• Journal of the Korean Wood Science and Technology
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• v.41 no.5
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• pp.385-391
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• 2013

X-ray computed tomography is a very powerful nondestructive technique in safety inspection of historic timber building. But, in field, various testing condition makes it difficult to carry out X-ray CT testing. Limited size in X-ray digital detector is one of the problems. In this study, a pitch pine disk with two holes was used to know how imperfection in X-ray projection affects CT image resolution. Using various number of projections, CT image was reconstructed by filtered back projection method, and then it was investigated how many projection is required to identify the holes in different location. Two artificial holes could be differently detected according to their location in cross section of specimen. One hole in center part of specimen was identified using more than 9 radiographs, but the other one which located in outer part of cross section could not be detected until more than 36 projections were used. Even though there is data missing in outer part of cross section due to limited size of detector, the center part of CT image could be reconstructed well and the resolution of outer part became higher with increase of the number of projections. For field application, the number of projections for CT image reconstruction needs to be decided with consideration of another nondestructive testing and the location of interest.

• Korean Journal of Remote Sensing
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• v.33 no.5_1
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• pp.571-585
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• 2017

The number of spaceborne optical sensors including red-edge band has been increasing since red-edge band is known to be effective to enhance the information content on biophysical characteristics of vegetation. Considering that the Agriculture and Forestry Satellite is planning to carry an imaging sensor having red-edge band, we tried to analyze the current status and potential of red-edge band. As a case study, we analyzed the effect of using red-edge band and tried to find the optimum band width and wavelength region of the red-edge band to estimate leaf area index (LAI) of very dense tree canopy. Field spectral measurements were conducted from April to October over two tree species (white oak and pitch pine) having high LAI. Using the spectral measurement data, total 355 red-edge bands reflectance were simulated by varying five band width (10 nm, 20 nm, 30 nm, 40 nm, 50 nm) and 71 central wavelength. Two red-edge based spectral indices(NDRE, CIRE) were derived using the simulated red-edge band and compared with the LAI of two tree species. Both NDRE and CIRE showed higher correlation coefficients with the LAI than NDVI. This would be an alternative to overcome the limitation of the NDVI saturation problem that NDVI has not been effective to estimate LAI over very dense canopy situation. There was no significant difference among five band widths of red-edge band in relation to LAI. The highest correlation coefficients were obtained at the red-edge band of center wavelength near the 720 nm for the white oak and 710 nm for the pitch pine. To select the optimum band width and wavelength region of the red-edge band, further studies are necessary to examine the relationship with other biophysical variables, such as chlorophyll, nitrogen, water content, and biomass.

• Journal of the Korean Wood Science and Technology
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• v.16 no.2
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• pp.69-78
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• 1988

For the modification of kiln drying schedule, rela ons between drying resistance R and moisture content or drying times were found 2.5cm-and 5.0cm-thick pitch pine (Pinus rigida Mill.) board and dimension lumber by the conventional kiln drying schedule until the average moisture content was 10%. The results of this study were as follows. 1. Drying resistance increased curvilinearly as moisture content decreased, and was higher for dimension lumber than for board at a given moisture content. The relationships between drying resistance and moisture content for the conventional kiln drying schedule and thickness of lumber were 1) $R_{2.5}=6.795\times10^3M^{-1.27^{**}}$ for 2.5cm-thick board by the conventional kiln drying schedule. 3) $R_{5.0}=5.206\times10^4M^{-1.55^{**}}$ for 5.0cm-thick dimension lumber by the conventional kiln drying schedule. 2. As drying time increased, moisture content decreased and drying resistance increased at the same time. Gradient of slope for dimension lumber was gentler than board. 3. The predicted drying times to 10% moisture content with the conventional kiln drying schedule were a little shorter than actual drying times with relatively small error. 4. It is necessary for the conventional kiln drying schedule to be modified to provide the desired final moisture content at minimum drying time with no significant degrade under severe drying conditions. 5. The kiln factors for 2.5cm-thick board and 5.0cm-thick dimension lumber with the conventional kiln drying schedule were 1.112, 1.136, respectively.

