• Journal of Korean Society of Forest Science
• /
• v.96 no.6
• /
• pp.611-619
• /
• 2007

This study was carried out to analyze the landslide characteristics and forest environment factors on the landslide area of 7 national parks in korea. The results obtained from this study were summarized as follows; The total number of landslide occurrence was 44 areas. The average length of the landslides scar was 152 m, average width was 17 m. And the average area was $2,818m^2$. The factors influencing landslides were highly occurred in Metamorphic rock, mixed forest type. And also, $30{\sim}35^{\circ}$ in slope gradient, NE in slope aspect, slope higher than 1,000 m, concave (凹) type in vertical and cross slope, 0 ordered stream. The main factors affecting landslide area in stepwise regression analysis were sheet type in landslided shape, NE in slope aspect, 2 ordered stream, SE in slope aspect, slope gradient and complex slope in cross slope type in order of regression coefficient.

• Journal of Korean Society of Forest Science
• /
• v.99 no.6
• /
• pp.891-899
• /
• 2010

The purpose of this study is to estimate economic value of forest landscape function using conditional logit model, applied by Choice Experiment. For the study, we have chosen attributes and levels of forest landscape. In specific, topographical forest type, forest type, forest density, recreational factor (side trip, accessibility of valley) and WTP were included in attributes. Based on factors, we have made 48 choice sets with Balanced and Orthogonal form using SAS 9.1. The efficiency of questionnaire was 6.02 (D-Error: 0.1) and choice set and socio-economic variable were selected. In order to reduce cognitive load of respondent, 96 choice sets were divided into 4 types in questionnaire so that respondent could respond to 12 choice sets respectively. Population was citizens from 7 metropolitan cities including Seoul, and the interview survey was conducted to find out average annual WTP per household for the total 280 interviewees. As a result, In the Non-ASC model, Mcfadden' ${\rho}$ had 0.21, and Log Likelihood: -2,631. Average annual WTP per household for forest landscape was 266,723 Won(Korean currency).

• Journal of the Korean Wood Science and Technology
• /
• v.34 no.4
• /
• pp.31-36
• /
• 2006

This study was conducted to improve the bond strength of plywood bonded with F/U molar ratio urea-formaldehyde (UF) resins modified with the selected FGMDI prepolymer contents for various purposes. The amount of FGMDI was mixed with liquid UF resin at 0 wt% (as control), 2 wt%, 5 wt%, 10 wt%, 25 wt%, and 50 wt% based on the resin solids. As results, in bonding strength, plywood with F/U molar ratio of 1.4 showed the highest value in Type 2 test and all molar ratio UF resins modified with over 25 wt% of the FGMDI showed more than $11kgf/cm^2$, which was satisfied the minimum requirement of KS standard, $7.5kgf/cm^2$, after Type1.5 testing. As F/U molar ratio was increased and the FGMDI addition in the UF resin was increased, average reduction rate of Type 1.5 bonding strength compared with Type 2 was significantly decreased.

• Journal of Korean Society of Forest Science
• /
• v.109 no.4
• /
• pp.361-370
• /
• 2020

Long-term observation of the life cycle of plants allows the identification of critical signals of the effects of climate change on plants. Indeed, plant phenology is the simplest approach to detect climate change. Observation of seasonal changes in plants using digital repeat imaging helps in overcoming the limitations of both traditional methods and satellite remote sensing. In this study, we demonstrate the utility of camera-based repeat digital imaging in this context. We observed the biological events of plants and quantified their phenophases in the northern temperate type deciduous broadleaf forest of Jeombong Mountain. This study aimed to identify trends in seasonal characteristics of Quercus mongolica (deciduous broadleaf forest) and Pinus densiflora (evergreen coniferous forest). The vegetation index, green chromatic coordinate (GCC), was calculated from the RGB channel image data. The magnitude of the GCC amplitude was smaller in the evergreen coniferous forest than in the deciduous forest. The slope of the GCC (increased in spring and decreased in autumn) was moderate in the evergreen coniferous forest compared with that in the deciduous forest. In the pine forest, the beginning of growth occurred earlier than that in the red oak forest, whereas the end of growth was later. Verification of the accuracy of the phenophases showed high accuracy with root-mean-square error (RMSE) values of 0.008 (region of interest [ROI]1) and 0.006 (ROI3). These results reflect the tendency of the GCC trajectory in a northern temperate type deciduous broadleaf forest. Based on the results, we propose that repeat imaging using digital cameras will be useful for the observation of phenophases.

