy openness

Treesearch

Sebastian Seibold; Claus Bässler; Petr Baldrian; Lena Reinhard; Simon Thorn; Michael D. Ulyshen; Ingmar Weiß; Jörg Müller

2016-01-01

Restoring dead-wood amounts in forests is an increasingly and successfully applied conservation measure to counteract negative effects of intensive logging on biodiversity of saproxylic taxa. By contrast, if and how dead-wood addition benefits the vast number of non-saproxylic forest taxa, and how this varies with contextual factors like canopy openness, remains poorly...

Potential Effects of the Fuelwood Market on Wood-using Industries in Northern New England and New York

Treesearch

Susan B. Remington; Paul E. Sendak; Paul E. Sendak

1984-01-01

The increased use of fuelwood in northern New England and New York has raised concern about future supplies of manufactured wood products. Direct effects were measured by estimating the competitive advantages of the kraft pulp, waferboard, and oriented strand board industries in purchasing wood. lncreased stumpage prices in the region would have the greatest impact on...

Manual for LS-DYNA Wood Material Model 143

DOT National Transportation Integrated Search

2007-08-01

An elastoplastic damage model with rate effects was developed for wood and was implemented into LS-DYNA, a commercially available finite element code. This manual documents the theory of the wood material model, describes the LS-DYNA input and output...

Effect of PF impregnation and surface densification on the mechanical properties of small-scale wood laminated poles

Treesearch

Huaqiang Yu; Chung Y. Hse; Zehui Jiang

2009-01-01

The wood poles in the United States are from high-valued trees that are becoming more expensive and less available. Wood laminated composite poles (LCP) are a kind of alternative to solid poles. Considerable interest has developed in last century in the resin impregnation and wood surface densification to improve its physical and mechanical properties. In this...

Effect of weathering on chromated copper arsenate (CCA) treated wood : leaching of metal salts and change in water repellency

Treesearch

R. Sam Williams; Stan Lebow; Patricia Lebow

2003-01-01

Wood pressure-treated with chromated copper arsenate (CCA) wood preservative is commonly used for outdoor construction. Oxides of arsenic, copper, and chromium are bound in the wood by a complex series of chemical reactions, but a small percentage of these compounds are gradually released by leaching and weathering. Recent studies suggest that the release of these...

A two end-member model of wood dynamics in headwater neotropical rivers

Treesearch

Ellen Wohl; Susan Bolton; Daniel Cadol; Francesco Comiti; Jaime R. Goode; Luca Mao

2012-01-01

Geomorphic and ecological effects of instream wood have been documented primarily along rivers in the temperate zones. Instream wood loads in tropical rivers might be expected to differ from those in analogous temperate rivers because of the higher transport capacity and higher rates of wood decay in the tropics. We use data from four field sites in Costa Rica and...

Effect of fiber surface and mechanical properties on the stiffness and strength of medium-density fiberboard

Treesearch

Leslie H. Groom; Laurence Mott; Stephen M. Shaler; Tom Pesacreta

1999-01-01

The mechanical properties of wood-based composites are dependent upon the properties of the wood components (e.g., wood fibers, wood strands) and the manner in which they are combined. The relationship between fiber mechanical properties and fiber-based composites has been discussed in several publications. This paper will focus primarily on the influence of fiber...

Potassium methyl siliconate-treated pulp fibers and their effects on wood plastic composites: Water sorption and dimensional stability

Treesearch

Cheng Piao; Zhiyong Cai; Nicole M. Stark; Charles J. Monlezun

2013-01-01

Potassium methyl siliconate (PMS) was investigated as a new nano modifier of wood fiber and wood flour to improve the compatibility between the fiber/flour and the plastic matrix in fiber reinforced plastic composites. Before injection molding, bleached and brown pulp fibers and mixed species wood flour were pretreated in PMS solutions. The morphology of the treated...

Effects of live crown on vertical patterns of wood density and growth in Douglas-fir.

Treesearch

Barbara L. Gartner; Eric M. North; G.R. Johnson; Ryan Singleton

2002-01-01

It would be valuable economically to know what are the biological triggers for formation of mature wood (currently of high value) and (or) what maintains production of juvenile wood (currently of low value), to develop silvicultural regimes that control the relative production of the two types of wood. Foresters commonly assume the bole of softwoods produces juvenile...

Wood surface modification by in-situ sol-gel deposition of hybrid inorganic-organic thin films

Treesearch

Mandla A. Tshabalala; Li-Piin Sung

2007-01-01

Interest in the use of nanoparticles of iron, titanium, aluminum, and zinc oxides in transparent coatings for wood is increasing. Such nano-composite coatings have the potential of not only preserving the natural color of the wood, but also stabilizing the wood surface against the combined degradative effects of sunlight and moisture. The nanoparticles can be used as...

Heat treatment of wet wood fiber: A study of the effect of reaction conditions on the formation of furfurals

Treesearch

Mandla A. Tshabalala; James D. McSweeny; Roger M. Rowell

2012-01-01

Furan monomers are produced when wood is heated at high temperatures. To understand the process conditions for production of furfural (FF) and hydroxymethylfurfural (HMF) from wood, samples of milled aspen wood were subjected to autohydrolyzis by microwave heating in a sealed Teflon reactor. The experiments were designed to simulate temperature and pressure variables...

Elevated tropospheric CO2 and O3 may not alter initial wood decomposition rate or wood-decaying fungal community composition of Northern hardwoods

Treesearch

Emmanuel Ebanyenle; Andrew J. Burton; Andrew J. Storer; Dana L. Richter; Jessie A. Glaeser

2016-01-01

We examined the effects of elevated CO2 and/or O3 on the wood-decaying basidiomycete fungal community and wood decomposition rates at the Aspen Free-Air CO2 and O3 Enrichment (Aspen FACE) project. Mass loss rates were determined after one year of log decomposition on the soil...

Ecology of bison, elk, and vegetation in an arid ecosystem

USGS Publications Warehouse

Schoenecker, Kathryn A.

2012-01-01

Herbivory has profound effects on vegetation production and structure in many different plant communities. The influence of herbivory on plants and ultimately ecosystem processes is shaped by the types of plants consumed, the intensity of herbivory, the evolutionary history of grazing, and the availability of water and nutrients to plants. The effect of ungulate herbivores on vegetation is of great interest to ecologists, land managers and agriculturalists. In addition, the Department of Interior recently established a Bison Conservation Initiative to provide for the conservation and restoration of North American plains- and wood bison, which includes establishing new populations and expanding existing populations. The San Luis Valley, Colorado, is being considered as a potential location for a bison conservation herd. Resource managers need to know the vegetation impacts of adding a second large ungulate to a system that already has elk.

The effects of storage on the net calorific value of wood pellets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Jun Sian; Sokhansanj, S.; Lau, A. K.

The wood pellet export from Canada to Europe has been increasing steadily in recent years (roughly 1.8 million ton in 2013). Due to distances involved, wood pellets remain in transit and storage for months before their final consumption. The net calorific value determines the price of wood pellet purchase in Europe. There have been concerns about the changes of net calorific values over time. In this study, the effects of storage time, storage configuration, storage temperature, and wood pellet quality on the net calorific value of wood pellets for a period of 6 months were investigated. Storage configurations were openmore » or closed and storage temperatures were 25 °C, 35 °C and 45 °C. Two types of wood pellets used were whitewood and mixed. The results in closed storage indicated that storage time had a positive effect on the net calorific value where the net calorific value increased by 1% to 2% over the storage period. In open storage, the moisture content had the most significant impact on the net calorific value. The net calorific values of the two types of wood pellets were found to be significantly different at p < 0.001. A multivariable linear regression and analyses of variance performed verified the graphical results. Lastly, the authors postulated that the higher energy potential compounds, such as aldehyde and ketone, produced during pellet storage, caused the increase in net calorific values.« less

The effects of storage on the net calorific value of wood pellets

DOE PAGES

Lee, Jun Sian; Sokhansanj, S.; Lau, A. K.; ...

2015-06-30

The wood pellet export from Canada to Europe has been increasing steadily in recent years (roughly 1.8 million ton in 2013). Due to distances involved, wood pellets remain in transit and storage for months before their final consumption. The net calorific value determines the price of wood pellet purchase in Europe. There have been concerns about the changes of net calorific values over time. In this study, the effects of storage time, storage configuration, storage temperature, and wood pellet quality on the net calorific value of wood pellets for a period of 6 months were investigated. Storage configurations were openmore » or closed and storage temperatures were 25 °C, 35 °C and 45 °C. Two types of wood pellets used were whitewood and mixed. The results in closed storage indicated that storage time had a positive effect on the net calorific value where the net calorific value increased by 1% to 2% over the storage period. In open storage, the moisture content had the most significant impact on the net calorific value. The net calorific values of the two types of wood pellets were found to be significantly different at p < 0.001. A multivariable linear regression and analyses of variance performed verified the graphical results. Lastly, the authors postulated that the higher energy potential compounds, such as aldehyde and ketone, produced during pellet storage, caused the increase in net calorific values.« less

Empirical relations between large wood transport and catchment characteristics

NASA Astrophysics Data System (ADS)

Steeb, Nicolas; Rickenmann, Dieter; Rickli, Christian; Badoux, Alexandre

2017-04-01

The transport of vast amounts of large wood (LW) in water courses can considerably aggravate hazardous situations during flood events, and often strongly affects resulting flood damage. Large wood recruitment and transport are controlled by various factors which are difficult to assess and the prediction of transported LW volumes is difficult. Such information are, however, important for engineers and river managers to adequately dimension retention structures or to identify critical stream cross-sections. In this context, empirical formulas have been developed to estimate the volume of transported LW during a flood event (Rickenmann, 1997; Steeb et al., 2017). The data base of existing empirical wood load equations is, however, limited. The objective of the present study is to test and refine existing empirical equations, and to derive new relationships to reveal trends in wood loading. Data have been collected for flood events with LW occurrence in Swiss catchments of various sizes. This extended data set allows us to derive statistically more significant results. LW volumes were found to be related to catchment and transport characteristics, such as catchment size, forested area, forested stream length, water discharge, sediment load, or Melton ratio. Both the potential wood load and the fraction that is effectively mobilized during a flood event (effective wood load) are estimated. The difference of potential and effective wood load allows us to derive typical reduction coefficients that can be used to refine spatially explicit GIS models for potential LW recruitment.

The Long-Term Effects of Large Wood Placement on Salmonid Habitat in East Fork Mill Creek, Redwood National and State Park, California

NASA Astrophysics Data System (ADS)

Rodriguez, D. L.; Stubblefield, A. P.

2017-12-01

The conservation and recovery of anadromous salmonids (Oncorhynchus sp.) depend on stream restoration and protection of freshwater habitats. Instream large wood dictates channel morphology, increase retention of terrestrial inputs such as organic matter, nutrients and sediment, and enhances the quality of fish habitat. Historic land use/land cover changes have resulted in aquatic systems devoid of this component. Restoration by placement of large wood jams is intended to restore physical and biological processes. An important question for scientists and managers, in addition to the initial effectiveness of restoration, is the persistence and fate of this type of project. In this study we compare channel change and large wood attributes on the East Fork of Mill Creek, a tributary of the Smith River in northern California, eight years after a major instream wood placement effort took place. Our results are compared with previously published data from before and one year after the restoration. Preliminary results suggest the dramatic increase in spawning gravel abundance and large wood accumulation observed in the earlier study have persisted. From 2008 to 2016 a reduction in median sediment size, ranging from 103-136 percent, has been observed in a majority of the sites. The sites have continued to grow in size and influence by racking floating wood from upstream and destabilizing proximate banks of riparian alder, increasing both instream large wood volume (5-196 %) and floodplain connectivity. Preliminary results also show a decrease in residual pool depth and an increase in pool length which may be attributed to floodplain connectivity. Changes to the following attributes are evaluated: 1) wood loading (total site wood volume, total wood volume in active channel, and wood piece count); 2) percent pool cover by large wood; 3) residual pool depth; 4) upstream sediment aggradation; 5) floodplain connectivity; and 6) mean sediment size directly above and below large wood. We present on these results and statistical comparisons of total site wood volume with response factors.

Floods and Fluvial Wood

NASA Astrophysics Data System (ADS)

Comiti, F.

2014-12-01

Several studies have recently addressed the complex interactions existing at various spatial scales among riparian vegetation, channel morphology and wood storage. The majority of these investigations has been carried out in relatively natural river systems, focusing mostly on the long-term vegetation-morphology dynamics under "equilibrium" conditions. Little is still known about the role of flood events - of different frequency/magnitude - on several aspects of such dynamics, e.g. entrainment conditions of in-channel wood, erosion rates of vegetation from channel margins and from islands, transport distances of wood elements of different size along the channel network. Even less understood is how the river's evolutionary trajectory may affect these processes, and thus the degree to which conceptual models derivable from near-natural systems could be applicable to human-disturbed channels. Indeed, the different human pressures - present on most river basins worldwide - have greatly impaired the morphological and ecological functions of fluvial wood, and the attempts to "restore" in-channel wood storage are currently carried out without a sufficient understanding of wood transport processes occurring during floods. On the other hand, the capability to correctly predict the magnitude of large wood transport during large floods is now seen as crucial - especially in mountain basins - for flood hazard mapping, as is the identification of the potential wood sources (e.g. landslides, floodplains, islands) for the implementation of sound and effective hazard mitigation measures. The presentation will first summarize the current knowledge on fluvial wood dynamics and modelling at different spatial and temporal scales, with a particular focus on mountain rivers. The effects of floods of different characteristics on vegetation erosion and wood transport will be then addressed presenting some study cases from rivers in the European Alps and in the Italian Apennines featuring different degrees of human alteration. Finally, several conclusions about the applicability of wood transport modelling and on rationale vegetation/wood management strategies will be drawn.

Priority effects of early successional insects influence late successional fungi in dead wood.

PubMed

Jacobsen, Rannveig Margrete; Birkemoe, Tone; Sverdrup-Thygeson, Anne

2015-11-01

Community assembly is an integral process in all ecosystems, producing patterns of species distributions, biodiversity, and ecosystem functioning. Environmental filters and colonization history govern the assembly process, but their relative importance varies depending on the study system. Dead wood decomposition is a slow process, allowing decomposer communities to develop within a slowly changing substrate for decades. Despite this, there are few long-term studies of priority effects from colonization history in this ecosystem. In this study, we investigate the importance of insects in early succession of dead wood on the fungal community present one decade later. Sixty aspen trees were killed in two study landscapes, each tree producing one aspen high stump and log. Insects were sampled with flight interception traps during the first 4 years after tree death, and fungal fruiting bodies were registered in year twelve. We found positive priority effects of two fungivorous beetles, the sap beetle Glischrochilus quadripunctatus and the round fungus beetle Agathidium nigripenne, on the Artist's bracket (Ganoderma applanatum) and a positive priority effect of wood-boring beetles on the ascomycete Yellow fairy cup (Bisporella citrina). The Aspen bracket (Phellinus tremulae) did not respond to insects in early succession of the dead wood. Our results suggest that early successional insects can have significant, long-lasting effects on the late successional fungal community in dead wood. Also, the effect can be specific, with one fungus species depending on one or a few fungivorous beetle species. This has implications for decomposition and biodiversity in dead wood, as loss of early colonizing beetles may also affect the successional pathways they seem to initiate.

Effects of wood chip amendments on the revegetation performance of plant species on eroded marly terrains in a Mediterranean mountainous climate (Southern Alps, France)

NASA Astrophysics Data System (ADS)

Breton, Vincent; Crosaz, Yves; Rey, Freddy

2016-04-01

The establishment of plant species can limit soil erosion dynamics in degraded lands. In marly areas in the Southern French Alps, both harsh water erosion and drought conditions in summer due to the Mediterranean mountainous climate prevent the natural implementation and regeneration of vegetation. Soil fertility improvement is sometimes necessary. With the purpose of revegetating such areas, we aimed to evaluate the effects of wood chip amendments on the revegetation performance of different native or sub-spontaneous plant species. We conducted two experiments on steep slopes over three growing seasons (2012-2014). The first consisted of planting seedlings (10 species), and the second consisted of seeding (nine species including six used in the first experiment). First we noted that wood chips were able to remain in place even in steep slope conditions. The planting of seedlings showed both an impact of wood chip amendment and differences between species. A positive effect of wood chips was shown with overall improvement of plant survival (increasing by 11 % on average, by up to 50 % for some species). In the seeding experiment, no plants survived after three growing seasons. However, intermediate results for the first and second years showed a positive effect of wood chips on seedling emergence: seeds of four species only sprouted on wood chips, and for the five other species the average emergence rate increased by 50 %.

Experimental Design on Laminated Veneer Lumber Fiber Composite: Surface Enhancement

NASA Astrophysics Data System (ADS)

Meekum, U.; Mingmongkol, Y.

2010-06-01

Thick laminate veneer lumber(LVL) fibre reinforced composites were constructed from the alternated perpendicularly arrayed of peeled rubber woods. Glass woven was laid in between the layers. Native golden teak veneers were used as faces. In house formulae epoxy was employed as wood adhesive. The hand lay-up laminate was cured at 150° C for 45 mins. The cut specimen was post cured at 80° C for at least 5 hours. The 2k factorial design of experimental(DOE) was used to verify the parameters. Three parameters by mean of silane content in epoxy formulation(A), smoke treatment of rubber wood surface(B) and anti-termite application(C) on the wood surface were analysed. Both low and high levels were further subcategorised into 2 sub-levels. Flexural properties were the main respond obtained. ANOVA analysis of the Pareto chart was engaged. The main effect plot was also testified. The results showed that the interaction between silane quantity and termite treatment is negative effect at high level(AC+). Vice versa, the interaction between silane and smoke treatment was positive significant effect at high level(AB+). According to this research work, the optimal setting to improve the surface adhesion and hence flexural properties enhancement were high level of silane quantity, 15% by weight, high level of smoked wood layers, 8 out of 14 layers, and low anti termite applied wood. The further testes also revealed that the LVL composite had superior properties that the solid woods but slightly inferior in flexibility. The screw withdrawn strength of LVL showed the higher figure than solid wood. It is also better resistance to moisture and termite attack than the rubber wood.

Nitrogen removal in wood chip combined substrate baffled subsurface-flow constructed wetlands: impact of matrix arrangement and intermittent aeration.

PubMed

Li, Huai; Chi, Zifang; Yan, Baixing; Cheng, Long; Li, Jianzheng

2017-02-01

In this study, two lab-scale baffled subsurface-flow constructed wetlands (BSFCWs), including gravel-wood chips-slag and gravel-slag-wood chips, were operated at different intermittent aeration to evaluate the effect of artificial aeration and slow-released carbon source on the treatment efficiency of high-strength nitrogen wastewater. Results indicated that gravel-slag-wood chips extended aerobic/anaerobic alternating environment to gravel and slag zones and maintained anaerobic condition in the subsequent wood chip section. The order of gravel-slag-wood chip was more beneficial to pollutant removal. Sufficient carbon source supply resulted from wood-chip-framework substrate simultaneously obtained high removals of COD (97%), NH 4 + -N (95%), and TN (94%) in BSFCWs at 2 h aeration per day. The results suggest that intermittent aeration combined with wood chips could achieve high nitrogen removal in BSFCWs.

Syringyl-rich lignin renders poplars more resistant to degradation by wood decay fungi.

PubMed

Skyba, Oleksandr; Douglas, Carl J; Mansfield, Shawn D

2013-04-01

In order to elucidate the effects of lignin composition on the resistance of wood to degradation by decay fungi, wood specimens from two transgenic poplar lines expressing an Arabidopsis gene encoding ferulate 5-hydroxylase (F5H) driven by the cinnimate-4-hydroxylase promoter (C4H::F5H) that increased syringyl/guaiacyl (S/G) monolignol ratios relative to those in the untransformed control wood were incubated with six different wood decay fungi. Alterations in wood weight and chemical composition were monitored over the incubation period. The results showed that transgenic poplar lines extremely rich in syringyl lignin exhibited a drastically improved resistance to degradation by all decay fungi evaluated. Lignin monomer composition and its distribution among cell types and within different cell layers were the sole wood chemistry parameters determining wood durability. Since transgenic poplars with exceedingly high syringyl contents were recalcitrant to degradation, where wood durability is a critical factor, these genotypes may offer improved performance.

Syringyl-Rich Lignin Renders Poplars More Resistant to Degradation by Wood Decay Fungi

PubMed Central

Skyba, Oleksandr; Douglas, Carl J.

2013-01-01

In order to elucidate the effects of lignin composition on the resistance of wood to degradation by decay fungi, wood specimens from two transgenic poplar lines expressing an Arabidopsis gene encoding ferulate 5-hydroxylase (F5H) driven by the cinnimate-4-hydroxylase promoter (C4H::F5H) that increased syringyl/guaiacyl (S/G) monolignol ratios relative to those in the untransformed control wood were incubated with six different wood decay fungi. Alterations in wood weight and chemical composition were monitored over the incubation period. The results showed that transgenic poplar lines extremely rich in syringyl lignin exhibited a drastically improved resistance to degradation by all decay fungi evaluated. Lignin monomer composition and its distribution among cell types and within different cell layers were the sole wood chemistry parameters determining wood durability. Since transgenic poplars with exceedingly high syringyl contents were recalcitrant to degradation, where wood durability is a critical factor, these genotypes may offer improved performance. PMID:23396333

Cytochemical localization of cellulases in decayed and nondecayed wood

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murmanis, L.; Highley, T.L.; Palmer, J.G.

1987-01-01

Sawdust from undecayed western hemlock wood and from wood previously decayed by the brown-rot fungus Poria placenta or by the white-rot fungus Ganoderma applanatum was incubated with commercial cellulase from Trichoderma viride. Samples were treated cytochemically to locate cellulase activity and examined by TEM. Results showed that cellulase degraded undecayed wood extensively, with the attack starting on the outer border of a cell wall and progressing inside. Wood decayed by P. placenta, with or without cellulase incubation, and treated by the cytochemical test showed uniform distribution of electron dense particles throughout the cell walls. In wood decayed by G. applanatum,more » cellulase degradation was similar to that in undecayed wood. From measurements of particle diameter it is suggested that electron dense particles are cellulase. It is concluded that brown-rot and white-rot fungi have different effects on the microstructure of wood. The brown-rot fungus appears to open the wood microstructure so that cellulase can diffuse throughout the degraded tracheid wall.« less

Changes in wood density, wood anatomy and hydraulic properties of the xylem along the root-to-shoot flow path in tropical rainforest trees.

PubMed

Schuldt, Bernhard; Leuschner, Christoph; Brock, Nicolai; Horna, Viviana

2013-02-01

It is generally assumed that the largest vessels are occurring in the roots and that vessel diameters and the related hydraulic conductance in the xylem are decreasing acropetally from roots to leaves. With this study in five tree species of a perhumid tropical rainforest in Sulawesi (Indonesia), we searched for patterns in hydraulic architecture and axial conductivity along the flow path from small-diameter roots through strong roots and the trunk to distal sun-canopy twigs. Wood density differed by not more than 10% across the different flow path positions in a species, and branch and stem wood density were closely related in three of the five species. Other than wood density, the wood anatomical and xylem hydraulic traits varied in dependence on the position along the flow path, but were unrelated to wood density within a tree. In contrast to reports from conifers and certain dicotyledonous species, we found a hump-shaped variation in vessel diameter and sapwood area--specific conductivity along the flow path in all five species with a maximum in the trunk and strong roots and minima in both small roots and twigs; the vessel size depended on the diameter of the organ. This pattern might be an adaptation to the perhumid climate with a low risk of hydraulic failure. Despite a similar mean vessel diameter in small roots and twigs, the two distal organs, hydraulically weighted mean vessel diameters were on average 30% larger in small roots, resulting in ∼ 85% higher empirical and theoretical specific conductivities. Relative vessel lumen area in percent of sapwood area decreased linearly by 70% from roots to twigs, reflecting the increase in sclerenchymatic tissue and tracheids in acropetal direction in the xylem. Vessel size was more closely related to the organ diameter than to the distance along the root-to-shoot flow path. We conclude that (i) the five co-occurring tree species show convergent patterns in their hydraulic architecture despite different growth strategies, and (ii) the paradigm assuming continuous acropetal vessel tapering and decrease in specific conductance from fine roots towards distal twigs needs reconsideration.

Using ring width correlations to study the effects of plantation density on wood density and anatomical properties of red pine (Pinus resinosa Ait.)

Treesearch

J. Y. Zhu; C. T. Scott; K. L. Scallon; G. C. Myers

2006-01-01

This study demonstrated that average ring width (or average annual radial growth rate) is a reliable parameter to quantify the effects of tree plantation ndensity (growth suppression) on wood density and tracheid anatomical properties. The average ring width successfully correlated wood density and tracheid anatomical properties of red pines (Pinus resinosa Ait.) from...

Effect of thermo-mechanical refining pressure on the properties of wood fibers as measured by nanoindentation and atomic force microscopy

Treesearch

Cheng Xing; Siqun Wang; George M. Pharr; Leslie H. Groom

2008-01-01

Refined wood fibers of a 54-year-old loblolly pine (Pinus taeda L.) mature wood were investigated by nanoindentation and atomic force microscopy (AFM). The effect of steam pressure, in the range of 2?18 bar, during thermomechanical refining was investigated and the nanomechanical properties and nano- or micro-level damages of the cell wall were...

The effect of density and thermal diffusivity of wood on the rate of burning of wood cribs

Treesearch

H.D. Bruce; W.Y. Pong; W.L. Fons

1961-01-01

A program of research on free-burning wood fires is being conducted by the Forest Service to build up experimental data on the properties of such fires, with the iltimate objective of describing the physical phenomena in terms of fundamental laws. Density was the first wood property investigated. This report gives data on the rate of burning of cribs of five species...

