Woody Fiber Research Articles

Study on fungal growth process based on K-means clustering and Lotka-Volterra interspecific competition Model

The carbon cycle has a great impact on the environmental changes of the Earth, and fungus play a crucial role in the decomposition of ground litter and woody fibers in nature, so it is very necessary to study the growth process of fungus. First, we used the K-means Clustering Algorithm to classify the different species of fungus into four categories according to their growth rates as well as their moisture tolerance. This not only measures the similarity between various fungus more intuitively, but also reduces the difficulty of subsequent modeling work. Second, we considered environmental accommodation, intra- and interspecific competition, and used this to modify the Lotka-Volterra interspecific competition Model and to derive the relationship between fungal growth rate and time. Then, we used this model for long-term and short-term prediction of fungal growth. In the short term, the growth rate of fungi increased rapidly with time; in the long term, the fungal population tended to be stable.

Investigation of the Extraction Processes and Performance Properties of Kudzu Fibers

ABSTRACT Kudzu plants have become increasingly invasive in the US, yet are not highly utilized. Intending to produce eco-friendly fibers, this research used fresh kudzu vines to produce fibers by four different processes: boiling, retting, enzymatic and mild chemical processes. Two types of fibers resulted from each process – soft and woody. Unlike more popularly used natural bast fibers such as linen, there is no standard description of the surface structure of kudzu fibers established, this report provides a broad microscopic analysis and images for kudzu fibers. Resultant kudzu fibers, with an average length of 20–300 cm, exhibited a breaking load of 4–20 kg/tex and a breaking elongation of 22.67–37.94%. Results suggest that soft kudzu fibers are promising for apparel and use in fiber-reinforced composites while woody fiber as basketry or paper.

Physico-Mechanical Properties of Wood and Non-Wood Plaster of Paris Bonded Composite Ceiling Boards

Woody ( Alzibia zygia ) and Non-woody (rattan and yarn strands) fibres were used comparatively to improve the physicomechanical properties of Plaster of Paris bonded composite which is used as ceiling boards. The addition of fibre reinforcement in a discrete form improves the engineering properties of the Plaster of Paris. The woody and nonwoody residues were varied in 10, 20, 30, 40, and 50% of the whole mix while the Plaster of Paris used were in the ratio 100 (control), 90, 80, 70, 60, and 50%. The mean density of the composite produced is 3250 kg/m3. The mean thickness swelling after 2 and 24 hours is 0.84 % and 0.88 % respectively with the mean water absorption at 13.8% after 2 hours and 16.2 % after 24 hours. The MOR and MOE of the composites produced ranged from 1.21-1.22 N/mm 2 , 2431-51488N/mm 2 for sawdust, 1.17-1.22 N/mm 2 , 10027-49940 N/mm 2 for yarn strands and 1.20-1.22 N/mm 2 , 23566-86210 N/mm 2 for the rattan strands. The results showed physicomechanical properties of POP-bonded fibre reinforced composites were increased for both wood and non-wood fibres and rattan strands compared best.

Phenolic Resin Foam Composites Reinforced by Acetylated Poplar Fiber with High Mechanical Properties, Low Pulverization Ratio, and Good Thermal Insulation and Flame Retardant Performance.

Phenolic foam composites (PFs) are of substantial interest due to their uniform closed-cell structure, low thermal conductivity, and good thermal insulation performance. However, their disadvantages of a high pulverization rate and poor mechanical properties restrict their application in building exterior insulation. Therefore, the toughening of these composites is necessary. In this paper, poplar fiber was treated with an acetylation reagent, and the acetylated fiber was used to prepare modified phenolic foams (FTPFs); this successfully solved the phenomenon of the destruction of the foam structure due to the agglomeration of poplar fiber in the resin substrate. The foam composites were comprehensively evaluated via the characterization of their chemical structures, surface morphologies, mechanical properties, thermal conductivities, and flame retardant properties. It was found that the compressive strength and compressive modulus of FTPF-5% respectively increased by 28.5% and 37.9% as compared with those of PF. The pulverization ratio was reduced by 32.3%, and the thermal insulation performance and flame retardant performance (LOI) were improved. Compared with other toughening methods for phenolic foam composites, the phenolic foam composites modified with surface-compatibilized poplar fiber offer a novel strategy for the value-added utilization of woody fiber, and improve the toughness and industrial viability of phenolic foam.

