Search

Biocontrol strategies are gaining tremendous attention in insect pest management, such as controlling termite damage, due to the growing awareness of the irreparable harm caused by the continuous use of synthetic pesticides. This study examines the proteolytic and chitinolytic activities of Bacillus velezensis CE 100 and its termiticidal effect through cuticle degradation. The proteolytic and chitinolytic activities of B. velezensis CE 100 systematically increased with cell growth to the respective peaks of 68.3 and 128.3 units/mL after seven days of inoculation, corresponding with the highest cell growth of 16 × 107 colony-forming units (CFU)/mL. The in vitro termiticidal assay showed that B. velezensis CE 100 caused a rapid and high rate of termite mortality, with a median lethal time (LT50) of >1 h and the highest mortality rates of 91.1% and 92.2% recorded at 11 h and 12 h in the bacterial broth culture and crude enzyme fraction, respectively. In addition to broken setae and deformed sockets, termites treated with the bacterial broth culture exhibited degraded epicuticles, while the crude enzyme fraction caused severe disintegration of both the epicuticle and endocuticle. These results indicate the tremendously higher potential of B. velezensis CE 100 in the biological control of subterranean termites compared to the previously used entomopathogenic bacteria.

Subterranean termites of the species Reticulitermes speratus kyushuensis Morimoto (Isoptera: Rhinotermitidae) are notoriously destructive soil-dwelling pests that feed on the cellulosic wood biomass. This leads to tremendous losses of forest trees such as Pinus densiflora Siebold and Zucc. (Pinales: Pinaceae) and precious wooden structures of cultural heritage. This study investigated the efficacy of chitinase and protease produced by Bacillus licheniformis PR2 as cuticle-degrading enzymes for the biocontrol of worker termites. Bacillus licheniformis PR2 produced a strong chitinase and protease activity up to a maximum of 82.3 unit/mL and 35.9 unit/mL, respectively, and caused a lethal effect on termites under laboratory conditions. Treatment of termites with the bacterial broth culture and the crude enzyme fraction of B. licheniformis PR2 resulted in a maximum mortality rate (with a median lethal time (ET50)) of 83.3% (3 h, 36 min) and 88.9% (2 h, 59 min), respectively. The termites treated with B. licheniformis PR2 exhibited loss of setae, disintegration of epicuticle, rupturing of procuticle, and swelling at sockets. The degradation of cuticular chitin and glycoprotein polymers in the termite cuticle by chitinase and protease enzymes produced by B. licheniformis PR2 represents an effective eco-friendly strategy for controlling termite damage in Korean cultural heritage sites and forests.

황장목(黃腸木)은 적황색을 띠는 심재부의 비율이 높고 연륜폭이 매우 조밀하며 최소 수령이 100년 이상 되는 귀중한 소나무 자원이다. 조선시대에는 황장목을 궁궐, 사찰 등 중요 건축물에 사용하였다. 하지만 황장목의 재질특성에 관한 연구는 매우 부족한 실정이다. 본 연구에서는 황장목의 천연내구성을 검토하기 위하여 부후균 및 흰개미 저항성을 조사하였다. 공시균은 갈색부후균(Fomitopsis palustris)과 백색부후균(Trametes versicolor) 균주를 사용하였고, 공시흰개미는 일본흰개미(Reticulitermes speratus)를 사용하였다. 그 결과, 갈색 및 백색부후균에 의한 중량감소율은 심재부에서 3.7∼5.6%, 변재부에서는 16.1∼26.3%로 나타났다. 또한, 흰개미 사충률은 심재부에서 약 47%로 매우 높게 나타났다. 이러한 결과를 통하여 황장목의 심재부는 부후균 및 흰개미에 대한 저항력이 뛰어난 것을 알 수 있었다.

구리 기반 목재 방부제 중 MCQ를 이용하여, 목재 내 주입량에 따른 부후 특성을 조사하였다. 목재 시편에 주입량을 달리하여 약제를 주입한 후, 갈색부후균인 부후개떡버섯에 의한 방부효력 시험을 진행하였다. 이후, 질량감소율을 측정한 결과 무처리재는 35% 이상의 질량감소율을 보였으며, 실내 부후에 의한 MCQ 약제의 ...