Some observations of wood density and anatomical properties in a Douglas-fir sample with suppressed growth

Treesearch

J.Y. Zhu; David W. Vahey; C. Tim Scott

2008-01-01

This study used ring width correlations to examine the effects of tree-growth suppression on within-tree local wood density and tracheid anatomical properties. A wood core sample was taken from a 70-yr-old Douglas-fir that grew under various degrees of suppression in a natural forest setting. SilviScan and an imaging technique were used to obtain wood density and...

Investigation of bio-composites using Novolac type liquefied wood resin: effects of liquefaction and fabrication conditions

Treesearch

Hui Pan; Chung-Yun Hse; Todd F. Shupe

2009-01-01

Wood liquefaction using an organic solvent and an acid catalyst has long been studied as a novel technique to utilize biomass as an alternative to petroleum-based products. Oxalic acid is a weaker organic acid than a mineral acid and wood liquefaction with oxalic acid as a catalyst will result in a higher amount of wood residue than that with a mineral acid....

Young's modulus and internal friction of the SiC/Si biomorphic composite based on the sapele wood precursor

NASA Astrophysics Data System (ADS)

Kardashev, B. K.; Orlova, T. S.; Smirnov, B. I.; de Arellano-Lopez, A. R.; Martinez-Fernandez, J.

2009-04-01

The effect of the vibrational strain amplitude on the Young’s modulus and ultrasound absorption (internal friction) of a SiC/Si biomorphic composite prepared by pyrolysis of sapele wood followed by infiltration of silicon were investigated. The studies were conducted in air and in vacuum by the acoustic resonance method with the use of a composite vibrator in longitudinal vibrations at frequencies of about 100 kHz. Measurements performed on sapele wood-based bio-SiC/Si samples revealed a substantial effect of adsorption-desorption of molecules contained in air on the effective elasticity modulus and elastic vibration decrement. Microplastic characteristics of the SiC/Si composites prepared from wood of different tree species were compared.

Effects of removal of different chemical components on moisture sorption property of Populus euramericana Cv. under dynamic hygrothermal conditions

NASA Astrophysics Data System (ADS)

Yang, Tiantian; Zhou, Haizhen; Ma, Erni; Wang, Jiamin

2018-09-01

Effects of chemical components on wood sorption property under dynamic condition were investigated for the first time. Hemicellulose, lignin and extractive (denoted as DHC, DL and DE, respectively) were removed from Populus euramericana Cv., 20 mm in radial (R) and tangential (T) directions with thickness of 4 mm along the grain, then the wood was subjected to cyclic tests where relative humidity (RH) varied from 45% to 75% sinusoidally at 25 °C. Based on measured data automatically, the results showed that, various chemical components had different effects on dynamic sorption behaviors of wood. The DL exhibited the largest moisture content and diffusion coefficient, followed by the DE, Control and DHC. This indicated lignin or extractive removal accelerated the dynamic sorption process and improved hygroscopicity of wood, while hemicellulose removal caused opposite effects. Theoretical sorption model was further applied and the modeled curves fitted satisfactorily with experimental data. Dynamic moisture gradient distribution inside the different treated wood was investigated and amplitude of moisture showed negative relation with wood element depth, while phase lag presented an opposite trend. Amplitude of DL was the largest while its phase lag was the least. Conditioning thickness for RH was greatest for DHC, about twice as much as the minimum of DL.

Body-mass, survival, and pairing consequences of winter-diet restriction in wood ducks

USGS Publications Warehouse

Demarest, D.W.; Kaminski, R.M.; Brennan, L.A.; Boyle, C.R.

1997-01-01

We conducted feeding experiments with captive, wild-strain wood ducks (Aix sponsa) during winters 1990-91 and 1991-92 to test effects of increasing levels of food restriction on body mass dynamics, mortality, and pair formation. Male and female wood ducks fed restricted diets (i.e., 5, 10, 15, or 20% less food [g] than consumed on the previous day by a control group fed ad libitum) weighed less (P ??? 0.037) than birds fed ad libitum; those on 15 and 20% restricted diets weighed least. Increased mortality and decreased pair formation occurred only within the 20% restricted group (P ??? 0.049). We concluded that food restriction ranging between 15 and 20% of ad libitum intake may signify a threshold above which survival and reproduction of captive wood ducks may be impaired. Because energy costs of free living are greater than in captivity, a lower threshold may exist for wild wood ducks. Research is needed to validate the threshold theory for free-ranging wood ducks and other waterfowl, and to evaluate its potential application for conservation of winter foraging habitat. Conservation of bottomland hardwood ecosystems, which provide important foraging habitat for migrating and wintering wood ducks, should be encouraged to prevent potential negative effects on wood duck life-cycle events.

Enrichment with Wood Blocks Does Not Affect Toxicity Assessment in an Exploratory Toxicology Model Using Sprague–Dawley Rats

PubMed Central

Ditewig, Amy C; Bratcher, Natalie A; Davila, Donna R; Dayton, Brian D; Ebert, Paige; Lesuisse, Philippe; Liguori, Michael J; Wetter, Jill M; Yang, Hyuna; Buck, Wayne R

2014-01-01

Environmental enrichment in rodents may improve animal well-being but can affect neurologic development, immune system function, and aging. We tested the hypothesis that wood block enrichment affects the interpretation of traditional and transcriptomic endpoints in an exploratory toxicology testing model using a well-characterized reference compound, cyclophosphamide. ANOVA was performed to distinguish effects of wood block enrichment separate from effects of 40 mg/kg cyclophosphamide treatment. Biologically relevant and statistically significant effects of wood block enrichment occurred only for body weight gain. ANOVA demonstrated the expected effects of cyclophosphamide on food consumption, spleen weight, and hematology. According to transcriptomic endpoints, cyclophosphamide induced fewer changes in gene expression in liver than in spleen. Splenic transcriptomic pathways affected by cyclophosphamide included: iron hemostasis; vascular tissue angiotensin system; hepatic stellate cell activation and fibrosis; complement activation; TGFβ-induced hypertrophy and fibrosis; monocytes, macrophages, and atherosclerosis; and platelet activation. Changes in these pathways due to cyclophosphamide treatment were consistent with bone marrow toxicity regardless of enrichment. In a second study, neither enrichment nor type of cage flooring altered body weight or food consumption over a 28-d period after the first week. In conclusion, wood block enrichment did not interfere with a typical exploratory toxicology study; the effects of ingested wood on drug level kinetics may require further consideration. PMID:24827566

Where Does Wood Most Effectively Enhance Storage? Network-Scale Distribution of Sediment and Organic Matter Stored by Instream Wood

NASA Astrophysics Data System (ADS)

Pfeiffer, Andrew; Wohl, Ellen

2018-01-01

We used 48 reach-scale measurements of large wood and wood-associated sediment and coarse particulate organic matter (CPOM) storage within an 80 km2 catchment to examine spatial patterns of storage relative to stream order. Wood, sediment, and CPOM are not distributed uniformly across the drainage basin. Third- and fourth-order streams (23% of total stream length) disproportionately store wood and coarse and fine sediments: 55% of total wood volume, 78% of coarse sediment, and 49% of fine sediment, respectively. Fourth-order streams store 0.8 m3 of coarse sediment and 0.2 m3 of fine sediment per cubic meter of wood. CPOM storage is highest in first-order streams (60% of storage in 47% of total network stream length). First-order streams can store up to 0.3 m3 of CPOM for each cubic meter of wood. Logjams in third- and fourth-order reaches are primary sediment storage agents, whereas roots in small streams may be more important for storage of CPOM. We propose the large wood particulate storage index to quantify average volume of sediment or CPOM stored by a cubic meter of wood.

Synthesis and evaluation of phosphortriamidates in wood for thermal and fungal decay protection

Treesearch

George C. Chen

2008-01-01

The objective of this study was to evaluate the possibility of simplification of the process. The question in focus was simply whether phosphortriamidates impregnated wood would be as effective concerning fire resistance and fungal decay as phosphoramidate bonded wood.

MODELING OF ALKANE EMISSIONS FROM A WOOD STAIN

EPA Science Inventory

The article discusses full-scale residential house tests to evaluate the effects of organic emissions from a wood finishing product--wood stain--on indoor air quality (IAQ). The test house concentrations of three alkane species, nonane, decane, and undecane, were measured as a fu...

Chemical Analysis and Study of Phenolics, Antioxidant Activity, and Antibacterial Effect of the Wood and Bark of Maclura tinctoria (L.) D. Don ex Steud.

PubMed Central

Lamounier, K. C.; Cunha, L. C. S.; de Morais, S. A. L.; de Aquino, F. J. T.; Chang, R.; do Nascimento, E. A.; de Souza, M. G. M.; Martins, C. H. G.; Cunha, W. R.

2012-01-01

Maclura tinctoria (L.) D. Don ex Steud. has one of the highest qualities among the coefficients for Brazilian woods (up to 9.6) and resistance rates equivalent to Indian teak (Tectona grandis). In this study, the macromolecular constituents and total phenols compounds as well as the antioxidant and antibacterial activities of this wood were evaluated. Total phenols and proanthocyanidin levels were higher in wood when compared with bark levels. The antioxidant activity of wood extracts (IC50 = 18.7 μg/mL) was more effective than that of bark extracts (IC50 = 20.9 μg/mL). Wood and bark extracts revealed a high potential for inhibition of aerobic and anaerobic bacteria. The bark extracts were the most active (MIC from 20 to 60 μg/mL). Both antioxidant activity and high potential for bacteria inhibition turn these extracts promising for drug formulations, especially as antibacterial agent. PMID:22454666

Protection of Wood from Microorganisms by Laccase-Catalyzed Iodination

PubMed Central

Engel, J.; Thöny-Meyer, L.; Schwarze, F. W. M. R.; Ihssen, J.

2012-01-01

In the present work, Norway spruce wood (Picea abies L.) was reacted with a commercial Trametes versicolor laccase in the presence of potassium iodide salt or the phenolic compounds thymol and isoeugenol to impart an antimicrobial property to the wood surface. In order to assess the efficacy of the wood treatment, a leaching of the iodinated and polymerized wood and two biotests including bacteria, a yeast, blue stain fungi, and wood decay fungi were performed. After laccase-catalyzed oxidation of the phenols, the antimicrobial effect was significantly reduced. In contrast, the enzymatic oxidation of iodide (I−) to iodine (I2) in the presence of wood led to an enhanced resistance of the wood surface against all microorganisms, even after exposure to leaching. The efficiency of the enzymatic wood iodination was comparable to that of a chemical wood preservative, VP 7/260a. The modification of the lignocellulose by the laccase-catalyzed iodination was assessed by the Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) technique. The intensities of the selected lignin-associated bands and carbohydrate reference bands were analyzed, and the results indicated a structural change in the lignin matrix. The results suggest that the laccase-catalyzed iodination of the wood surface presents an efficient and ecofriendly method for wood protection. PMID:22865075

Evaluating landfill disposal of chromated copper arsenate (CCA) treated wood and potential effects on groundwater: evidence from Florida.

PubMed

Saxe, Jennifer K; Wannamaker, Eric J; Conklin, Scott W; Shupe, Todd F; Beck, Barbara D

2007-01-01

Chromated copper arsenate (CCA) treated wood has been used for more than 50 years. Recent attention has been focused on appropriate disposal of CCA-treated wood when its service life ends. Groups in the US and Europe concerned with the possibility of arsenic migration to groundwater from disposed CCA-treated wood have proposed that consumers be required to dispose of the wood as a hazardous waste, in the most protective of landfills. We examined available data for evidence of arsenic migration from unlined construction and demolition (C&D) debris landfills in Florida, where CCA-treated wood is disposed. Florida was chosen because soil, groundwater, landfill design, weather, and levels of CCA-treated wood use make the state a uniquely sensitive indicator for observing arsenic migration from CCA-treated wood disposal sites, should it occur. We developed and quality-checked a CCA-treated wood disposal model to estimate the amount of wood and associated arsenic disposed. By 2000, an estimated 13 million kg of arsenic in CCA-treated wood was disposed in Florida; however, groundwater monitoring data do not indicate that arsenic is migrating from unlined C&D landfills. Our results provide evidence that highly stringent regulation of CCA-treated wood disposal, such as treatment as a hazardous waste, is unnecessary.

Processing bulk natural wood into a high-performance structural material.

PubMed

Song, Jianwei; Chen, Chaoji; Zhu, Shuze; Zhu, Mingwei; Dai, Jiaqi; Ray, Upamanyu; Li, Yiju; Kuang, Yudi; Li, Yongfeng; Quispe, Nelson; Yao, Yonggang; Gong, Amy; Leiste, Ulrich H; Bruck, Hugh A; Zhu, J Y; Vellore, Azhar; Li, Heng; Minus, Marilyn L; Jia, Zheng; Martini, Ashlie; Li, Teng; Hu, Liangbing

2018-02-07

Synthetic structural materials with exceptional mechanical performance suffer from either large weight and adverse environmental impact (for example, steels and alloys) or complex manufacturing processes and thus high cost (for example, polymer-based and biomimetic composites). Natural wood is a low-cost and abundant material and has been used for millennia as a structural material for building and furniture construction. However, the mechanical performance of natural wood (its strength and toughness) is unsatisfactory for many advanced engineering structures and applications. Pre-treatment with steam, heat, ammonia or cold rolling followed by densification has led to the enhanced mechanical performance of natural wood. However, the existing methods result in incomplete densification and lack dimensional stability, particularly in response to humid environments, and wood treated in these ways can expand and weaken. Here we report a simple and effective strategy to transform bulk natural wood directly into a high-performance structural material with a more than tenfold increase in strength, toughness and ballistic resistance and with greater dimensional stability. Our two-step process involves the partial removal of lignin and hemicellulose from the natural wood via a boiling process in an aqueous mixture of NaOH and Na 2 SO 3 followed by hot-pressing, leading to the total collapse of cell walls and the complete densification of the natural wood with highly aligned cellulose nanofibres. This strategy is shown to be universally effective for various species of wood. Our processed wood has a specific strength higher than that of most structural metals and alloys, making it a low-cost, high-performance, lightweight alternative.

Processing bulk natural wood into a high-performance structural material

NASA Astrophysics Data System (ADS)

Song, Jianwei; Chen, Chaoji; Zhu, Shuze; Zhu, Mingwei; Dai, Jiaqi; Ray, Upamanyu; Li, Yiju; Kuang, Yudi; Li, Yongfeng; Quispe, Nelson; Yao, Yonggang; Gong, Amy; Leiste, Ulrich H.; Bruck, Hugh A.; Zhu, J. Y.; Vellore, Azhar; Li, Heng; Minus, Marilyn L.; Jia, Zheng; Martini, Ashlie; Li, Teng; Hu, Liangbing

2018-02-01

Synthetic structural materials with exceptional mechanical performance suffer from either large weight and adverse environmental impact (for example, steels and alloys) or complex manufacturing processes and thus high cost (for example, polymer-based and biomimetic composites). Natural wood is a low-cost and abundant material and has been used for millennia as a structural material for building and furniture construction. However, the mechanical performance of natural wood (its strength and toughness) is unsatisfactory for many advanced engineering structures and applications. Pre-treatment with steam, heat, ammonia or cold rolling followed by densification has led to the enhanced mechanical performance of natural wood. However, the existing methods result in incomplete densification and lack dimensional stability, particularly in response to humid environments, and wood treated in these ways can expand and weaken. Here we report a simple and effective strategy to transform bulk natural wood directly into a high-performance structural material with a more than tenfold increase in strength, toughness and ballistic resistance and with greater dimensional stability. Our two-step process involves the partial removal of lignin and hemicellulose from the natural wood via a boiling process in an aqueous mixture of NaOH and Na2SO3 followed by hot-pressing, leading to the total collapse of cell walls and the complete densification of the natural wood with highly aligned cellulose nanofibres. This strategy is shown to be universally effective for various species of wood. Our processed wood has a specific strength higher than that of most structural metals and alloys, making it a low-cost, high-performance, lightweight alternative.

Using wood creep data to discuss the contribution of cell-wall reinforcing material.

PubMed

Gril, Joseph; Hunt, David; Thibaut, Bernard

2004-01-01

Longitudinal four-point creep bending tests were performed on small clear-wood spruce specimens having various microfibrillar angles. Cell-wall compliance was deduced from macroscopic data by accounting for porosity. Time-dependent compliance was converted into complex compliance and rigidity using the value and the slope of the compliance versus logarithm of time. Complex rigidity plots of all specimens, for the time range 10(3)-10(6) s, could be superimposed by a horizontal shift depending on the microfibrillar angle. The shape of complex trajectories allowed a decomposition of the cell-wall relaxation modulus as the sum of an elastic contribution function of the microfibrillar angle and a time-dependent term unrelated to it, and suggested a discussion on the contribution of the various cell-wall layers to the observed relaxation process.

Cambium

NASA Technical Reports Server (NTRS)

Savidge, Rodney

2009-01-01

The Cambium investigation is one in a pair of investigations which utilizes the Advanced Biological Research System (ABRS). Cambium seeks definitive evidence that gravity has a direct effect on cambial cells (cells located under the inner bark where secondary growth occurs) in willow, Salix babylonica. The Cambium investigation uses willow plants flown on the International Space Station to better understand the fundamental processes by which plants produce cellulose and lignin, the two main structural materials found in plant matter. On Earth, the nature of wood within tree stems varies depending on position, and that within-tree variation includes differences in cell types and chemistry including lignin and cellulose, two major components of wood influencing wood strength, usefulness and carbon content. Reaction wood is an extreme example of such variation, and it is believed that reaction wood develops as a reaction to the influence of gravity. For the Cambium experiment, young willow plants will be launched to the ISS where their stems will be looped in an attempt to induce reaction wood formation. After on-orbit growth, the plants will be preserved and returned to Earth for analysis. Understanding the role of gravity in wood formation is expected to enable wiser management of forests for carbon sequestration as well as better utilization of trees for wood products. Detailed Research Description: The Cambium experiment will provide an understanding of physiological processes such as gene expression, metabolism and general plant development that are affected in plant systems exposed to space flight. Cambium seeks definitive evidence that gravity has a direct effect on the cambial cells (cells located under the inner bark where secondary growth occurs) that contribute to xylogenesis (reaction wood formation) in willow plants, Salix babylonica. Tension wood fibers differentiate on the upper sides of stems when the stem is altered from its normal (vertical) growth position by looping. This reaction wood response does not occur if the orientation of the plant stem with respect to gravity is not altered. If a localized zone of tension wood should be formed in looped stems under microgravity conditions, this would be the first conclusive evidence that gravity is not required. On the other hand, if a zone of tension wood is not produced in looped stems (subjected to tension on one side, compression on the other) in microgravity, this would be the first definitive evidence that gravity has a direct effect on the cambial cells which contribute to reaction wood formation. Following return to Earth the plants will be analyzed by microscopy and chemical methods.

[Environmental and health impacts of wood combustion to produce heat and power].

PubMed

Valerio, Federico

2012-01-01

Toxic chemicals such as benzene, polycyclic aromatic hydrocarbons, dioxins, and ultra fine particles were found in the smoke produced by wood combustion. Emission factors confirm that, to produce the same energy amount, many more pollutants are emitted by wood than by natural gas. Biomass burning produces a relevant deterioration of air quality inside and outside houses, notably due to emissions of fine and ultra fine dust (PM10, PM2.5) according to reviewed studies. Important improvements in emission quality are obtained with the use of more efficient household heating systems, both in developed and in developing countries. Numerous studies have assessed the possible health effects produced by wood smoke, providing sufficient evidence that the indoor exposure to wood smoke, even in developed countries, can have adverse effects on human health. In 2010 IARC classified wood smoke as a possible human carcinogen. In Europe, electricity generation from biomass combustion is increasing (12% each year) thanks to incentives provided to reduce greenhouse gas emissions and use of fossil fuels.Today adequate studies to assess the environmental and health effects of emissions from power plants fuelled by solid biomasses are still needed.

A new methodology for monitoring wood fluxes in rivers using a ground camera: Potential and limits

NASA Astrophysics Data System (ADS)

Benacchio, Véronique; Piégay, Hervé; Buffin-Bélanger, Thomas; Vaudor, Lise

2017-02-01

Ground imagery, which produces large amounts of valuable data at high frequencies, is increasingly used by fluvial geomorphologists to survey and understand processes. While such technology provides immense quantities of information, it can be challenging to analyze and requires automatization and associated development of new methodologies. This paper presents a new approach to automate the processing of image analysis to monitor wood delivery from the upstream Rhône River (France). The Génissiat dam is used as an observation window; all pieces of wood coming from the catchment are trapped here, hence a wood raft accumulates over time. In 2011, we installed an Axis 211W camera to acquire oblique images of the reservoir every 10 min with the goal of automatically detecting a wood raft area, in order to transform it to wood weight (t) and flux (t/d). The methodology we developed is based on random forest classification to detect the wood raft surface over time, which provided a good classification rate of 97.2%. Based on 14 mechanical wood extractions that included weight of wood removed each time, conducted during the survey period, we established a relationship between wood weight and wood raft surface area observed just before the extraction (R2 = 0.93). We found that using such techniques to continuously monitor wood flux is difficult because the raft undergoes very significant changes through time in terms of density, with a very high interday and intraday variability. Misclassifications caused by changes in weather conditions can be mitigated as well as errors from variation in pixel resolution (owing to camera position or window size), but a set of effects on raft density and mobility must still be explored (e.g., dam operation effects, wind on the reservoir surface). At this stage, only peak flow contribution to wood delivery can be well calculated, but determining an accurate, continuous series of wood flux is not possible. Several recommendations are made in terms of maximizing the potential benefit of such monitoring.

Mechanical characteristics of antibacterial epoxy resin adhesive wood biocomposites against skin disease

PubMed Central

Chen, Zi-xiang; Zhang, Zhong-feng; Aqma, Wan Syaidatul

2015-01-01

Moldy wood can cause some skin disease. However epoxy resin adhesive (EP) can inhibit mold growth. Therefore, antibacterial EP/wood biocomposites were reinforced and analyzed by the nonlinear finite element. Results show that glass fiber cloth and aluminum foil have the obvious reinforced effect under flat pressure, but this was not the case under side pressure. And when the assemble pattern was presented in 5A way, the strengthening effect was better. The nonlinear finite element showed that the aluminum foil and glass fiber cloth have the obvious reinforced effect. The mutual influence and effect of span, thickness and length on the ultimate bearing capacity of specimen were studied. And the simulation results agreed with the test. It provided a theoretical basis on the preparation of antibacterial EP/wood biocomposites against skin disease. PMID:26858557

Radiography and partial tomography of wood with thermal neutrons

NASA Astrophysics Data System (ADS)

Osterloh, K.; Fratzscher, D.; Schwabe, A.; Schillinger, B.; Zscherpel, U.; Ewert, U.

2011-09-01

The effective high neutron scattering absorption coefficient of hydrogen (48.5 cm 2/g) due to the scattering allows neutrons to reveal hydrocarbon structures with more contrast than X-rays, but at the same time limits the sample size and thickness that can be investigated. Many planar shaped objects, particularly wood samples, are sufficiently thin to allow thermal neutrons to transmit through the sample in a direction perpendicular to the planar face but not in a parallel direction, due to increased thickness. Often, this is an obstacle that prevents some tomographic reconstruction algorithms from obtaining desired results because of inadequate information or presence of distracting artifacts due to missing projections. This can be true for samples such as the distribution of glue in glulam (boards of wooden layers glued together), or the course of partially visible annual rings in trees where the features of interest are parallel to the planar surface of the sample. However, it should be possible to study these features by rotating the specimen within a limited angular range. In principle, this approach has been shown previously in a study with fast neutrons [2]. A study of this kind was performed at the Antares facility of FRM II in Garching with a 2.6×10 7/cm 2 s thermal neutron beam. The limit of penetration was determined for a wooden step wedge carved from a 2 cm×4 cm block of wood in comparison to other materials such as heavy metals and Lucite as specimens rich in hydrogen. The depth of the steps was 1 cm, the height 0.5 cm. The annual ring structures were clearly detectable up to 2 cm thickness. Wooden specimens, i.e. shivers, from a sunken old ship have been subjected to tomography. Not visible from the outside, clear radial structures have been found that are typical for certain kinds of wood. This insight was impaired in a case where the specimen had been soaked with ethylene glycol. In another large sample study, a planar board made of glulam has been studied to show the glued layers. This study shows not only the limits of penetration in wood but also demonstrates access to structures perpendicular to the surface in larger planar objects by tomography with fast neutrons, even with incomplete sets of projection data that covers an angular range of only 90° or even 60°.

Sustainable biofuel contributions to carbon mitigation and energy independence

DOE PAGES

Lippke, Bruce; Gustafson, Richard; Venditti, Richard; ...

2011-10-19

The growing interest in US biofuels has been motivated by two primary national policy goals, (1) to reduce carbon emissions and (2) to achieve energy independence. However, the current low cost of fossil fuels is a key barrier to investments in woody biofuel production capacity. The effectiveness of wood derived biofuels must consider not only the feedstock competition with low cost fossil fuels but also the wide range of wood products uses that displace different fossil intensive products. Alternative uses of wood result in substantially different unit processes and carbon impacts over product life cycles. We developed life cycle datamore » for new bioprocessing and feedstock collection models in order to make life cycle comparisons of effectiveness when biofuels displace gasoline and wood products displace fossil intensive building materials. Wood products and biofuels can be joint products from the same forestland. Furthermore, substantial differences in effectiveness measures are revealed as well as difficulties in valuing tradeoffs between carbon mitigation and energy independence.« less

40 CFR 268.30 - Waste specific prohibitions-wood preserving wastes.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 27 2011-07-01 2011-07-01 false Waste specific prohibitions-wood preserving wastes. 268.30 Section 268.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... specific prohibitions—wood preserving wastes. (a) Effective August 11, 1997, the following wastes are...