The Dyeing Properties of Woody Fiber Regenerated from Waste MDF by Reactive Dyes

This study aims to review the relations between the dyeing conditions (i.e., dye concentration, addition amounts of salt and alkali, and dyeing temperature) and dyeing properties and color fastness to light for identifying the optimal dyeing conditions when dyed regenerated woody fibers were obtained through the defibration of waste medium density fiberboard (MDF) using reactive Red H-E3B (Bis-monochlorotriazine (MCT)/MCT type) and reactive Red RB133% (Bis-MCT/Vinyl sulphone type). The dyeing yield (K/S) obtained using two types of reactive dyes increased as the dye concentration increased by 1–10% (on the weight of fiber (OWF)). In addition, the K/S of H-E3B was higher than that of RB133% irrespective of the dye concentration. The color difference of H-E3B after ultraviolet (UV) radiation was lower than that of RB133%, denoting good resistance to discoloration by UV. As the amount of sodium sulfate increased, the color difference and K/S also increased, and the adequate salt content was determined to be 50–70 g/L. Further, the color difference and K/S significantly increased only the addition of 2 g/L of sodium carbonate; however, almost no difference was observed when more than 2 g/L of sodium carbonate was added. The addition amount of sodium carbonate was adequate 5–10 g/L to dyeing the fiber and the pH at this addition level was 10. The dyeing yield of H-E3B increased when the dyeing temperature increased; however, it subsequently decreased after the dyeing temperature became 80°C. The dyeing yield of RB133% was almost the same up to 60–70°C but declined subsequently. Thus, the adequate temperatures were 80°C and 60°C for H-E3B and RB133%, respectively. If the waste MDF woody fiber was dyed under the aforementioned optimal conditions, dyed regenerated woody fiber can be obtained having the following colors: 1.5 to 2.0R with the H-E3B dye and 9.6 to 10.0 PR with RB133%.

Textile Hemp vs. Salinity: Insights from a Targeted Gene Expression Analysis.

Soil salinity is a serious threat to agriculture, because it compromises biomass production and plant productivity, by negatively affecting the vegetative growth and development of plants. Fiber crops like textile hemp (Cannabis sativa L.) are important natural resources that provide, sustainably, both cellulosic and woody fibers for industry. In this work, the response to salinity (200 mM NaCl) of a fiber variety of hemp (Santhica 27) was studied using quantitative real-time PCR. The responses of plantlets aged 15 days were analyzed by microscopy and by measuring the changes in expression of cell wall-related genes, as well as in the general response to exogenous constraints. The results presented here show that a different response is present in the hemp hypocotyls and leaves. In the leaves, genes coding for heat shock proteins were significantly upregulated, together with a phytohormone-related transcript (ethylene-responsive factor 1 ERF1) and genes involved in secondary cell wall biosynthesis (cellulose synthase CesA4, fasciclin-like arabinogalactan proteins FLA10 and FLA8). Moreover, a tendency towards upregulation was also observed in the leaves for genes involved in lignification (4CL, CAD, PAL); a finding that suggests growth arrest. In the hypocotyl, the genes involved in lignification did not show changes in expression, while a gene related to expansion (expansin EXPA8), as well as transcripts coding for calcium-dependent lipid-binding family proteins (CALB), were upregulated. Microscopic analyses on the hypocotyl cross sections revealed changes in the vascular tissues of salt-exposed plantlets, where the lumen of xylem vessels was reduced. The gene expression results show that a different response is present in the hemp hypocotyls and leaves. The data presented contribute to our understanding of the regulatory gene network in response to salinity in different tissues of an important fiber crop.

Impact of Silicon in Plant Biomass Production: Focus on Bast Fibres, Hypotheses, and Perspectives.

