Institute of Wood Science and Technology

Transparent wood (TW) has garnered signifcant global attention due to its unique properties. In this study, TW composites were fabricated using two timber species of diferent density classes: Ailanthus triphysa (common name: Ailanthus wood) and Hevea brasiliensis (common name: Rubberwood). Sodium hydroxide (NaOH) and Hydrogen peroxide-based alkali method was used to modify the lignin in these veneer samples, producing a white cellulose template with a fully intact hierarchical cell structure. Subsequently, a cost-efective thermosetting unsaturated polyester resin (UPR) was infltrated into the redesigned framework and polymerized to create rigid nanostructured transparent composites. High optical haze (of 94% and 89%) and favourable light transmittance of 59 and 55 percent were exhibited by the UPR-TW composites made from rubberwood and ailanthus wood, respectively. TW was characterised using Scanning electron microscopy and Fourier-transform infrared spectroscopy. The mechanical properties of TW were measured and compared with those of natural wood and pure-polymer. Furthermore, the anisotropic light difusion behaviour displayed by TW in accordance with the fbre orientation indicates the utility of material as a potential light shaping device. Therefore, a cost-efective and commercially viable strategy to fabricate multipurpose TW composites using a combination of lesser-known timber species (LKTS) and UPR resin was successfully demonstrated.

The efficacy of bifenthrin-propiconazole preservative treatment of Dendrocalamus brandisii strips-based laminated bamboo lumber (LBL) was evaluated against fungal decay. The effect of preservative treatment on a few important physico-mechnical properties of LBL was also studied. The changes in chemical structure, microstructure and crystallinity of bamboo after exposure to fungi were studied using Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction analytical techniques. The treatment of bamboo strips with bifenthrin alone did not improve the decay resistance of LBL. A gradual reduction in percent weight loss was observed as the propiconazole concentration was increased indicating increased treatment efficacy. The mechanical properties namely MOR, MOE compressive strength parallel to fiber direction and glue shear strength were not much affected. The LBL prepared from 1.2% propiconazole and 3% bifenthrin-treated strips showed relatively lower changes in different functional groups and crystalline structure compared to untreated LBL after exposure to rotting fungi. The propiconazole-treated LBL did not show evidences of deep penetration of hyphae after exposure to both fungi. Hence, propiconazole-based formulations may be used to improve the decay resistance of LBL against fungal attack to class 1 without detrimental effects on physico-mechanical properties.

Transparent wood (TW) has attracted tremendous research interest due to its numerous adaptive features and applications as a sustainable material. The present study unveils a novel and simple method of preparing luminescent transparent wood (LTW) with good optical properties and UV-blocking nature. LTW was prepared by pre-treatment of lignin-modified wood (LMW) with a commercial fabric brightener/optical brightener (Ranipal ®) prior to polymer infiltration. The resultant LTW showed unique bluish photoluminescence upon UV light irradiation. Under normal light illumination, the LTW exhibited a brilliant bright/white appearance compared to untreated TW samples. LTW fabricated using 1 mm thick silver oak wood veneer exhibited high transparency (82%) and high haze (90%) with enhanced UV blocking property. The novel LTW fabrication method using a readily available and low-cost fabric brightener has significantly reduced the overall process complexity of LTW preparation. The treatment with optical brightener had no adverse effect on the material quality. The fabricated LTW with good optical features can be an excellent bio-based input material to the multifunctional smart material category.

Bamboo is a widely available bio-resource that is considered as a sustainable and eco-friendly raw material for fabricating composites that could replace timber and timber-based products. Several structural bamboo composites (SBCs) have been developed as a sustainable alternative to traditional load-bearing materials in different applications. These composites utilise bamboo in its converted forms viz., strips or strands, bonded with structural grade polymeric adhesives, and compacted and cured under pressure and at high temperature, forming thick panels or beams with standardized cross-sections. With recent advances in processing technologies, several interventions have been undertaken to improve the production efficiency and overall properties and performance of SBCs. While the properties of these composites are comparable or even better than those of commonly used wood and wood-based mass timber products, their performance is strongly influenced by the different processing parameters used in their fabrication. This article presents a comprehensive overview of the recent literature about the production process of SBCs and their physico-mechanical and other properties, factors affecting these quality parameters and current developments in processing technologies. It also examines potential applications and the future scope of research work in this area.