40 CFR 268.30 - Waste specific prohibitions-wood preserving wastes.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Waste specific prohibitions-wood preserving wastes. 268.30 Section 268.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... specific prohibitions—wood preserving wastes. (a) Effective August 11, 1997, the following wastes are...

Effect of changing slope of grain on ash, maple, and yellow birch in bending strength

Treesearch

David E. Kretschmann; James J. Bridwell; Timothy C. Nelson

2010-01-01

The presence of slope of grain (SoG) in wood can severely reduce the bending strength in wood. Failure to recognize the degree to which SoG can reduce strength can be catastrophic if wood is in single member use. In the United States, a growing concern in the sport of baseball relates to the high frequency of multi-piece broken wood bats. It was observed that hard...

The Effect of Heat Treatment on the chemical and color change of Black Locust (Robinia Pseudoacacia) wood flour

Treesearch

Yao Chen; Yongming Fan; Jianmin Gao; Nicole M. Stark

2012-01-01

The aim of this study was to investigate the effects of oxygen and moisture content (MC) on the chemical and color changes of black locust (Robinia pseudoacacia) wood during heat treatment. The wood flour was conditioned to different initial MCs and heated for 24 h at a constant temperature of 120°C in either oxygen or nitrogen atmosphere. The pH values and...

The Effect of Stringer Repair Methods and Repair Frequency on the Performance of GMA-Style 48x40-Inch Wood Pallets

Treesearch

John W. Clarke; Marshall S. White; Philip A. Araman

2004-01-01

Over 135 million wood pallets were repaired for reuse in 1995. One of the most commonly damaged components in a wood pallet is the notched stringer. Metal plates, half companion stringers, and full companion stringers are repair methods described in the U.S. industry standard published by the American Society of Mechanical Engineers. This study evaluated the effect of...

Birefringence of wood at terahertz frequencies

NASA Astrophysics Data System (ADS)

Todoruk, Tara M.; Schneider, Jon; Hartley, Ian D.; Reid, Matthew

2008-06-01

Fibre content of solid wood plays an important role in the wood products industry in terms of value. Additionally, fibre structure in composite wood products such as Oriented Strand Board (OSB) and paper products plays an important role in terms of strength properties. The effect of moisture content on wood properties is important in the manufacturing process and final product performance, and therefore its effect on the birefringence is of considerable interest. Since solid wood exhibits strong birefringence at terahertz frequencies, there may be potential applications of terahertz spectroscopy to fibre content and structure sensing. There are two potential sources for this strong birefringence: (i) form birefringence resulting from the porous structure of solid wood and (ii) intrinsic birefringence resulting from the dielectric properties of the material itself. In this report, the variability of birefringence within and between species, the dependence of the birefringence on moisture content and the relative contributions from form and intrinsic birefringence are examined. In order to clarify the role of these contributions to the measured birefringence, polarized terahertz reflection spectroscopy is examined and compared to the results obtained in a transmission geometry. Comparison of the birefringence measured in transmission and reflection geometries suggests that form birefringence may dominate.

Coatings to reduce wood preservative leaching.

PubMed

Nejad, Mojgan; Cooper, Paul

2010-08-15

The efficiency of semitransparent penetrating stains to reduce leaching of wood preservative components was evaluated. Five commercial wood deck finishes were applied to untreated and chromated copper arsenate (CCA), alkaline copper quat (ACQ), and copper azole (CA) treated wood, and leachates were collected and analyzed during 3 years of natural weathering exposure in Toronto, Canada. All stains evaluated effectively reduced the cumulative leaching of all inorganic preservative components by about 60% on average. Although most coatings showed significant film degradation starting around 12 months, the reduced leaching persisted even after 3 years. This suggests that temporary protection of wood with a coating during the early stages of use resulted in long-term reduction in preservative leaching potential. A two-week screening leaching test was able to predict the long-term leaching performance of different coatings reasonably well. Cured coating glass transition temperature (Tg) and liquid coating viscosity were the most important variables affecting a leaching prediction model. To effectively reduce leaching of preservative components from treated wood, coatings should have Tg low enough to withstand stresses caused by freezing in winter and have adequate viscosity to form a barrier film layer on the wood surface.

Technology Insertion (TI)/Industrial Process Improvement (IPI) Task Order Number 1. Data Base Documentation Book for WR-ALC/MANPSB (Sheet Metal)

DTIC Science & Technology

1989-08-14

peel the cover skins using a wood chisel, tin snips, pliars, etc. to remove the skin without damaging the wires or the heating elements. O.5T-.3...called " Banana Boxes" because they are about the same shape and construction as the boxes used to ship bananas . These boxes would be similar to the ones

Quality of refiner groundwood pulp as related to handsheet properties and gross wood characteristics

Treesearch

Charles W. McMillin

1969-01-01

Pulp quality, in terms of a fiber shape factor S and a fiber length factor L, was determiend for 96 pulps disk-refined from chips of varying characteristics. S was evaluated in terms of the Canadian Standard Freeness of the 48/100 fiber length fraction and is a parameter inversely proportional to specific surface. L is the percentage, by weight, of pulp retained on a...

AMS Radiocarbon Dating of Large Za Baobabs (Adansonia za) of Madagascar

PubMed Central

Patrut, Adrian; Patrut, Roxana T.; Danthu, Pascal; Leong Pock-Tsy, Jean-Michel; Rakosy, Laszlo; Lowy, Daniel A.; von Reden, Karl F.

2016-01-01

The article reports the radiocarbon investigation of Anzapalivoro, the largest za baobab (Adansonia za) specimen of Madagascar and of another za, namely the Big cistern baobab. Several wood samples collected from the large inner cavity and from the outer part/exterior of the tree were investigated by AMS (accelerator mass spectrometry) radiocarbon dating. For samples collected from the cavity walls, the age values increase with the distance into the wood up to a point of maximum age, after which the values decrease toward the outer part. This anomaly of age sequences indicates that the inner cavity of Anzapalivoro is a false cavity, practically an empty space between several fused stems disposed in a ring-shaped structure. The radiocarbon date of the oldest sample was 780 ± 30 bp, which corresponds to a calibrated age of around 735 yr. Dating results indicate that Anzapalivoro has a closed ring-shaped structure, which consists of 5 fused stems that close a false cavity. The oldest part of the biggest za baobab has a calculated age of 900 years. We also disclose results of the investigation of a second za baobab, the Big cistern baobab, which was hollowed out for water storage. This specimen, which consists of 4 fused stems, was found to be around 260 years old. PMID:26760300

AMS Radiocarbon Dating of Large Za Baobabs (Adansonia za) of Madagascar.

PubMed

Patrut, Adrian; Patrut, Roxana T; Danthu, Pascal; Leong Pock-Tsy, Jean-Michel; Rakosy, Laszlo; Lowy, Daniel A; von Reden, Karl F

2016-01-01

The article reports the radiocarbon investigation of Anzapalivoro, the largest za baobab (Adansonia za) specimen of Madagascar and of another za, namely the Big cistern baobab. Several wood samples collected from the large inner cavity and from the outer part/exterior of the tree were investigated by AMS (accelerator mass spectrometry) radiocarbon dating. For samples collected from the cavity walls, the age values increase with the distance into the wood up to a point of maximum age, after which the values decrease toward the outer part. This anomaly of age sequences indicates that the inner cavity of Anzapalivoro is a false cavity, practically an empty space between several fused stems disposed in a ring-shaped structure. The radiocarbon date of the oldest sample was 780 ± 30 bp, which corresponds to a calibrated age of around 735 yr. Dating results indicate that Anzapalivoro has a closed ring-shaped structure, which consists of 5 fused stems that close a false cavity. The oldest part of the biggest za baobab has a calculated age of 900 years. We also disclose results of the investigation of a second za baobab, the Big cistern baobab, which was hollowed out for water storage. This specimen, which consists of 4 fused stems, was found to be around 260 years old.

Continuous microcellular foaming of polyvinyl chloride and compatibilization of polyvinyl chloride and polylactide composites

NASA Astrophysics Data System (ADS)

Shah, Bhavesh

This dissertation focuses on overcoming existing limitations of WPCs which prevent them from realizing their full market potential. These limitations include: (i) lack of a continuous extrusion process for microcellular foaming of polyvinyl chloride (PVC) and its composites using supercritical fluids to reduce the high density of the WPCs, (ii) need for an efficient coupling agent for WPCs to overcome the poor compatibility between wood and plastic, and (iii) unproven use of wood as a filler for the biopolymer polylactide (PLA) to make "green" composites. These limitations were addressed through experimentation to develop a continuous extrusion process for microcellular foaming, and through surface modification of wood flour using natural coupling agents. The effects of wood flour, acrylic modifier and plasticizer content on the rheological properties of PVC based WPCs were studied using an extrusion capillary rheometer and a two-level factorial design. Wood flour content and acrylic modifier content were the major factors affecting the die swell ratio. Addition of plasticizer decreased the true viscosity of unfilled and filled PVC, irrespective of the acrylic modifier content. However, the addition of acrylic modifier significantly increased the viscosity of unfilled PVC but decreased the composite viscosity. Results of the rheological study were used to set baseline conditions for the continuous extrusion foaming of PVC WPCs using supercritical CO 2. Effects of material composition and processing conditions on the morphology of foamed samples were investigated. Foamed samples were produced using various material compositions and processing conditions, but steady-state conditions could not be obtained for PVC. Thus the relationships could not be determined. Incompatibility between wood flour and PVC was the focus of another study. The natural polymers chitin and chitosan were used as novel coupling agents to improve interfacial adhesion between the polymer matrix and wood fiber. Results indicated that addition of chitin and chitosan significantly increased the flexural properties and storage modulus of PVC WPCs, compared to composites without coupling agent. Significant improvements were attained with 0.5 wt. % chitosan and with 6.67 wt. % chitin. Based on the efficiency of chitosan as a coupling agent for PVC based WPCs, a biodegradable composite using polylactide (PLA) and chitosan was developed. Wood flour (0--40 wt. %) was evaluated as a filler for PLA composites and its effect on mechanical, thermal and chemical properties was studied with and without chitosan (0--10 wt. %). Addition of wood flour significantly increased the flexural and storage moduli of PLA-wood flour composites, but had no effect on glass transition temperature (Tg). Chitosan had no significant effect on any of the properties of the composites studied. Development of an efficient and effective coupling agent for PVC wood composite is a significant development which will increase performance while reducing cost. Wood filled PLA composites can further expand WPCs into applications such as packaging and automotive. Results from these studies have broadened the current knowledge base for WPC products and will be useful in the continued expansion of wood composites technology into a variety of industries.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bouza, R.; Barral, L.; Abad, M. J.

The effects of Pinus Sylvestris wood flour as filler in polypropylene matrix was evaluated. The mechanical properties and the morphology of different wood flour/polypropylene composites (WPC) were studied. The composites materials were prepared with several amounts of wood flour from 10 to 30% wt. Mechanical properties show that the wood flour incorporation increases the rigidity of the composites. Morphological analysis indicates that agglomerates are formed, with amounts exceeding 30% of wood flour. For the silane--treated composites, the dispersion of the filler into the polypropylene (PP) matrix improved. Shore D hardness of the composites is decreased with the addition of themore » coupling agent.« less

The evolution of soil-burrowing cockroaches (Blattaria: Blaberidae) from wood-burrowing ancestors following an invasion of the latter from Asia into Australia.

PubMed

Maekawa, Kiyoto; Lo, Nathan; Rose, Harley A; Matsumoto, Tadao

2003-06-22

Morphologically similar cockroaches in the subfamilies Panesthiinae and Geoscapheinae (Blattaria: Blaberidae) display contrasting feeding habits, behaviour and biogeographical distributions. Panesthiinae, found throughout Asia and Australia, all live in and feed on decaying wood that they burrow into. Geoscapheinae are restricted to Australia and construct and live in burrows in the soil, where they feed on dry leaves taken from the surface. A lack of knowledge about phylogenetic relationships among these cockroaches hinders an understanding of the factors that have shaped the evolution of their diverse lifestyles and biogeography. To address this issue, we sequenced three genes from representatives of nine of the 10 genera in the two subfamilies, and performed phylogenetic analyses. The well-supported topology revealed the Panesthiinae to be paraphyletic with respect to the Geoscapheinae. Soil-burrowing cockroaches appear to have evolved from a lineage of wood burrowers that invaded Australia from the north some time after the merging of the Asian and Australian tectonic plates ca. 20 Myr ago. The main factor promoting the evolution of soil burrowing is likely to have been one of the periods of strong aridity that Australia has experienced since the Miocene period.

Instream large wood: Denitrification hotspots with low N2O production

EPA Science Inventory

We examined the effect of instream large wood on denitrification capacity in two contrasting, lower order streams — one that drains an agricultural watershed with no riparian forest and minimal stores of instream large wood and another that drains a forested watershed with an ext...

A comparative study of wood highway sound barriers

Treesearch

Stefan Grgurevich; Thomas Boothby; Harvey Manbeck; Courtney Burroughs; Stephen Cegelka; Craig Bernecker; Michael A. Ritter

2002-01-01

Prototype designs for wood highway sound barriers meeting the multiple criteria of structural integrity, acoustic effectiveness, durability, and potential for public acceptance have been developed. Existing installations of wood sound barriers were reviewed and measurements conducted in the field to estimate acoustic insertion losses. A complete matrix of design...

16 CFR 1406.1 - Scope, purpose, and effective date.

Code of Federal Regulations, 2012 CFR

2012-01-01

... REGULATIONS COAL AND WOOD BURNING APPLIANCES-NOTIFICATION OF PERFORMANCE AND TECHNICAL DATA § 1406.1 Scope... coal and wood burning appliances, as defined in § 1406.3(a), to provide consumers with a specified... information provided with coal and wood burning appliances. This rule does not replace any voluntary standards...

16 CFR 1406.1 - Scope, purpose, and effective date.

Code of Federal Regulations, 2014 CFR

2014-01-01

... REGULATIONS COAL AND WOOD BURNING APPLIANCES-NOTIFICATION OF PERFORMANCE AND TECHNICAL DATA § 1406.1 Scope... coal and wood burning appliances, as defined in § 1406.3(a), to provide consumers with a specified... information provided with coal and wood burning appliances. This rule does not replace any voluntary standards...

16 CFR 1406.1 - Scope, purpose, and effective date.

Code of Federal Regulations, 2011 CFR

2011-01-01

... REGULATIONS COAL AND WOOD BURNING APPLIANCES-NOTIFICATION OF PERFORMANCE AND TECHNICAL DATA § 1406.1 Scope... coal and wood burning appliances, as defined in § 1406.3(a), to provide consumers with a specified... information provided with coal and wood burning appliances. This rule does not replace any voluntary standards...

16 CFR 1406.1 - Scope, purpose, and effective date.

Code of Federal Regulations, 2010 CFR

2010-01-01

... REGULATIONS COAL AND WOOD BURNING APPLIANCES-NOTIFICATION OF PERFORMANCE AND TECHNICAL DATA § 1406.1 Scope... coal and wood burning appliances, as defined in § 1406.3(a), to provide consumers with a specified... information provided with coal and wood burning appliances. This rule does not replace any voluntary standards...

The trait contribution to wood decomposition rates of 15 Neotropical tree species.

PubMed

van Geffen, Koert G; Poorter, Lourens; Sass-Klaassen, Ute; van Logtestijn, Richard S P; Cornelissen, Johannes H C

2010-12-01

The decomposition of dead wood is a critical uncertainty in models of the global carbon cycle. Despite this, relatively few studies have focused on dead wood decomposition, with a strong bias to higher latitudes. Especially the effect of interspecific variation in species traits on differences in wood decomposition rates remains unknown. In order to fill these gaps, we applied a novel method to study long-term wood decomposition of 15 tree species in a Bolivian semi-evergreen tropical moist forest. We hypothesized that interspecific differences in species traits are important drivers of variation in wood decomposition rates. Wood decomposition rates (fractional mass loss) varied between 0.01 and 0.31 yr(-1). We measured 10 different chemical, anatomical, and morphological traits for all species. The species' average traits were useful predictors of wood decomposition rates, particularly the average diameter (dbh) of the tree species (R2 = 0.41). Lignin concentration further increased the proportion of explained inter-specific variation in wood decomposition (both negative relations, cumulative R2 = 0.55), although it did not significantly explain variation in wood decomposition rates if considered alone. When dbh values of the actual dead trees sampled for decomposition rate determination were used as a predictor variable, the final model (including dead tree dbh and lignin concentration) explained even more variation in wood decomposition rates (R2 = 0.71), underlining the importance of dbh in wood decomposition. Other traits, including wood density, wood anatomical traits, macronutrient concentrations, and the amount of phenolic extractives could not significantly explain the variation in wood decomposition rates. The surprising results of this multi-species study, in which for the first time a large set of traits is explicitly linked to wood decomposition rates, merits further testing in other forest ecosystems.

Performance and value of CAD-deficient pine- Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bailian Li; Houmin Chang; Hasan Jameel

2007-02-28

The southern US produces 58% of the nation's timber, much of it grown in intensively managed plantations of genetically improved loblolly pine. One of the fastest-growing loblolly pine selections made by the NCSU-Industry Cooperative Tree Improvement Program, whose progeny are widely planted, is also the only known natural carrier of a rare gene, cadn1. This allele codes for deficiency in an enzyme, cinnamyl alcohol dehydrogenase, which catalyzes the last step in the biosynthesis of lignin precursors. This study is to characterize this candidate gene for marker-assisted selection and deployment in the breeding program. This research will enhance the sustainability ofmore » forest production in the South, where land-use pressures will limit the total area available in the future for intensively managed plantations. Furthermore, this research will provide information to establish higher-value plantation forests with more desirable wood/fiber quality traits. A rare mutant allele (cad-n1) of the cad gene in loblolly pine (Pinus taeda L.) causes a deficiency in the production of cinnamyl alcohol dehydrogenase (CAD). The effects of this allele were examined by comparing wood density and growth traits of cad-n1 heterozygous trees with those of wild-type trees in a 10-year-old open-pollinated family trial growing under two levels of fertilization in Scotland County, North Carolina. In all, 200 trees were sampled with 100 trees for each treatment. Wood density measurements were collected from wood cores at breast height using x-ray densitometry. We found that the substitution of cad-n1 for a wild-type allele (Cad) was associated with a significant effect on wood density. The cad-n1 heterozygotes had a significantly higher wood density (+2.6%) compared to wild-type trees. The higher density was apparently due to the higher percentage of latewood in the heterozygotes. The fertilization effect was highly significant for both growth and wood density traits. While no cad genotype x treatment interactions was found for any of the traits studied, in the fertilized plots, the effect of the cad-n1 allele on wood density was reduced. The study indicates that the cad-n1 allele could be a valuable gene to the pulp and paper industry for the purpose of enhancing pulp yields through increasing wood density. Stem growth and wood density associated with a mutant null (cad-n1) allele were examined in three 15-year-old loblolly pine diallel tests, established on two sites in the southern United States. In each diallel test, one or two cad-n1 heterozygous parents were crossed with five unrelated wild-type parents, to produce five or ten full-sib families. In all, 839 trees from 20 full-sib families in four genetic backgrounds (a cad-n1 heterozygote x 5 unrelated trees) were sampled, genotyped at the cad locus, and assessed for growth and wood density traits. In a combined analysis of all four genetic backgrounds, we found evidence for effects of increased wood density associated with the cad-n1 allele at age 15 (p=0.03) years and height growth at ages 6 (p=0.03) and 15 (p=0.005). There were large differences in the cad-n1 effects for the various growth and wood traits among the diallel tests. This variation may be due to either different genetic backgrounds among the parents of the different diallel tests, or for different growing environments at the field sites. Even though the cad-n1 effect on growth and wood density was significant across genetic backgrounds, the effect was variable among full-sib families within backgrounds. We speculate that certain wild-type alleles from second parents specifically interact with cad-n1 producing large positive effects. In addition, pleiotropic effects on growth and wood density appear to be associated with the cad-n1 allele. While substantial gains are possible through deployment of trees carrying cad-n1, these gains may be family-specific and should be verified for each cross through field testing.« less

Monte Carlo Simulations for the Detection of Buried Objects Using Single Sided Backscattered Radiation.

PubMed

Yip, Mary; Saripan, M Iqbal; Wells, Kevin; Bradley, David A

2015-01-01

Detection of buried improvised explosive devices (IEDs) is a delicate task, leading to a need to develop sensitive stand-off detection technology. The shape, composition and size of the IEDs can be expected to be revised over time in an effort to overcome increasingly sophisticated detection methods. As an example, for the most part, landmines are found through metal detection which has led to increasing use of non-ferrous materials such as wood or plastic containers for chemical based explosives being developed. Monte Carlo simulations have been undertaken considering three different commercially available detector materials (hyperpure-Ge (HPGe), lanthanum(III) bromide (LaBr) and thallium activated sodium iodide (NaI(Tl)), applied at a stand-off distance of 50 cm from the surface and burial depths of 0, 5 and 10 cm, with sand as the obfuscating medium. Target materials representing medium density wood and mild steel have been considered. Each detector has been modelled as a 10 cm thick cylinder with a 20 cm diameter. It appears that HPGe represents the most promising detector for this application. Although it was not the highest density material studied, its excellent energy resolving capability leads to the highest quality spectra from which detection decisions can be inferred. The simulation work undertaken here suggests that a vehicle-born threat detection system could be envisaged using a single betatron and a series of detectors operating in parallel observing the space directly in front of the vehicle path. Furthermore, results show that non-ferrous materials such as wood can be effectively discerned in such remote-operated detection system, with the potential to apply a signature analysis template matching technique for real-time analysis of such data.

Effects of experimental egg composition on rejection by Village Weavers (Ploceus cucullatus)

USGS Publications Warehouse

Prather, J.W.; Cruz, A.; Weaver, P.F.; Wiley, J.W.

2007-01-01

We experimentally parasitized nests of the Village Weaver (Ploceus cucullatus) in Hispaniola using real and artificial eggs made from wood and modeling clay. Artificial eggs were similar in size and shape to real weaver eggs and were coated with acrylic paint and glazed. Real eggs were actual weaver eggs taken from Village Weaver nests. Experimental parasitic eggs (1) mimicked natural weaver eggs, (2) differed in color only, (3) differed in spotting only, or (4) mimicked Shiny Cowbird (Molothrus bonariensis) egg color and spotting pattern. Parasitized nests were checked after 2-6 days. Real eggs were ejected from weaver nests with increasing frequency as they became less similar to the eggs in the nest with cowbirds eggs having the highest rejection (81%). However, for artificial egg types there were no significant within-composition differences in patterns of rejection. Clay eggs were usually ejected from the nests, whereas nests containing wood eggs often ended empty, or with only the artificial egg remaining in the nest. These patterns may reflect the differential ability of weavers to recognize and remove foreign eggs of different compositions from their nests. Researchers undertaking egg-rejection experiments should use real eggs either in addition or in place of artificial eggs to assess the cost of rejection and the coevolutionary relationships between parasite and host.

Traits drive global wood decomposition rates more than climate.

PubMed

Hu, Zhenhong; Michaletz, Sean T; Johnson, Daniel J; McDowell, Nate G; Huang, Zhiqun; Zhou, Xuhui; Xu, Chonggang

2018-06-14

Wood decomposition is a major component of the global carbon cycle. Decomposition rates vary across climate gradients, which is thought to reflect the effects of temperature and moisture on the metabolic kinetics of decomposers. However, decomposition rates also vary with wood traits, which may reflect the influence of stoichiometry on decomposer metabolism as well as geometry relating the surface areas that decomposers colonize with the volumes they consume. In this paper, we combined metabolic and geometric scaling theories to formalize hypotheses regarding the drivers of wood decomposition rates, and assessed these hypotheses using a global compilation of data on climate, wood traits, and wood decomposition rates. Our results are consistent with predictions from both metabolic and geometric scaling theories. Approximately half of the global variation in decomposition rates was explained by wood traits (nitrogen content and diameter), while only a fifth was explained by climate variables (air temperature, precipitation, and relative humidity). These results indicate that global variation in wood decomposition rates is best explained by stoichiometric and geometric wood traits. Our findings suggest that inclusion of wood traits in global carbon cycle models can improve predictions of carbon fluxes from wood decomposition. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Effect of oak wood barrel capacity and utilization time on phenolic and sensorial profile evolution of an Encruzado white wine.

PubMed

Nunes, Paulo; Muxagata, Sara; Correia, Ana C; Nunes, Fernando M; Cosme, Fernanda; Jordão, António M

2017-11-01

Several studies have reported the influence of diverse winemaking technologies in white wine characteristics. However, the impact of the use of different oak wood barrel capacities and utilization time on the evolution of white wine phenolic content and sensorial characteristics are not usually considered. Thus the aim of this work was to evaluate the effect of oak wood barrel capacity and utilization time on the evolution of phenolic compounds, browning potential index and sensorial profile of an Encruzado white wine. For the 180 aging days considered, the use of new oak wood barrels induced a greater increase in global phenolic composition, including several individual compounds, such as gallic and ellagic acid, independently of the barrel capacity. Tendency for a lesser increase of the browning potential index values was detected for white wines aged in new oak wood barrels. The sensorial profile evolution, showed significant differences only for the aroma descriptors, namely for 'wood aroma' and 'aroma intensity', white wine aged in 225 L new oak wood barrels being the highest scored. The results show that, in general, the use of different capacities and utilization time of oak wood barrels used for white wine aging could play an important role in white wine quality. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Modeling decay rates of dead wood in a neotropical forest.

