Resinous Research Articles

THE EFFECT OF PINE TREE RESIN ON THE THERMAL AND MECHANICAL PROPERTIES OF PLASTER WITH EXPANDED CLAY

This study focused on a new type of insulation plaster consisting of pine tree resin, expanded clay (EC), and gypsum. Gypsum plaster mortars were prepared with ECs with grain diameters of 0-2 mm and 2-4 mm and gypsum binder at 20%, 40%, 60%, and 80% by volume. The resin was added to each mortar at 0.5%, 1%, and 2% of the mix weight to create artificial pores. Samples with 32 different combinations were obtained. The samples were subjected to tests (such as thermal conductivity, compressive strength, ultrasonic sound velocity, and water absorption). The results showed that the higher the pine tree resin volume, the lower the density and thermal conductivity and the higher the compressive strength and porosity. The samples had high water absorption rates. The results indicate that these plasters can be used as interior plasters for insulation purposes and can be painted with any kind of paint.

Initial Ignition Time and Calorific Value Enhancement of Briquette with Added Pine Resin

The increasing demand for clean energy requires considerable effort to find alternative energy sources, such as briquettes. This research aims to develop a charcoal briquette with added pine resin (API) that has excellent combustion speed and distinctive aroma. Briquettes are composed of charcoal, pine resin (concentration: 0%–30%), and starch (up to 7%). They are produced in several stages, including coconut shell pyrolysis in conventional combustion, to obtain charcoal for the briquette precursor. Briquette compaction is conducted by mixing and densifying the charcoal, pine resin, and starch using a hydraulic press for 3 min. The hydraulic press has a total surface area and diameter of 57.7 cm2 and 3.5 cm, respectively. The briquettes are dried at different temperatures, reaching 70°C for 24 h. The study results show that the briquettes have a thickness and diameter of up to 2 and 3.5 cm, respectively; moisture of 2.18%–2.62%; ash of 11.61%–13.98%; volatile matter of 27.15%–51.74%; and fixed carbon content of 40.24%–59.46%. The compressive strength of the briquettes is 186–540 kg/cm2. Their calorific value is 5,338–6,120 kcal/kg, combusting at a high speed of 0.15–0.40 s. The methoxy naphthalene, phenol, benzopyrrole, and lauryl alcohol; ocimene, valencene, and cembrene are found in the API. The API briquette has several chemical compounds, such as musk ambrette, ocimene, sabinene, limonene, 1-(p-cumenyl) adamantane, butane, and propanal, which improve aroma, drug application, and fuel production. Accordingly, API briquettes have considerable potential as an alternative energy source and a health improvement product.

Characterization of Sound Absorption Coefficient and Acoustic Impedance of Palm Frond Fiber Composites with Pine Resin on Various Composition Variations

This research aims to investigate the ability of sound absorption coefficient and the acoustic impedance of Palm Frond Fiber Composites using the one-microphone impedance tube method. We used Palm Frond Fibers as a filler and pine resin as an alternative adhesive of composite with a volume fraction of 50%: 50%, 60%: 40%, 70%: 30%, 80%: 20%, and 90%: 10%. The sound absorption coefficient and acoustic impedance of composites were studied at 500, 1000 Hz, 1500 Hz, 2000 Hz, and 2500 Hz frequency. The results showed that the highest sound absorption coefficient was found in 1500 Hz frequency and using volume fraction 70%:10%. The highest acoustic impedance response was found in composite with a fiber composition of 90% and at the test frequency with a range of 500 Hz -1500 Hz. The composition of the adhesive and fiber greatly affects the impedance value because it was related to the formation of pores in the composite. Based on ISO standard 11654:1997, the value of the sound absorption of sound waves was 0.15, and Palm Frond Fiber had a value above, so it had the potential used as sound absorption material.

Aqueous-phase hydrogenation of α-pinene to cis-pinane using an amphiphilic Ni-based catalyst

Alpha-pinene is an important forest chemical resource, and the cis-pinane obtained by its hydrogenation reaction is used in spices, medicine, and other industries. A hollow nanospheric material with amphiphilic properties in a two-sided structure was prepared, with a nitrogen-doped carbon layer towards the inside and mesoporous silica in the outer layer of the nanospheres. The amphiphilic catalyst with non-precious nickel as the active component was synthesized by loading nickel onto the nanospheres using a simple impregnation method and applied to the aqueous phase hydrogenation reaction of α-pinene. The mesoporous structure of the catalyst shortened the mass transfer distance and thus reduced the mass transfer resistance. The nitrogen atoms doped in the carbon matrix provided anchor points for stabilizing the metal nanoparticles; the hydrophilic outer surface and hydrophobic hollow cavity enabled the catalyst to be well dispersed in water while still enriching the organic matter in aqueous solution. The effect of various reaction conditions on the catalytic reaction was investigated. The catalysts showed excellent activity and good stability, suggesting a new green and efficient method for more effective exploitation of biomass pine resin resources, and providing a reference for expanding the application of non-precious metal catalysts.