Tectona grandis L.f. (teak), though considered a paragon among timber species, raises several questions on quality parameters when grown on farmlands. The growth characteristics and important wood quality parameters such as equilibrium moisture content, density, shrinkage, static bending strength and stiffness, compressive strength parallel and perpendicular to grain, hardness, nail and screw holding powers of 24–25-year-old teak from intensively managed block (Bim), partially managed line (Lpm) and unmanaged block (Bum) plantations grown under agroforestry practices (AFP) were studied. Overall growth rate of teak trees of Bim was greater than Lpm and Bum. Few wood quality parameters of Bum were comparatively better than Bim and Lpm. However, teak from three AFP exhibited lower wood quality parameters compared to average values of forest teak. Superiority of Bum is reflected mainly in density and bending strength compared to Bim and Lpm. Other properties like compressive strength, hardness and nail and screw holding powers were almost comparable among three AFP. Flexural strength, compression parallel to grain and hardness of Bim and Lpm were found to be comparable. Average wood properties of both managed plantations were lower than Bum. There was no significant effect observed in specific gravity of wood when age of trees increased from 12 to 24 years. Although, Bum exhibited better or comparable properties to Bim and Lpm, average growth was significantly lower than managed plantations. Selective harvesting of Bum at pole stage may support optimal resource utilization, reduce inter-tree competition and provide an option to further delay felling of unharvested residual trees. Delayed harvesting of teak may provide more optimal economic utilisation as strength parameters are predicted to improve with increased maturity. If a decision to enhance financial returns is warranted, commercial felling could be initiated for Bim among the three options, due to its higher growth rate and moderate wood properties which can translate into higher returns. The outcome of the present study may be useful to stakeholders for taking appropriate management decisions for optimal utilization of the farm grown teak bioresource.

The performance of two bamboo composites namely laminated bamboo lumber (LBL) and bamboo stand lumber (BSL) coated with solvent- and water-based polyurethane (PUS and PUW) surface protectants against accelerated UV and natural weathering was evaluated and compared. Thin strips and crushed strands of B. bambos were processed using phenol formaldehyde (PF) adhesive in a hydraulic hot press to prepare the LBL and BSL respectively. The uncoated LBL and BSL exhibited severe darkening of the surfaces on exposure to both weathering regimes. All the polyurethane (PU) coated LBL and BSL showed tendency to undergo photo-yellowing after UV exposure. The roughness, wettability and reduction in glossiness of the coated samples was observed to be increased with increasing exposure period however, the rate of changes in these parameters were lower compared to their uncoated counterparts. The FT-IR spectroscopy results revealed that the lignin present in uncoated LBL and BSL deteriorated rapidly on exposure to UV and natural weathering conditions. It was concluded that the both PUS and PUW coatings on the bamboo composites provided substantial resistance against UV irradiation. The PUS coated LBL exhibited better performance by showing lower colour changes and surface cracking compared to coated BSL on exposure to natural weathering. Overall the performance of PUS coated specimens against natural weathering condition was found to be strongly influenced by the surface properties of the bamboo composites.

This chapter summarizes information on a selected number of phytoplasma diseases of temperate trees, with emphasis on molecular and taxonomic aspects of the associated phytoplasmas. The reviewed diseases are widespread and of considerable economic and ecological significance. They differ in their geographic distribution, number, and size of the various taxonomic groups and subgroups of the associated phytoplasma(s), and insect-vector relationships. Various diseases such as European stone fruit yellows, X-disease, apple proliferation, elm yellows, alder yellows, and ash yellows appear to be specific because they are induced by specific pathogens, which exhibit a high plant host and insect vector specificity. For each of these diseases, in addition to the specific pathogen, the occurrence of “nonspecific” phytoplasmas has also been reported to be associated in some instances. However, the etiological role of these “nonspecific” phytoplasmas needs to be validated by pathological studies. Other phytoplasma diseases of trees such as those affecting conifers and eucalyptus are each associated with taxonomically different phytoplasmas, which induce identical symptoms in a given plant host and are present in the same areas or different countries. Phytoplasma diseases of trees very often escape observation because affected plants show nonspecific symptoms only such as yellowing, stunting, and/or decline. Also, the phytoplasma titer in diseased plants is often so low that infections can only be detected through highly sensitive nested PCR assays. Latent phytoplasma infections, which are common in trees, can serve as inoculum reservoirs for further spread to susceptible plants.