This study presents composite aerogel beads prepared by mixing dissolved cellulose with Chlamydomonas angulosa and Nostoc commune cells, respectively, at 0.1, 0.3, and 0.5% (w/w). The manufactured composites (termed regenerated cellulose (RC)), with C. angulosa (RCCA-(1, 3, and 5)), and with N. commune (RCNC-(1, 3, and 5)) were analyzed. Both RCCA-5 and RCNC-5 showed the high specific surface area to be about 261.3 and 332.8 m2·g−1. In the microstructure analysis, network structures were observed in the cross-sections of RC, RCCA-5, and RCNC-5. The pyrolysis temperature of the RCCA-5 and RCNC-5 composite aerogel beads was rapidly increased about 250 °C during the mixing of cellulose with C. angulosa and N. commune. The chemical analysis of RC, RCCA-5, and RCNC-5 showed peaks corresponding to various functional groups, such as amide, carboxyl, and hydroxyl groups from protein, lipid, and carbohydrate. RCNC-5 at pH 6 demonstrated highest Cd2+ removal rate about 90.3%, 82.1%, and 63.1% at 10, 25, and 50 ppm Cd2+, respectively. At pH 6, Cd2+ adsorption rates per unit weight of the RCNC-5 were about 0.9025, 2.0514, and 3.1547 mg/g at 10, 25, and 50 ppm, respectively. The peaks assigned to the amide, carboxyl, and hydroxyl groups in RCCA-5, RCNC-5, and RC were shifted or disappeared immediately after adsorption of Cd2+. The specific surface area, total pore volume, and mean pore diameter of composites was decreased due to adsorption of Cd2+ on the developed materials. As can be seen in the X-ray powder diffraction (XRD) spectrum, significant changes in the molecular structure of the composite aerogel beads were not observed even after adsorption of Cd2+.

우리나라에는 어둡고 습한 환경을 선호하는 지중흰개미의 일종인 일본흰개미(Reticulitermes speratus)가 전국적으로 분포하고 있으며, 점차적으로 목재 건축물에 대한 흰개미 피해가 증가하고 있다. 특히 일본흰개미는 국내 건축재로 많이 쓰이고 있는 소나무를 쉽게 가해한다. 전 세계적으로 다양한 종류의 흰개미가 분포하고는 있지만, 피해가 심해지는 만큼 적절한 방제방법을 선택하기는 어렵다. 무엇보다 분포하는 흰개미의 종류가 다양하기 때문에 훈증처리, 토양처리, 방부·방충처리, 군체제거시스템, 화학약품 처리, 물리 및 생물학적 처리 등의 방법을 이용하여 흰개미의 특성에 맞게 적용시켜야 한다. 본 연구는 현재 친환경 방부제로 사용되고 있는 구리계 방부제 Alkaline copper quaternary (ACQ), Copper Azole (CuAZ), Micronized copper quat (MCQ)가 흰개미로부터 목구조물의 피해를 방지할 수 있는지 그 효력을 조사하기 위하여 수행하였다. 그 결과 3종의 목재방부제로 처리된 방부목재가 무처리재보다 높은 방의 효과가 있는 것으로 나타났다. 또한, 각 방부제의 주입량에 따라 방의효력이 다르게 나타났다.

In this study, we report the first record of Reticulitermes kanmonensis from Korea verified using soldier morphological characters and haplotypes obtained from two mitochondrial genes. R. kanmonensis Takematsu, 1999 (Isoptera: Rhinotermitidae) was collected from Pinus densiflora Siebold & Zucc. (Pinaceae) stumps in two provinces, Jeollabuk-do and Chungcheongnam-do, Korea. We compared R. kanmonensis with the more common Reticulitermes speratus kyushuensis Morimoto, 1968 using morphological and molecular characters. In the morphological comparison, R. kanmonensis was distinguished from R. speratus kyushuensis by a significantly higher number of hairs on the pronotum and ratio of the posterior postmentum width and length. In the molecular comparison, R. kanmonensis revealed genetic differences of 5.49% (range 5.20%–5.80%) and 8.11% (range 8.00%–8.80%) from R. speratus kyushuensis using the cytochrome oxidase subunit I (COI) and subunit II (COII) gene sequences, respectively.