PubMed

Hérault, Bruno; Beauchêne, Jacques; Muller, Félix; Wagner, Fabien; Baraloto, Christopher; Blanc, Lilian; Martin, Jean-Michel

2010-09-01

Variation of dead wood decay rates among tropical trees remains one source of uncertainty in global models of the carbon cycle. Taking advantage of a broad forest plot network surveyed for tree mortality over a 23-year period, we measured the remaining fraction of boles from 367 dead trees from 26 neotropical species widely varying in wood density (0.23-1.24 g cm(-3)) and tree circumference at death time (31.5-272.0 cm). We modeled decay rates within a Bayesian framework assuming a first order differential equation to model the decomposition process and tested for the effects of forest management (selective logging vs. unexploited), of mode of death (standing vs. downed) and of topographical levels (bottomlands vs. hillsides vs. hilltops) on wood decay rates. The general decay model predicts the observed remaining fraction of dead wood (R2 = 60%) with only two biological predictors: tree circumference at death time and wood specific density. Neither selective logging nor local topography had a differential effect on wood decay rates. Including the mode of death into the model revealed that standing dead trees decomposed faster than downed dead trees, but the gain of model accuracy remains rather marginal. Overall, these results suggest that the release of carbon from tropical dead trees to the atmosphere can be simply estimated using tree circumference at death time and wood density.

Cellulose and lignin biosynthesis is altered by ozone in wood of hybrid poplar (Populus tremula×alba)

PubMed Central

Richet, Nicolas; Afif, Dany; Huber, Françoise; Pollet, Brigitte; Banvoy, Jacques; El Zein, Rana; Lapierre, Catherine; Dizengremel, Pierre; Perré, Patrick; Cabané, Mireille

2011-01-01

Wood formation in trees is a dynamic process that is strongly affected by environmental factors. However, the impact of ozone on wood is poorly documented. The objective of this study was to assess the effects of ozone on wood formation by focusing on the two major wood components, cellulose and lignin, and analysing any anatomical modifications. Young hybrid poplars (Populus tremula×alba) were cultivated under different ozone concentrations (50, 100, 200, and 300 nl l−1). As upright poplars usually develop tension wood in a non-set pattern, the trees were bent in order to induce tension wood formation on the upper side of the stem and normal or opposite wood on the lower side. Biosynthesis of cellulose and lignin (enzymes and RNA levels), together with cambial growth, decreased in response to ozone exposure. The cellulose to lignin ratio was reduced, suggesting that cellulose biosynthesis was more affected than that of lignin. Tension wood was generally more altered than opposite wood, especially at the anatomical level. Tension wood may be more susceptible to reduced carbon allocation to the stems under ozone exposure. These results suggested a coordinated regulation of cellulose and lignin deposition to sustain mechanical strength under ozone. The modifications of the cellulose to lignin ratio and wood anatomy could allow the tree to maintain radial growth while minimizing carbon cost. PMID:21357770

Wood-Based Nanocomposite Derived by in Situ Formation of Organic-Inorganic Hybrid Polymer within Wood via a Sol-Gel Method.

PubMed

Dong, Xiaoying; Zhuo, Xiao; Wei, Jie; Zhang, Gang; Li, Yongfeng

2017-03-15

Solid wood materials and wood-plastic composites as two kinds of lightweight materials are attracting great interest from academia and industry due to their green and recycling nature. However, the relatively lower specific strength limits their wider applications. In particular, solid wood is vulnerable to moisture and decay fungi in nature, resulting in its poor durability for effectively long-term utilization. Inspired from the porous structure of wood, we propose a new design to build a wood-based nanocomposite with higher specific strength and satisfactory durability by in situ generation of organic-inorganic hybrid polymer within wood via a sol-gel method. The derived composite has 50-1200% improvement of impact toughness, 56-192% improvement of tensile strength, and 110-291% improvement of flexural strength over those of typical wood-plastic composites, respectively; and even 34% improvement of specific tensile strength than that of 36A steel; 208% enhancement of hardness; and 156% enhancement of compression strength than those of compared solid wood, respectively; as well as significantly improved dimensional stability and decay resistance over those of untreated natural wood. Such materials could be potentially utilized as lightweight and high-strength materials for applications in construction and automotive industries. This method could be extended to constitute other inorganic nanomaterials for novel organic-inorganic hybrid polymer within wood.

Degree of contamination and sources of polychlorinated biphenyls in Meandering Road Creek and Woods Inlet of Lake Worth, Fort Worth, Texas, 2004 and 2006-07

USGS Publications Warehouse

Braun, Christopher L.; Wilson, Jennifer T.; Van Metre, Peter C.

2008-01-01

Lake Worth is a reservoir on the West Fork Trinity River on the western edge of Fort Worth, Texas. Air Force Plant 4 (AFP4) is on the eastern shore of Woods Inlet, an arm of Lake Worth that extends south from the main body of the lake. Two previous reports documented ele-vated polychlorinated biphenyl (PCB) concentrations in surficial sediment in Woods Inlet relative to those in surficial sediment in other parts of Lake Worth. This report presents the results of another USGS study, done in cooperation with the U.S. Air Force, to indicate the degree of PCB contamination of Meandering Road Creek and Woods Inlet and to identify possible sources of PCBs in Meandering Road Creek and Woods Inlet on the basis of suspended, streambed, and lake-bottom sediment samples collected there in 2004 and 2006-07. About 40 to 80 percent of total PCB concentrations (depending on how total PCB concentration is computed) in suspended sediment exceed the threshold effect concentration, a concentration below which adverse effects to benthic biota rarely occur. About 20 percent of total PCB concentrations (computed as sum of three Aroclors) in suspended sediment exceed the probable effect concentration, a concentration above which adverse effects to benthic biota are expected to occur frequently. About 20 to 30 percent of total PCB concentrations in streambed sediment exceed the threshold effect concentration; and about 6 to 20 percent of total PCB concentrations in lake-bottom (Woods Inlet) sediment exceed the threshold effect concentration. No streambed or lake-bottom sediment concentrations exceed the probable effect concentration. The sources of PCBs to Meandering Road Creek and Woods Inlet were investigated by comparing the relative distributions of PCB congeners of suspended sediment to those of streambed and lake-bottom sediment. The sources of PCBs were identified using graphical analysis of normalized concentrations (congener ratios) of 11 congeners. For graphical analysis, the sampling sites were divided into three groups with each group associated with one of the three outfalls sampled: SSO, OF4, and OF5. The variations of normalized PCB congener concentrations from Woods Inlet, from outfalls along Meandering Road Creek, and from streambed sediment sampling sites along Meandering Road Creek generally form similar patterns within sample groups, which is indicative of a common source of PCBs to each group. Overall, the variations in congener ratios indicate that PCBs in surficial lake-bottom sediment of Woods Inlet probably entered Woods Inlet primarily from Meandering Road Creek, and that runoff from AFP4 is a prominent source of PCBs in Meandering Road Creek. Sixteen of the 20 box core sites in Woods Inlet had lower PCB concentrations in the 2006 cores compared to those in the 2003 cores.

Variation of arsenic concentration on surfaces of in-service CCA-treated wood planks in a park and its influencing field factors.

PubMed

Tang, Ya; Gao, Wei; Wang, Xiuli; Ding, Shiming; An, Taicheng; Xiao, Weiyang; Wong, Ming H; Zhang, Chaosheng

2015-01-01

Wood preservatives can protect wood from dry rot, fungi, mould and insect damage, and chromated copper arsenate (CCA) has been used as an inorganic preservative for many years. However, wood treated with CCA has been restricted from residential uses in the EU from June 30, 2004, due to its potential toxicity. Such a regulation is not in place in China yet, and CCA-treated wood is widely used in public parks. A portable XRF analyser was used to investigate arsenic (As) concentration on surfaces of in-service CCA-treated wood planks in a popular park as well as the influencing field factors of age in-service, immersion and human footfall. With a total of 1207 readings, the observed As concentrations varied from below the detection limit (<10 mg/kg) to 15,746 mg/kg with a median of 1160 mg/kg. Strong variation of As concentrations were observed in different wood planks of the same age, on the surface of the same piece of wood, inside the same piece of wood, and different surfaces of walkway planks, hand rails and poles in the field. The oldest planks exhibited high As concentrations, which was related to its original treatment with high retention of CCA preservative. The effect of immersion in the field for about 4 months was insignificant for As concentration on the surfaces. However, a significant reduction of As was observed for immersion combined with human footfall (wiping by shoes). Human traffic in general caused slightly reduced and more evenly distributed As concentrations on the wood surfaces. The strong variation, slow aging and relatively weak immersion effects found in this study demonstrate that the in-service CCA-treated wood poses potential health risks to the park users, due to easy dermal contact especially when the wood is wet after rainfall. It is suggested that further comprehensive investigations and risk assessments of CCA-treated wood in residential areas in China are needed, and precautionary measures should be considered to reduce the potential risks to residents and visitors, especially children.

The role of large wood in retaining fine sediment, organic matter and plant propagules in a small, single-thread forest river

NASA Astrophysics Data System (ADS)

Osei, Nana A.; Gurnell, Angela M.; Harvey, Gemma L.

2015-04-01

This paper investigates associations among large wood accumulations, retained sediment, and organic matter and the establishment of a viable propagule bank within a forested reach of a lowland river, the Highland Water, UK. A wood survey within the 2-km study reach, illustrates that the quantity of wood retained within the channel is typical of relatively unmanaged river channels bordered by deciduous woodland and that the wood accumulations (jams) that are present are well developed, typically spanning the river channel and comprised of wood that is well decayed. Sediment samples were obtained in a stratified random design focusing on nine subreaches within which samples were aggregated from five different types of sampling location. Two of these locations were wood-associated (within and on bank faces immediately adjacent to wood jams), and the other three locations represented the broader river environment (gravel bars, bank faces, floodplain). The samples were analysed to establish their calibre, organic, and viable plant propagule content. The gravel bar sampling locations retained significantly coarser sediment containing a lower proportion of organic matter and viable propagules than the other four sampling locations. The two wood-related sampling locations retained sediment of intermediate calibre between the gravel bar and the bank-floodplain samples but they retained significantly more organic matter and viable propagules than were found in the other three sampling locations. In particular, the jam bank samples (areas of sediment accumulation against bank faces adjacent to wood jams) contained the highest number of propagules and the largest number of propagule species. These results suggest that retention of propagules, organic matter and relatively fine sediment in and around wood jams has the potential to support vegetation regeneration, further sediment retention, and as a consequence, landform development within woodland streams, although this process is arrested by grazing at the study site. These results also suggest that self-restoration using wood is a potentially cost-effective and far-reaching river restoration strategy but that its full effects develop gradually and require the establishment of a functioning wood budget coupled with grazing levels that are in balance with vegetation growth.

Influence of local riparian cover and watershed runoff potential on invertebrate communities in agricultural streams in the Minnesota River Basin

USGS Publications Warehouse

ZumBerge, Jeremy Ryan; Perry, James A.; Lee, Kathy E.

2003-01-01

While it is difficult to determine the relative influence of watershed runoff potential and local riparian cover, invertebrate communities may be more strongly influenced by local wooded riparian cover than by watershed runoff potential. Invertebrate community measures indicate greater degradation at the open riparian cover, high runoff potential sites and less degradation at the wooded riparian cover, low runoff potential sites. In addition, differences between streams with wooded riparian cover and sites with open riparian cover were greater in watersheds with high runoff potential. The variance explained by riparian cover and runoff potential is relatively independent of other land-use effects. Wooded riparian cover influences invertebrate community composition by its relation to the other physical environmental variables. This study indicates that wooded riparian cover may be effective in maintaining stream biotic integrity in watersheds dominated by agricultural land use.

How chip size impacts steam pretreatment effectiveness for biological conversion of poplar wood into fermentable sugars

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeMartini, Jaclyn D.; Foston, Marcus; Meng, Xianzhi

We report that woody biomass is highly recalcitrant to enzymatic sugar release and often requires significant size reduction and severe pretreatments to achieve economically viable sugar yields in biological production of sustainable fuels and chemicals. However, because mechanical size reduction of woody biomass can consume significant amounts of energy, it is desirable to minimize size reduction and instead pretreat larger wood chips prior to biological conversion. To date, however, most laboratory research has been performed on materials that are significantly smaller than applicable in a commercial setting. As a result, there is a limited understanding of the effects that largermore » biomass particle size has on the effectiveness of steam explosion pretreatment and subsequent enzymatic hydrolysis of wood chips. To address these concerns, novel downscaled analysis and high throughput pretreatment and hydrolysis (HTPH) were applied to examine whether differences exist in the composition and digestibility within a single pretreated wood chip due to heterogeneous pretreatment across its thickness. Heat transfer modeling, Simons’ stain testing, magnetic resonance imaging (MRI), and scanning electron microscopy (SEM) were applied to probe the effects of pretreatment within and between pretreated wood samples to shed light on potential causes of variation, pointing to enzyme accessibility (i.e., pore size) distribution being a key factor dictating enzyme digestibility in these samples. Application of these techniques demonstrated that the effectiveness of pretreatment of Populus tremuloides can vary substantially over the chip thickness at short pretreatment times, resulting in spatial digestibility effects and overall lower sugar yields in subsequent enzymatic hydrolysis. Finally, these results indicate that rapid decompression pretreatments (e.g., steam explosion) that specifically alter accessibility at lower temperature conditions are well suited for larger wood chips due to the non-uniformity in temperature and digestibility profiles that can result from high temperature and short pretreatment times. Furthermore, this study also demonstrated that wood chips were hydrated primarily through the natural pore structure during pretreatment, suggesting that preserving the natural grain and transport systems in wood during storage and chipping processes could likely promote pretreatment efficacy and uniformity.« less

How chip size impacts steam pretreatment effectiveness for biological conversion of poplar wood into fermentable sugars

DOE PAGES

DeMartini, Jaclyn D.; Foston, Marcus; Meng, Xianzhi; ...

2015-12-09

We report that woody biomass is highly recalcitrant to enzymatic sugar release and often requires significant size reduction and severe pretreatments to achieve economically viable sugar yields in biological production of sustainable fuels and chemicals. However, because mechanical size reduction of woody biomass can consume significant amounts of energy, it is desirable to minimize size reduction and instead pretreat larger wood chips prior to biological conversion. To date, however, most laboratory research has been performed on materials that are significantly smaller than applicable in a commercial setting. As a result, there is a limited understanding of the effects that largermore » biomass particle size has on the effectiveness of steam explosion pretreatment and subsequent enzymatic hydrolysis of wood chips. To address these concerns, novel downscaled analysis and high throughput pretreatment and hydrolysis (HTPH) were applied to examine whether differences exist in the composition and digestibility within a single pretreated wood chip due to heterogeneous pretreatment across its thickness. Heat transfer modeling, Simons’ stain testing, magnetic resonance imaging (MRI), and scanning electron microscopy (SEM) were applied to probe the effects of pretreatment within and between pretreated wood samples to shed light on potential causes of variation, pointing to enzyme accessibility (i.e., pore size) distribution being a key factor dictating enzyme digestibility in these samples. Application of these techniques demonstrated that the effectiveness of pretreatment of Populus tremuloides can vary substantially over the chip thickness at short pretreatment times, resulting in spatial digestibility effects and overall lower sugar yields in subsequent enzymatic hydrolysis. Finally, these results indicate that rapid decompression pretreatments (e.g., steam explosion) that specifically alter accessibility at lower temperature conditions are well suited for larger wood chips due to the non-uniformity in temperature and digestibility profiles that can result from high temperature and short pretreatment times. Furthermore, this study also demonstrated that wood chips were hydrated primarily through the natural pore structure during pretreatment, suggesting that preserving the natural grain and transport systems in wood during storage and chipping processes could likely promote pretreatment efficacy and uniformity.« less

Fluidized bed combustion of pelletized biomass and waste-derived fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chirone, R.; Scala, F.; Solimene, R.

2008-10-15

The fluidized bed combustion of three pelletized biogenic fuels (sewage sludge, wood, and straw) has been investigated with a combination of experimental techniques. The fuels have been characterized from the standpoints of patterns and rates of fuel devolatilization and char burnout, extent of attrition and fragmentation, and their relevance to the fuel particle size distribution and the amount and size distribution of primary ash particles. Results highlight differences and similarities among the three fuels tested. The fuels were all characterized by limited primary fragmentation and relatively long devolatilization times, as compared with the time scale of particle dispersion away frommore » the fuel feeding ports in practical FBC. Both features are favorable to effective lateral distribution of volatile matter across the combustor cross section. The three fuels exhibited distinctively different char conversion patterns. The high-ash pelletized sludge burned according to the shrinking core conversion pattern with negligible occurrence of secondary fragmentation. The low-ash pelletized wood burned according to the shrinking particle conversion pattern with extensive occurrence of secondary fragmentation. The medium-ash pelletized straw yielded char particles with a hollow structure, resembling big cenospheres, characterized by a coherent inorganic outer layer strong enough to prevent particle fragmentation. Inert bed particles were permanently attached to the hollow pellets as they were incorporated into ash melts. Carbon elutriation rates were very small for all the fuels tested. For pelletized sludge and straw, this was mostly due to the shielding effect of the coherent ash skeleton. For the wood pellet, carbon attrition was extensive, but was largely counterbalanced by effective afterburning due to the large intrinsic reactivity of attrited char fines. The impact of carbon attrition on combustion efficiency was negligible for all the fuels tested. The size distribution of primary ash particles liberated upon complete carbon burnoff largely reflected the combustion pattern of each fuel. Primary ash particles of size nearly equal to that of the parent fuel were generated upon complete burnoff of the pelletized sludge. Nonetheless, secondary attrition of primary ash from pelletized sludge is large, to the point where generation of fine ash would be extensive over the typical residence time of bed ash in fluidized bed combustors. Very few and relatively fine primary ash particles were released after complete burnoff of wood pellets. Primary ash particles remaining after complete burnoff of pelletized straw had sizes and shapes that were largely controlled by the occurrence of ash agglomeration phenomena. (author)« less

Species selection in secondary wood products: implications for product design and promotion

Treesearch

Matthew S. Bumgardner; Scott A. Bowe; Scott A. Bowe

2002-01-01

This study investigated the perceptions that people have of several commercially important wood species and determined if word-based and specimen-based evaluations differed. Such knowledge can help secondary wood manufacturers better understand their products and develop more effective design concepts and promotional messages. A sample of more than 250 undergraduate...

Properties of seven Colombian woods

Treesearch

B. A. Bendtsen; M. Chudnoff

1981-01-01

Woods from abroad are an important raw material to the forest products industries in the United States. A major concern in effective utilization of this resource is the lack of technical information on many species. This report presents the results of an evaluation of the mechanical properties of small, clear specimens of seven Colombian woods. These results are...

Antioxidant effects of four heartwood extractives on midgut enzyme activity in Heterotermes indicola (Blattodea: Rhinotermitidae)

Treesearch

Babar Hassan; Sohail Ahmed; Grant Kirker; Mark E Mankowski; Muhammad Misbah-ul-Haq

2018-01-01

Heterotermes indicola (Wasmann) (Blattodea: Rhinotermitidae) is a species of subterranean termite that is a destructive pest of wood and wood products in Pakistan. This study evaluated the antioxidant and antienzyme potential of heartwood extractives against H. indicola. Heartwood extractives of four durable wood species, Tectona grandis...

16 CFR § 1406.1 - Scope, purpose, and effective date.

Code of Federal Regulations, 2013 CFR

2013-01-01

... ACT REGULATIONS COAL AND WOOD BURNING APPLIANCES-NOTIFICATION OF PERFORMANCE AND TECHNICAL DATA § 1406... importers, of coal and wood burning appliances, as defined in § 1406.3(a), to provide consumers with a... associated with inadequate information provided with coal and wood burning appliances. This rule does not...

Public opinion and wood energy

Treesearch

Sarah Hitchner; John Schelhas; Teppo Hujala; J. Peter Brosius

2014-01-01

As wood-based bioenergy continues to develop around the world, it will utilize forestlands in new ways and will have different effects on a number of stakeholders, including forest landowners, local communities, extant industries, policymakers, investors, and others. As more stakeholders become involved in the wood energy web, and as the general public becomes more...

Chemical yields from low-temperature pyrolysis of CCA-treated wood

Treesearch

Qirong Fu; Dimitris Argyropolous; Lucian Lucia; David Tilotta; Stan Lebow

2009-01-01

Low-temperature pyrolysis offers a feasible option for wood-waste management and the recovery of a variety of useful chemicals. The effect of chromated copper arsenate (CCA) wood preservative on the yield and composition of various pyrolysis products was investigated in the present research. A novel quantitative 31P nuclear magnetic resonance (...

Evaluation of the antifungal effects of bio-oil prepared with lignocellulosic biomass using fast pyrolysis technology.

PubMed

Kim, Kwang Ho; Jeong, Han Seob; Kim, Jae-Young; Han, Gyu Seong; Choi, In-Gyu; Choi, Joon Weon

2012-10-01

This study was performed to investigate the utility of bio-oil, produced via a fast pyrolysis process, as an antifungal agent against wood-rot fungi. Bio-oil solutions (25-100 wt.%) were prepared by diluting the bio-oil with EtOH. Wood block samples (yellow poplar and pitch pine) were treated with diluted bio-oil solutions and then subjected to a leaching process under hot water (70°C) for 72 h. After the wood block samples were thoroughly dried, they were subjected to a soil block test using Tyromyces palustris and Trametes versicolor. The antifungal effect of the 75% and 100% bio-oil solutions was the highest for both wood blocks. Scanning electron microscopy analysis indicated that some chemical components in the bio-oil solution could agglomerate together to form clusters in the inner part of the wood during the drying process, which could act as a wood preservative against fungal growth. According to GC/MS analysis, the components of the agglomerate were mainly phenolic compounds derived from lignin polymers. Copyright © 2012 Elsevier Ltd. All rights reserved.

Compression Debarking of Stored Wood Chips

Treesearch

James A. Mattson

1974-01-01

Two 750 ft. piles of unbarked chips were stored for 1 year to evaluate the effect of chip storage on the effectiveness of bark-chip separations-segregation methods under study. in processing stored chips suffered more wood loss than fresh chips.

Transplantation of subalpine wood-pasture turfs along a natural climatic gradient reveals lower resistance of unwooded pastures to climate change compared to wooded ones.

PubMed

Gavazov, Konstantin; Spiegelberger, Thomas; Buttler, Alexandre

2014-04-01

Climate change could impact strongly on cold-adapted mountain ecosystems, but little is known about its interaction with traditional land-use practices. We used an altitudinal gradient to simulate a year-round warmer and drier climate for semi-natural subalpine grasslands across a landscape of contrasting land-use management. Turf mesocosms from three pasture-woodland land-use types-unwooded pasture, sparsely wooded pasture, and densely wooded pasture-spanning a gradient from high to low management intensity were transplanted downslope to test their resistance to two intensities of climate change. We found strong overall effects of intensive (+4 K) experimental climate change (i.e., warming and reduced precipitation) on plant community structure and function, while moderate (+2 K) climate change did not substantially affect the studied land-use types, thus indicating an ecosystem response threshold to moderate climate perturbation. The individual land-use types were affected differently under the +4 K scenario, with a 60% decrease in aboveground biomass (AGB) in unwooded pasture turfs, a 40% decrease in sparsely wooded pasture turfs, and none in densely wooded ones. Similarly, unwooded pasture turfs experienced a 30% loss of species, advanced (by 30 days) phenological development, and a mid-season senescence due to drought stress, while no such effects were recorded for the other land-use types. The observed contrasting effects of climate change across the pasture-woodland landscape have important implications for future decades. The reduced impact of climate change on wooded pastures as compared to unwooded ones should promote the sustainable land use of wooded pastures by maintaining low management intensity and a sparse forest canopy, which buffer the immediate impacts of climate change on herbaceous vegetation.

Compensatory mechanisms mitigate the effect of warming and drought on wood formation.

PubMed

Balducci, Lorena; Cuny, Henri E; Rathgeber, Cyrille B K; Deslauriers, Annie; Giovannelli, Alessio; Rossi, Sergio

2016-06-01

Because of global warming, high-latitude ecosystems are expected to experience increases in temperature and drought events. Wood formation will have to adjust to these new climatic constraints to maintain tree mechanical stability and long-distance water transport. The aim of this study is to understand the dynamic processes involved in wood formation under warming and drought. Xylogenesis, gas exchange, water relations and wood anatomy of black spruce [Picea mariana (Mill.) B.S.P.] saplings were monitored during a greenhouse experiment where temperature was increased during daytime or night-time (+6 °C) combined with a drought period. The kinetics of tracheid development expressed as rate and duration of the xylogenesis sub-processes were quantified using generalized additive models. Drought and warming had a strong influence on cell production, but little effect on wood anatomy. The increase in cell production rate under warmer temperatures, and especially during the night-time warming at the end of the growing season, resulted in wider tree-rings. However, the strong compensation between rates and durations of cell differentiation processes mitigates warming and drought effects on tree-ring structure. Our results allowed quantification of how wood formation kinetics is regulated when water and heat stress increase, allowing trees to adapt to future environmental conditions. © 2015 John Wiley & Sons Ltd.

Physiological Effects of Touching Coated Wood.

PubMed

Ikei, Harumi; Song, Chorong; Miyazaki, Yoshifumi

2017-07-13

This study examined the physiological effects of touching wood with various coating with the palm of the hand on brain activity and autonomic nervous activity. Participants were 18 female university students (mean age, 21.7 ± 1.6 years). As an indicator of brain activity, oxyhemoglobin concentrations were measured in the left and right prefrontal cortices using near-infrared time-resolved spectroscopy. Heart rate variability (HRV) and heart rate were used as indicators of autonomic nervous activity. The high-frequency (HF) component of HRV, which reflects parasympathetic nervous activity, and the low-frequency (LF)/HF ratio, which reflects sympathetic nervous activity, were measured. Plates of uncoated, oil-finished, vitreous-finished, urethane-finished, and mirror-finished white oak wood were used as tactile stimuli. After sitting at rest with their eyes closed for 60 s, participants touched the stimuli with their palm for 90 s each. The results indicated that tactile stimulation with uncoated wood calmed prefrontal cortex activity (vs. urethane finish and mirror finish), increased parasympathetic nervous activity (vs. vitreous finish, urethane finish, and mirror finish), and decreased heart rate (vs. mirror finish), demonstrating a physiological relaxation effect. Further, tactile stimulation with oil- and vitreous-finished wood calmed left prefrontal cortex activity and decreased heart rate relative to mirror-finished wood.

