소나무 용적밀도의 적용성 및 불확도 평가

표정기 ( Jung Kee Pyo ),손영모 ( Yeong Mo Son ),이경학 ( Kyeong Hak Lee ),김래현 ( Rae Hyun Kim ),김영환 ( Yeong Hwan Kim ),이영진 ( Young Jin Lee ) 한국산림과학회 2010 한국산림과학회지 Vol.99 No.6

According to the IPCC guideline (2006), uncertainty assessment is very important in terms of the greenhouse gas inventory. Therefore, the purpose of this study is to estimate the basic wood density (BWD) and its uncertainty for Pinus densiflora in Korea. In this study, Pinus densiflora forests were divided into two ecotypes which were Gangwon and Jungbu regions. A total of 33 representative sampling plots was selected to collect sample trees after considering the tree ages and DBH distributions. The BWD showed statistically no difference between age classes based on IPCC`s classification. While, it showed statistically difference(p-value= 0.0017) between eco-types. The BWD and uncertainty was 0.396(g/cm3) and 12.9(%) for Pinus densiflora in Gangwon, while it was 0.470(g/cm3) and 3.8(%) for Pinus densiflora in Jungbu. The values of the BWD uncertainty for Pinus densiflora were more precised than the values given by the IPCC guideline.

부트스트랩을 이용한 소나무의 목재기본밀도 추정 및 평가

표정기 ( Jung Kee Pyo ),손영모 ( Yeong Mo Son ),김영환 ( Yeong Hwan Kim ),김래현 ( Rae Hyun Kim ),이경학 ( Kyeong Hak Lee ),이영진 ( Young Jin Lee ) 한국임학회 2011 한국산림과학회지 Vol.100 No.3

본 연구의 목적은 부트스트랩 시뮬레이션(Bootstrap simulation)을 이용하여 소나무의 목재기본밀도를 평가하고자 하였다. 소나무의 목재기본밀도는 생태형에 따라 강원지방소나무와 중부지방소나무의 자료로 구분하여 분석하였다. 비모수통계 방법의 하나인 부트스트랩 시뮬레이션 기법을 이용하여 추정된 목재기본밀도는 강원지방소나무에서 0.418(g/cm3), 중부지방소나무에서 0.464(g/cm3)으로 나타났다. 부트스트랩 시뮬레이션에서 100, 500, 1,000, 5,000번 반복 시행한 결과에 의하면, 모수 추정치의 95%신뢰구간은 일정한 수치로 나타난 반면에, 표본오차는 감소하는 경향으로 나타났다. 본 연구 결과로 제시된 목재기본밀도 추정치는 기존의 계수에 대한 단점을 보완하고, 신뢰성 높은 목재기본밀도 추정치로 적용이 가능할 것으로 사료된다. The purpose of this study was to develop the basic wood density (Abbreviated BWD) for Pinus densiflora and to evaluate the applicability of bootstrap simulation method. The data sets were divided into two groups based on eco-types in Korea, one from Gangwon type and the other from Jungbu type. The estimated BWDs derived from bootstrap simulation, which is one of the non-parametric statistics, were 0.418 (g/cm3) in the Pinus densiflora in Gangwon while 0.464 (g/cm3) in the Pinus densiflora in Jungbu. To evaluate the bootstrap simulation, the mean BWD, standard error and 95% confidence interval of probability density were estimated. The number of replication were 100, 500, 1,000, and 5,000 times that showed constant 95% confidence interval, while tended to decrease in terms of standard errors. The results of this study could be very useful to apply basic wood density values to calculate reliable carbon stocks for Pinus densiflora in Korea.

몬테 카를로 시뮬레이션을 이용한 소나무 탄소배출계수의 불확도 평가

표정기 ( Jung Kee Pyo ),손영모 ( Yeong Mo Son ),장광민 ( Gwang Min Jang ),이영진 ( Young Jin Lee ) 한국산림과학회 2013 한국산림과학회지 Vol.102 No.4