This research focused on the natural durability of twenty one lesser known tropical wood species planted in West Java, Indonesia against subterranean termite (Coptotermes curvignathus). It was observed that both heartwood and sapwood of Kiara payung (Filicium decipiens); heartwoods of Nangka (Arthocarpus heterophyllus), Mahoni (Swietenia macrophylla) and Simpur (Dillenia grandifolia); and sapwood of Bungur (Lagerstroemia speciosa) were rated as resistant (natural durability class II) according to Indonesian standard SNI 01.7207.2006 (BSN 2006). Both heartwood and sapwood of Salam (Syzigium polyanthum), Pasang (Lithocarpus sundaicus), Bisbul (Diospyros discolor), Rukam (Flacourtia rukam) and Trembesi (Samanea saman); heartwood of Puspa (Schima walichii), Bungur, Tanjung (Mimusops elangi) and Angsana (Pterocarpus indicus) were rated as moderately resistant (natural durability class III). Both heartwood and sapwood of Sungkai (Peronema canescens), Pine (Pinus merkusii), Mangium (Acacia mangium) and Afrika (Maesopsis eminii); sapwoods of Mahoni, Puspa and Tanjung were rated as poorly resistant (natural durability class IV). Both heartwood and sapwood of Agathis (Agathis dammara), Durian (Durio zibethinus), Ki sampang (Evodia latifolia) and Jabon (Anthocephalus cadamba); sapwoods of Nangka and Angsana were rated as very poorly resistant (natural durability class V). This reserach showed that woods with lower resistance against C. curvignathus attack (natural durability class IV and V) tend to have lower termite mortality values compared to woods with higher resistance against C. curvignathus attack (natural durability class II and III). Results of the study will provide some valuable information on termite resistance of twenty one lesser known tropical wood species planted in Indonesia.

국내에서 사용되고 있는 가압주입 처리용 구리·붕소·아졸화합물계의 목재 방부제 Copper Azole (CuAz)의 목재내 주입량별 부후 특성을 조사하였다. 여러 가지 주입량으로 CuAz-2 방부제를 가압주입한 시편을 이용하여 갈색부후균인 부후개떡버섯에 의한 방부효력시험을 실시한 후 질량감소율을 측정하였다. 또한, CuAz-2 처리 시편을 부후개떡버섯으로 부후시킨 후 광학현미경과 전자현미경으로 부후 특성을 관찰하였다. 그 결과, 부후개떡버섯에 의한 무처리재는 40% 이상의 질량감소율을 보여주었고 실내 부후에 의한 CuAz-2 약제의 방부효력을 나타내는 값은 1.79∼3.32 kg/m 이었다. CuAz-2의 주입량에 따라 횡단면, 방사단면, 접선단면에서의 목재조직은 무처리 시편과 비교하여 부후 정도가 다르게 나타났다. 횡단면에서는 조재와 만재부분에서 수직수지구, 방사조직의 부후가 많이 관찰되었고, 방사단면에서는 방사가도관, 방사유세포, 벽공 부분이 부후되어 파괴되었고, 접선단면에서는 방사조직, 수평수지구가 심하게 부후되었다. 따라서 본 연구에서 주입량에 따른 부후 현상이 크게 차이가 난 점 등을 고려하여, 현재의 CuAz-2 주입량에 대한 적정성 검토가 국내 환경에 대해서 이루어져야 할 것으로 생각된다.

Old architectural wood materials damaged by a fire were evaluated on the basis of wood species and scanning elec-tron microscopy (SEM) observation of wood tissues in combination with energy dispersive X-ray spectroscopy (EDXS) analysis. Results of SEM observation showed that tracheid wall thickness of burned parts was very thin com-pared with undamaged and sound wood, and tylosoid in the resin canals disappeared after the exposure to fire. SEM-EDXS analysis indicated that carbon and oxygen peaks occurred in the original energy band, and the carbon peak was higher than that of the oxygen in the burned part. A computerized tomography was also undertaken to in-vestigate the carbonization layer formed by fire and possible internal defects. Keywords : architecture wood material, SEM-EDXS, computed tomography, wood tissues, carbonized wood 1 Date Received April 14, 2013, Date Accepted August 14, 2014 2 Department of Forest Products, Korea Forest Research Institute, Seoul 130-712, Korea

The physical and mechanical characteristics of 10 Indonesian wood species were investigated. Mangium, Gandaria and Rambutan showed higher density. Mangium, Gandaria and Mangga appeared lower in shrinkage, and the ratio of tangential/radial was low in Albizia, Kupa and Mangga. The compression strength parallel to the grain and hardness

The deterioration in wood by the brown-rot fungus (Fomitopsispalustris) and the white-rot fungus (Trametesversicolor) were measured using ultrasonic velocity. Those were used for the decay exposure and 4 wood species of wood as the test specimens, Pinusdensiflora, Larixkaempferi, Pinuskoraiensis and Pinusrigida, were chosen with both the brown- and white-rot culture petridish during 12 weeks. After 12 weeks, the decrease rate of ultrasonic velocity was measured at 10~15%. In both brown- and white-rot exposure experiments, P. rigida showed significant decrease in ultrasonic velocity (20%), L. kaempferi on the other hand did not show decrease in ultrasonic velocity. After the fungal exposure experiment, the inside of specimens was investigated by computer tomography (C/T). After C/T investigation, bending tests were performed.