• Journal of the Korean Wood Science and Technology
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• v.17 no.1
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• pp.3-11
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• 1989

This study was carried out to investigate the physical and mechanical properties. durability of adhesive bond and paint film for the basic data which were required to determine the suitability as a raw material for furniture the laminated veneer lumber (LVL) with pitch pine (Pinus rigida Mill). The results obtained were as follows; 1) The proper pressing time for making the LVL was over 45 second per milimeter of LVL thickness. 2) The bending strength of the LVL was lower than that of the solid wood but the compressive strength of the LVL was similar to that of the solid wood. The strength increased with the decrease of veneer thickness. 3) The impact bending absorbed energy of the LVL was 0 to 0.3 kg.m/$cm^2$ in the direction of parallel to the grain. The energy of the LVL was lower than that of the solid wood (0.68 kg.m/$cm^2$). 4) In warm water soaking and cold-dry tests, delamination of adhered layers surface crack, swelling, and color change were not found when the hot pressing time was over 45 second per milimeter of LVL thickness. As a result of soak under vacuum test shrinkage in the direction of parallel to the grain was about -1.0 percent and. was about 3.0 percent in the direction of the perpendicular to the grain. 6) The film cacks on the LVL's surface after the wet and cold-dry test were not found at all. 7) In the use of the LVL for interior decoration it was considered that the surface of the LVL be overlaid crossly with fancy veneers of birch and paulownia, etc. This cross overlayirg methods have resulted in few cracks on the fancy veneer.

• Journal of the Korean Wood Science and Technology
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• v.39 no.1
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• pp.53-59
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• 2011

A connection was made between a single stretcher and 2 headers with 2 threaded nails (Type-A), and another one between 2 stretchers and 2 headers with 4 threaded nails (Type-B) to use as specimens. Type-C was the stretchers that are connected with 2 threaded nails by half lap joint at end-distance 5D to reinforce Type-B, Type-C1 the stretchers that are connected by half lap joint at end-distance 10D, and Type-C2 with 3 threaded nails at end-distance 10D. Compressive shear strength of Type-C, the supplementation of Type-B, was decreased by 30%, compared with that of Type-B. Those of Type-B and Type-C1 that used longer end-distance than Type-C were about the same, and that of Type-C2 connected with 3 threaded nails was 1.28-times stronger than that of Type-C1. Connection of the retaining wall using existing square timber has a problem between long and short stretchers and 2 headers. So it was investigated in the experiment to replace it. Therefore, if Type-B is replaced with Type-C2 in constructing the retaining wall, the crack and the rupture of timber caused by threaded nail as well as construction period can be reduced, and also it can be expected to increase their own strength.

• Journal of Ecology and Environment
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• v.31 no.1
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• pp.23-29
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• 2008

The effectiveness of rehabilitation programs for coal mining spoils in Samcheok, Jeongsun, and Mungyung were evaluated based on the physicochemical properties of soil in the rehabilitated areas. These spoils were reclaimed by introducing plants such as black locust (Robinia pseudoacacia), pitch pine (Pinus rigida), birch (Betula platyphylla var. japonica), alder (Alnus hirsuta), bush clover (Lespedeza cyrtobotrya), and grass (Lolium perenne) in planting beds covered with forest soil. In the surface soil, the pH, organic matter, total N, available P, and exchangeable Ca showed significant changes over the years after reclamation. The pH and exchangeable Ca content decreased exponentially over time, whereas organic matter increased linearly and total N and available P increased exponentially. Changes in the physicochemical properties of subsurface soils displayed a different pattern. There were significant changes over time in the organic matter, available P, and exchangeable Ca and Mg contents of the soil. Organic matter increased logarithmically with years since rehabilitation and available P increased exponentially. Meanwhile, exchangeable Ca decreased exponentially, and Mg decreased logarithmically. The changes in the subsurface soil were not as dramatic as those in the surface soil. This result suggests that the ameliorating effects of the establishment and growth of plants more pronounced on the surface soil layer. Stand ordination data showed different relationships with time since rehabilitation in the early and later stages of the rehabilitation process. In the early stages of rehabilitation, stands tended to be arranged in the order of reclamation age. However, in the later stages, there was not a clear relationship between reclamation age and vegetation characteristics. This result suggests that soil amelioration is required for the early stages, after which an autogenic effect becomes more prominent as the vegetation becomes better established.