Silicon (Si) is an abundant element which, when supplied to plants, confers increased vigor and resistance to exogenous stresses, as well as enhanced stem mechanical strength. Plant species vary in their ability to take Si up and to accumulate it under the form of silicon dioxide (SiO2) in their tissues: emblematic of this is the example of Poales, among which there is rice, a high Si accumulator. Monocots usually accumulate more Si than dicots; however, the impact that Si has on dicots, notably on economically important dicots, is a subject requiring further study and scientific efforts. In this review, we discuss the impact that Si has on bast fibre-producing plants, because of the potential importance that this element has in sustainable agriculture practices and in light of the great economic value of fibre crops in fostering a bio-economy. We discuss the data already available in the literature, as well as our own research on textile hemp. In particular, we demonstrate the beneficial effect of Si under heavy metal stress, by showing an increase in the leaf fresh weight under growth on Cd 20 µM. Additionally, we propose an effect of Si on bast fibre growth, by suggesting an action on the endogenous phytohormone levels and a mechanical role involved in the resistance to the turgor pressure during elongation. We conclude our survey with a description of the industrial and agricultural uses of Si-enriched plant biomass, where woody fibres are included in the survey.

Lightweight Composites Based on Technical Hemp Hurds in Construction Industry

This article discusses about the possibility of using technical hemp as a source of natural fibres for purpose of construction. The technical hemp (Cannabis Sativa) is the source of two types of fibres; bast fibres (used mainly in the paper and textile industries) and woody fibres - hurds. In recent decades hemp hurds have experienced a renaissance in use in the construction industry. This material is waste resulting from the processing of hemp stem on bast fibres. For the purposes of construction, it has potential thanks to their exceptional thermal insulation, antiseptic, acoustic and mechanical properties. One of the aspects of using hemp products in building industry is its environmentally friendly properties in comparison to the conventional materials (such as insulating materials with polymer matrix or based on mineral wool). Due to the low density and high porosity of the hemp fibres, the combination of hemp and binder creates high-quality products such as hemp concrete, fibre boards and lightweight composites. In this paper, the physical and mechanical properties of lightweight composites based on pre-treated hemp hurds and alternative binder MgO-cement are studied after their hardening in indoor condition for 28 days. The results of the parameters (density, density changes after thermal stress, water absorbability, thermal conductivity coefficient, compressive and tensile strength) of composites presented with emphasis on their usage as thermal insulation material show some differences which are determined by properties of modified filler (hemp material) as well as by properties of filler/binder interface.

Food Habits of Asian ElephantsElephas maximusin a Rainforest of Northern Peninsular Malaysia

Little is known about the food habits of Asian elephants (Elephas maximus) in tropical rainforests of Southeast Asia. In Peninsular Malaysia, elephant habitat has been extensively modified by human intervention in the past few decades. Most of the primary forest has been logged or given way to plantations, infrastructure, and human inhabitation. Here we compare the food habits of wild elephants in three habitats of Belum-Temengor Forest Complex (BTFC): (1) primary forest, (2) selectively-logged forest, and (3) by the side of a road that bisects the forest complex. We used microhistological fecal analysis to describe elephants' diet. Elephant dung in the primary forest was mainly composed of non-grass monocotyledonous leaves (22%), woody debris (32%), and woody fiber (20%). Those in the logged forest were similar; non-grass monocotyledonous leaves accounted for 33%, woody debris for 24%, and fiber for 26%. At the roadside, elephant dung was dominated by grasses (47%). We conclude that by the road elephants shift their diet into grasses, suggesting that the road acts like a large forest gap, promoting the availability of grasses and other early succession plants. Elephant feeding by the road poses potential conservation conflicts by means of road accidents and increased contact with people.

Cannabis sativa: The Plant of the Thousand and One Molecules.