Anatomical characteristics of White Jabon (Arthocephalus cadamba) and Red Jabon (Arthocephalus macrophyllus) were investigated by IAWA hardwood feature list. Both species were diffuse-porous, and radial multiple pore with 2~3 rows was mostly observed. Tangential diameter of vessel lumina was 100 to , and vessels per square millimeter were 5 to 20. White Jabon has more vessels than Red Jabon. The number of solitary pore per square millimeter in both species was similar, but more pore multiple was observed in White Jabon. Axial parenchyma diffuse was observed in both species, but axial parenchyma of White Jabon was hardly identified on the cross section. Rays were classified into "body ray cells procumbent with over 4 rows of upright/square marginal cells" type and partly "all ray cells upright and/or square" type on radial section. Ray width 1 to 3 cells and 1 to 2 cells observed in White Jabon and Red Jabon, respectively. Ray height of White Jabon was and Red Jabon . Fiber length was the range of 900 to in both species, and it showed a tendency to increase from pith to bark. Consequently, it is considered that pore multiple, ray width and axial parenchyma are to be suggested the keys for identification of both species.

Urea-melamine-formaldehyde (UMF) resins were synthesized and used for manufacturing medium-density fiberboard (MDF). As melamine content was increased at the same formaldehyde/urea (F/U) molar ratio, the solids content of the resin increased. Physical properties and storage stability of the resins tended to improve slightly when the final pH of resin was 8.5 compared with 7.5 and 9.5. At the same F/U molar ratio, free formaldehyde content and gel time of the resins decreased as melamine content increased. Chemical structures of the resins were proposed from the results of 13C nuclear magnetic resonance and Fourier transform infrared analyses. Formaldehyde emissions of MDF prepared with UMF resins with the same F/U molar ratio decreased as melamine content of resin was increased. MDF fabricated with UMF resin showed slightly better resistance against decay fungi and termites compared with MDF fabricated with urea-formaldehyde (UF) resin. Other physical properties of MDF fabricated with UMF resin w...

Pitch pine (Pinus rigida Miller) retaining walls using Steel bar, of which the constructability and strength performance are good at the construction site, were manufactured and their strength properties were evaluated. The wooden retaining wall using Steel bar was piled into four stories stretcher and three stories header, which is 770 mm high, 2,890 mm length and 782 mm width. Retaining wall was made by inserting stretchers into Steel bar after making 18 mm diameter of holes at top and bottom stretcher, and then stacking other stretchers and headers which have a slit of 66 mm depth and 18 mm width. The strength properties of retaining walls were investigated by horizontal loading test, and the deformation of structure by image processing (AlCON 3D OPA-PRO system). Joint (Type-A) made with a single long stretcher and two headers, and joint (Type-B) made with two short stretchers connected with half lap joint and two headers were in the retaining wall using Steel bar. The compressive shear strength of joint was tested. Three replicates were used in each test. In horizontal loading test the strength was 1.6 times stronger in wooden retaining wall using Steel bar than in wooden retaining wall using square timber. The timber and joints were not fractured in the test. When testing compressive shear strength, the maximum load of type-A and Type-B was 130.13 kN and 130.6 kN, respectively. Constructability and strength were better in the wooden retaining wall using Steel bar than in wooden retaining wall using square timber.

라디에타소나무 단판적층재(LVL)를 제조함에 있어서, CuAz 및 ACQ 방부처리와 비처리, 수성비닐우레탄 접착제와 페놀변성 리조시놀수지 접착제의 상온경화형 접착제를 적용함에 따른 밀도경사, 접착·강도성능 및 내부후성(방부효력)을 살펴보았다. 결과, LVL의 밀도경사에서 접착층 주변이 원추형으로 밀도가 커지는 경사패턴을 보였다. 접착성은 수성비닐우레탄 접착의 경우, 자비반복시험 후 전층이 박리되거나, 일부 층이 박리하고 할렬·틈새 현상이 일어났다. 페놀변성 리조시놀수지 접착제 접착의 경우, 자비반복시험 후 접착층의 응력이 큰데 연유한 굽음과 상하 접착층 사이의 단판의 수직할렬 현상이 있었으나, 접착층의 박리나 할렬이 거의 발견되지 않아 침지박리접착력은 높은 것으로 판단되었다. 한편, 방부효력시험에 있어서, 수성비닐우레탄 접착제로 적층한 LVL의 경우 갈색부후균에 의한 부후도가 백색부후균보다 크게 나타났다. 페놀변성 리조시놀수지 접착제로 LVL을 제조한 경우에는 갈색부후균에 의한 질량감소가 적었고, 약제를 처리하지 않더라도 그 피해가 낮았으며, 약제처리한 것은 질량감소율 0 수준을 보일 정도로 방부효력이 큰 것을 알 수 있었다.

