• Journal of Korean Society of Forest Science
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• v.87 no.2
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• pp.173-178
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• 1998

Twelve Camellia sinensis populations were studied to investigate the biomass distribution related to stand structure. With increasing mean age of the population, mean root collar diameter increased, while mean height, density and root collar area had no correlation with the age. The result of dimension analysis after cutting the sample trees showed that dry weights of stems +branches and root were exponentially increased and dry weights of current leaves and twigs were linearly increased with increasing root collar diameter. However, the dry weight of older leaves was not related to the root collar diameter. The range of total biomass was 1,162~11,474kg/ha and the range of current leaf biomass was 165~1,341kg/ha. The range of T/R ratio was 1.5~2.8. The biomass of stems+branches and root were significantly correlated with the root collar area of the population and were not significantly correlated with the mean age, mean root collar diameter and density of the population. The biomass of current leaves and twigs were significantly correlated with the root collar area and density of the population.

• Journal of Korean Neurosurgical Society
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• v.47 no.5
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• pp.352-357
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• 2010

Objective : This retrospective study was performed to evaluate the clinical and radiological results of anterior lumbar interbody fusion (ALIF) using two different stand-alone cages in the treatment of lumbar intervertebral foraminal stenosis (IFS). Methods : A total of 28 patients who underwent ALIF at L5-S1 using stand-alone cage were studied [Stabilis$^{(R)}$ (Stryker, Kalamazoo, MI, USA); 13, SynFix-LR$^{(R)}$ (Synthes Bettlach, Switzerland); 15]. Mean follow-up period was 27.3 ${\pm}$ 4.9 months. Visual analogue pain scale (VAS) and Oswestry disability index (ODI) were assessed. Radiologically, the change of disc height, intervertebral foraminal (IVF) height and width at the operated segment were measured, and fusion status was defined. Results : Final mean VAS (back and leg) and ODI scores were significantly decreased from preoperative values (5.6 ${\pm}$ 2.3 ${\rightarrow}$ 2.3 ${\pm}$ 2.2, 6.3 ${\pm}$ 3.2 ${\rightarrow}$1.6 ${\pm}$ 1.6, and 53.7 ${\pm}$ 18.6 ${\rightarrow}$ 28.3 ${\pm}$ 13.1, respectively), which were not different between the two devices groups. In Stabilis$^{(R)}$ group, postoperative immediately increased disc and IVF heights (10.09 ${\pm}$ 4.15 mm ${\rightarrow}$ 14.99 ${\pm}$ 1.73 mm, 13.00 ${\pm}$ 2.44 mm ${\rightarrow}$ 16.28 ${\pm}$ 2.23 mm, respectively) were gradually decreased, and finally returned to preoperative value (11.29 ${\pm}$ 1.67 mm, 13.59 ${\pm}$ 2.01 mm, respectively). In SynFix-LR$^{(R)}$ group, immediately increased disc and IVF heights (9.60 ${\pm}$ 2.82 mm ${\rightarrow}$ 15.61 ${\pm}$ 0.62 mm, 14.01 ${\pm}$ 2.53 mm ${\rightarrow}$ 21.27 ${\pm}$ 1.93 mm, respectively) were maintained until the last follow up (13.72 ${\pm}$ 1.21 mm, 17.87 ${\pm}$ 2.02 mm, respectively). The changes of IVF width of each group was minimal pre- and postoperatively. Solid arthrodesis was observed in 11 patients in Stabilis group (11/13, 84.6%) and 13 in SynFix-LR$^{(R)}$ group (13/15, 86.7%). Conclusion : ALIF using stand-alone cage could assure good clinical results in the treatment of symptomatic lumbar IFS in the mid-term follow up. A degree of subsidence at the operated segment was different depending on the device type, which was higher in Stabilis$^{(R)}$ group.

• Journal of Korean Society of Forest Science
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• v.90 no.5
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• pp.650-662
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• 2001

The growth and yield models for five different kinds of natural forest types were systemically developed in the natural Broadleaved-Korean pine Forests in Northeast China. The data were collected from 359 temporary plots and 58 permanent plots with area ranged from 0.06 ha to 1.0 ha, ranging in stand age from 43 to 364 years. The Site Class Index (SCI) was introduced to evaluate site quality and the Crown Competition Factor (CCF) was selected as a measure of stand density for the mixed natural forest. The Chapman-Richards function was adopted to develop SCI equation and height-diameter curve. The Schumacher growth function was selected as base model to develop the DBH, basal area, and stand volume growth models by using re-parameterized method. In modeling mean DBH and basal area growth, it was found that the asymptotic parameter A of Schumacher function was exponentially related to site quality (SCI) and stand density (CCF). The rate parameter k was related to stand density and it was independent of SCI. Several validation measures for predicted stand variables were evaluated in the growth and yield models using independent data sets. The results indicated that relative mean errors (RME) in predicted stand attributes were less than ${\pm}5%$ and the estimated precision values of the stand variables were all greater than 95%.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2010.09a
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• pp.134-141
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• 2010