Cannabis sativa L. is an important herbaceous species originating from Central Asia, which has been used in folk medicine and as a source of textile fiber since the dawn of times. This fast-growing plant has recently seen a resurgence of interest because of its multi-purpose applications: it is indeed a treasure trove of phytochemicals and a rich source of both cellulosic and woody fibers. Equally highly interested in this plant are the pharmaceutical and construction sectors, since its metabolites show potent bioactivities on human health and its outer and inner stem tissues can be used to make bioplastics and concrete-like material, respectively. In this review, the rich spectrum of hemp phytochemicals is discussed by putting a special emphasis on molecules of industrial interest, including cannabinoids, terpenes and phenolic compounds, and their biosynthetic routes. Cannabinoids represent the most studied group of compounds, mainly due to their wide range of pharmaceutical effects in humans, including psychotropic activities. The therapeutic and commercial interests of some terpenes and phenolic compounds, and in particular stilbenoids and lignans, are also highlighted in view of the most recent literature data. Biotechnological avenues to enhance the production and bioactivity of hemp secondary metabolites are proposed by discussing the power of plant genetic engineering and tissue culture. In particular two systems are reviewed, i.e., cell suspension and hairy root cultures. Additionally, an entire section is devoted to hemp trichomes, in the light of their importance as phytochemical factories. Ultimately, prospects on the benefits linked to the use of the -omics technologies, such as metabolomics and transcriptomics to speed up the identification and the large-scale production of lead agents from bioengineered Cannabis cell culture, are presented.

Cellulose Triacetate Synthesis from Cellulosic Wastes by Heterogeneous Reactions

Cellulosic fibers from cotton fibers (CF), recycled writing papers (RWP), recycled newspapers (RN), and macerated woody fibers of Leucaena leucocephala (MWFL) were acetylated by heterogeneous reactions with glacial acetic acid, concentrated H2SO4, and acetic anhydride. The resultant cellulose triacetate (CTA) was characterized for yield and solubility as well as by using 1H-NMR spectroscopy and SEM. The acetylated product (AP) yields for CF, RWP, RN, and MWFL were 112, 94, 84, and 73%, respectively. After isolation of pure CTA from the AP, the CTA yields were 87, 80, 68, and 54%. The solubility test for the CTA’s showed a clear solubility in chloroform, as well as mixture of chloroform and methanol (9:1v/v) and vice versa for acetone. The degree of substitution (DS) values for the CTA’s produced were nearly identical and confirmed the presence of CTA. In addition, the pore diameter of the CTA skeleton ranged from 0.072 to 0.239 µm for RWP and RN, and within the dimension scale of the CTA pinholes confirm the synthesis of CTA. Accordingly, pouring of the AP liquor at 25 °C in distilled water at the end of the acetylation and filtration did not hydrolyze the CTA to cellulose diacetate.

Innovative Use of Biomass Based on Technical Hemp in Building Industry

This article discusses about the possibility of using industrial hemp as a source of natural fibres for purpose of construction. The technical hemp (Cannabis Sativa) is the source of two types of fibres; bast fibres (used mainly in the paper and textile industries) and woody fibres - hurds. In recent decades hemp hurds have experienced a renaissance in use in the construction industry. This material is waste resulting from the processing of hemp stem on bast fibres. For the purposes of construction it has potential thanks to their exceptional thermal insulation, antiseptic, acoustic and mechanical properties. One of the aspects of using hemp products in building industry is that these materials are environmentally friendly in comparison to the used conventional materials (such as conventional insulating materials with polymer matrix or based on mineral wool).In this article, the lightweight composites based on hemp hurds (as a biomass) and nonconventional binders MgO-cement are tested. The physical and mechanical properties of the composites hardened in indoor condition (28, 60, 90, 180 days) are studied. The results of the obtained parameters (density, water content, compressive strength, thermal conductivity coefficient) of hardened composites are presented.