Plasticity of maritime pine (Pinus pinaster) wood-forming tissues during a growing season.

PubMed

Paiva, J A P; Garnier-Géré, P H; Rodrigues, J C; Alves, A; Santos, S; Graça, J; Le Provost, G; Chaumeil, G; Da Silva-Perez, D; Bosc, A; Fevereiro, P; Plomion, C

2008-01-01

The seasonal effect is the most significant external source of variation affecting vascular cambial activity and the development of newly divided cells, and hence wood properties. Here, the effect of edapho-climatic conditions on the phenotypic and molecular plasticity of differentiating secondary xylem during a growing season was investigated. Wood-forming tissues of maritime pine (Pinus pinaster) were collected from the beginning to the end of the growing season in 2003. Data from examination of fibre morphology, Fourier-transform infrared spectroscopy (FTIR), analytical pyrolysis, and gas chromatography/mass spectrometry (GC/MS) were combined to characterize the samples. Strong variation was observed in response to changes in edapho-climatic conditions. A genomic approach was used to identify genes differentially expressed during this growing season. Out of 3512 studied genes, 19% showed a significant seasonal effect. These genes were clustered into five distinct groups, the largest two representing genes over-expressed in the early- or late-wood-forming tissues, respectively. The other three clusters were characterized by responses to specific edapho-climatic conditions. This work provides new insights into the plasticity of the molecular machinery involved in wood formation, and reveals candidate genes potentially responsible for the phenotypic differences found between early- and late-wood.

Physiological Effects of Touching Coated Wood

PubMed Central

2017-01-01

This study examined the physiological effects of touching wood with various coating with the palm of the hand on brain activity and autonomic nervous activity. Participants were 18 female university students (mean age, 21.7 ± 1.6 years). As an indicator of brain activity, oxyhemoglobin concentrations were measured in the left and right prefrontal cortices using near-infrared time-resolved spectroscopy. Heart rate variability (HRV) and heart rate were used as indicators of autonomic nervous activity. The high-frequency (HF) component of HRV, which reflects parasympathetic nervous activity, and the low-frequency (LF)/HF ratio, which reflects sympathetic nervous activity, were measured. Plates of uncoated, oil-finished, vitreous-finished, urethane-finished, and mirror-finished white oak wood were used as tactile stimuli. After sitting at rest with their eyes closed for 60 s, participants touched the stimuli with their palm for 90 s each. The results indicated that tactile stimulation with uncoated wood calmed prefrontal cortex activity (vs. urethane finish and mirror finish), increased parasympathetic nervous activity (vs. vitreous finish, urethane finish, and mirror finish), and decreased heart rate (vs. mirror finish), demonstrating a physiological relaxation effect. Further, tactile stimulation with oil- and vitreous-finished wood calmed left prefrontal cortex activity and decreased heart rate relative to mirror-finished wood. PMID:28703777

Physicochemical patterns of ozone absorption by wood

NASA Astrophysics Data System (ADS)

Mamleeva, N. A.; Lunin, V. V.

2016-11-01

Results from studying aspen and pine wood ozonation are presented. The effect the concentration of ozone, the reagent residence time, and the content of water in a sample of wood has on ozone consumption rate and ozone demand are analyzed. The residence time is shown to determine the degree of ozone conversion degree and the depth of substrate destruction. The main patterns of ozone absorption by wood with different moisture content are found. Ways of optimizing the ozonation of plant biomass are outlined.

Plywood production wastes to energy

NASA Astrophysics Data System (ADS)

Lyubov, V. K.; Popov, A. N.

2017-11-01

Wood and by-products of its processing are a renewable energy source with carbon neutral and may be used in solving energy problems. ZAO «Arkhangelsk plywood factory» installed and put into operation the boiler with capacity of 22 MW (saturated steam of 1.2 MPa) to reduce the cost of thermal energy, the impact of environmental factors on stability of the company’s development and for reduction of harmful emissions into the environment. Fuel for boiler is the mixture consists of chip plywood, birch bark, wood sanding dust (WSD) and sawdust of the plywood processing. The components of the fuel mixture significantly differ in thermotechnical characteristics and technological parameters but especially in size composition. Particle dimensions in the fuel mixture differ by more than a thousand times which makes it «unique» and very difficult to ensure the effective and non-explosive use. WSD and sawdust from line of cutting of plywood are small fraction material and relate to IV group of explosion. Criterion of explosive for them has great values (КfWSD=10.85 Кfsaw=9.66). Boiler’s furnace equipped with reciprocating grate where implemented a three-stage scheme of combustion. For a comprehensive survey of the effectiveness of installed equipment was analyzed the design features of the boiler, defined the components of thermal balance, studied nitrogen oxide emissions, carbon and particulate matter with the determination of soot emissions. Amount of solid particles depending on their shape and size was analyzed.

Instream wood recruitment, channel complexity, and their relationship to stream ecology in forested headwater streams under alternative stable states

NASA Astrophysics Data System (ADS)

Livers, B.; Wohl, E.

2015-12-01

Human alteration to forests has had lasting effects on stream channels worldwide. Such land use changes affect how wood enters and is stored in streams as individual pieces and as logjams. Changes in wood recruitment affect the complexity and benefits wood can provide to the stream environment, such as zones of flow separation that store fine sediment and organic matter, increased nutrient processing, and greater habitat potential, which can enhance biota and cascade through stream-riparian ecosystems. Previous research in our study area shows that modern headwater streams flowing through old-growth, unmanaged forests have more wood than streams in young, managed forests, but does not explicitly evaluate how wood affects channel complexity or local ecology. 'Managed' refers to forests previously or currently exposed to human alteration. Alteration has long since ceased in some areas, but reduced wood loads in managed streams persist. Our primary objective was to quantify stream complexity metrics, with instream wood as a mediator, on streams across a gradient of management and disturbance histories in order to examine legacy effects of human alteration to forests. Data collected in the Southern Rocky Mountains include 24 2nd to 3rd order subalpine streams categorized into: old-growth unmanaged; younger, naturally disturbed unmanaged; and younger managed. We assessed instream wood loads and logjams and evaluated how they relate to channel complexity using a number of metrics, such as standard deviation of bed and banks, volume of pools, ratios of stream to valley lengths and stream to valley area, and diversity of substrate, gradient, and morphology. Preliminary results show that channel complexity is directly related to instream wood loads and is greatest in streams in old-growth. Related research in the field area indicates that streams with greater wood loads also have increased nutrient processing and greater abundance and diversity of aquatic insect predators.

Wood ash application increases pH but does not harm the soil mesofauna.

PubMed

Qin, Jiayi; Hovmand, Mads Frederik; Ekelund, Flemming; Rønn, Regin; Christensen, Søren; Groot, Gerard Arjen de; Mortensen, Louise Hindborg; Skov, Simon; Krogh, Paul Henning

2017-05-01

Application of bioash from biofuel combustion to soil supports nutrient recycling, but may have unwanted and detrimental ecotoxicological side-effects, as the ash is a complex mixture of compounds that could affect soil invertebrates directly or through changes in their food or habitat conditions. To examine this, we performed laboratory toxicity studies of the effects of wood-ash added to an agricultural soil and the organic horizon of a coniferous plantation soil with the detrivore soil collembolans Folsomia candida and Onychiurus yodai, the gamasid predaceous mite Hypoaspis aculeifer, and the enchytraeid worm Enchytraeus crypticus. We used ash concentrations spanning 0-75 g kg -1 soil. As ash increases pH we compared bioash effects with effects of calcium hydroxide, Ca(OH) 2 , the main liming component of ash. Only high ash concentrations above 15 g kg -1 agricultural soil or 17 t ha -1 had significant effects on the collembolans. The wood ash neither affected H. aculeifer nor E. crypticus. The estimated osmolalities of Ca(OH) 2 and the wood ash were similar at the LC 50 concentration level. We conclude that short-term chronic effects of wood ash differ among different soil types, and osmotic stress is the likely cause of effects while high pH and heavy metals is of minor importance. Copyright © 2017 Elsevier Ltd. All rights reserved.

Physical and chemical evaluation of furniture waste briquettes.

PubMed

Moreno, Ana Isabel; Font, Rafael; Conesa, Juan A

2016-03-01

Furniture waste is mainly composed of wood and upholstery foam (mostly polyurethane foam). Both of these have a high calorific value, therefore, energy recovery would be an appropriate process to manage these wastes. Nevertheless, the drawback is that the energy content of these wastes is limited due to their low density mainly that of upholstery foam. Densification of separate foam presents difficulties due to its elastic character. The significance of this work lies in obtaining densified material by co-densification of furniture wood waste and polyurethane foam waste. Densification of furniture wood and the co-densification of furniture wood waste with polyurethane foam have been studied. On the one hand, the parameters that have an effect on the quality of the furniture waste briquettes have been analysed, i.e., moisture content, compaction pressure, presence of lignin, etc. The maximum weight percentage of polyurethane foam that can be added with furniture wood waste to obtain durable briquettes and the optimal moisture were determined. On the other hand, some parameters were analysed in order to evaluate the possible effect on the combustion. The chemical composition of waste wood was compared with untreated wood biomass; the higher nitrogen content and the concentration of some metals were the most important differences, with a significant difference of Ti content. Copyright © 2016 Elsevier Ltd. All rights reserved.

Magnetic Fields of the Cerebral Cortex,

DTIC Science & Technology

1980-06-15

with worm gears on two separate horizontal shafts . One shaft (the declination axle ) near the end of the frame rotates the dewar. The other near the...carriage is fabricated from fiberglass or wood wherever possible. Vertical movement of the dewar is permitted by a 6 cm diameter cylindrical axle of...hardwood that runs between sets of aluminum rollers having double conical shape. The axle is supported by four strands of nylon parachute cord, each

Respiratory morbidity of pattern and model makers exposed to wood, plastic, and metal products

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robins, T.G.; Haboubi, G.; Demers, R.Y.

Pattern and model makers are skilled tradespersons who may be exposed to hardwoods, softwoods, phenol-formaldehyde resin-impregnated woods, epoxy and polyester/styrene resin systems, and welding and metal-casting fumes. The relationship of respiratory symptoms (wheezing, chronic bronchitis, dyspnea) and pulmonary function (FVC% predicted, FEV1% predicted, FEV1/FVC% predicted) with interview-derived cumulative exposure estimates to specific workplace agents and to all work with wood, plastic, or metal products was investigated in 751 pattern and model makers in southeast Michigan. In stratified analyses and age- and smoking-adjusted linear and logistic regression models, measures of cumulative wood exposures were associated with decrements in pulmonary function andmore » dyspnea, but not with other symptoms. In similar analyses, measures of cumulative plastic exposures were associated with wheezing, chronic bronchitis, and dyspnea, but not with decrements in pulmonary function. Prior studies of exposure levels among pattern and model makers and of respiratory health effects of specific agents among other occupational groups support the plausibility of wood-related effects more strongly than that of plastic-related effects.« less

Energetic valorization of wood waste: estimation of the reduction in CO2 emissions.

PubMed

Vanneste, J; Van Gerven, T; Vander Putten, E; Van der Bruggen, B; Helsen, L

2011-09-01

This paper investigates the potential CO(2) emission reductions related to a partial switch from fossil fuel-based heat and electricity generation to renewable wood waste-based systems in Flanders. The results show that valorization in large-scale CHP (combined heat and power) systems and co-firing in coal plants have the largest CO(2) reduction per TJ wood waste. However, at current co-firing rates of 10%, the CO(2) reduction per GWh of electricity that can be achieved by co-firing in coal plants is five times lower than the CO(2) reduction per GWh of large-scale CHP. Moreover, analysis of the effect of government support for co-firing of wood waste in coal-fired power plants on the marginal costs of electricity generation plants reveals that the effect of the European Emission Trading Scheme (EU ETS) is effectively counterbalanced. This is due to the fact that biomass integrated gasification combined cycles (BIGCC) are not yet commercially available. An increase of the fraction of coal-based electricity in the total electricity generation from 8 to 10% at the expense of the fraction of gas-based electricity due to the government support for co-firing wood waste, would compensate entirely for the CO(2) reduction by substitution of coal by wood waste. This clearly illustrates the possibility of a 'rebound' effect on the CO(2) reduction due to government support for co-combustion of wood waste in an electricity generation system with large installed capacity of coal- and gas-based power plants, such as the Belgian one. Copyright © 2011 Elsevier B.V. All rights reserved.

Recent advances quantifying the large wood dynamics in river basins: New methods and remaining challenges

NASA Astrophysics Data System (ADS)

Ruiz-Villanueva, Virginia; Piégay, Hervé; Gurnell, Angela A.; Marston, Richard A.; Stoffel, Markus

2016-09-01

Large wood is an important physical component of woodland rivers and significantly influences river morphology. It is also a key component of stream ecosystems. However, large wood is also a source of risk for human activities as it may damage infrastructure, block river channels, and induce flooding. Therefore, the analysis and quantification of large wood and its mobility are crucial for understanding and managing wood in rivers. As the amount of large-wood-related studies by researchers, river managers, and stakeholders increases, documentation of commonly used and newly available techniques and their effectiveness has also become increasingly relevant as well. Important data and knowledge have been obtained from the application of very different approaches and have generated a significant body of valuable information representative of different environments. This review brings a comprehensive qualitative and quantitative summary of recent advances regarding the different processes involved in large wood dynamics in fluvial systems including wood budgeting and wood mechanics. First, some key definitions and concepts are introduced. Second, advances in quantifying large wood dynamics are reviewed; in particular, how measurements and modeling can be combined to integrate our understanding of how large wood moves through and is retained within river systems. Throughout, we present a quantitative and integrated meta-analysis compiled from different studies and geographical regions. Finally, we conclude by highlighting areas of particular research importance and their likely future trajectories, and we consider a particularly underresearched area so as to stress the future challenges for large wood research.

Temporal Trend in Wood Dust Exposure During the Production of Wood Pellets.

PubMed

Eriksson, Kåre; Bryngelsson, Ing-Liss; Hagström, Katja

2017-05-01

Wood dust data collected in the production of wood pellets during 2001 to 2013 were evaluated to study a temporal trend in inhalation exposure. A linear mixed effects model of natural ln-transformed data was used to express the relative annual difference in inhalation wood dust exposure. There was an annual decrease of -20.5% of the geometric mean wood dust exposure during 2001 until 2013. The results were based on 617 inhalable dust samples collected at 14 different production units. The exposure to wood dust at the industrial premises investigated has decreased from a relatively high level of 6.4 mg m-3 in 2001 to 1.0 mg-3 in 2013. The Swedish Occupational Exposure Limit (SOEL) of 2 mg m-3 may still be exceeded. Analysis of the temporal trend in soft wood production units revealed declines in exposure of 20.5% per annum. It is important that precautions are taken to protect workers from a hazardous exposure to wood dust at the premises as the SOEL of 2 mg m-3 at some occasions is still exceeded. Additional measurements of wood dust exposure should be carried out on a regular basis in wood pellet production units in Sweden as well in other countries. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Comparative evaluation of different thermally modified wood samples finishing with UV-curable and waterborne coatings

NASA Astrophysics Data System (ADS)

Herrera, René; Muszyńska, Monika; Krystofiak, Tomasz; Labidi, Jalel

2015-12-01

Thermally modified wood has been developed as an industrial method to improve durability and dimensional stability of wood and thus extends the range of uses and service life of wood-based products. Despite the improvements gained by treatment, surface finishing using coatings prevents esthetical changes such as color degradation or occasional growth of mold adding protection in outdoor use and extending the service life of products. The wood finishing process was carried out with commercially available waterborne and UV-curable coatings on industrially modified at 192, 200, 212 °C and unmodified European ash (Fraxinus excelsior L.) wood, using an industrial rollers system and a laboratory brushing system. Changes caused by thermal treatment which could affect the surface finish were measured and compared with control samples, such as water uptake, wettability and acidity. Following the wood finishing, surface properties and esthetic changes were evaluated; as well as the coatings performance. Thermally modified wood presented improved adherence compared with unmodified wood with a significant improvement in samples modified at 212 °C, which also present the highest hardness when UV-cured. Finishes with UV-curing maintain the hydrophobic effect of thermally modified wood, whereas waterborne finishes increase the surface wettability. Thermal modification did not negatively influence on the elastic properties of the coated substrate and thus allows this material to be finished with different coating systems in the same conditions as unmodified wood.

From Wood to Textiles: Top-Down Assembly of Aligned Cellulose Nanofibers.

PubMed

Jia, Chao; Chen, Chaoji; Kuang, Yudi; Fu, Kun; Wang, Yilin; Yao, Yonggang; Kronthal, Spencer; Hitz, Emily; Song, Jianwei; Xu, Fujun; Liu, Boyang; Hu, Liangbing

2018-06-07

Advanced textiles made of macroscopic fibers are usually prepared from synthetic fibers, which have changed lives over the past century. The shortage of petrochemical resources, however, greatly limits the development of the textile industry. Here, a facile top-down approach for fabricating macroscopic wood fibers for textile applications (wood-textile fibers) comprising aligned cellulose nanofibers directly from natural wood via delignification and subsequent twisting is demonstrated. Inherently aligned cellulose nanofibers are well retained, while the microchannels in the delignified wood are squeezed and totally removed by twisting, resulting in a dense structure with approximately two times higher mechanical strength (106.5 vs 54.9 MPa) and ≈20 times higher toughness (7.70 vs 0.36 MJ m -3 ) than natural wood. Dramatically different from natural wood, which is brittle in nature, the resultant wood-textile fibers are highly flexible and bendable, likely due to the twisted structures. The wood-textile fibers also exhibit excellent knitting properties and dyeability, which are critical for textile applications. Furthermore, functional wood-textile fibers can be achieved by preinfiltrating functional materials in the delignified wood film before twisting. This top-down approach of fabricating aligned macrofibers is simple, scalable, and cost-effective, representing a promising direction for the development of smart textiles and wearable electronics. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wood Stove Pollution in the Developed World: A Case to Raise Awareness Among Pediatricians.

PubMed

Rokoff, Lisa B; Koutrakis, Petros; Garshick, Eric; Karagas, Margaret R; Oken, Emily; Gold, Diane R; Fleisch, Abby F

2017-06-01

Use of wood for residential heating is regaining popularity in developed countries. Currently, over 11 million US homes are heated with a wood stove. Although wood stoves reduce heating costs, wood smoke may adversely impact child health through the emission of gaseous and particulate air pollutants. Our purpose is to raise awareness of this environmental health issue among pediatricians. To summarize the state of the science, we performed a narrative review of articles published in PubMed and Web of Science. We identified 36 studies in developed countries that reported associations of household wood stove use and/or community wood smoke exposure with pediatric health outcomes. Studies primarily investigated respiratory outcomes, with no evaluation of cardiometabolic or neurocognitive health. Studies found community wood smoke exposure to be consistently associated with adverse pediatric respiratory health. Household wood stove use was less consistently associated with respiratory outcomes. However, studies of household wood stoves always relied on participant self-report of wood stove use, while studies of community wood smoke generally assessed air pollution exposure directly and more precisely in larger study populations. In most studies, important potential confounders, such as markers of socioeconomic status, were unaccounted for and may have biased results. We conclude that studies with improved exposure assessment, that measure and account for confounding, and that consider non-respiratory outcomes are needed. While awaiting additional data, pediatricians can refer patients to precautionary measures recommended by the US Environmental Protection Agency (EPA) to mitigate exposure. These include replacing old appliances with EPA-certified stoves, properly maintaining the stove, and using only dry, well-seasoned wood. In addition, several studies have shown mechanical air filters to effectively reduce wood stove pollution exposure in affected homes and communities. Copyright © 2017 Mosby, Inc. All rights reserved.

Wood Stove Pollution in the Developed World: A Case to Raise Awareness Among Pediatricians

PubMed Central

Rokoff, Lisa B.; Koutrakis, Petros; Garshick, Eric; Karagas, Margaret R.; Oken, Emily; Gold, Diane R.; Fleisch, Abby F.

2017-01-01

Use of wood for residential heating is regaining popularity in developed countries. Currently, over 11 million US homes are heated with a wood stove. Although wood stoves reduce heating costs, wood smoke may adversely impact child health through the emission of gaseous and particulate air pollutants. Our purpose is to raise awareness of this environmental health issue among pediatricians. To summarize the state of the science, we performed a narrative review of articles published in PubMed and Web of Science. We identified 36 studies in developed countries that reported associations of household wood stove use and/or community wood smoke exposure with pediatric health outcomes. Studies primarily investigated respiratory outcomes, with no evaluation of cardiometabolic or neurocognitive health. Studies found community wood smoke exposure to be consistently associated with adverse pediatric respiratory health. Household wood stove use was less consistently associated with respiratory outcomes. However, studies of household wood stoves always relied on participant self-report of wood stove use, while studies of community wood smoke generally assessed air pollution exposure directly and more precisely in larger study populations. In most studies, important potential confounders, such as markers of socioeconomic status, were unaccounted for and may have biased results. We conclude that studies with improved exposure assessment, that measure and account for confounding, and that consider non-respiratory outcomes are needed. While awaiting additional data, pediatricians can refer patients to precautionary measures recommended by the US Environmental Protection Agency (EPA) to mitigate exposure. These include replacing old appliances with EPA-certified stoves, properly maintaining the stove, and using only dry, well-seasoned wood. In addition, several studies have shown mechanical air filters to effectively reduce wood stove pollution exposure in affected homes and communities. PMID:28583817

Xylem traits, leaf longevity and growth phenology predict growth and mortality response to defoliation in northern temperate forests.

PubMed

Foster, Jane R

2017-09-01

Defoliation outbreaks are biological disturbances that alter tree growth and mortality in temperate forests. Trees respond to defoliation in many ways; some recover rapidly, while others decline gradually or die. Functional traits such as xylem anatomy, growth phenology or non-structural carbohydrate (NSC) storage could explain these responses, but idiosyncratic measures used by defoliation studies have frustrated efforts to generalize among species. Here, I test for functional differences with published growth and mortality data from 37 studies, including 24 tree species and 11 defoliators from North America and Eurasia. I synthesized data into standardized variables suitable for numerical models and used linear mixed-effects models to test the hypotheses that responses to defoliation vary among species and functional groups. Standardized data show that defoliation responses vary in shape and degree. Growth decreased linearly or curvilinearly, least in ring-porous Quercus and deciduous conifers (by 10-40% per 100% defoliation), whereas growth of diffuse-porous hardwoods and evergreen conifers declined by 40-100%. Mortality increased exponentially with defoliation, most rapidly for evergreen conifers, then diffuse-porous, then ring-porous species and deciduous conifers (Larix). Goodness-of-fit for functional-group models was strong (R2c = 0.61-0.88), if lower than species-specific mixed-models (R2c = 0.77-0.93), providing useful alternatives when species data are lacking. These responses are consistent with functional differences in leaf longevity, wood growth phenology and NSC storage. When defoliator activity lags behind wood-growth, either because xylem-growth precedes budburst (Quercus) or defoliator activity peaks later (sawflies on Larix), impacts on annual wood-growth will always be lower. Wood-growth phenology of diffuse-porous species and evergreen conifers coincides with defoliation and responds more drastically, and lower axial NSC storage makes them more vulnerable to mortality as stress accumulates. These functional differences in response apply in general to disturbances that cause spring defoliation and provide a framework that should be incorporated into forest growth and vegetation models. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Chemical modification of wood : a short review

Treesearch

Roger M. Rowell

2006-01-01

For most markets for wood, it is used without any treatments or modifications. When wood is used in adverse environments, it may be treated with chemicals to help prevent decay, improve water resistance, reduce the effects of ultraviolet radiation or increase fire retardancy. Many of these treatments involve the use of toxic or corrosive chemicals that can harm the...

Modeling the Effect of Nail Corrosion on the Lateral Strength of Joints

Treesearch

Samuel L. Zelinka; Douglas R. Rammer

2012-01-01

This article describes a theoretical method of linking fastener corrosion in wood connections to potential reduction in lateral shear strength. It builds upon published quantitative data of corrosion rates of metals in contact with treated wood for several different wood preservatives. These corrosion rates are then combined with yield theory equations to calculate a...

Fundamental characteristics of microwave explosion pretreatment of wood. I, Properties of temperature development

Treesearch

Xian-jun Li; Ke-yang Lu; Lan-ying Lin; Yong-dong Zhou; Zhi-yong Cai; Feng Fu

2010-01-01

In this study, the effects of microwave radiation intensity, radiation time and initial wood moisture content (MC) on the properties of temperature development in Eucalyptus urophylla wood samples during the microwave explosion pretreatment have been investigated using a new microwave pretreatment equipment. The results show that 1) with the increase of microwave...

Guide for minimizing the effect of preservative-treated wood on sensitive environments

Treesearch

Stan T. Lebow; Michael Tippie

2001-01-01

Preservative-treated wood is often used for construction of highway and foot bridges, wetland boardwalks, and other structures in or over water or sensitive environments. In these applications it is important that release of preservative from the wood into the environment is minimized. This publication addresses this concern by describing the various types of pressure-...

