• Title/Summary/Keyword: forest management corporation

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Growth Characteristics and Vegetation Structure of the Pinus densiflora Forest for Sugumagi of Unmun Temple, Cheongdo-gun, Korea (청도군 운문사 입구 수구막이 소나무림 식생구조 및 생육 특성)

  • Kang, Gi Won;Lee, Do-I;Han, Bong-Ho;Kwak, Jeong-In
    • Journal of the Korean Institute of Landscape Architecture
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    • v.48 no.5
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    • pp.1-15
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    • 2020
  • This study was designed to come up with a way of managing a cultural landscape forest by conducting research on the vegetation structure and growth characteristics. This study's target site, which was 45,201㎡ in size, was Pinus densiflora forest for Sugumagi placed at the entrance of Unmun Temple, Sinwon-ri, Unmun-myeon, and Cheongdo-gun in the southernmost part of Gyeongsangbuk-do, Korea. Sugumagi means the water of the valley flows far away, and where no downstream is visible according to feng shui. The historical sources of the Sugumagi Pinus densiflora forest at the entrance of Unmun Temple isn't clear. It waw only found at that location. The Pinus densiflora forest at the entrance of Unmun Temple is located in the waterway in terms of Feng Shui. The present condition of growth was investigated through a grid surveys of 98 trees and Pinus densiflora growth. As a result of the analysis of growth status, Pinus densiflora, Larix leptolepis, Zelkova serrata, Celtis sinensis, and Rhus javanica were distributed in the conopy layer, and 28 species including Ailanthus altissima were grown in the understroy layer, and 92 species, including Ampelopsis brevipedunculata, in the shrub layer. The plant community structure was divided into low, medium and high-density Pinus densiflora forests in the study area, based on the number in the conopy layer and the grade of and the trees analyzed. As a result of the analysis, the Pinus densiflora dominated the low, medium and high-density Pinus densiflora forests, and there were no competitive species. The relative dominance of the low-density Pinus densiflora forests was 46.9% on average, medium-density was 62.6% and 50.2% was found in high-density. The mean species diversity of Shannon in the low-density study was 0.7055, medium-density study was 0.8966 and the average species diversity of Shannon in the high-density study was 0.8317. The analysis of the age and growth of 25 sample trees in the Sugumagi Pinus densiflora forest shows that the distribution of the chest diameter (DBH) of the sample Pinus densiflora is 38 to 77cm with the average chest diameter being 61.1cm. The age was 84-161 years and the average was 114 years. In the Pinus densiflora forest, most(670,659, or 98.3%) of the tree trunk wound was collected for rosins during the Japanese colonia Era, Of the total 670, 659 were Pinus densiflora, 98.3% of the total. 394 were surgically repaired in 2005. For the preservation of the Sugumagi Pinus densiflora forest, dead trees should be replaced with substitute trees appropriate to the middle and south topography. It is demanded that foreign species such as Larix leptolepis in the research area should be removed and Pinus densiflora that underwent surgical operations should be regularly sterilized. It is also emphasized that the management of insecticide is important.

An Analytical Study on the Revegetation Methods for Highway Slopes (고속도로 절·성토 비탈면 녹화 공법의 적용 실태 연구)

  • Kim, Namchoon;Song, Hokyung;Park, Gwansoo;Jeon, Giseong;Lee, Sanghwa;Lee, Byungjoon
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.10 no.2
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    • pp.1-15
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    • 2007
  • A variety of revegetation methods are being utilized and developed. However, most of revegetation methods used on highway slopes in Korea are based on foreign-introduced plant varieties to stabilize road surfaces and to administer afforestation for surface covering at an earlier phase. Therefore. it results in various problems. such as failure to achieve harmony with the surrounding vegetation and 10 cause re-denudation of slopes as the foreign-in introduced plant varieties wane out from 2~3 years after hydro-seeding, etc. In addition, some of the revegetation plants seeded in the earlier phase grow excessively high, thus causes successional problems, such as to inhibit the invasion of the secondary vegetation from the surrounding areas, etc. Therefore, in this study, 160 slopes located in the nationwide express highways have been investigated and analyzed in order to produce basic data for restoration of ecological environment in slopes created on a long-term basis by investigating and analyzing locational characteristics of cut and filled slopes in express highways, status of revegetation methods, characteristics of soil and plant-ecological environment. 1. Investigation on cut and embanked slopes in express highways was carried out in the total of 160 locations, which include 108 cut slopes and 52 embanked slopes. As a whole, the most frequently used revegetation method was seed spray, which was found to be used in the total of 55 target slops investigated. 2. Planting method of Wistaria floribunda applied to some of the blasted rock zones was found to cause damages as Wistaria floribunda trailed up the surrounding vegetation and the secondary invaded trees. In order to prevent this, this method must be used only in the lowest parts of large-sized slopes. Also, it will be required to administer continuous management and maintenance in the areas already planted with this plants. 3. The areas of blasted rock and ripping rock slopes were applied with coir net (net + seeding) method. However, many of these areas failed in achieving ground covering. Most areas where revegetation was in progress, they were covered with Eragrostis curvula(Weeping lovegrass) only. In areas with soil, such as decomposition of granite, where afforestation is difficult. In this slopes, soil base must be improved by hrdroseeding with thin-layer vegetation base application methods in order to achieve success in afforestation with native plants. 4. Woody species, rather than herb species, are more helpful in stabilization of slope surfaces. Therefore, it is important to be able to grow and protect woody species on highway slopes. Growth of woody vegetation is most largely influenced by soil depth. Thus, when hydro-seeding woody plants, it is recommended to apply at the upper layer of the slopes, which is capable to sufficiently provide the fundamentals required in plant growth.