Societal Impact Statement Sandalwood and other high value tree species are under significant threat from illegal harvest. Illegal logging is an increasing problem contributing to deforestation, biodiversity loss, human rights abuses and funding transnational crime. Successful prosecution of illegal logging is hindered by a lack of methods to provide evidence of the origin of timber. New analytical techniques have been developed to trace timber back to its source. These methods, together with the establishment of sustainable sources of forest resources, can help protect vulnerable species by providing evidence to prosecute illegal harvest and ensure that commercially available forest products come from sustainable sources. Summary Sandalwood is highly valued for its fragrant oil and has a long history of cultural and economic importance in many regions of the world. Historical overharvest and poor management have depleted natural populations of sandalwood, which are slow to regenerate. The increasing establishment of plantation sandalwood creates an alternative resource for the sandalwood industry while potentially relieving harvesting pressure on natural stands. Due to the high demand for sandalwood, remaining wild populations are still under threat from illegal logging and methods to identify the source of harvested sandalwood are needed. Laws and regulations aimed at preventing illegal harvest and possession of sandalwood have been put in place but cannot be enforced without the forensic tools to independently verify claimed origin or product quality. The high value of sandalwood combined with the difficulties in enforcing illegal logging laws makes these species particularly vulnerable to poaching. There is an immediate need to develop tools that can identify illegally sourced and adulterated sandalwood products. This paper reviews the current and developing scientific tools that can help identify and control illegal activity in sandalwood supply chains and provides recommendations for future research. Topics include isotope and DNA analysis for tracing illegally harvested sandalwood, chemical profiling for quality control of sandalwood oils, network and policy development to establish a framework for future regulation of the sandalwood trade.

Microbes, especially viruses, microbial eukaryotes, bacteria, fungi, protozoa, and archaea, play a key part in the aquatic ecosystem and help in providing a wide range of environmental services. Microbial coalitions can be found as detrimental microbial traps, biofilms, and planktonic microalgal‐bacterial complexes that help in the breakdown of organic matter and the purification of aquatic ecosystems. Rich microbial diversity depends on nutritional and current environmental circumstances that support the healthy functioning of an aquatic ecosystem. Microbes contribute significantly to the biogeochemical cycle by involving themselves in nitrogen fixation, oxygen generation, nutrient and mineral cycling, and methanogenesis. They also contribute to energy flow in aquatic ecosystems, thereby improving water quality by decaying environmental contaminants. Microbes play a critical part in the treatment of polluted water through the bioremediation process which converts harmful toxic substances to less toxic and desirable end products, such as CO 2 and H 2 O. It is a less expensive technology that produces no waste as a byproduct and gives the finest alternative to traditional wastewater treatment and management technologies in order to maintain a healthy environment.

Garcinia indica, commonly known as Kokum is a vulnerable species and endemic to Western Ghats. The fruits are commercially important and have multifarious uses. Genetic variation within the species is studied using DNA finger printing for its commercial exploitation. Extraction of DNA from Garcinia indica is challenging due to the presence of high level of secondary metabo-lites like polyphenols and flavonoids. The present study focuses on extraction and estimation of DNA from silica-gel dried leaves. Leaf samples were collected from two different regions of Western Ghats viz., Kukke Subramanya (n=4) and Karwar(n=6). The leaf samples were stored in silica-gel during transportation to laboratory, dried well in silica-gel and later stored at-20ºC for long-term storage. The DNA was extracted with 4% Cetyl trimethyl ammonium bromide (CTAB). The concentration of polyvinyl pyrrolidone (PVP) and β-mercaptoethanol was modified in extraction buffer to reduce the interference of secondary metabolites. The determination of quality and quantity of DNA are essential for amplification of DNA in PCR. The DNA obtained showed absorbance ratio (A260/280) between 1.6-1.9 indicating the good quality of DNA and the quantity varied from 111.8-297.9 ng/μl in the silica-gel dried samples. In the present investigation, the modified method of extraction of DNA found to be best method for obtaining good quality and quantity of DNA from the silica-gel dried leaves of Garcinia indica.

Bamboo culms of Dendrocalamus strictus (Roxb.) were subjected to thermal modification at different treatment temperatures of 160, 180 and 200 °C under partial vacuum. Control and thermally modified bamboos were converted into strips and crushed strands to produce laminated (LBL) and scrimber (SBL) composites respectively using melamine formaldehyde adhesive. Effects of treatment temperatures on various properties including decay resistance were studied and characterized using XRD and FTIR. Average EMC was reduced to different levels depending on severity of thermal treatments. Density of composite was improved significantly and increasing treatment temperatures exhibited greater anti-swelling efficiency. Dark colour of modified bamboo was influenced by treatment parameters, while microstructure was not much affected. Most of mechanical parameters of composites produced from bamboo modified were enhanced. However, higher temperature (≥ 200 °C) showed detrimental effects on strength. Modified bamboo exhibited greater decay resistance against two rotting fungi. Some changes in crystalline structure and certain functional groups were observed after thermal modification. With desirable improvements in aesthetic and quality parameters, composites from thermally modified bamboo may be considered as ecological alternative to preservative treated materials. The LBL and SBL may, therefore, be utilized in production of valued-added lifestyle artifact in allied bamboo industry sectors.

