• The Korean Journal of Ecology
• /
• v.17 no.3
• /
• pp.251-260
• /
• 1994

Nitrification potential bioassay and terpenoid analyses were performed to determine the roles of terpenoid as an inhibitor of nitrification in the Douglas fir (Pseudotsuga menziesii) forests. The effect of terpenoids in the forest floor was also tested by adding $10{\mu}g/ml$ of four terpenoids(${\alpha}-pinene,{\beta}-pinene,{\gamma}-terpinene, and terpinolene) to mineral soils. The amount of terpenoids in the litter was higher than that in the soil and varied over time, but the amount of terpenoids in the soils was relatively constant. The correlation between the amount of terpenoids in the litter and ammonium oxidation was in inverse proportion to that in the mineral layers $(r^2=0.678)$. Inhibition of ammonium oxidation by terpenoids in the litter was always higher than in the mineral layer, but nitrite oxidation was different from the ammonium oxidation. The fact that there was greater nitrate production from ammonium in the mineral layer than in the forest floor layer seems to be due to the less amounts of terpenoids in the mineral layer. The result of the experiment in which four terpenoids were added to the mineral layer suggests that, after some lag time, the four terpenoids were effective in inhibiting ammonium oxidation. However, nitrite oxidation did not appear to be affected by the four terpenoids. Accordingly, all of our results suggested that terpenoids in Douglas fir forests apparently would act as a part of the inhibitors of nitrification.

• The Plant Pathology Journal
• /
• v.28 no.3
• /
• pp.311-316
• /
• 2012

Fusarium root disease can be a serious problem in forest and conservation nurseries in the western United States. Fusarium inoculum is commonly found in most container and bareroot nurseries on healthy and diseased seedlings, in nursery soils, and on conifer seeds. Fusarium spp. within the F. oxysporum species complex have been recognized as pathogens for more than a century, but attempts to distinguish virulence by correlating morphological characteristics with results of pathogenicity tests were unsuccessful. Recent molecular characterization and pathogenicity tests, however, revealed that selected isolates of F. oxysporum are benign on Douglas-fir (Pseudotsuga menziesii) seedlings. Other morphologically indistinguishable isolates, which can be virulent, were identified as F. commune, a recently described species. In a replicated greenhouse study, inoculating Douglas-fir seedlings with one isolate of F. oxysporum prevented expression of disease caused by a virulent isolate of F. commune. Moreover, seedling survival and growth was unaffected by the presence of the F. oxysporum isolate, and this isolate yielded better biological control than a commercial formulation of Bacillus subtilis. These results demonstrate that an isolate of nonpathogenic F. oxysporum can effectively reduce Fusarium root disease of Douglas-fir caused by F. commune under nursery settings, and this biological control approach has potential for further development.

• Journal of Korean Society of Forest Science
• /
• v.87 no.1
• /
• pp.40-49
• /
• 1998

This study aimed to provide a strategy for selecting an adequate combination of growth intervals(i.e. times between age $T_1$ and age $T_2$) to be used to improve the reality of the growth equation through obtaining better precision of parameter estimates. Variety of growth functions were fitted to the data and one equation which best fitted the data was chosen for the analysis. A modified Schumacher projection equation, selected as a best equation, that included dummy variables representing locality as a predictor variable was fitted for basal area and height equations with nonoverlapping growth interval and all possible growth interval data sets of Douglas-fir(Pseudotsuga menziesii Mirb.Franco). The data were measured in all parts of the South Island of New Zealand. It was found that the precision of parameter estimates was increased in both basal area and height equations by using data set which contained a range of measurement intervals from short to long term.