Performance of copper-based wood preservatives in soil bed exposures

Treesearch

Stan T. Lebow; Thomas Nilsson; Jeffrey J. Morrell

Copper-based biocides are widely used to protect wood from biological attack in a variety of environments. Chromated copper arsenate (CCA) is the dominant copper-based preservative for wood protection (J. T. MICKLEWRIGHT, 1989). First developed in India in the 1930s, CCA contains a very effective combination of materials. Copper provides protection against most...

Moldicidal properties of seven essential oils

Treesearch

Vina W. Yang; Carol A. Clausen

2006-01-01

When wood and wood products are exposed to moisture during storage, construction or while in-service, mold growth can occur in 24 to 48 hours. Mold growth could be suppressed or prevented if wood was treated with an effective mold inhibitor. The objective of this study was to evaluate the mold inhibiting properties of natural plant extracts such as essential oils....

Composites from southern pine juvenile wood. Part 3. Juvenile and mature wood furnish mixtures

Treesearch

A.D. Pugel; E.W. Price; Chung-Yun Hse; T.F. Shupe

2004-01-01

Composite panelsmade from mixtures ofmature andjuvenile southern pine (Pinus taeda L.) were evaluated for initial mechanical properties and dimensional stability. The effect that the proportion of juvenile wood had on panel properties was analyzed by regression and rule-of-mixtures models. The mixed furnish data: 1) highlighted the degree to which...

Interaction of Substrate and Nutrient Availability on wood Biofilm Processes in Streams

Treesearch

Jennifer L. Tank; J.R. Webster

1998-01-01

We examined the effect of decomposing leaf litter and dissolved inorganic nutrients on the heterotrophic biofilm of submerged wood in streams with and without leaves. Leaf litter was excluded from one headwater stream in August 1993 at Coweeta Hydrologic Laboratory in the southern Appalachian Mountains. We compared microbial processes on wood in the litter-excluded...

Wood properties of trembling aspen and paper birch after 5 years of exposure to elevated concentrations of CO2 and O3

Treesearch

Katri Kostiainen; Seija Kaakinen; Elina Warsta; Mark E. Kubiske; Neil D. Nelson; Jaak Sober; David F. Karnosky; Pekka Saranpaa; Elina Vapaavuori

2008-01-01

We investigated the interactive effects of elevated concentrations of carbon dioxide ([CO2]) and ozone ([O3]) on radial growth, wood chemistry and structure of five 5-year-old trembling aspen (Populus tremuloides Michx.) clones and the wood chemistry of paper birch (Betula papyrifera...

Contrasting effects of insect exclusion on wood loss in a temperate forest

Treesearch

Michael Ulyshen; Terry Wagner; Joseph E. Mulrooney

2014-01-01

Experimental efforts to determine how insects influence terrestrial wood decomposition are few, especially in temperate regions. To address this need, a five-year exclusion study was conducted in northern Mississippi, U.S.A., to quantify insect contributions to wood decay using one-meter loblolly pine (Pinus taeda L.) bolts. The study included three...

Evaluation of adhesive penetration of wood fibre by nanoindentation and microscopy

Treesearch

Christopher G. Hunt; Joseph E. Jakes; Warren Grigsby

2010-01-01

Adhesives used in wood products sometimes infiltrate, or diffuse into the solid material of, wood cell walls, potentially modifying their properties. These changes in cell wall properties are likely to impact the performance of adhesive bonds. While adhesive infiltration has been observed by multiple methods, the effect on cell wall properties is not well understood....

Improved understanding of moisture effects on outdoor wood–adhesive bondlines

Treesearch

Joseph E. Jakes; Nayomi Plaza-Rodriguez; Xavier Arzola Villegas; Charles R. Frihart

2017-01-01

The development of improved moisture-durable wood adhesives for outdoor applications, such as repairing historic covered bridges, is hindered by an incomplete mechanistic understanding of what makes a wood–adhesive bond moisture-durable. The wood–adhesive bondline is extraordinarily difficult to study because of the chemical, structural, and mechanical complexities and...

The effect of polarity of extractives on the durability of wood

Treesearch

Roderquita K. Moore; Jonathan Smaglick; Erick Arellano-ruiz; Michael Leitch; Doreen Mann

2015-01-01

Extractives are low molecular weight compounds and regarded as nonstructural wood constituents. These compounds are present in trees and can be extracted by organic solvents. Extractives consist of several classes of compounds that diversify the biological function of the tree. Fats are an energy source for the wood cells whereas terpenoids, resin acids, and phenolic...

The role of boron in flame-retardant treatments

Treesearch

S. L. LeVan; H. C. Tran

1990-01-01

Flame retardants for wood alter the combustion properties of wood to reduce surface flame spread. Flame retardant chemicals cause acid catalyzed dehydration reactions in wood to facilitate the formation of char and reduce the effective heat of combustion, resulting in lower heat release and flame spread. Boron compounds can also form glassy fiis that may inhibit mass...

Effect of Bioenergy Demands and Supply Response on Markets, Carbon, and Land Use

Treesearch

Karen L. Abt; Robert C. Abt; Christopher Galik

2012-01-01

An increase in the demand for wood for energy, including liquid fuels, bioelectricity, and pellets, has the potential to affect traditional wood users, forestland uses, management intensities, and, ultimately, carbon sequestration. Recent studies have shown that increases in bioenergy harvests could lead to displacement of traditional wood-using industries in the short...

Performance of two solid fumigants in covered bridges

Treesearch

Matthew J. Konkler; Mark A. Newbill; Stan Lebow; Jeffrey J. Morrell

2017-01-01

The potential for two solid wood fumigants, dazomet and methylisothiocyanate (MITC), to move through wood at levels sufficient to arrest decay in covered bridges was assessed. Dazomet alone failed to decompose to MITC and move into the wood at effective levels, probably because too little moisture was available for breakdown. Adding a copper accelerant improved dazomet...

Investigating interphase development is wood polymer composites by inverse gas chromatography

Treesearch

Timothy G. Rials; John Simonsen

2000-01-01

The influence of secondary interactions on the development of interfacial structure in composites of wood and amorphous thermoplastic polymers is not well understood. This study used inverse gas chromatography to investigate the effect of different polymers on the surfirce energy of partially or fully coated white pine wood meal. In this way, the development of the...

Treated wood preservatives linked to aquatic damage, human illness, and death--a societal problem.

PubMed

Edlich, Richard F; Winters, Kathryne L; Long, William B

2005-01-01

On February 12, 2002, the US Environmental Protection Agency (EPA) announced a voluntary decision by industry to move consumer use of treated lumber products away from a variety of pressure-treated wood that contains arsenate (As) by December 31, 2003, in favor of new alternative wood preservatives. Chromated copper arsenate (CCA) is a chemical mixture consisting of three pesticidal compounds (As, chromium, and copper) registered for wood preservative uses. CCA is injected into wood by a process that uses high pressure to saturate wood products with the chemical. Only people who have received the proper safety training should use CCA to treat wood products. Around the home, CCA-treated wood is commonly used for decks, walkways, fences, gazebos, boat docks, and playground equipment. Other common uses of CCA-treated wood include highway noise barriers, sign posts, utility posts, and retaining walls. As of January 1, 2004, the EPA is no longer allowing CCA products to be used to treat wood intended for any of these residential uses. This decision will facilitate the voluntary transition to new alternative wood preservatives that do not contain As in both the manufacturing and retail sectors. To its credit, the EPA has developed consumer safety information sheets, hanging signs, end signs, and bin stickers that provide comprehensive information about the dangers of CCA-treated wood, use-site, and handling precautions. The EPA has not concluded that CCA-treated wood poses any unreasonable risk to the public or the environment. Nevertheless, As is a known human carcinogen and, thus, the EPA believes that any reduction in the levels of potential exposure to As is desirable. The toxicologic manifestations have been primarily related to the effects of As exposure from drinking water sources and include the following: acute poisoning incidents, cardiovascular effects, diabetes mellitus, and cancer. Understanding the biomethylation of As is central to elucidating its action as a toxin and a carcinogen. In humans as in many other species, inorganic As is enzymatically converted to the methylated products methyl As (MAs) and dimethyl As (DMAs). The aforementioned voluntary agreement to reduce the uses of CCA-treated wood does not include a ban on the use of CCA for residential roofing. A major reason that this wood product should be banned from residential roofing is that it does not provide a Class "A" fire-rated roof system, which markedly reduce the frequency of residential roof fires.

Experimental investigation of the laser ablation process on wood surfaces

NASA Astrophysics Data System (ADS)

Panzner, M.; Wiedemann, G.; Henneberg, K.; Fischer, R.; Wittke, Th.; Dietsch, R.

1998-05-01

Processing of wood by conventional mechanical tools like saws or planes leaves behind a layer of squeezed wood only slightly adhering to the solid wood surface. Laser ablation of this layer could improve the durability of coatings and glued joints. For technical applications, thorough knowledge about the laser ablation process is necessary. Results of ablation experiments by excimer lasers, Nd:YAG lasers, and TEA-CO 2 lasers on surfaces of different wood types and cut orientations are shown. The process of ablation was observed by a high-speed camera system and optical spectroscopy. The influence of the experimental parameters are demonstrated by SEM images and measurement of the ablation rate depending on energy density. Thermal effects like melting and also carbonizing of cellulose were found for IR- and also UV-laser wavelengths. Damage of the wood surface after laser ablation was weaker for excimer lasers and CO 2-TEA lasers. This can be explained by the high absorption of wood in the ultraviolet and middle infrared spectral range. As an additional result, this technique provides an easy way for preparing wood surfaces with excellently conserved cellular structure.

Changes in the Chemical Composition and Decay Resistance of Thermally-Modified Hevea brasiliensis Wood

PubMed Central

2016-01-01

In this study the effect of thermal treatment on the equilibrium moisture content, chemical composition and biological resistance to decay fungi of juvenile and mature Hevea brasiliensis wood (rubber wood) was evaluated. Samples were taken from a 53-year-old rubber wood plantation located in Tabapuã, Sao Paulo, Brazil. The samples were thermally-modified at 180°C, 200°C and 220°C. Results indicate that the thermal modification caused: (1) a significant increase in the extractive content and proportional increase in the lignin content at 220°C; (2) a significant decrease in the equilibrium moisture content, holocelluloses, arabinose, galactose and xylose content, but no change in glucose content; and (3) a significant increase in wood decay resistance against both Pycnoporus sanguineus (L.) Murrill and Gloeophyllum trabeum (Pers.) Murrill decay fungi. The greatest decay resistance was achieved from treatment at 220°C which resulted in a change in wood decay resistance class from moderately resistant to resistant. Finally, this study also demonstrated that the influence of thermal treatment in mature wood was lower than in juvenile wood. PMID:26986200

Factors affecting sodium hypochlorite extraction of CCA from treated wood.

PubMed

Gezer, E D; Cooper, P A

2009-12-01

Significant amounts of chromated copper arsenate (CCA) treated wood products, such as utility poles and residential construction wood, remain in service. There is increasing public concern about environmental contamination from CCA-treated wood when it is removed from service for reuse or recycling, placed in landfills or burned in commercial incinerators. In this paper, we investigated the effects of time, temperature and sodium hypochlorite concentration on chromium oxidation and extraction of chromated copper arsenate from CCA-treated wood (Type C) removed from service. Of the conditions evaluated, reaction of milled wood with sodium hypochlorite for one hour at room temperature followed by heating at 75 degrees C for two hours gave the highest extraction efficiency. An average of 95% Cr, 99% Cu and 96% As could be removed from CCA-treated, milled wood by this process. Most of the extracted chromium was oxidized to the hexavalent state and could therefore be recycled in a CCA treating solution. Sodium hypochlorite extracting solutions could be reused several times to extract CCA components from additional treated wood samples.

Higher fungal diversity is correlated with lower CO2 emissions from dead wood in a natural forest.

PubMed

Yang, Chunyan; Schaefer, Douglas A; Liu, Weijie; Popescu, Viorel D; Yang, Chenxue; Wang, Xiaoyang; Wu, Chunying; Yu, Douglas W

2016-08-24

Wood decomposition releases almost as much CO2 to the atmosphere as does fossil-fuel combustion, so the factors regulating wood decomposition can affect global carbon cycling. We used metabarcoding to estimate the fungal species diversities of naturally colonized decomposing wood in subtropical China and, for the first time, compared them to concurrent measures of CO2 emissions. Wood hosting more diverse fungal communities emitted less CO2, with Shannon diversity explaining 26 to 44% of emissions variation. Community analysis supports a 'pure diversity' effect of fungi on decomposition rates and thus suggests that interference competition is an underlying mechanism. Our findings extend the results of published experiments using low-diversity, laboratory-inoculated wood to a high-diversity, natural system. We hypothesize that high levels of saprotrophic fungal biodiversity could be providing globally important ecosystem services by maintaining dead-wood habitats and by slowing the atmospheric contribution of CO2 from the world's stock of decomposing wood. However, large-scale surveys and controlled experimental tests in natural settings will be needed to test this hypothesis.

Higher fungal diversity is correlated with lower CO2 emissions from dead wood in a natural forest

PubMed Central

Yang, Chunyan; Schaefer, Douglas A.; Liu, Weijie; Popescu, Viorel D.; Yang, Chenxue; Wang, Xiaoyang; Wu, Chunying; Yu, Douglas W.

2016-01-01

Wood decomposition releases almost as much CO2 to the atmosphere as does fossil-fuel combustion, so the factors regulating wood decomposition can affect global carbon cycling. We used metabarcoding to estimate the fungal species diversities of naturally colonized decomposing wood in subtropical China and, for the first time, compared them to concurrent measures of CO2 emissions. Wood hosting more diverse fungal communities emitted less CO2, with Shannon diversity explaining 26 to 44% of emissions variation. Community analysis supports a ‘pure diversity’ effect of fungi on decomposition rates and thus suggests that interference competition is an underlying mechanism. Our findings extend the results of published experiments using low-diversity, laboratory-inoculated wood to a high-diversity, natural system. We hypothesize that high levels of saprotrophic fungal biodiversity could be providing globally important ecosystem services by maintaining dead-wood habitats and by slowing the atmospheric contribution of CO2 from the world’s stock of decomposing wood. However, large-scale surveys and controlled experimental tests in natural settings will be needed to test this hypothesis. PMID:27553882

Small-angle x-ray scattering investigation of the effect of heating temperature on the submicroscopic pore structure of wood charcoal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmidt, P.W.; Cutter, B.E.; Kalliat, M.

1984-04-01

In order to learn about the effects of higher preparation temperatures, we recently examined a series of charcoals from black cherry (Prunus serotina Ehrh.) wood heated to temperatures from 600/sup 0/ to 2000/sup 0/C. The results are summarized in this report. In addition to obtaining some information about the pore structure of black cherry charcoal, we have developed a general picture of how the charcoal porosity depends on the temperature to which the wood was heated during pyrolysis. These results have led us to propose that the macropores in charcoals are similar to those in wood and that the mainmore » effect which pyrolysis at temperatures above 400/sup 0/C exerts on the pore structure is to cause the micropores and transitional pores to grow, while leaving the macropores almost unchanged.« less

Gibberellin is required for the formation of tension wood and stem gravitropism in Acacia mangium seedlings

PubMed Central

Nugroho, Widyanto Dwi; Yamagishi, Yusuke; Nakaba, Satoshi; Fukuhara, Shiori; Begum, Shahanara; Marsoem, Sri Nugroho; Ko, Jae-Heung; Jin, Hyun-O; Funada, Ryo

2012-01-01

Background and Aims Angiosperm trees generally form tension wood on the upper sides of leaning stems. The formation of tension wood is an important response to gravitational stimulus. Gibberellin appears to be involved in the differentiation of secondary xylem, but it remains unclear whether gibberellin plays a key role in the formation of tension wood and plant gravitropism. Therefore, a study was designed to investigate the effects of gibberellin and of inhibitors of the synthesis of gibberellin, namely paclobutrazole and uniconazole-P, on the formation of tension wood and negative stem gravitropism in Acacia mangium seedlings. Methods Gibberellic acid (GA3), paclobutrazole and uniconazole-P were applied to seedlings via the soil in which they were growing. Distilled water was applied similarly as a control. Three days after such treatment, seedlings were tilted at an angle of 45° from the vertical, and samples of stems were collected for analysis 2 weeks, 2 months and 6 months after tilting. The effects of treatments on the stem recovery degree (Rº) were analysed as an index of the negative gravitropism of seedlings, together the width of the region of tension wood in the upper part of inclined stems. Key Results It was found that GA3 stimulated the negative gravitropism of tilted seedling stems of A. mangium, while paclobutrazole and uniconazole-P inhibited recovery to vertical growth. Moreover, GA3 stimulated the formation of tension wood in tilted A. mangium seedlings, while paclobutrazole and uniconazole-P strongly suppressed the formation of tension wood, as assessed 2 weeks after tilting. Conclusions The results suggest that gibberellin plays an important role at the initial stages of formation of tension wood and in stem gravitropism in A. mangium seedlings in response to a gravitational stimulus. PMID:22843341

Gibberellin is required for the formation of tension wood and stem gravitropism in Acacia mangium seedlings.

PubMed

Nugroho, Widyanto Dwi; Yamagishi, Yusuke; Nakaba, Satoshi; Fukuhara, Shiori; Begum, Shahanara; Marsoem, Sri Nugroho; Ko, Jae-Heung; Jin, Hyun-O; Funada, Ryo

2012-09-01

Angiosperm trees generally form tension wood on the upper sides of leaning stems. The formation of tension wood is an important response to gravitational stimulus. Gibberellin appears to be involved in the differentiation of secondary xylem, but it remains unclear whether gibberellin plays a key role in the formation of tension wood and plant gravitropism. Therefore, a study was designed to investigate the effects of gibberellin and of inhibitors of the synthesis of gibberellin, namely paclobutrazole and uniconazole-P, on the formation of tension wood and negative stem gravitropism in Acacia mangium seedlings. Gibberellic acid (GA(3)), paclobutrazole and uniconazole-P were applied to seedlings via the soil in which they were growing. Distilled water was applied similarly as a control. Three days after such treatment, seedlings were tilted at an angle of 45° from the vertical, and samples of stems were collected for analysis 2 weeks, 2 months and 6 months after tilting. The effects of treatments on the stem recovery degree (Rº) were analysed as an index of the negative gravitropism of seedlings, together the width of the region of tension wood in the upper part of inclined stems. It was found that GA(3) stimulated the negative gravitropism of tilted seedling stems of A. mangium, while paclobutrazole and uniconazole-P inhibited recovery to vertical growth. Moreover, GA(3) stimulated the formation of tension wood in tilted A. mangium seedlings, while paclobutrazole and uniconazole-P strongly suppressed the formation of tension wood, as assessed 2 weeks after tilting. The results suggest that gibberellin plays an important role at the initial stages of formation of tension wood and in stem gravitropism in A. mangium seedlings in response to a gravitational stimulus.

Wood decomposition as influenced by invertebrates.

PubMed

Ulyshen, Michael D

2016-02-01

The diversity and habitat requirements of invertebrates associated with dead wood have been the subjects of hundreds of studies in recent years but we still know very little about the ecological or economic importance of these organisms. The purpose of this review is to examine whether, how and to what extent invertebrates affect wood decomposition in terrestrial ecosystems. Three broad conclusions can be reached from the available literature. First, wood decomposition is largely driven by microbial activity but invertebrates also play a significant role in both temperate and tropical environments. Primary mechanisms include enzymatic digestion (involving both endogenous enzymes and those produced by endo- and ectosymbionts), substrate alteration (tunnelling and fragmentation), biotic interactions and nitrogen fertilization (i.e. promoting nitrogen fixation by endosymbiotic and free-living bacteria). Second, the effects of individual invertebrate taxa or functional groups can be accelerative or inhibitory but the cumulative effect of the entire community is generally to accelerate wood decomposition, at least during the early stages of the process (most studies are limited to the first 2-3 years). Although methodological differences and design limitations preclude meta-analysis, studies aimed at quantifying the contributions of invertebrates to wood decomposition commonly attribute 10-20% of wood loss to these organisms. Finally, some taxa appear to be particularly influential with respect to promoting wood decomposition. These include large wood-boring beetles (Coleoptera) and termites (Termitoidae), especially fungus-farming macrotermitines. The presence or absence of these species may be more consequential than species richness and the influence of invertebrates is likely to vary biogeographically. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Tomography reconstruction methods for damage diagnosis of wood structure in construction field

NASA Astrophysics Data System (ADS)

Qiu, Qiwen; Lau, Denvid

2018-03-01

The structural integrity of wood building element plays a critical role in the public safety, which requires effective methods for diagnosis of internal damage inside the wood body. Conventionally, the non-destructive testing (NDT) methods such as X-ray computed tomography, thermography, radar imaging reconstruction method, ultrasonic tomography, nuclear magnetic imaging techniques, and sonic tomography have been used to obtain the information about the internal structure of wood. In this paper, the applications, advantages and disadvantages of these traditional tomography methods are reviewed. Additionally, the present article gives an overview of recently developed tomography approach that relies on the use of mechanical and electromagnetic waves for assessing the structural integrity of wood buildings. This developed tomography reconstruction method is believed to provide a more accurate, reliable, and comprehensive assessment of wood structural integrity

Effect of prenatal exposure to kitchen fuel on birth weight.

PubMed

Kadam, Yugantara Ramesh; Mimansa, Anugya; Chavan, Pragati Vishnu; Gore, Alka Dilip

2013-10-01

Maternal exposure to kitchen fuel smoke may lead to impaired fetal growth. To study the effect of exposure to various kitchen fuels on birth weight. Retrospective analytical. Hospital based. Mothers and their newborns. Mothers registered in first trimester with minimum 3 visits, non-anemic, full-term, and singleton delivery. History of Pregnancy Induced Hypertension (PIH), Diabetes Mellitus (DM), tobacco chewers or mishri users. 328 mothers and their new-borne. Six months. Study tools: Chi-square, Z-test, ANOVA, and binary logistic regression. Effect of confounders on birth weight was tested and found to be non-significant. Mean ± SD of birth weight was 2.669 ± 0.442 in Liquid Petroleium Gas (LPG) users (n = 178), 2.465 ± 0.465 in wood users (n = 94), 2.557 ± 0.603 in LPG + wood users (n = 27) and 2.617 ± 0.470 in kerosene users (n = 29). Infants born to wood users had lowest birth weight and averagely 204 g lighter than LPG users (F = 4.056, P < 0.01). Percentage of newborns with low birth weight (LBW) in wood users was 44.68% which was significantly higher than in LPG users (24.16%), LPG + wood users (40.74%) and in kerosene users (34.48%) (Chi-square = 12.926, P < 0.01). As duration of exposure to wood fuel increases there is significant decline in birth weight (F = 3.825, P < 0.05). By using logistic regression type of fuel is only best predictor. Cooking with wood fuel is a significant risk-factor for LBW, which is modifiable.

A study of Lusitano mare lactation curve with Wood's model.

PubMed

Santos, A S; Silvestre, A M

2008-02-01

Milk yield and composition data from 7 nursing Lusitano mares (450 to 580 kg of body weight and 2 to 9 parities) were used in this study (5 measurements per mare for milk yield and 8 measurements for composition). Wood's lactation model was used to describe milk fat, protein, and lactose lactation curves. Mean values for the concentration of major milk components across the lactation period (180 d) were 5.9 g/kg of fat, 18.4 g/kg of protein, and 60.8 g/kg of lactose. Milk fat and protein (g/kg) decreased and lactose (g/kg) increased during the 180 d of lactation. Curves for milk protein and lactose yields (g) were similar in shape to the milk yield curve; protein yield peaked at 307 g on d 10 and lactose peaked at 816 g on d 45. The fat (g) curve was different in shape compared with milk, protein, and lactose yields. Total production of the major milk constituents throughout the 180 d of lactation was estimated to be 12.0, 36.1, and 124 kg for fat, protein, and lactose, respectively. The algebraic model fitted by a nonlinear regression procedure to the data resulted in reasonable prediction curves for milk yield (R(a)(2) of 0.89) and the major constituents (R(a)(2) ranged from 0.89 to 0.95). The lactation curves of major milk constituents in Lusitano mares were similar, both in shape and values, to those found in other horse breeds. The established curves facilitate the estimation of milk yield and variation of milk constituents at different stages of lactation for both nursing and dairy mares, providing important information relative to weaning time and foal supplementation.

Structural development of redwood branches and its effects on wood growth.

PubMed

Kramer, Russell D; Sillett, Stephen C; Carroll, Allyson L

2014-03-01

Redwood branches provide all the carbohydrates for the most carbon-heavy forests on Earth, and recent whole-tree measurements have quantified trunk growth rates associated with complete branch inventories. Providing all of a tree's photosynthetic capacity, branches represent an increasing proportion of total aboveground wood production as trees enlarge. To examine branch development and its effects on wood volume growth, we dissected 31 branches from eight Sequoia sempervirens (D. Don) Endl. and seven Sequoiadendron giganteum Lindl. trees. The cambium-area-to-leaf-area ratio was maintained with size and age but increased with light availability, whereas the heartwood-deposition-area-to-leaf-area ratio increased with size and age but was insensitive to light availability. The proportion of foliage mass arrayed in <1-cm-diameter epicormic shoots increased with decreasing light and was higher in Sequoia (20-60%) than in Sequoiadendron (3-16%). Well-illuminated branches concentrated leaves higher and distally, while shaded branches distributed leaves lower and proximally. In similar light environments, older branches distributed leaves lower and more proximally than younger branches. Branch size, light, species, heartwood area, a heartwood-area-species interaction, and ovulate cone mass predicted 87.5% of the variability in wood volume growth of branches. After accounting for the positive effects of size and light, wood volume growth declined with heartwood area and age. The effect of age was trivial compared to the effect of heartwood area, suggesting that heartwood expansion caused the age-related decline in wood volume growth. Additionally, Sequoiadendron branches of similar size and light environment with more ovulate cones produced less wood, even though these cones were long-lived and photosynthetic, reflecting the energetic cost of seed production. These results contributed to a conceptual model of branch development in which light availability, injury, heartwood content, gravity, and time interact to produce the high degree of branch structural variation evident within redwood crowns.