This study aimed to characterize the surface quality of beech wood (Fagus sylvatica L.) cut by a CO2-laser. Boards were conditioned to a low (about 8% moisture content), 12%, and a high, (about 18%) moisture content. Laser cutting was performed at varying processing parameters, i.e. cutting speed, gas pressure and focal-point position. A confocal microscope was used to determine the average surface roughness perpendicular to the grain. The anatomical structures of the laser-cut surfaces were examined with scanning electron microscope. The result showed that smoother surfaces were obtained at the low moisture content when processed at a gas pressure of 21 bar. Focal-point positioning did only have an effect on the surface roughness at 12% moisture content whereas the value was substantially lower for focal-point positioned on the surface. The surfaces cut at 18% moisture content, and at a cutting speed of 3.5 m/min generated a rougher surface than cut at low moisture content and at a lower speed. Laser cutting produced a rougher surface as compared to sawn surface (circular saw). The structural integrity of the laser-cut surface was more intact when the wood was having high moisture content and processed at a high cutting speed.

The Sandalwood Spike disease (SSD)-related to ‘Ca. Phytoplasma asteris’ has threatened the existence of sandalwood in India. The epidemiology of SSD is still poorly understood despite the efforts to understand the involvement of insect vectors in SSD transmission and alternate plant hosts over the last two decades. Apart from the transmission of SSD phytoplasma through insect vectors, the information on vertical transmission is entirely unknown. Over 200 seeds from SSD-affected trees and over 500 seedlings generated using commercially purchased seeds were screened for the presence of SSD phytoplasma to understand the vertical transmission in an insect-free environment. The end-point nested PCR and real-time nested PCR-based screening revealed an alarming rate of 38.66% and 23.23% phytoplasma positivity in one-month and four-month-old seedlings, respectively. These results were further validated by visualizing the phytoplasma bodies in sandalwood tissues using scanning electron microscopy. The presence of phytoplasma DNA in the seeds and seedlings is a concern for the commercial distribution of sandalwood seedlings in the current setup. This also poses a fear of spreading the disease to newer areas and negatively affecting the economy. The seedling mortality was also suspected to be associated with isolated bacterial and fungal isolates such as Erwinia, Curtobacterium, Pseudomonas, Rhodococcus, Aspergillus, Fusarium, and Neofusicoccum isolated using a culture-dependent approach. These findings strongly recommend the accreditation of commercial production of sandalwood seedlings curtailing SSD phytoplasma’s menace. Additionally, a new nested end-point and qRT PCR assays developed in this study proved valuable for the rapid screening of phytoplasma in many plant samples to detect phytoplasmas.

Forests harbour most of the known insects, and they perform multiple functions in forest ecosystems. Their ubiquitous presence in diversified forest habitats proves their adaptive behaviour, which makes them the most successful. Their roles in forests are so diverse that they can be seen in all the trophic systems, as herbivores, detritivores, parasites, predators, pollinators, etc. The classification as beneficial and harmful insects is because of their functional diversity, which is more or less the same as in other terrestrial or aquatic ecosystems. The cultural, aesthetic, and nutritional values of forest insects are seldom valued and made use of. The status issues on diversity are more or less parallel to the type of forests and the topographical and climatic regimes. The issues are mostly related to plant diversity and the diverse roles that insects play. Challenges are mainly the management of pests, their spread potential, and outbreaks due to disruption of natural balances. The major challenge is their multiplication rate and devastation potential. Unlike in agriculture, natural mechanisms of biological control play a major role in pest regulation. However, anthropogenic interventions in forest management and maintenance disrupt the natural functions and create skewed outcomes, which lead to pest outbreaks and uncontrollable damage to specific ecosystems. The invasive alien species, especially weeds, sometimes cause unmanageable population buildups so that the native plants get affected badly. The natural and manmade climatic changes add to the imbalance in the natural balance of floral and faunal components, but the capacity of forests to build resilience comes to the rescue of the faunal components, especially the insects. The population shifts in distribution often save them from extinction. The insects in forests are really a mystery still, and it may take many more years to unravel the hidden treasures of insect life in forests. This chapter deals with the forest insect groups from a trophic level perspective, the functionality, habits of living, adaptation behaviour, and their ecosystem services.KeywordsTrophic levelHerbivoresParasitesPredatorsPollinatorsClimate changeBio control