• Journal of agriculture & life science
• /
• v.45 no.4
• /
• pp.1-11
• /
• 2011

The aim of this study was development of natural antifungal compounds from softwood. We investigated antifungal activities of extracts from Pseudotsuga menziesii and Chamaecyparis obtusa against Tricholderma genus which is virus causing green mold disease and analyzed antifungal compounds by Gas chromatography -Mass Spetrometer. Extracts from P. menziesii had inhibition activities against Tricholderma genus on 1,000 ppm and had high antifungal activities against T. viride by 70.1%, T. harzianum by 67.3% and T. aggressivum by 64.7% on 4,000 ppm. And extracts from C. obtusa had antifungal activities against Tricholderma genus on 1,000 ppm and had high antifungal activities against T. viride by 63.2%, T. harzianum by 59.3% and T. aggressivum by 59.1% on 4,000 ppm. But mixing compounds which are made from P. menziesii and C. obtusa extracts by variety ratio had lower antifungal activities than original extracts. Main antifungal active components of P. menziesii extracts against Tricholderma genus were 2-Isopropoxy-ethylamine 46.5%, epifluorohydrin 8.6%, trans-2,3-Di-methyloxirane 7.6%, (IR)-(-)-Myrtenal 6.0%, 2-Methoxy-4-Vinylphenol 3.9% and benzaldehyde 2.8%. In case of C. obtusa extracts, they were ${\alpha}$-Terpinenyl acetate 14.9%, Sabinene 10.9%, dl-Limonene 9.6%, ${\alpha}$-Terpinolene 7.5% and ${\alpha}$-Pinene 7.1%. As mentioned above, these results revealed extracts from P. menziesii and C. obtusa of softwood could be used as potential agents to inhibit Trichoderma genus.

• Journal of the Korean Wood Science and Technology
• /
• v.19 no.3
• /
• pp.72-76
• /
• 1991

The new preparative separation techneque of dihydroquercetin (2, 3-trans-dihdroxy-3, 3', 4', 5, 7-pentahydroxydihydroflavonol) was investigated by liquid chromatography. Also some typical coniferous wood bark were examined for the sources of dihydroquercetin. The good sources of dihydroquercetin were Douglas-fir[Pseudotsuga menziesii] bark and pitch pine [Pinus rigida] bark. There is no dependance the produced place and species dihyroquercetin which is separated by silica-gel column chromatography was taken with white needle-like crystals. This crystals were very stable in the humidity and on the light. It also can stored very long without derivatives.

• Journal of the Korea Furniture Society
• /
• v.10 no.2
• /
• pp.63-71
• /
• 1999

본 연구는 목재중의 수분량이 변화하는 비정상태하에 있어서의 액체투과성을 평가하기 위한 새로운 방법으로써 원심법에 의한 액체투과성을 평가하기 위한 새로운 방법으로써 원심법에 의한 액체투과성의 평가법을 확립해 보고자 실시하였다. 이 방법은 원심력장에 있어서의 액체투과성과 원심처리부로부터 액체투과성을 평가하는 것이다. 실험결과, 삼나무(Cryptomeria japonica)와 미송 (Pseudotsuga menziesii)은 서로 다른 탈수경과를 나타내었다. 삼나무는 미송보다 더 많은 탈수량을 보였고 재내의 태수량의 변이가 심하였다. 한편 변재와 심재의 탈수거동에 있어서 삼나무는 기체투과성에 의해 평가된 값과 상반된 결과를 나타내었다. 즉, 2200∼3300rpm의 범위에서 편재는 심재보다 탈수량이 적었다.

• Journal of Korean Society of Forest Science
• /
• v.88 no.2
• /
• pp.142-148
• /
• 1999

This research describes the construction of a site index equation and curves for Douglas-fir plantation (Pseudotsuga menziesii Mirb. Franco) in Nelson, New Zealand. The data sets of 146 Permanent Sample Plots (PSP) were used to build the model, and it was developed using the difference equation method. Parameter estimates were obtained using the non-linear routine of the SAS, PROC NLIN procedure. Of the models tested, a variant of the Schumacher polymorphic yield function showed the higher precision of fitting. About 95% of the observations used to fit the model could be predicted within ${\pm}1.2m$ of the actual values. Therefore, polymorphic family of site index curves, which reflect different shapes for the different site index classes, were derived from the Schumacher equation. It was found that the polymorphic site index equation was more accurate than the anamorphic equation in this study.