October 2013 - This Month in JoVE

Here's a look at what's coming up in the October 2013 issue of JoVE (The Journal of Visualized Experiments). This month we are pleased to introduce JoVE Environment, multidisciplinary section devoted to research methods in environmental sciences and green technologies, from biofuels to oceanography to atmospheric sciences. These experimental techniques aim to understand the Earth, protect natural resources, and create a more sustainable and environmentally conscious planet. One video in JoVE Environment describes a technique called tree endotherapy, which might sound like tree hugging, but it's a method based on the fluid dynamics in the xylem vessels of woody plants for the targeted delivery of compounds (like pesticides). Endotherapy is progressively supplanting traditional air spray methods for trees. However, most tree endotherapy methods involve drilling into trees, which can cause damage or infections. Montecchio presents a new a drill-free method that uses a small, perforated blade to separate the woody fibers. This produces a Venturi effect, a phenomenon where fluid flowing through a pipe decreases in pressure and increases in velocity when the pipe becomes narrow. Because the Venturi effect causes the tree sap to flow faster, it also increases the uptake of external liquids. This method represents a significant advance in the development of minimally invasive endotherapeutic techniques. Also in JoVE Environment we feature optimized methods for performing crosses in Setaria viridis, which serves as a model for bioenergy feed stocks and grain crops. Genetic crosses in Setaria usually involve emasculation of the male parent by removing the anthers from the flowers. Jiang et al. present an alternative method that uses heat to kill the developing pollen grains. A GUS transgene driven by a rice ubiquitin promoter facilitates the identification of successful controlled genetic crosses. This method will help accelerate genetic discovery in this emerging model system. In JoVE Bioengineering, it is a common theme to build biological systems, such as the vasculature, on chips for in vitro assays. Li et al. have developed a system of endothelialized microchannels-on-a-chip, which mimics the three-dimensional geometry of in vivo microvessels and runs under controlled and continuous perfusion flow. By combining a photolithographic reflowable photoresist technique with soft lithography and microfluidics, this is a useful assay for microvascular research that allows steady and accurate flow control over cultured endothelial cells for up to two weeks. In JoVE Neuroscience, Silvestri et al. present an optical method called confocal light sheet microscopy (CLSM), which is capable of obtaining micron-scale images of mouse brains without the need to perform physical sectioning. Optical tomography stacks are obtained and stitched together to reconstruct the entire mouse brain. This method can be used to study the fine anatomical structure of the brain or other tissues. You've just had a sneak peek of a few highlights from the October 2013 issue of JoVE. Visit the website to see the full-length articles, plus many more, in JoVE (The Journal of Visualized Experiments).

Beyond Embodiment: John Dewey and the Integrated Mind

In 1916 John Dewey expressed a worry that American philosophy would be relegated to “chewing a historic cud long since reduced to a woody fibre, or an apologetics for lost causes (lost to natural science).”1 In this paper, I will attempt to contribute to a growing body of literature within the classical American philosophical tradition that seeks to avoid this fate by engaging Dewey’s thought with debates in contemporary philosophy of mind.2 To date, the vast majority of this work has centered around Dewey’s notion of embodiment and its relation to the thesis of the embodied mind. In this paper I will evaluate the degree to which the embodied mind thesis (henceforth “EMT”) provides the proper framework for understanding Dewey’s notion of embodiment. In doing so, I will advance a three-stage argument: (1) I will argue that although Dewey did anticipate the positions of many embodied mind theorists—a fact that is now approaching the status of the proverbial woody fiber—a thoroughgoing treatment of the biological/ecological dimension of Dewey’s notion of embodiment entails a more radical position than is traditionally attributed to philosophers of mind working in a Deweyan vein. This more radical position is the extended mind thesis (henceforth “XMT”). After briefly elucidating this thesis, (2) I will argue that, while XMT is compatible with EMT, and while the former does capture more of Dewey’s notion of embodiment than the latter, both theses may still fail to capture the full scope of Dewey’s notion of embodiment. Finally, (3) I will argue that the best solution to the conceptual problems presented in (1) and (2) is offered by Richard Menary’s notion of cognitive integration—a notion that turns on a Deweyan understanding of the organism-environment dynamic emphasized in (1). Thus, the conclusion to be argued for in this paper is that while

A Venturi Effect Can Help Cure Our Trees

In woody plants, xylem sap moves upwards through the vessels due to a decreasing gradient of water potential from the groundwater to the foliage. According to these factors and their dynamics, small amounts of sap-compatible liquids (i.e. pesticides) can be injected into the xylem system, reaching their target from inside. This endotherapic method, called "trunk injection" or "trunk infusion" (depending on whether the user supplies an external pressure or not), confines the applied chemicals only within the target tree, thereby making it particularly useful in urban situations. The main factors limiting wider use of the traditional drilling methods are related to negative side effects of the holes that must be drilled around the trunk circumference in order to gain access to the xylem vessels beneath the bark. The University of Padova (Italy) recently developed a manual, drill-free instrument with a small, perforated blade that enters the trunk by separating the woody fibers with minimal friction. Furthermore, the lenticular shaped blade reduces the vessels' cross section, increasing sap velocity and allowing the natural uptake of an external liquid up to the leaves, when transpiration rate is substantial. Ports partially close soon after the removal of the blade due to the natural elasticity and turgidity of the plant tissues, and the cambial activity completes the healing process in few weeks.