국내산 주요 침엽수 소경목의 활용 방안으로 리기다소나무를 이용한 목재 모형 옹벽을 제작하여 강도 성능을 평가하였다. 목재 모형 옹벽은 가로. 세로 11cm의 CUAZ-2 처리한 리기다소나무 방부 정각재를 사용하여 3개의 Type으로 제작하였다. 각 Type별 옹벽은 형목 4총 종목 3층 총 7층의 높이 86cm 길이 300cm, 폭 93cm로 제작 하였으며 기본형인 Type 1과 목재 사용량을 줄이기 위해 중간에 긴 종목과 짧은 종목을 번갈아 사용한 Type 2. Type 2와 동일하게 제작한 후 횡목의 연결부위를 보강목으로 보강한 Type 3으로 제작하였다. 각 Type별 옹벽은 수평 재하 시험을 통한 강도 성능 평가와 화상처리를 통한 구조물의 변형을 검토하였다. 수평재하 시험 결과 최대 하중을 비교해 보았을 때 Type 1은 63.17kN/m. Type 2는 57.80kN/m. Type 3은 60.97kN/m으로 나타났다. 화상 처리를 통해 측정된 전면부의 최상층 변형을 비교해 보았을 때 Type 1에 벼해 Type 2의 변형이 약 1.5배 많은 변형을 보였으며 Type 1과 Type 3은 비슷한 변형을 보이는 것을 알 수 있었다. 실험 결과 Type 3의 경우 목재 사용량을 절감하면서도 양호한 강도성능을 확인 할 수 있었다.

25%, 50% and 25%, respectively. Methane di-isocyanate (MDI, Type H3M) resin was used as an adhesive in amount of 7%. The amount of paraffin used was 1% based on oven dried strand. The strands were immersed in hot water at 80 °C for 2 hours, immersed in 2.5% of CCB preservative solution for 48 hours and steamed at 126 °C at 1.4 kg.cm -2 pressure for 1 hour prior to be blended with adhesive. The results indicated that OSB manufactured mostly consisted of quarter round and flat strands with high slenderness ratio and high aspect ratio. Pre-treatment of strand by immersing strands in hot water, immersing in preservative solution and steamed resulted in improvement of water absorption of board, some mechanical properties and dura- bility of OSB. Introducing 2.5% CCB preservative on the OSB significantly improved durability of OSB against termite attack but did not influence the strength of OSB. Untreated OSB, OSBs prepared from pre- served strands and steamed strands can be used for exterior application, while OSB prepared from hot water immersed strands only can be used for interior application. All OSB parameters manufactured in this experiment were superior when compared with the minimum requirement of CSA 0437.0 standard for Grade O-2 OSB.

Typical symptoms of rubberwood canker found in East Kalimantan, Indonesia, differ from those of conventional rubberwood peach canker. Rubberwood canker showed a conspicuous longitudinal canker with exposed xylem that was discolored and decayed. Bark wounds, resulting from regular tapping, were enclosed within the xylem, and the tissues had become integrated. The characteristics of abnormal and decayed xylem in this rubberwood canker were analyzed by light microscopy and scanning electron microscopy. Xylem in the vicinity of the enclosed bark contained fewer vessels of smaller diameter and shorter length, and significantly wider rays compared with normal xylem. Around the wide growth zones of the canker, axial cells were disoriented and warped toward the canker zones. In view of the separation among cells, and the concentric degradation of the cell walls starting from the lumen surfaces, decayed xylem appeared to be caused mainly by white-rot fungal attack.