• Korean Journal of Remote Sensing
• /
• v.22 no.1
• /
• pp.25-40
• /
• 2006

Synthetic aperture radar (SAR) from satellites provides the opportunity to regularly incorporate microwave information into forest classification. Radar backscatter can improve classification accuracy, and SAR interferometry could provide improved thematic information through the use of coherence. This research examined the potential of using multi-temporal JERS-l SAR (L band) backscatter information and interferometry in distinguishing forest classes of mountainous areas in the Northeastern U.S. for future forest mapping and monitoring. Raw image data from a pair of images were processed to produce coherence and backscatter data. To improve the geometric characteristics of both the coherence and the backscatter images, this study used the interferometric techniques. It was necessary to radiometrically correct radar backscatter to account for the effect of topography. This study developed a simplified method of radiometric correction for SAR imagery over the hilly terrain, and compared the forest-type discriminatory powers of the radar backscatter, the multi-temporal backscatter, the coherence, and the backscatter combined with the coherence. Statistical analysis showed that the method of radiometric correction has a substantial potential in separating forest types, and the coherence produced from an interferometric pair of images also showed a potential for distinguishing forest classes even though heavily forested conditions and long time separation of the images had limitations in the ability to get a high quality coherence. The method of combining the backscatter images from two different dates and the coherence in a multivariate approach in identifying forest types showed some potential. However, multi-temporal analysis of the backscatter was inconclusive because leaves were not the primary scatterers of a forest canopy at the L-band wavelengths. Further research in forest classification is suggested using diverse band width SAR imagery and fusing with other imagery source.

• Journal of Ecology and Environment
• /
• v.46 no.1
• /
• pp.85-98
• /
• 2022

Background: Korean white pine (Pinus koraiensis) is a major commercial species, and the importance of the oak trees (Quercus spp.) is increasing due to various factors such as environmental and ecological values. However, more information is required to clearly understand the growth characteristics of these species especially regarding thinning intensity. This study was performed to provide the basic information to develop the silvicultural guideline and field manual by analyzing tree and stand characteristics in line with thinning intensity in the Korean white pine plantation and oak-dominated natural deciduous forest. Results: Diameter at breast height (DBH) and volume changes by the thinning intensity in the Korean white pine plantation were significantly different from those in the oak-dominated deciduous natural forest. In particular, DBH distribution in the pine stand appeared that there were more large diameter trees as the thinning intensity was higher. DBH periodic annual increment (PAI) of the pine stand was higher as the thinning intensity was stronger and the growth period was shorter. This trend was similarly shown in the natural deciduous forest, but the amount of PAI was smaller than in pine stand. The volume PAI after thinning was not decreased over time. In each stand type, the PAI tended to be lower as stand density was higher. The volume PAI in the pine stand was significantly higher than that in the oak-dominated natural deciduous forest. Dead trees occurred the most in the unthinned plots of each stand type, and those were higher in the natural deciduous forest. Ingrowth trees were observed only in the natural deciduous forest, and its distribution was the lowest in unthinned plots; Korean white pine as ingrowth occurred the most frequently among many tree species. Conclusions: Different effects of thinning treatment on DBH and volume PAI, mortality, and ingrowth were observed for each stand. With respect to forest growth, Korean white pine plantation was superior to the oak-dominated natural deciduous forest. The results of this study offer fundamental information for the development of silvicultural guidelines for Korean white pine plantations and oak-dominated natural deciduous forests in Korea.