APPLICATION OF MAMDANI FUZZY METHOD TO PREDICT THE AMOUNT OF PINE RESIN PRODUCTION

PT. Inhutani IV Aceh District needs to plan the right production in order to achieve maximum profit. Therefore, the company needs to develop a system that can predict the amount of pine resin that can be produced. This study uses data from PT. Inhutani IV Aceh District which is engaged in the production of raw pine resin. This study uses the mamdani fuzzy method to predict the amount of latex production based on demand data, supply data and latex production data per month in 2019-2020. Based on the results of calculations that have been carried out, with the input variable demand in January 2021 of 91,404 kg and supply in December 2020 of 71,466 kg, with the fuzzy mamdani method, the prediction results of the pine resin that the company can produce is 191,763 kg in January 2021 and based on the results of calculations using the MAPE accuracy measure, the fuzzy mamdani method has a MAPE value of 45.69 % so it can be concluded that the mamdani fuzzy method is pretty good for predicting the production of pine resin at PT. Inhutani IV Aceh District.

EVALUASI TUTUPAN LAHAN PASCA PENETAPAN KAWASAN TAMAN BURU MASIGIT KAREUMBI (TBMK) BERBASIS SISTEM INFORMASI GEOGRAFIS

Masigit Kareumbi Game Park (Taman Buru Masigit Kareumbi or TBMK) is a conservation forest that can be used to accomodate game tourism with 12.42070 ha area. In 1998, PT. Prima Multi Sarana (PMS) was given permission to conduct pine resin extraction in 2005 in TBMK area of PT. PMS; however they disobeyed the code of conduct by taking away the wood forest products (Hasil Hutan Kayu or HHK) causing forest damage that leading to the change of land cover in TBMK area. The purpose of this research is to find out how much change of land cover in TBMK after the game park establishment, and the factors that affect the change. This study used spatial data method with SIG system and Snowball Sampling technique in getting respondents’ samples. The result showed that TBMK in Cimanggung Adminiatrative Area had 468,66 ha land cover change in each closing type area from 1997 to 2017. The factors that cause the change of land cover in TBMK are the misuse of permission by PT. PMS, farmers activities in the area, unsettled area border, the lack of area guard and the socialization for the villagers, and the weakness of law enforcement

Hydrogenated terpenic renewable fuels: Emissions and combustion analysis

Waste terpenes from paper industry, pine resin tapping or citric industry are abundant feedstocks that can be used as components in diesel blends. However, terpenes such as turpentine or orange oil are highly reactive, tend to form deposits and show high sooting tendency. These drawbacks can be solved with hydrogenation, which reduces the degree of unsaturation of the molecule and thus, the formation of soot. In this work, blends at 20 vol % of hydrogenated turpentine and hydrogenated orange oil in diesel fuel were tested in a Euro 6 diesel engine following Worldwide harmonized Light-duty Test Cycle (WLTC). Engine performance, gaseous and particle matter emissions and combustion analysis from these blends were compared with those from diesel fuel. Engine performance was similar for all fuels, with slight differences in equivalence ratio and exhaust gas recirculation (EGR) rate. CO and HC emissions were increased whereas NOx emissions remained constant when blends were tested, with respect to diesel. Sooting tendency was improved since particle mass emissions were reduced despite the particle number emissions were similar to those from diesel. Combustion was quite similar between all fuels and only ignition delay was longer and combustion velocity higher for blends in comparison with diesel.

Conifer-killing bark beetles locate fungal symbionts by detecting volatile fungal metabolites of host tree resin monoterpenes.