To further our understanding of wood decay in living light red meranti (Shorea smithiana) trees, microscopic characteristics of the cell and cell wall degradations of S. smithiana wood in the presence of the decay fungi, the identity of the causal fungi, and the decay potential and pattern by an isolated fungus were investigated. Cell wall degradations, including cell wall thinning, bore holes formation, rounded pit erosion, and eroded channel opening were clearly observed under light and scanning electron microscopy. In transverse view, many large voids resulting from a coalition of degraded wood tissue appeared in the decayed canker zone. All these observations suggest the well-known simultaneous decay pattern caused by white-rot fungi. By phylogenetic analysis based on the sequences of internal transcribed spacer region of ribosomal DNA, a basidiomycete fungus isolated from the decayed wood was identified as Schizophyllum commune. The degradation caused by this fungus on sound S. smithiana wood in an in situ laboratory decay test was classified as the early stage of simultaneous decay, and showed a similar pattern to that observed in the wood samples naturally decayed.

This study evaluated the effects of boron impregnation and heat treatment on the chemical and mechanical properties of wood. Sugi (Cryptomeria japonica D. Don) sapwood specimens treated with either boric acid (BA) or di-sodium octoborate tetrahydrate (DOT) solutions were exposed to heat treatments at either 180 or 220 °C for 2 or 4 h. Chemical composition and strength properties were then measured in heat-treated specimens in comparison with untreated, unheated specimens. The wood carbohydrates were significantly degraded in the heat-treated specimens, suggesting depolymerization and alterations through the cleavage of acetic acid from the acetyl side chains. Increases in the amount of Klason lignin were found in heat-treated specimens, probably because of the ongoing removal of hemicelluloses during thermal degradation. A direct relationship was found between strength and hemicellulose losses of the specimens. As the hemicellulose content in the specimens decreased, losses in the modulus of rupture (MOR) increased. There were mixing effects of BA, DOT and thermal treatments on the chemical composition and strength properties, and it is therefore difficult to distinguish how these factors contribute to the properties evaluated. However, the effect of heat treatment on the mechanical properties was much clearer at the highest temperature (220 °C) than at 180 °C. The reductions in the modulus of elasticity (MOE) in the untreated wood were slightly higher than those in the BA- and DOT-treated specimens; however, this trend disappeared at treatments of 220 °C for 2 and 4 h, in which MOE losses reached 100% for all specimens. More detailed studies are needed to determine the effects of boron compounds on wood properties.

The development of oriented fiberboards made from kenaf (Hibiscus cannabinus L.) and their suitability as a construction material has been investigated. Three different types of boards consisting of five layers with individual orientations were prepared using a combination of low molecular weight and high molecular weight phenol-formaldehyde (PF) resin for impregnation and adhesion purposes. Additional boards with the same structure were prepared using high molecular weight PF resin only. The mechanical properties of the boards have been examined as well as their resistance against fungal decay and termite attack. All kenaf fiberboards showed elevated mechanical properties compared with medium-density fiberboard made from wood fibers, and showed increased decay and termite resistance. Differences in the decay and termite resistance between the board types were caused by the presence of the low molecular weight PF resin for the impregnation of the fibers. No significant difference was found for the mechanical properties. The effect of the PF resin for impregnation was much clearer in fungal decay resistance than for termite resistance; however, fiber orientation had no effect on both decay and termite resistance of the specimens.

Heat treatments change the chemical and physical properties of wood and dimensional stability and hygroscopicity are affected as a result of modifications of wood cell components. This study evaluated the water absorption of wood specimens treated with boron compounds followed by heat treatment. Sugi (Cryptomeria japonica D. Don) sapwood specimens treated with either boric acid (BA) or disodium octoborate tetrahydrate (DOT) solutions were heat-modified at either 180° or 220°C for 2 or 4 h. Carbohydrate composition and water absorption of the specimens were then measured and compared with those of untreated and unheated specimens. Wood carbohydrates were significantly degraded in the specimens after heat treatment. The heat treatment evidently decreased the water absorption and the heat-modified specimens absorbed less water than unheated specimens. The higher the treatment temperature and the longer the treatment time, the lower the amount of absorbed water. The boron-treated and heat-modified specimens, however, showed increased water absorption due to the hygroscopic properties of BA and DOT.

This study describes a laboratory evaluation of the efficacy of two alkylammonium compounds [didecyldimethylammonium tetrafluoroborate (DBF) and didecyldimethylammonium chloride (DDAC)] when applied via vacuum impregnation or superficial treatment. Treated wood specimens were tested for their termite and microbial resistance under controlled laboratory conditions. The higher chemical retentions were needed to suppress the feeding by Coptotermes formosanus ≦3% mass loss in the multichoice test than in the no-choice test. The DBF and DDAC retention levels necessary to meet the performance requirement ≦3% mass loss after 12-week fungal exposure varied with wood species. The retention level of 3 kg/m3 for DBF and DDAC was generally high to keep the nondurable wood species free of decay. Although there was no difference between DBF and DDAC in the efficacy against decay and termite attack, the former slightly outperformed the latter as an antimold and antisapstain agent.