임분 단위의 재적 및 생체량은 LiDAR 자료의 높이 분포변수들로부터 추정될 수 있다. LiDAR 자료의 높이 분포변수들은 재적을 측정하는 임분고(stand height)와 임분평균 지하고(mean crown base height), 그리고 수관형태에 따른 평균수관장(mean crown depth) 등의 변수와 직 간접적인 연관성이 있다. 그러므로, 본 연구에서는 잣나무림의 샘플지역에서 반사된 LiDAR 자료의 높이분포변수를 이용하여 임분단위의 수간재적을 추정한 다음, 앞 세부연구에서 수행한 방법을 이용하여 임분의 생체량을 추정하였다. 변수는 임분 내에서 반사되는 LiDAR 자료의 평균높이, 최대 최소높이, 높이값들의 표준편차, 변이계수, 첨도, 왜도, 식생반사비율, 10분위 높이자료와 강도데이터의 기술통계량 등을 사용하였다. 그리고, 최종적인 임분수간재적은 다중회귀분석을 통하여 수행되었다. 다중회귀분석을 통하여 각 변수들은 임분수간재적과 가장 관련있는 2~3개의 변수들로 추려졌으며, 추정된 회귀식의 결정계수는 0.66으로 분석되었다. 또한 유보표본을 이용하여 검증한 결과의 결정계수는 0.59로 분석되어 LiDAR 자료의 높이분포변수들은 임분의 재적을 비교적 잘 설명할 수 있음이 밝혀졌다.

• Korean Journal of Agricultural and Forest Meteorology
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• v.4 no.1
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• pp.1-11
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• 2002

This study was conducted to reveal the effects of local climatic conditions on the early growth of Korean white pine progeny test stands. For this, stand variables such as mean DBH, mean height, basal area per hectare, and volume per hectare by stand age and locality were first measured and summarized for each stand. Based on these statistics, annual increments for 10 years from stand age 10 to 20 were calculated for each of stand variables. The effects of local climatic conditions as one of environmental factors on the growth were then analyzed by both a topoclimatological method and a spatial statistical technique. From yearly climatic estimates,30 climatic indices which affect the tree growth were computed for each of the progeny test stand. The annual increments were then correlated with and regressed on the climatic indices to examine effects of local climatic conditions on the growth. Gapyung area provided the best conditions for the early growth of Korean white pine and Kwangju area ranked second. On the other hand, the growth pattern in Youngdong ranked last overall as expected. It is also found that the local growth patterns of Korean white pine in juvenile stage were affected by typical weather conditions. The conditions such as low temperature and high relative humidity provide favor environment for the early growth of Korean white pine. Especially, it was concluded that the low temperature is a main factor influencing the early growth of Korean white pine based on the results of correlation analysis and regression equations developed far the prediction of annual increments of stand variables.

• Journal of Korean Neurosurgical Society
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• v.44 no.6
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• pp.370-374
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• 2008

Objective : Aim of study was to find a proper method for assessing subsidence using a radiologic measurement following anterior cervical discectomy and fusion (ACDF) with stand-alone polyetheretherketone (PEEK), $Solis^{TM}$ cage. Methods : Forty-two patients who underwent ACDF with $Solis^{TM}$ cage were selected. With a minimum follow-up of 6 months, the retrospective investigation was conducted for 37 levels in 32 patients. Mean follow-up period was 18.9 months. Total intervertebral height (TIH) of two fused vertebral bodies was measured on digital radiographs with built-in software. Degree of subsidence (${\Delta}TIH$) was reflected by the difference between the immediate postoperative and follow-up TIH. Change of postoperative disc space height (CT-MR ${\Delta}TIH$) was reflected by the difference between TIH of the preoperative mid-sagittal 2D CT and that of the preoperative mid-sagittal T1-weighted MRI. Results : Compared to preoperative findings, postoperative disc height was increased in all cases and subsidence was observed only in 3 cases. For comparison of subsidence and non-subsidence group, TIH and CT-MR ${\Delta}TIH$ of each group were analyzed. There was no statistically significant difference in TIH and CT-MR ${\Delta}TIH$ between each group at 4 and 8 weeks, but a difference was observed at the last follow-up TIH (p=0.0497). Conclusion : ACDF with $Solis^{TM}$ cage was associated with relatively good radiologic long-term results. Fusion was achieved in 94.5% and subsidence occurred in 8.1% by the radiologic assessment. Statistical analysis reveals that the subsidence seen later than 8 weeks after surgery and the development of subsidence does not correlate statistically with the change of the postoperative disc space height.