Outbreaks of the Eurasian spruce bark beetle (Ips typographus) have decimated millions of hectares of conifer forests in Europe in recent years. The ability of these 4.0 to 5.5 mm long insects to kill mature trees over a short period has been sometimes ascribed to two main factors: (1) mass attacks on the host tree to overcome tree defenses and (2) the presence of fungal symbionts that support successful beetle development in the tree. While the role of pheromones in coordinating mass attacks has been well studied, the role of chemical communication in maintaining the fungal symbiosis is poorly understood. Previous evidence indicates that I. typographus can distinguish fungal symbionts of the genera Grosmannia, Endoconidiophora, and Ophiostoma by their de novo synthesized volatile compounds. Here, we hypothesize that the fungal symbionts of this bark beetle species metabolize spruce resin monoterpenes of the beetle's host tree, Norway spruce (Picea abies), and that the volatile products are used as cues by beetles for locating breeding sites with beneficial symbionts. We show that Grosmannia penicillata and other fungal symbionts alter the profile of spruce bark volatiles by converting the major monoterpenes into an attractive blend of oxygenated derivatives. Bornyl acetate was metabolized to camphor, and α- and β-pinene to trans-4-thujanol and other oxygenated products. Electrophysiological measurements showed that I. typographus possesses dedicated olfactory sensory neurons for oxygenated metabolites. Both camphor and trans-4-thujanol attracted beetles at specific doses in walking olfactometer experiments, and the presence of symbiotic fungi enhanced attraction of females to pheromones. Another co-occurring nonbeneficial fungus (Trichoderma sp.) also produced oxygenated monoterpenes, but these were not attractive to I. typographus. Finally, we show that colonization of fungal symbionts on spruce bark diet stimulated beetles to make tunnels into the diet. Collectively, our study suggests that the blends of oxygenated metabolites of conifer monoterpenes produced by fungal symbionts are used by walking bark beetles as attractive or repellent cues to locate breeding or feeding sites containing beneficial microbial symbionts. The oxygenated metabolites may aid beetles in assessing the presence of the fungus, the defense status of the host tree and the density of conspecifics at potential feeding and breeding sites.

Analisis turunnya pendapatan petani penyadap getah Pinus di Jorong Talago Gunuang

The background of the problem in this research is the income earned by the pine resin tapping farmers which has decreased every year due to several factors. The type of research used in this research is field research, namely research conducted in the field with farmers tapping pine resin using purposive sampling method which conducts in-depth interviews with farmers tapping pine resin as resource persons. The purpose of this study was to analyze the factors causing the decline in the income of farmers tapping pine resin in Jorong Talago Gunuang. The results of this study indicate that the factors that cause a decrease in the income of pine resin tapping farmers are the decrease in the production of sap produced by pine resin tapping farmers, which is caused by several factors, namely: 1. Limited Land Area, 2. Lack of Labor , 3. Weather, 4. Abortion, 5. Drugs or Stimulant Liquids.Keywords: Factors Causing Decreased Income, Farmers, Pine Trees

Assessment of the Genotoxic and Cytotoxic Effects of Turpentine in Painters.

Turpentine is a fluid used mainly as a solvent for thinning oil-based paints, obtained by distilling the resin of coniferous trees. Fine art painters use turpentine on a daily basis. The aim of this study was to investigate the genotoxic effect of turpentine and to determine the lymphocyte proliferation index in the peripheral blood of individuals occupationally exposed to turpentine. For this purpose, the cytokinesis-block micronucleus assay (CBMN) was used to determine the total number of micronuclei (MNi), nucleoplasmic bridges (NPB), and nuclear buds (NBUD), as well as the cell proliferation index (CBPI) in the peripheral blood lymphocytes of the subjects. Twenty-two subjects exposed to turpentine daily through their work participated in the study and were compared to twenty subjects in the control group. The results showed a significant increase in the number of micronuclei and other genotoxicity parameters, as well as significant cytotoxicity based on CBPI values. In addition, the genotoxic and cytotoxic effects of turpentine were found to be time-dependent, i.e., the deleterious effects of turpentine on genetic material increase with prolonged exposure. These results strongly suggest that exposure to turpentine vapors may affect genome stability and that occupational safety measures should be taken when using turpentine.

Surface Properties of Concrete and Bonding Strength of Pine Resin-Based Adhesives to Concrete Surfaces

This article reports a quantitative investigation of the surface characteristics of normal concrete manufactured with different types of formworks and bonding strength between pine resin-based adhesives and concrete surfaces. Three types of formworks and adhesives with different ratios of pine resin to wax were prepared. Scanning electron microscopy, energy-dispersiveX-ray spectroscopy, white-light scanning interferometry, and electrophoretic light scattering were utilized for the surface characterization of concrete, and a bonding test was performed. Test results showed that the surface roughness of concrete was significantly influenced by the type of formwork; all techniques including visual observation provided similar results. On the contrary, chemical compositions and electrical characteristics were not influenced by the type of formwork. Bonding test results showed that bonding strength increased as the ratio of wax increased and the degree of the concrete surface roughness increased. The results of this study indicate the feasibility of pine resin-based adhesives for concrete structures as green construction materials.