• Journal of the Korean Wood Science and Technology
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• v.38 no.6
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• pp.532-540
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• 2010

The strength properties of wooden model retaining wall made of pitch pine (Pinus rigida Miller) was evaluated. Three different types of wooden model retaining wall were made of the 11cm square timber treated with CUAZ-2 (Copper Azole). The retaining wall was made into the 4 layers of crossbar and the 3 layers of vertical-bar, of which the size was 86 cm high, 200 cm long and 96 cm wide. Type I was control and in Type II 20 cm vertical-bars and 93 cm vertical-bars were arranged alternately to decrease wood usage. TypeIII was similar to TypeII except that the connection between crossbars was reinforced with the wooden armature. In each type, the strength properties of retaining wall were investigated by horizontal loading test and the deformation of structure by image processing (AICON 3D DPA-PRO system). In horizontal loading test of Type I, Type II and Type III was 63.17, 57.80, and 60.97 kN/m, respectively. The deformation of the top layer in Type II was 1.5 times larger than in Type I and Type III. Consequently, the economic efficiency and strength performance were better in Type III than in Type I and Type II.

• Journal of Korean Society of Forest Science
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• v.36 no.1
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• pp.47-55
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• 1977

Diameter growth was surveyed for 22 years-old pitch pine (Pinus rigida Mill.) growing on the forest land (site protected from artificial damage) and the resting place (site open for the recreation) of the Children Park, Seoul, Korea on September 28, 1975. The purpose of the survey was to find out difference in the tree growth between the two sites, and possible causes of the difference. Both the resting place and the forest land have deep fertile sandy-loam soil, moderate slope for south-west. The resting place, however, has much higher soil compactness by treading than the forest land. Before May 5, 1973, the opening date of the park, the trees on the resting place had higher diameter growth than those on the forest land as measured with increament borer. After the Park opening the trees on the resting place showed less growth than those on the forest land. In 1975, the growth on the resting place was less than that of the forest land by 6.5% at 1% significant level. The difference in growth was attributed to the soil compactness of the resting place by treading. The necessity for the same kind of study with other species for the tree management of parks was suggested.

• Journal of Korean Society of Forest Science
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• v.6 no.1
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• pp.19-23
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• 1967

The fungus which belongs to Alternaria has been isolated from "damping-off" infected seedlings of pitch pine (Pinus rigida Mill.) in the nursery (seed bed) of Chung Puk College, Cheong-Ju. The author has carried out this study regarding to (1) the effects of H-ion concentration on the growth of fungus, (2) the effects of temperature and humidity on the conidia germination, (3) the effects of temperature and humidity on the conidia formation. The summary of obtained in this experiments is as follows: 1. The suitable H-ion concentration for growth of isolated fungus is in the range of PH 4.0-9.5, the most suitable of it is PH 6.5-8.0. 2. The germination of the conidia is suppressed at below $0^{\circ}C$ or at $40^{\circ}C$ and above, the range of optimum temperature for the germination is $5^{\circ}C-35^{\circ}C$, the percentage of germination is highest at $20^{\circ}C$. And under relative humidities of 10% or below, the germination is suppressed, favorable relative humidities $85%{\cdots}100%$. 3. The formation of the conidia is suppressed at below $10^{\circ}C$ or at $34^{\circ}C$ and above, the favorable condition of the condia formation is as follows; Temperature; $22^{\circ}C-28^{\circ}C$ Relative humidity:85%-100%.

• Journal of the Korean Wood Science and Technology
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• v.39 no.4
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• pp.318-325
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• 2011

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.