• Journal of Korean Society of Forest Science
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• v.104 no.2
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• pp.239-247
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• 2015

Since 2006, new national forest inventory in Korea has been restructured to assess current status and and monitor the changes in forest resources based on permanent sample plots. The objective of estimate this study is to assess changes in forest resources such as land use/cover categories and forest stand variables. For this study, permanent plot data were collected between 2006-2008 and 2011-2013 in Chungcheongbuk-do, respectively. In order to produce land use/cover change matrix which plays an important role as an activity data for estimating GreenHouse Gas inventory, permanent plots were classified into six land use/cover categories. Additionally, matrixes for assessing the changes in age class and dominant tree species can provide more detailed information. For forest stand variables(tree density, basal area, growing stock, mean diameter at breath height, and mean height), their growth and change were assessed. The periodic annual growth ratios for tree density and basal area were slightly declined whereas that of growing stock was estimated to be about 3.7%. The uncertainty of changes in forest stand variables is less than 5%, except for tree density (RSE: 58%). The variation of tree density is relatively high compared to the other variables.

• Journal of Korean Society of Forest Science
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• v.85 no.3
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• pp.453-461
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• 1996

Three Phyllostachys stands of P. pubescens, P. bambusoides and P. nigra var, henonis in Sunchon were studied to investigate biomass, net production and nutrient distribution. Five $10m{\times}10m$ quadrats were set up and 20 sample culms of 2 years and over were harvested for dimension analysis in each stand. One year old culms and subterranean parts were estimated by the harvested quadrat method. The largest mean DBH, height and basal area were shown in P. pubescens stand, and followed by P. nigra var. henonis stand and P. bambusoides stand. There was little difference in accuracy among three allometric biomass regression models of logWt=A+B1ogD, $logWt=A+BlogD^2H$ and logWt=A+BlogD+ClogH, where Wt, D and H were dry weight, DBH and height, respectively. Analysis of covariance showed that there were significant differences in intercept among the linear allometric biomass regressons of three Phyllostachys species. Biomass included subterranean parts was the largest in P. pubescens stand(103.621t/ha), and followed by P. nigra var. henonis stand(86.447t/ha) and P. bambusoides stand(36.767t/ha). Leaf biomass was 6.3% to 7.8% of total biomass in each stands. The ratio of aboveground biomass and subterranean biomass in each stand was 1.87 to 2.26. Net production included subterranean parts was the greatest in P. pubescens stand(6.115t/ha/yr), and followed by P. nigra var. henonis stand(5.609t/ha/yr) and P, bambusoides stand(3.252t/ha/yr). The highest net assimilation ratio was estimated in P. pubescens stand(2.979), and followed by P. nigra var. henonis stand(2.752) and P. bambusoides stand(2.187). Biomass accumulation ratio of each stand was 2.679 to 5.358. Concentrations of N, P and Mg were the highest in leaves, and followed by subterranean parts, and culms+branches in all three species. Concentration of Ca was the highest in leaves, and followed by culms+branches, and subterranean parts in all three species. The difference in biomass among three species stands was caused by their culm size, leaf biomass, net assimilation ratio, and efficiency of leaves to produce culms.

• Korean Journal of Remote Sensing
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• v.31 no.2
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• pp.127-136
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• 2015

This study aims to quantify the stand-level above ground biomass in intact tropical rain forest of Brunei using airborne LiDAR data. Twenty four sub-plots with the size of 0.09ha ($30m{\times}30m$) were located in the 25ha study area along the altitudinal gradients. Field investigated data (Diameter at Breast Height (DBH) and individual tree position data) in sub-plots were used. Digital Surface Model (DSM), Digital Terrain Model (DTM) and Canopy Height Model (CHM) were constructed using airborne LiDAR data. CHM was divided into 24 sub-plots and 12 LiDAR height metrics were built. Multiple regression equation between the variables extracted from the LiDAR data and biomass calculated by using a allometric equation was derived. Stand-level biomass estimated from LiDAR data were distributed from 155.81 Mg/ha to 597.21 Mg/ha with the mean value of 366.48 Mg/ha. R-square value of the verification analysis was 0.84.

• Journal of Korean Society of Forest Science
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• v.101 no.4
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• pp.599-605
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• 2012

The purpose of this study is to estimate diameter distribution, volume per hectare, and carbon stock for Quercus variabilis stand. 354 Quercus variabilis stands were selected on the basis of age and structure, the data and samples for these stands are collected. For the prediction of diameter distribution, Weibull model was applied and for the estimation of the parameters, a simplified method-of-moments was applied. To verify the accuracy of estimates, models were developed using 80% of the total data and validation was done on the remaining 20%. For the verification of the model, the fitness index, the root mean square error, and Kolmogorov-Smirnov statistics were used. The fitness index of the site index, height, and volume equation estimated from verification procedure were 0.967, 0.727, and 0.988 respectively and the root mean square error were 2.763, 1.817, and 0.007 respectively. The Kolmogorov-Smirnov test applied to Weibull function resulted in 75%. From the models developed in this research, the estimated volume and above-ground carbon stock were derived as $188.69m^3/ha$, 90.30 tC/ha when site index and stem number of 50-years-old Quercus variabilis stand show 14 and 697 respectively. The results obtained from this study may provide useful information about the growth of broad-leaf species and prediction of carbon stock for Quercus variabilis stand.