The Coexistence and Competition of Natural Fibres with Man-Made Fibres and Future Prospects

The fibrous plants can grow from Northern to Southern Arctic Circle. Different parts of these lignocellulosic plants are valuable sources of lignocellulosic fibres used in textiles and eco-friendly composites, sources of human food, nutrients, animal feed, agro-fine-chemicals for cosmetics and other area of application. That they are completely sustainable, renewable, and biodegradable and they recycle the carbon dioxide (CO2). Fibrous plants were well known to mankind more than 7 000 BC. Some of these bast fibrous plants like flax and hemp could be explored for reclaiming the soil polluted by heavy metals. The total production of all natural fibres is expected at the level 35-40 million tons/year. Special treatment and functionalization of these fibres provides new promising features and expected new properties of these fibres. Natural fibres can be processed for production of woven goods, knitting, nonwoven, technical and 3D textiles, also as the reinforcement of more friendly composites. These whole plants and woody parts (shives) and fibres can be used for production of special pulp and paper and seeds some for obtaining the agro-fine-chemicals. Natural fibres and derived products have very important properties like: excellent air permeability, high hygroscopicity, high heat absorption, no release of substances harmful for health, they not cause allergy effect, as well as safer behaviour in flame and fire combustion versus man-made fibres. The new emerging method of genetic modification (GM) of these fibrous plants provides promising performance e.g. higher level of cellulose, possibility of creating polyhydroxy-alcanate (PHA) natural polyester in statu nascendi. Such GM modified plants are resistant to special herbicides, better resistant to drought also with controlled level of lignin and pectin.In 21st century the coexistence and competition between man-made and natural fibres is stabilized, especially in area of quality, sustainability and economy of their production.

탄화보드를 이용한 서각작품 제작

중밀도섬유판(MDF)에 글씨나 그림을 새김질한 목판을 제조하고, 이를 탄화하여 서각작품을 제작하는 방법을 개발하였다. 섬유판의 탄화에 따른 외형적 및 조직학적 변화를 검토하고 제작된 탄화보드 서각작품에 대한 미학적 특징을 고찰하였다. 서각한 MDF를 <TEX>$850^{\circ}C$</TEX>에서 탄화한 결과, 할열이나 뒤틀림은 관찰되지 않았으며, 치수는 가로 21.8%, 세로 18.8%, 두께 43.5% 줄어들었고, 중량은 69.2%, 밀도는 14.8% 감소하였다. 탄화보드의 전자 현미경에 의한 관찰 결과, 당초 섬유의 표면과 벽공을 둘러싸고 있던 접착제가 탄화되면서 목질섬유의 표면이 매끄럽게 변하고 벽공이 개열되며 섬유의 크기가 균일화되고 조직이 치밀화되는 현상을 나타내었다. 수작업에 의한 서각기법과 무할열 탄화기법의 융합에 의해 새로운 탄화보드 서각작품의 제작이 가능하였다. 탄화보드 서 각작품은 목탄의 기능성과 서각의 아름다움을 부여하는 새로운 친환경 예술영역의 한 분야로서 이용될 수 있을 것이다. This study was focused to make a wooden plate that is engraved with writings or pictures on the medium density fiberboard (MDF), and then to produce a calligraphy-carving artwork by carbonization of the carved MDF. The external appearances and anatomical changes were investigated on the carbonized MDF and aesthetic characteristics was also discussed. No split and no twist were found after the carbonization (at <TEX>$850^{\circ}C$</TEX>) of the calligraphy-encarved MDF, shrinkages of the MDF were observed with portions of 21.8% in length, 18.8% in width and 43.5% in thickness, and 69.2% of weight loss with density decrease of 14.8% were observed as well. From the observation of the carbonized board by a scanning electron microscope, specific phenomena were found: the adhesives, surrounding the fiber's surface and pits, were carbonized, the woody fibers were changed smoothly, the pits were opened, the fiber' size was uniformized, and the organization was compacted. By the combination of handmade calligraphy-woodcarving and crack-free carbonizing methods, it was able to find a new method for manufacture carbonized calligraphy-woodcarving artwork. It is concluded that the calligraphy-woodcarving artwork using carbonized board can be a new access for the eco-friendly art that has the advantage of the functionality of charcoal and the aesthetic of calligraphy-woodcarving simultaneously.