Development of High-frequency Data-based Inflow Water Temperature Prediction Model and Prediction of Changesin Stratification Strength of Daecheong Reservoir Due to Climate Change (고빈도 자료기반 유입 수온 예측모델 개발 및 기후변화에 따른 대청호 성층강도 변화 예측)

  • Han, Jongsu;Kim, Sungjin;Kim, Dongmin;Lee, Sawoo;Hwang, Sangchul;Kim, Jiwon;Chung, Sewoong
    • Journal of Environmental Impact Assessment
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    • v.30 no.5
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    • pp.271-296
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    • 2021
  • Since the thermal stratification in a reservoir inhibits the vertical mixing of the upper and lower layers and causes the formation of a hypoxia layer and the enhancement of nutrients release from the sediment, changes in the stratification structure of the reservoir according to future climate change are very important in terms of water quality and aquatic ecology management. This study was aimed to develop a data-driven inflow water temperature prediction model for Daecheong Reservoir (DR), and to predict future inflow water temperature and the stratification structure of DR considering future climate scenarios of Representative Concentration Pathways (RCP). The random forest (RF)regression model (NSE 0.97, RMSE 1.86℃, MAPE 9.45%) developed to predict the inflow temperature of DR adequately reproduced the statistics and variability of the observed water temperature. Future meteorological data for each RCP scenario predicted by the regional climate model (HadGEM3-RA) was input into RF model to predict the inflow water temperature, and a three-dimensional hydrodynamic model (AEM3D) was used to predict the change in the future (2018~2037, 2038~2057, 2058~2077, 2078~2097) stratification structure of DR due to climate change. As a result, the rates of increase in air temperature and inflow water temperature was 0.14~0.48℃/10year and 0.21~0.41℃/10year,respectively. As a result of seasonal analysis, in all scenarios except spring and winter in the RCP 2.6, the increase in inflow water temperature was statistically significant, and the increase rate was higher as the carbon reduction effort was weaker. The increase rate of the surface water temperature of the reservoir was in the range of 0.04~0.38℃/10year, and the stratification period was gradually increased in all scenarios. In particular, when the RCP 8.5 scenario is applied, the number of stratification days is expected to increase by about 24 days. These results were consistent with the results of previous studies that climate change strengthens the stratification intensity of lakes and reservoirs and prolonged the stratification period, and suggested that prolonged water temperature stratification could cause changes in the aquatic ecosystem, such as spatial expansion of the low-oxygen layer, an increase in sediment nutrient release, and changed in the dominant species of algae in the water body.

The Prediction of Export Credit Guarantee Accident using Machine Learning (기계학습을 이용한 수출신용보증 사고예측)