There is increasing public concern about environmental contamination from preservative treated wood due to release of toxic preservative components to the environment. Leaching of wood preservatives from treated wood in service can be affected by a number of factors such as wood and preservative treatment characteristics and properties of water and soil substrate in which treated wood is placed i.e. salinity, pH, and temperature. Laboratory leaching tests usually require distilled or deionized water for leaching procedure however treated wood is generally exposed to different types of water and soil conditions. This study evaluates the release of copper, chromium and arsenic elements from chromated copper arsenate (CCA)-treated wood exposed to either distilled water, tap water, sea water or humic acid. Leaching tests were conducted in laboratory conditions using wood blocks treated with CCA wood preservative at either low or high retention levels. Results showed that tap water resulted in less preservative release when compared to the other leaching media used in the study. Humic acid was the most effective medium causing more element leaching. The percentage of components leached was always higher in wood blocks treated at the high retention in comparison with the low retention level. Our results from the leaching tests can be important in developing more realistic standard leaching methods to evaluate preservative components to be released from treated wood.

A commercial silicon emulsion was applied to decrease boron leaching from either Na-borate or disodium octoborate tetrahydrate (DOT) treated wood. Treated wood specimens at target retention levels of 4, 8 and 12 kg/m3 Na-borate were soaked in the silicon emulsion and dried at 105 °C for 24 h. In the second trials, wood specimens previously treated with DOT solutions at 1% and 1.5% concentrations were surface treated with the silicon emulsion. The specimens were then subjected to a 10-day leaching process followed by decay and termite resistance tests under laboratory conditions. Retention levels of 1 kg/m3 were retained in the Na-borate and silicon emulsion-treated wood specimens after the leaching process, but nearly no boron remained in the wood specimens treated with Na-borate only. In the DOT treatments, about 2 kg/m3 retention levels were retained in the specimens after the leaching process. The Na-borate+silicon emulsion-treated and-leached specimens showed better performance than the Na-borate only treated specimens in decay resistance tests. The DOT and silicon emulsion-treated specimens remained almost intact even after the leaching process due to higher boron content compared to the Na-borate treatments. Even though termite resistance tests caused higher mass losses in the leached specimens in all treatment groups when compared to the decay resistance tests, silicon treatments also reduced the mass losses in the specimens after the leaching process. More detailed studies are needed to obtain a better understanding of the mechanisms of interaction between silicon emulsion and wood components.

This study evaluates the synergistic effect of wood extractives and quaternary ammonium compounds (QACs) on the resistance to termites of several treated wood species. Wood specimens from different natural durability classes were extracted with either hot water alone or hot water + ethanol/benzene. The extracted and unextracted wood specimens were treated with either didecyldimethylammonium tetrafluoroborate (DBF) or commercial didecyldimethylammonium chloride (DDAC) solutions and then exposed to subterranean termites, Coptotermes formosanus Shiraki, for 3 weeks under laboratory conditions. The results showed that extractives of the heartwood portions of the wood species contributed to increased resistance against termite attack in the presence of either DBF or DDAC wood preservatives. The synergistic effect of wood extractives and DBF was much clearer with Pseudotsuga menziesii (Mirbel) Franco and Tsuga heterophylla Sarg wood samples. Further studies are needed for a better understanding of the synergism between wood extractives and either DBF or DDAC using both the sapwood and heartwood portions of the same wood species.

This study evaluates the decay and termite resistance of wood treated with didecyl dimethyl ammonium tetrafluoroborate (DBF), a recently developed quaternary ammonia compound containing boron. Laboratory decay resistance tests were performed using brown-rot fungus, Fomitopsis palustris and white-rot fungus, Trametes versicolor. Treated wood specimens were also subjected a 3-week-termite resistance test using subterranean termites, Coptotermes formosanus. Decay resistance tests showed that wood specimens treated with 0.5 and 1.0% DBF solutions were well protected against both fungi even after a 10-day severe leaching process, suggesting the adequate fixation of DBF in wood. DBF treatment at 0.1% concentration was efficient against subterranean termites, Coptotermes formosanus Shiraki based on mass losses in both leached and unleached wood specimens. The ability of DBF to inhibit discolorations by selected mold and stain fungi was also screened in laboratory conditions. DBF at the highest concentration level (1%) provided limited protection against mold and staining fungi tested, however, it was effective for only short-term protection (1 or 2 weeks) at lower concentrations. These results suggest that DBF is promising to protect wood to be used outdoors against both fungal decay and termite attack however field tests are needed to observe the performance of DBF-treated wood in ground contact.