Genetic analysis and elite tree selection of the main resin components of slash pine.

Pine resin, as a natural material, has been widely used in food, pharmaceutical, and chemical industries. Slash pine (Pinus elliottii Engelm var. elliottii) is the primary tree species for resin tapping due to its high resin yield, low resin crystallization rate, and high turpentine content. Current researches focuse on the targeted improvement of several significant components to meet industrial needs rather than just resin yield. The objective of this study was to examine the genetic variation and correlation of genetic and phenotype for four main resin components (α pinene, β pinene, abietic acid, and levoprimaric acid) of 219 half-sib progenies from 59 families. The results showed that the levopimaric acid had the largest content (mean value = 21.63%), while the β pinene content had the largest variation coefficient (CV = 0.42). The α pinene content has the highest heritability (h2 = 0.67), while levopimaric acid has the lowest heritability (h2 = 0.51). There was a significant negative correlation between α pinene and the other three components and a significant positive correlation between β pinene and the two diterpenes. The family ranking and genetic gain suggested that it is possible to improve the contents of main resin components of slash pine through genetic breeding selection.

Unravelling the Egyptian embalming materials by a multi-method approach comprising high-resolution mass spectrometry

Deciphering the biomolecular composition of archaeological organic materials can contribute to understand the function of an object or the status of the buried person, and more generally to increase our knowledge on ancient civilizations. The determination of the organic substances composing the sample is based on identifying biomarkers, which is commonly carried out by gas chromatography-mass spectrometry (GC-MS). Here high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) was used, along with GC-MS and infrared spectroscopy, to investigate the organic compounds of embalming material of Egyptian crocodile mummies. FTICR MS was evidenced to provide complementary information with some advantages compared to GC-MS, such as an easier sample preparation. Moreover, although GC-MS allowed identifying 109 different compounds, FTICR MS enabled to assign up to 7000 molecular formulae and to detect higher-mass compounds. Some of the molecular assignments were putatively attributed with biomarkers, which suggested the use of pine resin, beeswax, and vegetal and animal fat, which was confirmed by GC-MS and FTICR MS-MS, for the pine resin. Furthermore, the FTICR MS molecular fingerprint obtained for the archaeological samples was compared with those of modern pine resin, which allowed assessing specie oxidation due the ageing and/or heating process. Consequently, FTICR MS can be regarded as a way to quickly achieve the biomolecular fingerprint of organic residues from archaeological materials and to assess the state of degradation of the sample.

Analisis Penerimaan Petani Penyadap Getah Pinus Di Hutan Kemasyarakatan Sipatuo Lembang Pa’tengko Kecamatan Mengkendek Kabupaten Tana Toraja

This study aims to analyze how much pine resin tapping farmers receive and describe the marketing channels of pine resin tapping farmers in the Sipatuo Community Forest, Lembang Pa'tengko, Mengkendek District, Tana Toraja Regency. The variables to be observed in this study are pine resin production, tapper farmers' revenue, socio-economic factors, management of Sipatuo HKm, and marketing channels. The data collection method was carried out through surveys and distributing questionnaires to pine resin tappers as many as 40 respondents. Data is analyzed descriptively and revenue is calculated based on the Total Revenue equation. The results showed that the Sipatuo HKm was a limited production forest managed by the Lembang Pa'tengko community, the tree stands that were managed were a government reforestation program in 1976-1978. Furthermore, the results of the analysis of the average tapper acceptance of Rp6,300,450 thus the reception of tappers at HKm Sipatuo is sufficient to meet household needs because the average acceptance of tappers exceeds the UMP of South Sulawesi. Marketing of pine resin in HKm is carried out on average once a month, with a selling price of pine resin, which is Rp. 9,500.00 where the pine resin is sold to partners as one intermediary, then the pine resin is sent to CV.Pindo Indonesia in Makassar as a large collector.