The purpose of this study was to calculate uncertainty of emission factor collected data and to evaluate the applicability of Monte Carlo simulation technique. To estimate the distribution of emission factors (Such as Basic wood density, Biomass expansion factor, and Root-to-shoot ratio), four probability density functions (Normal, Lognormal, Gamma, and Weibull) were used. The two sample Kolmogorov-Smirnov test and cumulative density figure were used to compare the optimal probability density function. It was observed that the basic wood density showed the gamma distribution, the biomass expansion factor results the log-normal distribution, and root-shoot ratio showd the normal distribution for Pinus densiflora in the Gangwon region; the basic wood density was the normal distribution, the biomass expansion factor was the gamma distribution, and root-shoot ratio was the gamma distribution for Pinus densiflora in the central region, respectively. The uncertainty assessment of emission factor were upper 62.1%, lower -52.6% for Pinus densiflora in the Gangwon region and upper 43.9%, lower -34.5% for Pinus densiflora in the central region, respectively.

반복측정자료 분석을 위한 혼합모형의 적용성 검토: 강원지역 굴참나무 임분을 대상으로

표정기 ( Jung Kee Pyo ),이상태 ( Sang Tae Lee ),서경원 ( Kyung Won Seo ),이경재 ( Kyung Jae Lee ) 한국산림과학회 2015 한국산림과학회지 Vol.104 No.1

The purpose of this study was to evaluate mixed model of dbh-height relation containing random effect. Data were obtained from a survey site for Quercus variabilis in Gangwon region and remeasured the same site after three years. The mixed model were used to fixed effect in the dbh-height relation for Quercus variabilis, with random effect representing correlation of survey period were obtained. To verify the evaluation of the model for random effect, the akaike information criterion (abbreviated as, AIC) was used to calculate the variance-covariance matrix, and residual of repeated data. The estimated variance-covariance matrix, and residual were -0.0291, 0.1007, respectively. The model with random effect (AIC = .215.5) has low AIC value, comparison with model with fixed effect (AIC = .154.4). It is for this reason that random effect associated with categorical data is used in the data fitting process, the model can be calibrated to fit repeated site by obtaining measurements. Therefore, the results of this study could be useful method for developing model using repeated measurement.

Weibull 분포 모형을 이용한 굴참나무 임분 재적 및 탄소저장량 추정

손영모 ( Yeong Mo Son ),표정기 ( Jung Kee Pyo ),김소원 ( So Won Kim ),이경학 ( Kyeong Hak Lee ) 한국산림과학회 2012 한국산림과학회지 Vol.101 No.4

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 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 188.69 m³/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.

부트스트랩 시뮬레이션을 이용한 리기다소나무림의 줄기밀도와 바이오매스 확장계수 평가

서연옥 ( Yeon Ok Seo ),이영진 ( Young Jin Lee ),표정기 ( Jung Kee Pyo ),김래현 ( Rae Hyun Kim ),손영모 ( Yeong Mo Son ),이경학 ( Kyeong Hak Lee ) 한국산림과학회 2011 한국산림과학회지 Vol.100 No.4

This study was conducted to examine the bootstrap evaluation of the stem density and biomass expansion factor for Pinus rigida plantations in Korea. The stem density (g/cm3) in less than 20 tree years were 0.460 while more than 21 tree years were 0.456 respectively. Biomass expansion factor of less than 20 years and more than 21 years were 2.013, 1.171, respectively. The results of 100 and 500 bootstrap iterations, stem density (g/cm3) in less than 20 years were 0.456~0.462 while more than 21 years were 0.457~0.456 respectively. Biomass expansion factor of less than 20 years and more than 21 years were 1.990~2.039, 1.173~1.170, respectively. The mean differences between observed biomass factor and average parameter estimates showed within 5 percent differences. The split datasets of younger stands and old stands were compared to the results of bootstrap simulations. The stem density in less than 20 years of mean difference were 0.441~1.049% while more than 21years were 0.123~0.206% respectively. Biomass expansion factor in less than 20 years and more than 21 years were -1.102~1.340%, -0.024~0.215% respectively. Younger stand had relatively higher errors compared to the old stand. The results of stem density and biomass expansion factor using the bootstrap simulation method indicated approximately 1.1% and 1.4%, respectively.