• Korean Journal of Remote Sensing
• /
• v.20 no.1
• /
• pp.13-21
• /
• 2004

The usefulness of the multi-temporal satellite image to monitoring the vegetation recovery process after forest fire was tested. Using multi-temporal Landsat TM and ETM＋data, NDVI and NBR changes over times were analyzed. Both NDVI and NBR values were rapidly decreased after the fire and gradually increased for all forest type and damage class. However, NBR curve showed much clearer tendency of vegetation recovery than NDVI. Both indices yielded the lowest values in severely damaged red pine forest. The results show the vegetation recovery process after forest fire can detect and monitor using multi-temporal Landsat image. NBR was proved to be useful to examine the recovering and development process of the vegetation after fire. In the not damaged forest, however the NDVI shows more potential capability to discriminate the forest types than NBR..

• Journal of the Korean Wood Science and Technology
• /
• v.44 no.1
• /
• pp.40-47
• /
• 2016

Instead of metal connector generally used on the structural glued laminated timber rahmen joints, the GFRP reinforced laminated plates combining veneer and GFRP (Glass Fiber Reinforced Plastic) and bonded type GFRP rod were used as the connectors. As a result of moment resistance performance evaluation on the joint part applied with these connectors, the yield moment of specimen using the GFRP reinforced laminated plates and GFRP rod pin was measured 4 % lower in comparison to the specimen (Type-1) using the metal connectors, but the initial rotational stiffness was measured 29% higher. Also, the yield moment and rotational stiffness of the specimen using the GFRP-reinforced laminated plates and wood (Eucalyptus marginata) pin showed were measured 11% and 56% higher in comparison to the Type-1 specimen, showing the best performance. It was also confirmed through the failure shape and perfect elasto-plasticity analysis that it showed ductility behavior, not brittle fracture, from the shear resisting force by the pin and the bonding strength increased and the unification of member was carried out. On the other hand, in case of the specimen bonded with GFRP rod, it was impossible to measure the bonding performance or it was measured very low due to poor bonding.

• Journal of Korean Society of Forest Science
• /
• v.97 no.6
• /
• pp.650-655
• /
• 2008

In an attempt to establish the mass proliferation system, Eucalyptus pellita, a 5-year-old plus tree, was cultured with three different culture types in 1L vessels: solid culture without ventilation (conventional culture), liquid culture without ventilation and open-type liquid culture with forced ventilation. Then the culture scale was subsequently increased from 1L to 10L in vessel volume. After 4 weeks of 1L-scale culture, the best growth was obtained by culturing plantlets on open-type liquid culture, suggesting that the in vitro plantlets growth can be enhanced by liquid medium and ventilation. In open-type large scale culture in 10L vessel, plantlets growth resulted in a 370% increase in the number of nodes, 3.6 times increase in leaf expansion, and 3.3 times increase in shoot length, while the conventional culture suppressed shoot growth due to the callusing on the leaves and lack of $CO_2$. The results indicated that the open-type large scale culture system was effective for enhancing productivity by improving growth of the plantlets in clonally proliferated plus tree, Eucalyptus pellita.

• Weed & Turfgrass Science
• /
• v.2 no.2
• /
• pp.184-190
• /
• 2013

It is important for genetic resources to collect and identify in native medium-leaf type zoysiagrasses species distributed in Korea. This study was conducted to investigate morphological variation and characteristics of native medium-leaf type zoysiagrasses from coastal, island and inland regions in Korea. Among them, 75 collected lines was confirmed to have various morphological variations, accessions were classified into 2 main based group coastal and inland regions by morphological characteristics and site environment. Group I included Z. sinica type, this group showed 3.7 mm in leaf width, 29 in number of seed per spikelet and 5.0 mm in seed length. Group II included Z. japonica type, this group showed 4.4 mm in leaf width, 42 in number of seed per spikelet and 3.5 mm in seed length. There is a need for additional research on growth characteristics and the molecular level for the introgressive hybridization between species which confirmed that cross-pollination is possible due to protogyny. The individuals showing variations should be preserved as valuable genetic resources for the expansion of variations in zoysiagrasses, and the results of this investigation on the genetic resources collected will be highly valuable in breeding high quality turfgrass.