On the Encoding of Panoramic Visual Scenes in Navigating Wood Ants.

PubMed

Buehlmann, Cornelia; Woodgate, Joseph L; Collett, Thomas S

2016-08-08

A natural visual panorama is a complex stimulus formed of many component shapes. It gives an animal a sense of place and supplies guiding signals for controlling the animal's direction of travel [1]. Insects with their economical neural processing [2] are good subjects for analyzing the encoding and memory of such scenes [3-5]. Honeybees [6] and ants [7, 8] foraging from their nest can follow habitual routes guided only by visual cues within a natural panorama. Here, we analyze the headings that ants adopt when a familiar panorama composed of two or three shapes is manipulated by removing a shape or by replacing training shapes with unfamiliar ones. We show that (1) ants recognize a component shape not only through its particular visual features, but also by its spatial relation to other shapes in the scene, and that (2) each segmented shape [9] contributes its own directional signal to generating the ant's chosen heading. We found earlier that ants trained to a feeder placed to one side of a single shape [10] and tested with shapes of different widths learn the retinal position of the training shape's center of mass (CoM) [11, 12] when heading toward the feeder. They then guide themselves by placing the shape's CoM in the remembered retinal position [10]. This use of CoM in a one-shape panorama combined with the results here suggests that the ants' memory of a multi-shape panorama comprises the retinal positions of the horizontal CoMs of each major component shape within the scene, bolstered by local descriptors of that shape. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of ionic liquid treatment on the ultrastructural and topochemical features of compression wood in Japanese cedar (Cryptomeria japonica).

PubMed

Kanbayashi, Toru; Miyafuji, Hisashi

2016-07-18

The morphological and topochemical changes in wood tissues in compression wood of Japanese cedar (Cryptomeria japonica) upon treated with two types of ionic liquids, 1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]) and 1-ethylpyridinium bromide ([EtPy][Br]) were investigated. Compression wood tracheids were swollen by both ionic liquids but their swelling behaviors were different in the types of ionic liquids used. Under the polarized light, we confirmed that crystalline cellulose in compression wood is amorphized by [C2mim][Cl] treatment whereas it changes slightly by [EtPy][Br] treatment. Raman microscopic analyses revealed that [C2mim][Cl] can preferentially liquefy polysaccharides in compression wood whereas [EtPy][Br] liquefy lignin. In addition, the interaction of compression wood with ionic liquids is different for the morphological regions. These results will assist in the use of ionic liquid treatment of woody biomass to produce valuable chemicals, bio-fuels, bio-based composites and other products.

Effect of ionic liquid treatment on the ultrastructural and topochemical features of compression wood in Japanese cedar (Cryptomeria japonica)

PubMed Central

Kanbayashi, Toru; Miyafuji, Hisashi

2016-01-01

The morphological and topochemical changes in wood tissues in compression wood of Japanese cedar (Cryptomeria japonica) upon treated with two types of ionic liquids, 1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]) and 1-ethylpyridinium bromide ([EtPy][Br]) were investigated. Compression wood tracheids were swollen by both ionic liquids but their swelling behaviors were different in the types of ionic liquids used. Under the polarized light, we confirmed that crystalline cellulose in compression wood is amorphized by [C2mim][Cl] treatment whereas it changes slightly by [EtPy][Br] treatment. Raman microscopic analyses revealed that [C2mim][Cl] can preferentially liquefy polysaccharides in compression wood whereas [EtPy][Br] liquefy lignin. In addition, the interaction of compression wood with ionic liquids is different for the morphological regions. These results will assist in the use of ionic liquid treatment of woody biomass to produce valuable chemicals, bio-fuels, bio-based composites and other products. PMID:27426470

Preparation of Desirable Porous Cell Structure Polylactide/Wood Flour Composite Foams Assisted by Chain Extender

PubMed Central

Wang, Youyong; Song, Yongming; Du, Jun; Xi, Zhenhao; Wang, Qingwen

2017-01-01

Polylactide (PLA)/wood flour composite foam were prepared through a batch foaming process. The effect of the chain extender on the crystallization behavior and dynamic rheological properties of the PLA/wood flour composites were investigated as well as the crystal structure and cell morphology of the composite foams. The incorporation of the chain extender enhanced the complex viscosity and storage modulus of PLA/wood flour composites, indicating the improved melt elasticity. The chain extender also led to a decreased crystallization rate and final crystallinity of PLA/wood flour composites. With an increasing chain extender content, a finer and more uniform cell structure was formed, and the expansion ratio of PLA/wood flour composite foams was much higher than without the chain extender. Compared to the unfoamed composites, the crystallinity of the foamed PLA/wood flour composites was improved and the crystal was loosely packed. However, the new crystalline form was not evident. PMID:28846604

Insights on wood combustion generated proinflammatory ultrafine particles (UFP).

PubMed

Corsini, Emanuela; Ozgen, Senem; Papale, Angela; Galbiati, Valentina; Lonati, Giovanni; Fermo, Paola; Corbella, Lorenza; Valli, Gianluigi; Bernardoni, Vera; Dell'Acqua, Manuela; Becagli, Silvia; Caruso, Donatella; Vecchi, Roberta; Galli, Corrado L; Marinovich, Marina

2017-01-15

This study aimed to collect, characterize ultrafine particles (UFP) generated from the combustion of wood pellets and logs (softwood and hardwood) and to evaluate their pro-inflammatory effects in THP-1 and A549 cells. Both cell lines responded to UFP producing interleukin-8 (IL-8), with wood log UFP being more active compared to pellet UFP. With the exception of higher effect observed with beech wood log UFP in THP-1, the ability of soft or hard woods to induce IL-8 release was similar. In addition, on weight mass, IL-8 release was similar or lower compared to diesel exhaust particles (DEP), arguing against higher biological activity of smaller size particles. UFP-induced IL-8 could be reduced by SB203580, indicating a role of p38MAPK activation in IL-8 production. The higher activity of beech wood log UFP in THP-1 was not due to higher uptake or endotoxin contamination. Qualitatively different protein adsorption profiles were observed, with less proteins bound to beech UFP compared to conifer UFP or DEP, which may provide higher intracellular availability of bioactive components, i.e. levoglucosan and galactosan, toward which THP-1 were more responsive compared to A549 cells. These results contribute to our understanding of particles emitted by domestic appliances and their biological effects. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Spatial heterogeneity in post-dispersal predation on Prunus and Uvularia seeds.

PubMed

Webb, Sara L; Willson, Mary F

1985-08-01

We investigated effects of seed density, distance from parent, and habitat (woods, open field) on post-dispersal predation risk (chiefly by rodents) for seeds of Prunus virginiana (Rosaceae). Additional study of the habitat effect (woods, open field, treefall gap) was made with seeds of Prunus avium (Rosaceae) and Uvularia grandiflora (Liliaceae). Density of Prunus seeds (range 2-40 seeds/group) did not affect predation risk for individual seeds. Distance from parent plants did influence predation risk, which was greatest directly beneath parents. This distance effect primarily comprised a sharp drop in risk within 2 m of parents, a distance too small to generate a "spacing rule" for conspecifics.We found that habitat strongly influenced predation intensity. Rates of removal of Prunus seeds were higher in woods than in open fields, except when overall predation intensity was very low and no pattern could be discerned. Prunus seed removal rates were higher in closed woods than in treefall gaps. Consequently, a Prunus seed will more likely escape predation if dispersed to an open site. In contrast, Uvularia seed removal rates were higher in open fields than in woods but did not differ between closed woods and tree-fall gaps.Predation intensity was spatially patchy between and within experimental arrays, but was consistent over time at some specific points in space, possibly reflecting home ranges of seed predators.

Determination of chemical changes in heat-treated wood using ATR-FTIR and FT Raman spectrometry

NASA Astrophysics Data System (ADS)

Özgenç, Özlem; Durmaz, Sefa; Boyaci, Ismail Hakki; Eksi-Kocak, Haslet

2017-01-01

In this study, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) and Fourier-transform Raman (FT-Raman) spectroscopy techniques were used to determine changes in the chemical structure of heat-treated woods. For this purpose, scots pine (Pinus sylvestris L.), oriental beech (Fagus orientalis L.), and oriental spruce (Picea orientalis L.) wood species were heat-treated at different temperatures. The effect of chemical changes on the FT-Raman and ATR-FTIR bands or ratios of heat-treated wood was related with the OH association of cellulose, functional groups, and the aromatic system of lignin. The effects of heat treatment on the carbohydrate and lignin peaks varied depending on the wood species. The spectral changes that occurred after heat treatment reflected the progress of the condensation reaction of lignin. Degradation of hemicelluloses led to a decrease in free hydroxyl groups. High temperature caused crystalline cellulose to increase due to the degradation of amorphous cellulose.

Determination of chemical changes in heat-treated wood using ATR-FTIR and FT Raman spectrometry.

PubMed

Özgenç, Özlem; Durmaz, Sefa; Boyaci, Ismail Hakki; Eksi-Kocak, Haslet

2017-01-15

In this study, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) and Fourier-transform Raman (FT-Raman) spectroscopy techniques were used to determine changes in the chemical structure of heat-treated woods. For this purpose, scots pine (Pinus sylvestris L.), oriental beech (Fagus orientalis L.), and oriental spruce (Picea orientalis L.) wood species were heat-treated at different temperatures. The effect of chemical changes on the FT-Raman and ATR-FTIR bands or ratios of heat-treated wood was related with the OH association of cellulose, functional groups, and the aromatic system of lignin. The effects of heat treatment on the carbohydrate and lignin peaks varied depending on the wood species. The spectral changes that occurred after heat treatment reflected the progress of the condensation reaction of lignin. Degradation of hemicelluloses led to a decrease in free hydroxyl groups. High temperature caused crystalline cellulose to increase due to the degradation of amorphous cellulose. Copyright © 2016 Elsevier B.V. All rights reserved.

The effects of heat treatment on technological properties in Red-bud maple (Acer trautvetteri Medw.) wood.

PubMed

Korkut, Süleyman; Kök, M Samil; Korkut, Derya Sevim; Gürleyen, Tuğba

2008-04-01

Heat treatment is often used to improve the dimensional stability of wood. In this study, the effects of heat treatment on technological properties of Red-bud maple (Acer trautvetteri Medw.) wood were examined. Samples obtained from Düzce Forest Enterprises, Turkey, were subjected to heat treatment at varying temperatures (120 degrees C, 150 degrees C and 180 degrees C) and for varying durations (2h, 6h and 10h). The technological properties of heat-treated wood samples and control samples were tested. Compression strength parallel to grain, bending strength, modulus of elasticity in bending, janka-hardness, impact bending strength, and tension strength perpendicular to grain were determined. The results showed that technological strength values decreased with increasing treatment temperature and treatment times. Red-bud maple wood could be utilized by using proper heat treatment techniques with minimal losses in strength values in areas where working, and stability such as in window frames, are important factors.

Mechanical properties of small-scale laminated wood composite poles: effects of taper and webs

Treesearch

Cheng Piao; Todd F. Shupe; R.C. Tang; Chung Y. Hse

2006-01-01

Laminated hollow wood composite poles represent an efficient utilization of the timber resource and a promising alternative for solid poles that are commonly used in the power transmission and telecommunication lines. The objective of this study was to improve the performance of composite poles by introducing the bio-mimicry concept into the design of hollow wood...

Thermal degradation of fire-retardant -treated wood : predicting residual service life

Treesearch

Jerrold E. Winandy

2001-01-01

This paper presents a review of more than 10 years of research on the effects of fire-retardant treatments on wood properties and the potential of these treatments for in-service degradation when exposed to elevated temperatures. It presents an in-depth discussion of the findings and implications of a major wood engineering research program to assess the current...

Effects of riparian buffer width on wood loading in headwater streams after repeated forest thinning

Treesearch

Julia I. Burton; Deanna H. Olson; Klaus J. Puettmann

2016-01-01

Forested riparian buffer zones are used in conjunction with upland forest management, in part, to provide for the recruitment for large wood to streams. Small headwater streams account for the majority of stream networks in many forested regions. Yet, our understanding of how riparian buffer width influences wood dynamics in headwater streams is relatively less...

Modeling temperature and moisture state effects on acoustic velocity in wood

Treesearch

Shan Gao; X. Wang; L. Wang; R.B. Bruce

2011-01-01

Previous research has proved the concept of acoustic wave propagation methods for evaluating wood quality of trees and logs during forest operations. As commercial acoustic equipment is implemented in field for various purposes, one has to consider the influence of operating temperature on acoustic velocity — a key parameter for wood property prediction. Our field...

Nanoindentation of the interphase region of a wood-reinforced polypropylene composite

Treesearch

Joseph E. Jakes; John C. Hermanson; Donald S. Stone

2007-01-01

The interphase region of a wood-reinforced polypropylene (PP) composite was investigated with nanoindentation techniques capable of separating intrinsic properties of PP in the interphase region from the effect of elastic discontinuity caused by the nearby wood cell wall. From data collected in this experiment, no differences in hardness or Young’s modulus for PP were...

Effect of Intensive Forest Management Practices on Wood Properties and Pulp Yield of Young, Fast Growing Southern Pine

Treesearch

Timothy D. Faust; Alexander Clark; Charles E. Courchene; Barry D. Shiver; Monique L. Belli

1999-01-01

The demand for southern pine fiber is increasing. However, the land resources to produce wood fiber are decreasing. The wood industry is now using intensive cultural treatments, such as competition control, fertilization, and short rotations, to increase fiber production. The impact of these intensive environmental treatments on increased growth is positive and...

The effects of different silane crosslinking approaches on composites of polyethylene blends and wood flour

Treesearch

Craig M. Clemons; Ronald C. Sabo; Kolby C. Hirth

2011-01-01

Though silane chemistry has been used to crosslink unfilled polyethylene for many years, such crosslinking has only been recently applied to wood plastic composites to improve properties such as creep resistance. However, the presence of wood significantly changes the silane chemistry and a greater understanding is necessary for optimal processing and performance. We...

Effects of species information and furniture price on consumer preferences for selected woods

Treesearch

Matthew Bumgardner; David Nicholls; Geoffrey Donovan

2007-01-01

Changing consumer tastes and species availability are influencing the design and manufacture of hardwood products. In addition, the globalization of wood product markets is exposing U.S. consumers to new species. This research evaluates consumer preferences for six domestic wood species--three from the eastern United States and three from the western United States. The...

Rapid microwave-assisted acid extraction of metals from chromated copper arsenate (CCA)-treated southern pine wood

Treesearch

Bin Yu; Chung Y. Hse; Todd F. Shupe

2009-01-01

The effects of acid concentration, reaction time, and temperature in a microwave reactor on recovery of CCA-treated wood were evaluated. Extraction of copper, chromium, and arsenic metals from chromated copper arsenate (CCA)-treated southern pine wood samples with three different acids (i.e., acetic acid, oxalic acid, and phosphoric acid) was investigated using in...

Analysis of off-axis tension test of wood specimens

Treesearch

Jen Y. Liu

2002-01-01

This paper presents a stress analysis of the off-axis tension test of clear wood specimens based on orthotropic elasticity theory. The effects of Poisson's ratio and shear coupling coefficient on stress distribution are analyzed in detail. The analysis also provides a theoretical foundation for the selection of a 10° grain angle in wood specimens for the...

Oxalic acid pretreatment of rice straw particles and loblolly pine chips : release of hemicellulosic carbohydrates

Treesearch

Xianjun Li; Zhiyong Cai; Eric Horn; Jerrold E. Winandy

2011-01-01

This study was conducted to evaluate the effect of oxalic acid (OA) pretreatment on carbohydrates released from rice straw particles and wood chips. The results showed that OA treatment accelerated carbohydrates extraction from rice straw particles and wood chips. OA pretreatment dramatically increased the amount of carbohydrates extracted, up to 24 times for wood...

Microstructure change in wood cell wall fracture from mechanical pretreatment and its influence on enzymatic hydrolysis

Treesearch

Jinxue Jiang; Jinwu Wang; Xiao Zhang; Michael Wolcott

2017-01-01

tMechanical pretreatment is an effective process for chemical or biochemical conversion of woodybiomass. The deconstruction features of the wood cell wall play an important role in its chemical or bio-chemical processing. In this work, we evaluated the wood cell wall fracture in the early stage of mechanicalpretreatment process conducted with various initial moisture...

Nondestructive structural evaluation of wood floor systems with a vibration technique.

Treesearch

Xiping Wang; Robert J. Ross; Lawrence Andrew Soltis

2002-01-01

The objective of this study was to determine if transverse vibration methods could be used to effectively assess the structural integrity of wood floors as component systems. A total of 10 wood floor systems, including 3 laboratory-built floor sections and 7 in-place floors in historic buildings, were tested. A forced vibration method was applied to the floor systems...

Effects of incising on treatability and leachability of CCA-C-treated eastern hemlock

Treesearch

S. Nami Kartal

2002-01-01

Incising is used to increase exposed wood surface and improve uptake and penetration of preservative during pressure treatment of refractory species. However, incising may also cause increased leaching of preservative when the wood is placed in service. This study compared the rate of leaching from unincised eastern hemlock to that of wood that had been incised to two...

A Mixed Methods Analysis of the Effects of an Integrative Geobiological Study of Petrified Wood in Introductory College Geology Classrooms

ERIC Educational Resources Information Center

Clary, Renee M.; Wandersee, James H.

2007-01-01

Mixed methods research conducted across three semesters in introductory college geology classes (n=187, 190, 138) attempted to ascertain whether integrated study of petrified wood could serve as a portal to improved student geobiological understanding of fossilization, geologic time, and evolution. The Petrified Wood Survey[TM] was administered as…

Weathering characteristics and moisture uptake properties of wood coated with water-borne sol-gel thin films

Treesearch

M. A. Tshabalala; C. Starr; N. R. Sutherland

2010-01-01

In this study, wood specimens were coated with water-borne silsesquioxane oligomers by an in situ sol-gel deposition process. The effect of these water-borne sol-gel thin films on weathering characteristics and moisture-uptake properties of the wood specimens were investigated. The weathering characteristics were investigated by exposure of the specimens to artificial...

Inhibitory effect of essential oils on decay fungi and mold growth on wood

Treesearch

Vina W. Yang; Carol A. Clausen

2007-01-01

Structural damage and potential health risks caused by wood decay and mold fungi in residential structures have been a major concern for homeowners, building contractors and insurance companies alike. The combined damage from decay fungi and mold claims exceeds several billion US dollars annually. Protection against decay and mold growth on wood is a critical economic...

Wood reinforcement of poplar by rice NAC transcription factor

PubMed Central

Sakamoto, Shingo; Takata, Naoki; Oshima, Yoshimi; Yoshida, Kouki; Taniguchi, Toru; Mitsuda, Nobutaka

2016-01-01

Lignocellulose, composed of cellulose, hemicellulose, and lignin, in the secondary cell wall constitutes wood and is the most abundant form of biomass on Earth. Enhancement of wood accumulation may be an effective strategy to increase biomass as well as wood strength, but currently only limited research has been undertaken. Here, we demonstrated that OsSWN1, the orthologue of the rice NAC Secondary-wall Thickening factor (NST) transcription factor, effectively enhanced secondary cell wall formation in the Arabidopsis inflorescence stem and poplar (Populus tremula×Populus tremuloides) stem when expressed by the Arabidopsis NST3 promoter. Interestingly, in transgenic Arabidopsis and poplar, ectopic secondary cell wall deposition in the pith area was observed in addition to densification of the secondary cell wall in fiber cells. The cell wall content or density of the stem increased on average by up to 38% and 39% in Arabidopsis and poplar, respectively, without causing growth inhibition. As a result, physical strength of the stem increased by up to 57% in poplar. Collectively, these data suggest that the reinforcement of wood by NST3pro:OsSWN1 is a promising strategy to enhance wood-biomass production in dicotyledonous plant species. PMID:26812961

Habitat creation and biodiversity maintenance in mangrove forests: teredinid bivalves as ecosystem engineers

PubMed Central

Michie, Laura; Taylor, Ben W.

2014-01-01

Substantial amounts of dead wood in the intertidal zone of mature mangrove forests are tunnelled by teredinid bivalves. When the tunnels are exposed, animals are able to use tunnels as refuges. In this study, the effect of teredinid tunnelling upon mangrove forest faunal diversity was investigated. Mangrove forests exposed to long emersion times had fewer teredinid tunnels in wood and wood not containing teredinid tunnels had very few species and abundance of animals. However, with a greater cross-sectional percentage surface area of teredinid tunnels, the numbers of species and abundance of animals was significantly higher. Temperatures within teredinid-attacked wood were significantly cooler compared with air temperatures, and animal abundance was greater in wood with cooler temperatures. Animals inside the tunnels within the wood may avoid desiccation by escaping the higher temperatures. Animals co-existing in teredinid tunnelled wood ranged from animals found in terrestrial ecosystems including centipedes, crickets and spiders, and animals found in subtidal marine ecosystems such as fish, octopods and polychaetes. There was also evidence of breeding within teredinid-attacked wood, as many juvenile individuals were found, and they may also benefit from the cooler wood temperatures. Teredinid tunnelled wood is a key low-tide refuge for cryptic animals, which would otherwise be exposed to fishes and birds, and higher external temperatures. This study provides evidence that teredinids are ecosystem engineers and also provides an example of a mechanism whereby mangrove forests support intertidal biodiversity and nurseries through the wood-boring activity of teredinids. PMID:25276505

[Assessment of occupational exposure to wood dust in the Polish furniture industry].

PubMed

Szewczyńska, Małgorzata; Pośniak, Małgorzata

2017-02-28

Occupational exposure to wood dust can be responsible for many different harmful health effects, especially in workers employed in the wood industry. The assessment of wood dust adverse effects to humans, as well as the interpretation of its concentration measurements carried out to assess potential occupational exposure are very difficult. First of all, it is due to possible occurrence of different kind of wood dust in the workplace air, namely wood dust from dozens of species of trees belonging to 2 kinds of botanical gymnosperms and angiosperms, as well as to its different chemical composition. Total dust and respirable wood dust in the workplace air in the furniture industry was determined using the filtration-gravimetric method in accordance with Polish Standards PN-Z-04030-05:1991 and PN-Z-04030-06:1991. Air samples were collected based on the principles of individual dosimetry. Total dust concentrations were 0.84-13.92 mg/m³ and inhalable fraction concentrations, obtained after the conversion of total dust by applying a conversion factor of 1.59, were 1.34-22.13 mg/m³. Respirable fraction concentrations were 0.38-4.04 mg/m³, which makes approx. 25% of the inhalable fraction on average. The highest concentrations occurred in grinding and the lowest during milling processes of materials used in the manufacture of furniture. The results indicate that the share of respirable fraction in the inhalable fraction of wood dust is considerable. Due to the determination of the threshold limit value (TLV) for the inhalable fraction of wood dust, it is necessary to replace the previously used samplers for total dust with samplers that provide quantitative separation of wood dust inhalable fractions in accordance with the convention of this fraction as defined in PN-EN 481:1998. Med Pr 2017;68(1):45-60. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Functional relationships between wood structure and vulnerability to xylem cavitation in races of Eucalyptus globulus differing in wood density.

PubMed

Barotto, Antonio José; Monteoliva, Silvia; Gyenge, Javier; Martinez-Meier, Alejandro; Fernandez, María Elena

2018-02-01

Wood density can be considered as a measure of the internal wood structure, and it is usually used as a proxy measure of other mechanical and functional traits. Eucalyptus is one of the most important commercial forestry genera worldwide, but the relationship between wood density and vulnerability to cavitation in this genus has been little studied. The analysis is hampered by, among other things, its anatomical complexity, so it becomes necessary to address more complex techniques and analyses to elucidate the way in which the different anatomical elements are functionally integrated. In this study, vulnerability to cavitation in two races of Eucalyptus globulus Labill. with different wood density was evaluated through Path analysis, a multivariate method that allows evaluation of descriptive models of causal relationship between variables. A model relating anatomical variables with wood properties and functional parameters was proposed and tested. We found significant differences in wood basic density and vulnerability to cavitation between races. The main exogenous variables predicting vulnerability to cavitation were vessel hydraulic diameter and fibre wall fraction. Fibre wall fraction showed a direct impact on wood basic density and the slope of vulnerability curve, and an indirect and negative effect over the pressure imposing 50% of conductivity loss (P50) through them. Hydraulic diameter showed a direct negative effect on P50, but an indirect and positive influence over this variable through wood density on one hand, and through maximum hydraulic conductivity (ks max) and slope on the other. Our results highlight the complexity of the relationship between xylem efficiency and safety in species with solitary vessels such as Eucalyptus spp., with no evident compromise at the intraspecific level. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Effects of Wood Pollution on Pore-Water Sulfide Levels and Eelgrass Germination

NASA Astrophysics Data System (ADS)

Ekelem, C.

2016-02-01

Historically, sawmills released wood waste onto coastal shorelines throughout the Pacific Northwest of the USA, enriching marine sediments with organic material. The increase in organic carbon boosts the bacterial reduction of sulfate and results in the production of a toxic metabolite, hydrogen sulfide. Hydrogen sulfide is a phytotoxin and can decrease the growth and survival of eelgrass. This is a critical issue since eelgrass, Zostera marina, forms habitat for many species, stabilizes sediment, and plays a role in nutrient cycling and sediment chemistry. The objective of our study was to determine the effects of wood debris on sediment pore-water hydrogen sulfide concentrations and eelgrass germination. To test the impact of wood inputs on sulfide production and seed germination, we conducted a laboratory mesocosm experiment, adding sawdust to marine sediments and measuring the sulfide levels weekly. We subsequently planted seeds in the mesocosms and measured germination rates. Higher concentrations of sawdust led to higher levels of pore-water hydrogen sulfide and drastically slower eelgrass germination rates. Treatments with greater than 10% wood enrichment developed free sulfide concentrations of 0.815 (± 0.427) mM after 118 days, suggesting sediments with greater than 10% wood pollution may have threateningly high pore-water hydrogen sulfide levels. These results can be used to set thresholds for remediation efforts and guide seed distribution in wood polluted areas.