• Journal of the Korean Wood Science and Technology
• /
• v.47 no.1
• /
• pp.90-100
• /
• 2019

This study aims to determine the ideal feed speed of a resistograph to evaluate the number of tree rings in several tree species. The needle speed was fixed at 1,500 r/min. Herein, various tree species, such as Pseudotsuga menziesii, Pinus koraiensis, Abies holophylla, and Zelkova serrata, were considered for experiments. Results showed that the most proper feed speed for Zelkova serrata, Larix kaempferi, Pseudotsuga menziesii, Abies holophylla, and Pinus koraiensis was 75, 100, 100, 150, and 175 cm/min, respectively. However, in all the cases, the electric resistance values of tree ring narrower than 1 mm were not suitable for determining tree-ring boundaries. Upon comparing the inter-annual time series of ring widths and electric resistance values of resistograph, a meaningful synchronization was verified. If resistograph would be improved to the extent that it can measure tree rings narrower than 1 mm, it can replace the conventional method used for counting the number of tree rings in the increment cores. Additionally, it can also be used to investigate the tree growth.

• Journal of agriculture & life science
• /
• v.43 no.3
• /
• pp.15-26
• /
• 2009

This study was undertaken to determine inhibitory compounds from extracts of the softwood (larix leptolepis, Pseudotsuga menziesii) sawdust against Trichoderma spp. The sawdust of L. leptolepis and P. menziesii were hot water extracted, which were with fraction extracted organic solvents. The organic solvent extractions were carried out by n-hexane, methylene chloride, ethyl acetate. The antifungal activity of hot water extracts of L. leptolepis sawdust was determined to be 20.6% inhibition at a concentration of 1,000 ppm against Trichoderma spp. The antifungal activity of P. menziesii sawdust was outstanding about 60.3% against Trichoderma spp. The yields of the fractions of n-hexane soluble, methylene chloride soluble and ethyl acetate soluble from the hot water extract of L. leptolepis sawdust were 4.0%, 6.0% and 8.0%, repectively. However, the yields of the fractions of three solvents of P. menziesii sawdust were 8.0%, 13.0 and 14.0% correspondingly. The antifungal activity of n-hexane soluble fraction from hot water extracts of L. leptolepis sawdust was highest to about 68.5% to 79.9% against Trichoderma spp. compared to others. The antifungal activities of n-hexane soluble fraction from hot water extracts of P. menziesii sawdust showed 68.5%, 71.4%. 71.9%, 75.7% and 82.3% against T. aggressivum, T. atroviride, T. harzianum, T. koningii and T.viride, respectively. The n-hexane soluble fraction revealed much higher antifungal activity than the other fractions did. This study demonstrated that the n-hexane fraction of the hot water extracts of L. leptolepis and P. menziesii exhibited the greatest antifungal activity against Trichoderma spp.

• Journal of the Korean Wood Science and Technology
• /
• v.18 no.2
• /
• pp.16-24
• /
• 1990

아세틸화(化) 고분자(高分子) 축합(縮合)탄닌의 젤침투 크로마토그래피 분석(分析)을 위해 일반적(一般的)으로 사용(使用)되고 있는 폴리스타이렌 표준물질(標準物質)은 부정확(不正確)한 교정(矯正)값을 준다. 한편 유도체화 하지않은 축합탄닌의 젤침투 크로마토그래피는 폴리스타이렌 디비닐벤젠 코폴리머 컬럼과 디메틸 포름아미드를 용매(溶媒)로 사용(使用)하여 매우 만족스럽게 분석(分析)될 수 있었다. 그 컬럼의 교정은 유도처리 되지않은 고분자(高分子) 축합(縮合)탄닌을 이용(利用)하여 수행되었으며 고분자 탄닌을 유도처리 할 필요가 없으므로 탄닌의 신속한 분자량(分子量) 결정(決定)이 가능하고 컬럼 크로마토그래피로 분리(分離)되어지는 탄닌을 연속적으로 분석(分析)할 수 있는 장점(長點)을 가진다.