충남 청양, 보령지역 소나무림의 지상부와 지하부 바이오매스 및 순생산량에 관한 연구

서연옥 ( Yeon Ok Seo ),이영진 ( Young Jin Lee ),표정기 ( Jung Kee Pyo ),김래현 ( Rae Hyun Kim ),손영모 ( Yeong Mo Son ),이경학 ( Kyeong Hak Lee ) 한국산림과학회 2010 한국산림과학회지 Vol.99 No.6

This study analyzed the above-and belowground biomass, net primary production, stem density, and biomass expansion factors for Pinus densiflora stands of Cheongyang and Boryeong regions in Chungnam. The total dry weights in Cheongyang and Boryeong regions were 122.36 kg/tree and 137.68 kg/tree while the aboveground biomass for these two regions were 72.23 Mg/ha and 143.27 Mg/ha, respectively. Total(above-and belowground) biomass were 91.77 Mg/ha and 178.98 Mg/ha, respectively. Net primary production of above-and belowground biomass in Cheongyang and Boryeong regions were 8.69 Mg/ha, 10.03 Mg/ha, 16.00 Mg/ha and 18.66 Mg/ha, respectively. Stem density (g/cm3) was 0.457 and 0.421 while the above and total biomass expansion factors were 1.394~1.662 and 1.324~1.639, respectively. These results suggested that stand density and site quality could be influenced on the biomass and net primary production of the two regions. In addition, the results of this study could be very useful to calculate carbon sequestrations by applying stem density values and biomass expansion factors for Pinus densiflora in these two regions.

리기다소나무림의 줄기밀도와 바이오매스 확장계수에 대한 불확실성 평가

서연옥 ( Yeon Ok Seo ),이영진 ( Young Jin Lee ),표정기 ( Jung Kee Pyo ),김래현 ( Rae Hyun Kim ),손영모 ( Yeong Mo Son ),이경학 ( Kyeong Hak Lee ) 한국임학회 2011 한국산림과학회지 Vol.100 No.2

본 연구는 리기다소나무림의 줄기밀도와 바이오매스 확장계수에 대한 불확실성을 평가하고자 하였다. 총 57본의 표본목을 벌채하였으며, 리기다소나무 20년생 이하의 유령임분과 21년생 이상의 성숙임분을 구분하여 t-검정을 실시한 결과, 줄기밀도는 영급별 차이가 나타나지 않는 반면(p=0.8070), 바이오매스 확장계수는 영급별 차이가 나타났다(p=0.0001). IPCC(Intergovernmental Panel on Climate Change)에서 제시한 불확실성 평가 방법을 이용하여 줄기밀도에 대한 불확실성을 평가한 결과, 20년생 이하에서 30.92%, 21년생 이상에서 25.12%으로 나타났으며, 바이오매스 확장계수에 대한 불확실성은 20년생 이하에서 60.32%, 21년생 이상에서 22.42%으로 나타났다. 줄기밀도의 불확실성은 영급별로 약 5.8%의 차이를 나타낸 반면, 바이오매스 확장계수의 불확실성은 20년생 이하가 21년생 이상 보다 약 37.9%로 매우 높은 것으로 나타났다. 즉, 성숙임분은 불확실성이 상대적으로 작게 나타났으며, 반면에 유령임분은 높게 나타났다. 따라서 줄기밀도와 바이오매스 확장계수를 사용할 경우, 20년생 이하의 영급과 21년생 이상의 영급을 구분하여 줄기밀도와 바이오매스 확장계수를 적용하여야 할 것으로 사료된다. This study was conducted to examine the uncertainty analysis of the stem density and biomass expansion factor for Pinus rigida in Korea. A total of 57 representative sample trees were harvested. The age class in Pinus rigida forests was divided into two, which were stands with less than 20 years and more than 21 years. The influence of stand ages on biomass expansion factor showed that it was statistically significant (p=0.0001), but it was not significant on stem density (p=0.8070). The results of this study based on the uncertainty evaluation method which were suggested by IPCC guide line indicated that stem density of the stand with less than 20 years were 30.92%, while were 25.12% the stands with more than 21years. The uncertainty in biomass expansion factor of less than 20 years and more than 21 years were 60.32% and 22.42%, respectively. The uncertainty of less than 20 years was higher compared to those stands with more than 21 years. In the case of old stand, it showed the lowest uncertainty results but younger stands showed the highest uncertainty results. This study could be applied to our country`s emission factor by using stem density and biomass expansion factors which were less than 20 years and more than 21 years for Pinus rigida in Korea.