Modifications in the structure of wood preserving quaternary ammonium compounds (QACs) may result in improvements in leaching of components and biological resistance of treated wood. In this study, we evaluated the leaching characteristics and termite resistance of wood treated with a newly developed QAC compound didecyldimethylammonium tetrafluoroborate (DBF) in comparison with commercial DDAC, another QAC compound. Laboratory leaching tests showed that amount of DBF released from treated wood specimens was less than that of DDAC. However there was no difference between DBF and DDAC in the resistance of treated wood specimens against termite attack. Retention level at about 3 kg/m3 of DBF and DDAC seems to be enough to protect wood against termite attack, however, no comparative data are available for resistance of DBF and DDAC-treated wood against wood degrading fungi. Field tests are also needed to determine the performance of DBF-treated wood in ground contact in comparison with DDAC.

Surface treatment of wood was carried out using acryl-silicon type resin including didecyl dimethyl ammonium tetrafluoroborate (DBF), boron-containing quaternary ammonia compound. Surface-treated wood specimens were exposed laboratory decay resistance tests after completing a 10-cyle severe weathering process. In laboratory decay resistance tests, one brown-rot decay fungus, Fomitopsis palustris and one white-rot decay fungus, Trametes versicolor were used. The specimens were also subjected to laboratory termite resistance tests using subterranean termites, Coptotermes formosanus. Wood specimens treated with 2% DBF and resin containing preservative solution showed improved decay and termite resistance suggesting that the preservative solution at 2% DBF concentration provides lasting protection against wood degradation owing to the amount of DBF remaining in the wood after severe weathering process. However field tests are needed to determine the performance of surface-treated wood with DBF and the acryl-silicon type resin in more realistic conditions.

A laboratory no-choice termite bioassay was conducted to evaluate the ability of copper HDO (CX-A or copper xyligen) to protect radiata pine (Pinus radiata D. Don) wood samples from attack by two subterranean termite species, Reticulitermes speratus and Coptotermes formosanus. A series of sapwood samples were pressure treated with either 0.25%, 0.50%, 0.75%, or 1.00% copper HDO solution. Samples treated with equivalent concentrations of a benchmark preservative, CCA-C, were used as treated controls. All samples (including controls) were subjected to an artificial weathering schedule before the bioassay. The samples were exposed to 30-day R. speratus tests and 3-week C. formosanus tests. Copper HDO was shown to deter termites from significant feeding on the treated wood. At a retention of 5.8 kg/m3 (treated with 0.75% solution) or higher, the mass loss from termite feeding did not exceed 3% for both the 30-day R. speratus tests and the 3-week C. formosanus tests. At each of the retentions tested, copper HDO performed comparably with equivalent retentions of CCA-C; however, field data are needed to validate these laboratory results. The preliminary findings are that copper HDO pressure treatment has potential as a viable method of protecting wood from attack by both termite species tested.

La recherche en préservation du bois se tourne à présent vers des produits à faibles impacts environnementaux. Nous avons étudié l'opportunité d'associer borates et huiles végétales pour accroître la rétention du bore ainsi que la résistance du bois aux termites et aux champignons xylophages. Les huiles végétales permettent de retenir environ 30 % du bore initial selon leurs propriétés de séchage. Ainsi, l'huile de lin est plus efficace que les huiles de soja et de colza. La durabilité d'éprouvettes d'aubier de C. japonica et F. crenata est améliorée par l'ajout d'huile de lin mais trop peu pour éviter les attaques de termites Coptotermes formosanus. En revanche, la combinaison d'une imprégnation par une solution d'acide borique à 1.0 % m/m suivi d'une traitement à l'huile protège efficacement C. japonica contre les termites et les champignons. Alors que son efficacité contre les termites semble principalement due à la rétention du bore, l'huile semble former une barrière efficace contre la pénétration des champignons xylophages. Les seuils d'efficacité d'environ 0.7 kg/m3 BAE, plus faible que ceux enregistrés pour les traitements classiques au bore indique que l'huile renforce l'effet biostatique du bore.