Anti‐parasitic function of tree‐rubbing behaviour in brown bears suggested by an in vitro test on a generalist ectoparasite

AbstractRubbing against various objects or self‐anointing with pungent substances are behaviours observed in many mammal species. The brown bear (Ursus arctos) is a non‐territorial species that rubs against trees with the main purpose being intraspecific communication. In addition, some odorous substances are known for eliciting rubbing behaviour and hence are used to lure bears to trees in studies relying on non‐invasive hair collection. Tree‐rubbing is often accompanied by clawing and debarking which release tree resin that impregnates the fur and can potentially deter ectoparasites. Here, we present a study aiming to determine whether ticks, being widely spread and an important vector of pathogens, are repelled by resin products known to attract bears and elicit rubbing behaviour, namely turpentine and beech tar. Dermacentor reticulatus ticks were offered a binary microhabitat choice by placing them in the middle of individual horizontal tubes with tested substances placed on filter paper at one end, and distilled water as a control (neutral) substance at the other. Their behaviour was recorded for three minutes. Ticks consistently touched the neutral end of the tube while avoiding treated ones. Overall, ticks remained at greater distances from treatments than from water. A fitted logarithmic regression showed ticks did not spend more than seconds at a treated side, supporting our prediction that ticks are repelled by turpentine and beech tar. Parasite repellency may bring a further advantage in rubbing behaviour trade‐offs, compensating some energetical costs, and adds a trait to the behaviour important in seemingly divergent contexts of intraspecific communication and defense against ectoparasites.

Amber Extract Suppressed Mast Cell-Mediated Allergic Inflammation via the Regulation of Allergic Mediators—An In Vitro Study

The various clinical approaches for treating allergy-related diseases have shown modest progress in low side effects and improved clinical outcomes. Therefore, finding alternative anti-allergic agents is crucial. The present study explored the anti-allergic effects of amber extract (fossilized tree resin) in RBL-2H3 mast cells stimulated with different allergens. In order to support the information on the inflammatory effect of the amber extract, NO production analysis on RAW 264.7 cells was conducted. β-Hexosaminidase release, an indicator of the efficacy of the amber extract in preventing mast cell activation and degranulation, reactive oxygen species (ROS) generation, and the effect of the amber extract on key cytokines production on RBL-2H3 cells, was evaluated. The results demonstrated that amber extract at concentrations up to 50 μg/mL had no cytotoxic effect on RAW 264.7 and RBL-2H3 cells. Amber extract inhibited NO production in RAW 264.7 cells. Treatment with amber extract significantly suppressed the release of β-hexosaminidase, especially at 50 μg/mL. Furthermore, amber extract suppressed the significantly increased ROS levels induced by allergen stimulation and allergy-associated cytokines. The results also suggested that amber extract exerts anti-allergic inflammatory effects by inhibiting the MAPK and NF-κB signaling pathways, resulting in decreased cytokines production. Thus, the amber extract is a promising anti-allergic agent.

Thermal and mechanical analysis of thermal power plant ashes, cement and resin composites

This study used thermal power plant fly ash (FA) and bottom ash (BA) as fill materials and investigated the thermal properties of composites made of cement and pine tree resin binders. For each ash group, 36 samples were prepared by adding 50% cement and 1% to 2% resin as binders. i) FA samples had 23.18%, 22.99%, and 77.01% lower density, thermal conductivity, and compressive strength than BA samples, respectively. FA samples had 9.42% higher porosity than BA samples. ii) FA (0.177 W/mK) and BA (0.221 W/mK) samples with resin and cement had the lowest heat transfer coefficients. iii) FA (14.46 MPa) and BA (36.96 MPa) samples (resin + cement binder) had the highest compressive strength values.

Effectiveness of three Gabonese tree resin fractions combined with tebuconazole as wood preservative formulations

Wood treatments based on oleoresins from Aucoumea Klaineana, Canarium schweinfurthii and Dacryodes edulis have shown interesting anti-termites properties but poor resistance to fungi and leaching. Oleoresins were combined with tebuconazole to produce both antifungal and anti-termite wood preservatives formulations with an expected better fixation of chemicals mixtures in the wood. Beech and Scots pine wood block samples were impregnated by these different formulations and exposed to white and brown rot, respectively, as well as to European termite (Reticulitermes flavipes). The use of aqueous formulations of each oleoresin of combined to tebuconazole improved the wood resistance against termites and mainly brown rot. In addition, the best formulation was found by using the raw resin from Aucoumea Klaineana. These results are mainly due to the antifungal activity of tebuconazole. In addition, the presence of antioxidant chemicals in the wood resins inhibits the wood decay fungi growth and acts as enzyme and metabolism inhibitors disturbing the treated wood digestion process by termites. For the future, the promising protection obtained should be formulated to be resistant to leaching.