Indian sandalwood (Santalum album), esteemed for its heartwood and oil is subjected to various important diseases which cause a lack of growth and consequently loss of the valuable heartwood and oil or may kill the trees. This can lead to a devastating economic loss to farmers. There is a pressing need to conserve health of sandalwood trees by determining disease prevention measures and to investigate pragmatic solutions to reduce losses caused by destructive diseases. The purpose of this review is mainly to inform the scientific community about so far reported deleterious pathogenic diseases in India, China, Australia, Bangladesh and their impact, thereby helping to facilitate development of a suitable suite of practices for combating the scourge of diseases affecting sandalwood, ultimately helping the sandalwood farming communities. A comprehensive review on the same is presented.

Plastic waste management is one of the most critical issues of the present era due to non-biodegradability of the material along with the enormous quantity of plastic waste generated globally. Repurposing the plastic waste is one of the possible solutions for managing such material. The present study explores the possibilities of using single use plastic food containers as an adhesive for making wood veneer based composite material akin plywood. The concept also addresses the formaldehyde emission based concerns during the manufacturing of conventional plywood using traditionally used adhesive i.e. Urea Formaldehyde, Phenol Formaldehyde, Melamine Urea Formaldehyde etc. The rate of generation of plastic waste is estimated to be 400 Mt year ⁻¹. In the present study the study focuses on preparation of plywood using Melia dubia veneers and polypropylene polymer based food containers as the binding agent. The containers were cut open to transform into sheet form and were placed between veneers and the assembly was hot-pressed to get panels. The effect of pressing temperature and type of food container (transparent and opaque) on the properties of the panels. Physical properties such as density, water absorption, thickness swelling and volumetric swelling were evaluated and mechanical properties like modulus of rupture, modulus of elasticity, tensile strength and glue share strength were also evaluated. There was no significant change in physical properties with variation in temperature and type of polypropylene boxes, however with change in pressing temperature there was significant change in mechanical properties. The modulus of rupture of plywood bonded with opaque polypropylene boxes at 165 °C and 185 °C was observed to be 85 ± 6.92 MPa and 73 ± 6 MPa, respectively.

This paper describes the fabrication of large size transparent wood composite (TWC) from longitudinal veneers of three hardwood wood species viz., Populus deltoides (Poplar), Grevillea robusta (Silver oak) and Melia dubia (Melia) based on two-step lignin modification bleaching process and polymer (epoxy resin) infiltration. High optical transmittance of ~83.5%, ~76.7% and ~72.8% was obtained at 550 nm wavelength for TWC prepared using 2 mm thick veneers of Poplar, Melia and Silver oak, respectively. Fourier transform infrared spectroscopy and scanning electron microscopy validate preservation of substantial lignin and successful inclusion of polymer in the wood micro-structure. X-Ray diffraction technique was used for analyzing crystallinity in wood and TWC material. Thermal behavior of wood and TWC was studied using thermogravimetric analysis and differential scanning calorimetry. TWC exhibited low density, good mechanical properties, low thermal conductivity (0.36 W/mK) and good thermal stability.

Wood fiber filled high density polyethylene composites (WPCs) were prepared using twin screw extruder and maleated polyethylene as a coupling agent. Bamboo fibers were initially treated with alkali (NaOH), boric acid - borax (Ba-Bx) and borax (Bx). The treated and untreated fibers were used in combination with ammonium polyphosphate (APP) to investigate their synergistic effects on thermal stability, flame retardancy and mechanical properties. Alkali pretreatment (5 % NaOH) of fibers showed significant improvement in performance of APP by increasing thermal stability in WPCs. The derivative thermogravimetric (DTG) results indicate significance of Ba-Bx in promoting char induction at lower temperatures (340 ºC) and thereby, improved the thermal stability in WPCs. Flammability decreased with addition of flame retardant additives. As compared to pure WPCs, composites containing APP 10 % / Ba-Bx 5 % exhibited maximum reduction in average heat release rate (HRR) by 69 %, peak heat release rate (PHRR) by 59 %, total heat released rate (THR) by 48 % and also increased time to ignition (TTI) by 62 %. However, no significant difference was found among the combinations i.e., APP with or without compounds towards reducing the flammability of WPCs. The strength properties also reduced significantly when boron compounds were added along with APP. In general, APP alone (15 %) is enough for imparting thermal stability and flame retardancy in WPCs.