Properties of wood-plastic composites: effect of inorganic additives

NASA Astrophysics Data System (ADS)

Bakraji, Elias Hanna; Salman, Numan

2003-01-01

Wood-plastic composites from Syrian tree species (white poplar, cypress tree, and white willow) were prepared using gamma-ray irradiation. Dry wood was impregnated with acrylamide or butylmethacrylate at various methanol compositions as the swelling solvent. Effect of inorganic additives and co-additives such as lithium nitrate (LiNO 3), copper sulfate (CuSO 4) and sulfuric acid (H 2SO 4), used at a very low concentration (1%), on the polymer loading (PL) and the compression strength (CS) was also investigated. It has been found that all the additives and co-additives, except Cu 2+, increase the PL values and only Li + has a positive effect on CS.

Polyurethanes from fluoroalkyl propyleneglycol polyethers

NASA Technical Reports Server (NTRS)

Trischler, F. D. (Inventor)

1969-01-01

A description is given of highly stable polyurethane polymers prepared by reacting a polyether with a diisocyanate. Compounded stocks of these polymers may be shaped and cured in conventional equipment used in the rubber industry. The solutions are dispersed gels prepared from the polymers and may be used for forming supported or unsupported films for coating fabrics or solid surfaces, and for forming adhesive bonds between a wide variety of plastics, elastomers, fabrics, metals, wood, leather, ceramics and the like.

Failure of structural elements made of polymer supported composite materials during the multiyear natural aging

NASA Astrophysics Data System (ADS)

Blinkov, Pavel; Ogorodov, Leonid; Grabovyy, Peter

2018-03-01

Modern high-rise construction introduces a number of limitations and tasks. In addition to durability, comfort and profitability, projects should take into account energy efficiency and environmental problems. Polymer building materials are used as substitutes for materials such as brick, concrete, metal, wood and glass, and in addition to traditional materials. Plastic materials are light, can be formed into complex shapes, durable and low, and also possess a wide range of properties. Plastic materials are available in various forms, colors and textures and require minimal or no color. They are resistant to heat transfer and diffusion of moisture and do not suffer from metal corrosion or microbial attack. Polymeric materials, including thermoplastics, thermoset materials and wood-polymer composites, have many structural and non-structural applications in the construction industry. They provide unique and innovative solutions at a low cost, and their use is likely to grow in the future. A number of polymer composite materials form complex material compositions, which are applied in the construction in order to analyze the processes of damage accumulation under the conditions of complex nonstationary loading modes, and to determine the life of structural elements considering the material aging. This paper present the results of tests on short-term compression loading with a deformation rate of v = 2 mm/min using composite samples of various shapes and sizes.

Simulated long-term effects of varying tree retention on wood production, dead wood and carbon stock changes.

PubMed

Santaniello, Francesca; Djupström, Line B; Ranius, Thomas; Weslien, Jan; Rudolphi, Jörgen; Sonesson, Johan

2017-10-01

Boreal forests are an important source of timber and pulp wood, but provide also other products and services. Utilizing a simulation program and field data from a tree retention experiment in a Scots pine forest in central Sweden, we simulated the consequences during the following 100 years of various levels of retention on production of merchantable wood, dead wood input (as a proxy for biodiversity), and carbon stock changes. At the stand level, wood production decreased with increased retention levels, while dead wood input and carbon stock increased. We also compared 12 scenarios representing a land sharing/land sparing gradient. In each scenario, a constant volume of wood was harvested with a specific level of retention in a 100-ha landscape. The area not needed to reach the defined volume was set-aside during a 100-year rotation period, leading to decreasing area of set-asides with increasing level of retention across the 12 scenarios. Dead wood input was positively affected by the level of tree retention whereas the average carbon stock decreased slightly with increasing level of tree retention. The scenarios will probably vary in how they favor species preferring different substrates. Therefore, we conclude that a larger variation of landscape-level conservation strategies, also including active creation of dead wood, may be an attractive complement to the existing management. Copyright © 2017 Elsevier Ltd. All rights reserved.

Oceanic dispersal, vicariance and human introduction shaped the modern distribution of the termites Reticulitermes, Heterotermes and Coptotermes.

PubMed

Bourguignon, Thomas; Lo, Nathan; Šobotník, Jan; Sillam-Dussès, David; Roisin, Yves; Evans, Theodore A

2016-03-30

Reticulitermes, Heterotermes and Coptotermes form a small termite clade with partly overlapping distributions. Although native species occur across all continents, the factors influencing their distribution are poorly known. Here, we reconstructed the historical biogeography of these termites using mitochondrial genomes of species collected on six continents. Our analyses showed that Reticulitermes split from Heterotermes + Coptotermesat 59.5 Ma (49.9-69.5 Ma 95% CI), yet the oldest split within Reticulitermes(Eurasia and North America) is 16.1 Ma (13.4-19.5 Ma) and the oldest split within Heterotermes + Coptotermesis 36.0 Ma (33.9-40.5 Ma). We detected 14 disjunctions between biogeographical realms, all of which occurred within the last 34 Ma, not only after the break-up of Pangaea, but also with the continents in similar to current positions. Land dispersal over land bridges explained four disjunctions, oceanic dispersal by wood rafting explained eight disjunctions, and human introduction was the source of two recent disjunctions. These wood-eating termites, therefore, appear to have acquired their modern worldwide distribution through multiple dispersal processes, with oceanic dispersal and human introduction favoured by the ecological traits of nesting in wood and producing replacement reproductives. © 2016 The Author(s).

Oceanic dispersal, vicariance and human introduction shaped the modern distribution of the termites Reticulitermes, Heterotermes and Coptotermes

PubMed Central

Bourguignon, Thomas; Lo, Nathan; Šobotník, Jan; Sillam-Dussès, David; Roisin, Yves; Evans, Theodore A.

2016-01-01

Reticulitermes, Heterotermes and Coptotermes form a small termite clade with partly overlapping distributions. Although native species occur across all continents, the factors influencing their distribution are poorly known. Here, we reconstructed the historical biogeography of these termites using mitochondrial genomes of species collected on six continents. Our analyses showed that Reticulitermes split from Heterotermes + Coptotermes at 59.5 Ma (49.9–69.5 Ma 95% CI), yet the oldest split within Reticulitermes (Eurasia and North America) is 16.1 Ma (13.4–19.5 Ma) and the oldest split within Heterotermes + Coptotermes is 36.0 Ma (33.9–40.5 Ma). We detected 14 disjunctions between biogeographical realms, all of which occurred within the last 34 Ma, not only after the break-up of Pangaea, but also with the continents in similar to current positions. Land dispersal over land bridges explained four disjunctions, oceanic dispersal by wood rafting explained eight disjunctions, and human introduction was the source of two recent disjunctions. These wood-eating termites, therefore, appear to have acquired their modern worldwide distribution through multiple dispersal processes, with oceanic dispersal and human introduction favoured by the ecological traits of nesting in wood and producing replacement reproductives. PMID:27030416

Incidence of bark- and wood-boring insects in firewood: a survey at Michigan's Mackinac Bridge.

PubMed

Haack, Robert A; Petrice, Toby R; Wiedenhoeft, Alex C

2010-10-01

Firewood is a major pathway for the inadvertent movement of bark- and wood-infesting insects. After discovery of Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) in southeastern Michigan in 2002, quarantines were enacted including prohibition of transporting firewood across the Mackinac Bridge between Michigan's Lower and Upper peninsulas. Drivers are required to surrender firewood before crossing the bridge. We surveyed recently surrendered firewood in April, July, and September 2008 and categorized it by genus, cross-sectional shape (whole, half, or quarter), approximate age (years since it was a live tree), presence of bark, and evidence of bark- and wood-boring insects. The 1045 pieces of firewood examined represented 21 tree genera: primarily Acer (30%), Quercus (18%), Fraxinus (15%), Ulmus (12%), Betula (5%), and Prunus (5%). Live borers (Bostrichoidea, Brentidae, Buprestidae, Cerambycidae, Cossidae, Curculionidae [Scolytinae and non-Scolytinae], and Siricidae) were found in 23% of the pieces and another 41% had evidence of previous borer infestation. Of the 152 Fraxinus firewood pieces, 13% had evidence of past A. planipennis infestation, but we found no live A. planipennis. We discuss national "don't move firewood" campaigns and U.S. imports of fuelwood. During 1996-2009, the United States imported fuelwood valued at > dollars U.S. 98 million from 34 countries.

Effects of Sleep on Training Effectiveness in Soldiers at Fort Leonard Wood, Missouri

DTIC Science & Technology

2010-11-01

Jarrett, & Kupfer, 1992; Selvi , Gulec, Agargun, & Besiroglu, 2007; Taub & Berger, 1973; Wood & Magnello, 1992). For example, Boivin and colleagues......of partial sleep deprivation on mood, with morning chronotypes exhibiting less sensitivity of mood. A pattern similar to that described by Selvi

Effect of surface preparation on gas permeability of wood

Treesearch

E.T. Choong; C.W. McMillin; F.O. Tesoro

1975-01-01

Surface preparation has a profound effect on the rate of flow of fluid through wood, particularly in the longitudinal direction of flow. For best results, the surface must be devoid of any debris and/or obstruction. The use of a sharp, thin knife appears to be an effective way of preparing samples for natural permeability measurements.

Mechanical, Thermomechanical and Reprocessing Behavior of Green Composites from Biodegradable Polymer and Wood Flour

PubMed Central

Morreale, Marco; Liga, Antonio; Mistretta, Maria Chiara; Ascione, Laura; La Mantia, Francesco Paolo

2015-01-01

The rising concerns in terms of environmental protection and the search for more versatile polymer-based materials have led to an increasing interest in the use of polymer composites filled with natural organic fillers (biodegradable and/or coming from renewable resources) as a replacement for traditional mineral inorganic fillers. At the same time, the recycling of polymers is still of fundamental importance in order to optimize the utilization of available resources, reducing the environmental impact related to the life cycle of polymer-based items. Green composites from biopolymer matrix and wood flour were prepared and the investigation focused on several issues, such as the effect of reprocessing on the matrix properties, wood flour loading effects on virgin and reprocessed biopolymer, and wood flour effects on material reprocessability. Tensile, Dynamic-mechanical thermal (DMTA), differential scanning calorimetry (DSC) and creep tests were performed, pointing out that wood flour leads to an improvement of rigidity and creep resistance in comparison to the pristine polymer, without compromising other properties such as the tensile strength. The biopolymer also showed a good resistance to multiple reprocessing; the latter even allowed for improving some properties of the obtained green composites. PMID:28793656

Effects of radio transmitters on migrating wood thrushes

USGS Publications Warehouse

Powell, L.A.; Krementz, D.G.; Lang, J.D.; Conroy, M.J.

1998-01-01

We quantified the effects of radio transmitters on Wood Thrushes (Hylocichla mustelina) using 4 yr of banding and telemetry data from Piedmont National Wildlife Refuge, Georgia. Flight performance models suggest that the 1.6-g transmitter shortens the migratory range of Wood Thrushes by only 60 km, and the estimated migratory range is adequate to accomplish migration even with limited fat stores. We used two strengths of line, 5- and 9-kg test-strength braided Dacron, to attach the transmitters using the thigh-harness method. We recaptured 13 returning radio-marked Wood Thrushes, seven of which were still marked. Six of the seven birds marked with the 5-kg test harnesses lost their transmitters within 1 yr while all six of the 9-kg test harnesses were still attached up to 21 mo later. Radio-marking did not reduce the return rates of adults and immatures, and the transmitters did not cause radio-marked birds to lose more mass than banded-only birds. Wood Thrushes can successfully carry a transmitter during migration with no detectable negative effects. We recommend continued use of the thigh-harness method, but we encourage the use of 5-kg cotton line.

Rheological Characterisation of the Flow Behaviour of Wood Plastic Composites in Consideration of Different Volume Fractions of Wood

NASA Astrophysics Data System (ADS)

Laufer, N.; Hansmann, H.; Koch, M.

2017-01-01

In this study, the rheological properties of wood plastic composites (WPC) with different polymeric matrices (LDPE, low-density polyethylene and PP, polypropylene) and with different types of wood filler (hardwood flour and softwood flour) have been investigated by means of high pressure capillary rheometry. The volume fraction of wood was varied between 0 and 60 %. The shear thinning behaviour of the WPC melts can be well described by the Ostwald - de Waele power law relationship. The flow consistency index K of the power law shows a good correlation with the volume fraction of wood. Interparticular interaction effects of wood particles can be mathematically taken into account by implementation of an interaction exponent (defined as the ratio between flow exponent of WPC and flow exponent of polymeric matrix). The interaction exponent shows a good correlation with the flow consistency index. On the basis of these relationships the concept of shear-stress-equivalent inner shear rate has been modified. Thus, the flow behaviour of the investigated wood filled polymer melts could be well described mathematically by the modified concept of shear-stress-equivalent inner shear rate. On this basis, the shear thinning behaviour of WPC can now be estimated with good accuracy, taking into account the volume fraction of wood.

Effect of Extraction Conditions on the Antioxidant Activity of Olive Wood Extracts

PubMed Central

Pérez-Bonilla, Mercedes; Salido, Sofía; Sánchez, Adolfo; van Beek, Teris A.; Altarejos, Joaquín

2013-01-01

An investigation to optimize the extraction yield and the radical scavenging activity from the agricultural by-product olive tree wood (Olea europaea L., cultivar Picual) using six different extraction protocols was carried out. Four olive wood samples from different geographical origin, and harvesting time have been used for comparison purposes. Among the fifty olive wood extracts obtained in this study, the most active ones were those prepared with ethyl acetate, either through direct extraction or by successive liquid-liquid partitioning procedures, the main components being the secoiridoids oleuropein and ligustroside. An acid hydrolysis pretreatment of olive wood samples before extractions did not improve the results. In the course of this study, two compounds were isolated from the ethanolic extracts of olive wood collected during the olives' harvesting season and identified as (7′′R)-7′′-ethoxyoleuropein (1) and (7′′S)-7′′-ethoxyoleuropein (2). PMID:26904608

Factors affecting distribution of wood, detritus, and sediment in headwater streams draining managed young-growth red alder - Conifer forests in southeast Alaska

USGS Publications Warehouse

Gomi, T.; Johnson, A.C.; Deal, R.L.; Hennon, P.E.; Orlikowska, E.H.; Wipfli, M.S.

2006-01-01

Factors (riparian stand condition, management regimes, and channel properties) affecting distributions of wood, detritus (leaves and branches), and sediment were examined in headwater streams draining young-growth red alder (Alnus rubra Bong.) - conifer riparian forests (40 years old) remained in channels and provided sites for sediment and organic matter storage. Despite various alder-conifer mixtures and past harvesting effects, the abundance of large wood, fine wood, and detritus accumulations significantly decreased with increasing channel bank-full width (0.5-3.5 m) along relatively short channel distances (up to 700 m). Changes in wood, detritus, and sediment accumulations together with changes in riparian stand characteristics create spatial and temporal variability of in-channel conditions in headwater systems. A component of alder within young-growth riparian forests may benefit both wood production and biological recovery in disturbed headwater stream channels. ?? 2006 NRC.

Seeing the tipping point: Balance perception and visual shape.

PubMed

Firestone, Chaz; Keil, Frank C

2016-07-01

In a brief glance at an object or shape, we can appreciate a rich suite of its functional properties, including the organization of the object's parts, its optimal contact points for grasping, and its center of mass, or balancing point. However, in the real world and the laboratory, balance perception shows systematic biases whereby observers may misjudge a shape's center of mass by a severe margin. Are such biases simply quirks of physical reasoning? Or might they instead reflect more fundamental principles of object representation? Here we demonstrate systematically biased center-of-mass estimation for two-dimensional (2D) shapes (Study 1) and advance a surprising explanation of such biases. We suggest that the mind implicitly represents ordinary 2D shapes as rich, volumetric, three-dimensional (3D) objects, and that these "inflated" shape representations intrude on and bias perception of the 2D shape's geometric properties. Such "inflation" is a computer-graphics technique for segmenting shapes into parts, and we show that a model derived from this technique best accounts for the biases in center-of-mass estimation in Study 1. Further supporting this account, we show that reducing the need for inflated shape representations diminishes such biases: Center-of-mass estimation improved when cues to shapehood were attenuated (Study 2) and when shapes' depths were explicitly depicted using real-life objects laser-cut from wood (Study 3). We suggest that the technique of shape inflation is actually implemented in the mind; thus, biases in our impressions of balance reflect a more general functional characteristic of object perception. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Preparation and characterizations of activated carbon monolith from rubber wood and its effect on supercapacitor performances

NASA Astrophysics Data System (ADS)

Taer, E.; Taslim, R.; Deraman, M.

2016-02-01

Preparation of activated carbon monolith (ACM) from rubber wood was investigated. Two kind of preparation method were carried out by pre-carbonized of rubber wood saw dust and rubber wood material as it is naturally. The samples were prepared with pelletizing method and small cutting of rubber wood in cross sectional method. Both of samples were characterized by physical and electrochemical technique. The physical properties such as morphology and porosity were investigated. The electrochemical properties of both samples such as equivalent series resistances (ESR) and specific capacitances were also compared. In conclusion, this study showed that both of different preparation method would propose a simple method of ACM electrode preparation technique for supercapacitor applications.

Biomass pre-extraction, hydrolysis and conversion process improvements fro an integrated biorefinery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jansen, Robert

In this project, Virdia will show that it can improve the production of sugars suitable for the conversion into advanced biofuels from a range of woods. Several biomass feedstocks (Pine wood chips & Eucalyptus wood chips) will be tested on this new integrated biorefinery platform. The resultant drop-in biodiesel can be a cost-effective petroleum-replacement that can compete with projected market prices

Decaying wood and tree regeneration in the Acadian Forest of Maine, USA

Treesearch

Jamie K. Weaver; Laura S. Kenefic; Robert S. Seymour; John C. Brissette

2009-01-01

We examined the effect of management history on the availability of decayed downed wood and the use of downed wood as a regeneration substrate in mixed-species stands in the Acadian Forest of Maine. Regeneration of red spruce (Picea rubens Sarg.), eastern hemlock (Tsuga canadensis (L.) Carr.), balsam fir (Abies balsamea L. Mill), and red maple (Acer rubrum L.) was...

Stem wood properties of Populus tremuloides, Betula papyrifera and Acer saccharum saplings after three years of treatments to elevated carbon dioxide and ozone

Treesearch

Seija Kaakinen; Katri Kostiainen; Fredrik Ek; Pekka Saranpaa; Mark E. Kubiske; Jaak Sober; David F. Karnosky; Elina Vapaavuori

2004-01-01

The aim of this study was to examine the effects of elevated carbon dioxide [CO2] and ozone [O3] and their interaction on wood chemistry and anatomy of five clones of 3-year-old trembling aspen (Populus tremuloides Michx.). Wood chemistry was studied also on paper birch (Betula papyrifera...

Online resources for the identification of North American wood decay fungi

Treesearch

Jessie A. Glaeser

2012-01-01

The ability to identify wood decay fungi is an important skill for an arborist. Knowing which fungus is colonizing a tree can be used to better assess the type, amount, and position of decay in the tree, and its subsequent effects on wood strength. Distinguishing species of fungi that colonize sapwood, heartwood, or roots can provide information to improve the quality...

The influence of plantation and seed-source elevation on wood specific gravity of 29-year-old ponderosa pines

Treesearch

R. M. Echols; M. T. Conkle

1971-01-01

Genetic, environmental, and age effects were found in 29-yr-old ponderosa pine progenies from different elevational sources, when they were grown at 960, 2730, and 5650 ft elevation in the Sierra Nevada of California. Wood specific gravity decreased as elevation of seed parents increased, and all genotypes produced significantly lower specific gravity wood in the high-...

Effect of adhesive applied to the tooth-wood interface on metal-plate connections loaded in tension

Treesearch

Leslie H. Groom

1991-01-01

The structural behavior of metal-plate connections (MPCs) is affected not only by the isolated properties of the adjoining wood members and metal plate but also by the interfacial region between individual teeth and the surrounding wood. This study looked at maintaining a good interface by applying an epoxy adhesive to metal-plate teeth immediately preceding joint...

Gene expression patterns of wood decay fungi Postia placenta and Phanerochaete chrysosporium are influenced by wood substrate composition during degradation

Treesearch

Oleksandr Skyba; Daniel Cullen; Carl J. Douglas; Shawn D. Mansfield

2016-01-01

Identification of the specific genes and enzymes involved in the fungal degradation of lignocellulosic biomass derived from feedstocks with various compositions is essential to the development of improved bioenergy processes. In order to elucidate the effect of substrate composition on gene expression in wood-rotting fungi, we employed microarrays based on the...

Influence of photostabilizers on wood flour-HDPE composites exposed to xenon-arc radiation with and without water spray

Treesearch

Nicole M. Stark; Laurent M. Matuana

2006-01-01

The weathering of wood-plastic composites changes their appearance and/or mechanical properties. These changes can be slowed through the addition of ultraviolet absorbers and pigments. The first phase of this study examined the effect of incorporating different concentrations of an ultraviolet absorber and/or pigment into wood-flour-filled high-density polyethylene (WF...

Discerning responses of down wood and understory vegetation abundance to riparian buffer width and thinning treatments: an equivalence-inequivalence approach

Treesearch

Paul D. Anderson; Mark A. Meleason

2009-01-01

We investigated buffer width and thinning effects on the abundance of down wood and understory vegetation in headwater stream catchments of 40- to 65-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forests in western Oregon, USA. Small-wood cover became more homogeneous among stream reaches within 5 years following thinning, primarily...

Thermochemical pretreatment of underutilized woody biomass for manufacturing wood composites

NASA Astrophysics Data System (ADS)

Pelaez Samaniego, Manuel Raul

Prescribed fires, one method for reducing hazardous fuel loads from forest lands in the US, are limited by geographical, environmental, and social impacts. Mechanical operations are an alternative type of fuel treatment but these processes are constrained by the difficulty of economically harvesting and/or using large amounts of low-value woody biomass. Adoption and integration of new technologies into existing wood composite facilities offer better utilization of this material. A pretreatment that enables integration of technologies in a typical composite facility will aid with diversification of product portfolio (e.g. wood composites, fuel pellets, liquid fuels, chemicals). Hot water extraction (HWE) is an option for wood pretreatment. This work provides a fundamental understanding of the physicochemical changes to wood resulting from HWE, and how these changes impact processing and performance of composites. Specific objectives were to: 1) review literature on studies related to the manufacture of composites produced with thermally pretreated wood, 2) manufacture wood plastic composites (WPC) and particleboard using HWE wood and evaluate the impacts of pretreatment on product properties, 3) develop an understanding of the effect of HWE on lignin properties, specifically lignin at the cells surface level after migration from cell walls and middle lamella, 4) discern the influence of lignin on the fiber surface on processing WPCs, and, 5) investigate the effect of changing the pretreatment environment (inert gas instead of water) on lignin behavior. Results show that HWE enhances the resistance of both WPCs and particleboard to water with positive or no effect on mechanical properties. Reduction of hemicelluloses and lignin property changes are suggested as the main reasons for enhancing interaction between wood fiber and resins during composite processing. Lignin on the surface of particles after HWE interacts with thermoplastics during WPCs compounding, thus improving bond quality between the constituents and maintaining the mechanical properties of the composites. The amount and properties of lignin on the fiber surfaces depends on the pretreatment conditions. Thus, it seems possible to control the pretreatment process to increase or decrease the amount of lignin on particles surfaces, which is of great interest for managing downstream processes within biorefinery concepts.

Automatically monitoring driftwood in large rivers: preliminary results

NASA Astrophysics Data System (ADS)

Piegay, H.; Lemaire, P.; MacVicar, B.; Mouquet-Noppe, C.; Tougne, L.

2014-12-01

Driftwood in rivers impact sediment transport, riverine habitat and human infrastructures. Quantifying it, in particular large woods on fairly large rivers where it can move easily, would allow us to improve our knowledge on fluvial transport processes. There are several means of studying this phenomenon, amongst which RFID sensors tracking, photo and video monitoring. In this abstract, we are interested in the latter, being easier and cheaper to deploy. However, video monitoring of driftwood generates a huge amount of images and manually labeling it is tedious. It is essential to automate such a monitoring process, which is a difficult task in the field of computer vision, and more specifically automatic video analysis. Detecting foreground into dynamic background remains an open problem to date. We installed a video camera at the riverside of a gauging station on the Ain River, a 3500 km² Piedmont River in France. Several floods were manually annotated by a human operator. We developed software that automatically extracts and characterizes wood blocks within a video stream. This algorithm is based upon a statistical model and combines static, dynamic and spatial data. Segmented wood objects are further described with the help of a skeleton-based approach that helps us to automatically determine its shape, diameter and length. The first detailed comparisons between manual annotations and automatically extracted data show that we can fairly well detect large wood until a given size (approximately 120 cm in length or 15 cm in diameter) whereas smaller ones are difficult to detect and tend to be missed by either the human operator, either the algorithm. Detection is fairly accurate in high flow conditions where the water channel is usually brown because of suspended sediment transport. In low flow context, our algorithm still needs improvement to reduce the number of false positive so as to better distinguish shadow or turbulence structures from wood pieces.