ДОСЛІДЖЕННЯ ВЛАСТИВОСТЕЙ ФУНКЦІОНАЛЬНИХ ДОБАВОК РОСЛИННОГО ПОХОДЖЕННЯ ДЛЯ МАЙОНЕЗНОЇ ПРОДУКЦІЇ

Mayonnaise and mayonnaise sauces hold a significant place in the diet of a modern person. Their production volume world-wide has a constant tendency to increase. The product range is expanding, considering the modern trends in healthy nutrition.Consumer demand for mayonnaise products with low fat content, free from animal-d erived ingredients, enriched with vitamins, trace elements, and dietary fibers, necessitates the search for new functional additives and the study of their technological prop-erties. The article presents the results of a study on the properties of vegetable fiber (cake), different fractions of crushed seeds and flour of flax, sesame, pumpkin, and their mixtures. A comprehensive thickener based on flax products is proposed.The use of plant-based functional additives in the production of low-fat mayonnaise and mayonnaise sauces allows for the enrichment of these products with a complex of beneficial nutrients and dietary fibers while contributing to the formation of a stable emulsion product.When developing recipes for water-fat emulsion products with a significant proportion of the water phase, it is necessary to consider the properties of the components, their influence on the quality of mayonnaise, and possible changes in properties during the production process. An important technological characteristic of special functional additives in low-fat mayonnaise products is their ability to retain water, thereby regulating the viscosity and consistency of the final product.Analysis of research and publications has shown that considerable attention is given to expanding the range of functional mayonnaise products (including dietary, vegan, and enriched with beneficial nutrients). Starches, pectins, microbial polysac-charides, a wide range of E-additives obtained from algae and tree resin are suggested as rheological additives in low-fat mayonnaise and mayonnaise sauces. Flour, cake, meal, and protein isolates obtained from them serve as effective thickeners.The aim of the article is to study the properties of both individual types of plant-based functional additives and their mixtures, as well as to establish the possibility of regulating a parameter such as moisture-retaining capacity for mixtures containing the same type of raw materials, including cake, flour, and crushed seeds in different ratios.The moisture-retaining capacity of the studied samples was determined using the centrifugation method. The highest moisture-retaining capacity is observed in flax seed cake (806.2%), while crushed pumpkin seeds show the lowest capacity (104.7%) due to their high fat content. The possibility of adjusting the moisture-retaining capacity parameter of mixtures of cake, flour, and crushed seeds by varying the amount of individual components in complex additives for low-fat mayonnaise was studied. A proposed recipe for eggless mayonnaise utilizes a complex based on flax products with a ratio of flax cake, flour, and crushed seeds (fraction with particle size up to 0.5 mm) of 1:1:0.5, respectively. For the produced mayonnaise with 25 % fat content and the complex functional additive, the emulsion stability indicator was determined, meeting the requirements of the relevant Ukrainian standards for mayonnaises and mayonnaise sauces.

Host odour alpha-pinene increases or reduces response of Ips avulsus (Coleoptera: Curculionidae: Scolytinae) to its aggregation pheromone, depending on separation of release points

Abstract Monoterpenes in the resin of host trees are important host-location and -selection signals for conifer-infesting bark beetles and can increase or reduce responses to aggregation pheromones. Research on this interaction has been largely limited to collocated release points of the semiochemicals; however, sources are often separated in nature. I performed a trapping experiment to investigate whether distance between semiochemical release points influences how host monoterpene alpha-pinene affects Ips avulsus (Eichhoff) (Coleoptera: Curculionidae) response to its aggregation pheromone (ipsdienol and lanierone). High release (8 g/day) of alpha-pinene from a pheromone-baited trap caused a reduction in catches, but the same release of alpha-pinene from 4 m away significantly increased catches relative to pheromone alone. A low release (0.06 g/day) of alpha-pinene with either arrangement had no effect. Hence, a host odour released at rates sufficient to deter I. avulsus responses to its pheromone may nevertheless enhance attraction if the release point is sufficiently displaced from the pheromone source. The result suggests that, for I. avulsus, the semiochemical alpha-pinene may influence host finding and close-range assessment of host suitability in different ways. Operational lure formulations for some species of bark beetle might be improved by separating pheromone and host odour components or by adding a displaced host odour device.