Effects of water dependence on the utilization pattern of woody vegetation by elephants in the Tembe Elephant Park, Maputaland, South Africa

AbstractThe utilization of vegetation and particularly trees in enclosed small reserves where elephant populations are confined is a contentious conservation issue. In Tembe Elephant Park in Maputaland, the diverse Sand Forest is considered the most valuable feature to conserve; yet it is considered at risk from increasing elephant utilization of the park’s vegetation in general. The mean canopy removal by elephants across the park was studied over two periods: a recent period including the twelve months before the study and an older period &gt;12 months earlier. Age of utilization was determined from the degree of decay observed on woody fibres. The relationships between intensity of utilization, vegetation unit selection and distance to water were evaluated. Results show that utilization patterns have shifted in the recent drier period, during which elephants used vegetation communities closer to permanent water. Concurringly, a significant decrease in utilization intensity was correlated to an increasing distance from water points in the park during that period, while this effect was not observed during the wetter old period. We debate that active water availability management may be a way to limit elephant utilization in small fenced reserves.

Pulp and Paper Potentials of Plantain Pseudostem

Homogenized pastes were prepared by adding top-bond white glue as binder to natural fibrous material prepared out of different proportions of bamboo (Ozizentera arbonica), coconut husk (Cocus nucifera), sponge (Acanthus montanus) and wood (cordial). Test samples were prepared from dried cast samples for creep and hardness tests. The results of the analysis were used to determine the material that has close properties to the commercially sourced gasket used as control. The overall assessment of the compatibility and suitability tests confirmed the possible applicability of the materials as gasket in fuel pump, carburetors and in engine oil pumps. The locally produced materials have been tested and found suitable as substitute to the conventional material in this order: Coconut husk mixed with sponge (Ch+Sp) in uniform proportion; Coconut husk (Ch) alone without any mixture, and the mixture of the four fibres (Ba+Ch+Sp+Wd). Keywords: Gasket, Agricultural woody fibres, Creep and Hardness. Journal of Science & Technology (Ghana) Vol. 28 (3) 2008: pp. 159-165

CHANGES IN ORGANIC CARBON AND PHYSICAL PROPERTIES OF SOIL AGGREGATES UNDER FIBER FARMING

Interest in intensive forestry systems to produce woody or fiber farming (FF) is increasing because of high energy costs and the risks of global warming. The FF-induced changes in soil structural properties at the microscale or aggregate level important to soil organic carbon (SOC) sequestration and soil-water dynamics are, however, not well understood. Thus, we compared differences in soil physical properties and SOC concentrations in aggregates among tree species after 7 years of plantation establishment on an Onaway fine sandy loam (fine loamy, mixed, active, frigid Inceptic Hapludalfs) at the Upper Peninsula Tree Improvement Center near Escanaba, Mich. Soil samples from 16.8 x 16.8-m plots under six tree taxa and three rates of wood ash application (0, 9, and 18 Mg ha -1 ) were collected in May, 2005. The six tree taxa were European larch (Larix deciduas Mill.), hybrid aspen (Populus tremula x Populus tremuloides), and four poplar taxa: NE-222 (Populus deltoids x Populus nigra var. caudina), DN-5 (Populus euramericana, cv. Gelrica), DN-34 (P. euramericana, cv. Eugenei), and NM-6 (P. nigra x Populus maximowiczii). Tree species induced measurable changes in most soil aggregate properties. Larch and DN-34 increased aggregate mean weight diameter more than N-222 and NM-6. Macroaggregates contained 20% more SOC concentration than microaggregates. Ash application increased tensile strength, soil water retention, and SOC concentration, indicating the benefits of applying ash in FF systems. Within both macroaggregates and microaggregates, NM-6 had the highest SOC concentration, whereas aspen had the lowest of all tree species. The SOC concentration increased with increase in biomass input. Results show that differences in aggregate physical properties and aggregate-associated SOC concentration among tree species were relatively small and depended on the soil property.