  • Cho, Jaeyoung;Joo, Jihwan;Han, Ingoo
    • Journal of Intelligence and Information Systems
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    • v.27 no.1
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    • pp.83-102
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    • 2021
  • The government recently announced various policies for developing big-data and artificial intelligence fields to provide a great opportunity to the public with respect to disclosure of high-quality data within public institutions. KSURE(Korea Trade Insurance Corporation) is a major public institution for financial policy in Korea, and thus the company is strongly committed to backing export companies with various systems. Nevertheless, there are still fewer cases of realized business model based on big-data analyses. In this situation, this paper aims to develop a new business model which can be applied to an ex-ante prediction for the likelihood of the insurance accident of credit guarantee. We utilize internal data from KSURE which supports export companies in Korea and apply machine learning models. Then, we conduct performance comparison among the predictive models including Logistic Regression, Random Forest, XGBoost, LightGBM, and DNN(Deep Neural Network). For decades, many researchers have tried to find better models which can help to predict bankruptcy since the ex-ante prediction is crucial for corporate managers, investors, creditors, and other stakeholders. The development of the prediction for financial distress or bankruptcy was originated from Smith(1930), Fitzpatrick(1932), or Merwin(1942). One of the most famous models is the Altman's Z-score model(Altman, 1968) which was based on the multiple discriminant analysis. This model is widely used in both research and practice by this time. The author suggests the score model that utilizes five key financial ratios to predict the probability of bankruptcy in the next two years. Ohlson(1980) introduces logit model to complement some limitations of previous models. Furthermore, Elmer and Borowski(1988) develop and examine a rule-based, automated system which conducts the financial analysis of savings and loans. Since the 1980s, researchers in Korea have started to examine analyses on the prediction of financial distress or bankruptcy. Kim(1987) analyzes financial ratios and develops the prediction model. Also, Han et al.(1995, 1996, 1997, 2003, 2005, 2006) construct the prediction model using various techniques including artificial neural network. Yang(1996) introduces multiple discriminant analysis and logit model. Besides, Kim and Kim(2001) utilize artificial neural network techniques for ex-ante prediction of insolvent enterprises. After that, many scholars have been trying to predict financial distress or bankruptcy more precisely based on diverse models such as Random Forest or SVM. One major distinction of our research from the previous research is that we focus on examining the predicted probability of default for each sample case, not only on investigating the classification accuracy of each model for the entire sample. Most predictive models in this paper show that the level of the accuracy of classification is about 70% based on the entire sample. To be specific, LightGBM model shows the highest accuracy of 71.1% and Logit model indicates the lowest accuracy of 69%. However, we confirm that there are open to multiple interpretations. In the context of the business, we have to put more emphasis on efforts to minimize type 2 error which causes more harmful operating losses for the guaranty company. Thus, we also compare the classification accuracy by splitting predicted probability of the default into ten equal intervals. When we examine the classification accuracy for each interval, Logit model has the highest accuracy of 100% for 0~10% of the predicted probability of the default, however, Logit model has a relatively lower accuracy of 61.5% for 90~100% of the predicted probability of the default. On the other hand, Random Forest, XGBoost, LightGBM, and DNN indicate more desirable results since they indicate a higher level of accuracy for both 0~10% and 90~100% of the predicted probability of the default but have a lower level of accuracy around 50% of the predicted probability of the default. When it comes to the distribution of samples for each predicted probability of the default, both LightGBM and XGBoost models have a relatively large number of samples for both 0~10% and 90~100% of the predicted probability of the default. Although Random Forest model has an advantage with regard to the perspective of classification accuracy with small number of cases, LightGBM or XGBoost could become a more desirable model since they classify large number of cases into the two extreme intervals of the predicted probability of the default, even allowing for their relatively low classification accuracy. Considering the importance of type 2 error and total prediction accuracy, XGBoost and DNN show superior performance. Next, Random Forest and LightGBM show good results, but logistic regression shows the worst performance. However, each predictive model has a comparative advantage in terms of various evaluation standards. For instance, Random Forest model shows almost 100% accuracy for samples which are expected to have a high level of the probability of default. Collectively, we can construct more comprehensive ensemble models which contain multiple classification machine learning models and conduct majority voting for maximizing its overall performance.

Effects of Thinning on Nutrient Input by Rainfall and Litterfall in Natural Hardwood Forest at Mt. Joongwang, Gangwon-do (강원도 중왕산 지역 천연활엽수림에서 간벌작업이 강우와 낙엽에 의한 양분 유입에 미치는 영향)

  • Jung, Mun-Ho;Lee, Don-Koo;Um, Tae-Won;Kim, Young-Soo;Kwon, Ki-Cheol;Jung, Kang-Ho
    • Korean Journal of Soil Science and Fertilizer
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    • v.41 no.1
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    • pp.1-8
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    • 2008
  • The objectives of this study were to compare nutrient natural input between thinned and unthinned natural hardwood stands at Mt. Joongwang, Pyongchang-gun, Gangwon-do. Throughfall, stemflow, A-layer and B-layer soil water as well as litterfall were sampled at two-week intervals during the period of June to October from 2002 to 2004. The amount of rainfall interception in thinned and unthinned natural hardwood stands was as 12% and 18%, respectively. The results indicated that there was no difference in annual nutrient input by rainfall between thinned and unthinned stands. $Na^+$, $Cl^-$ and $SO_4{^{2-}}$ concentrations of A-layer soil water in the unthinned stand were higher than those in the thinned stand. In the B-layer soil water, $Ca^{2+}$, $Cl^-$, $NO_3{^-}$ and $SO_4{^{2-}}$ concentrations in the unthinned stand were higher than those in thinned stand. Mean annual litterfall input was $2,706kg\;ha^{-1}$ in unthinned stand and $2,589kg\;ha^{-1}$ in thinned stand. Total-N input from litterfall was $50.28kg\;ha^{-1}yr^{-1}$ in the unthinned stand and $36.81kg\;ha^{-1}yr^{-1}$ in the thinned stand, while there was no difference in exchangeable cation input from litterfall between thinned and unthinned stands. Thus, the difference in nutrient inputs except for N by throughfall, stemflow and litterfall between the two stands was not influenced by thinning.

Plant Community Structure of the Soguemgang Valley in Odaesan National Park (오대산국립공원 소금강 계곡부 식물군집구조)

  • Kang, SeongChil;Han, BongHo;Park, SeokCheol;Choi, JinWoo
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.19 no.4
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    • pp.29-44
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    • 2016
  • This study was carried out to the structure of plant community, and ecological succession sere of forest ecosystem in Soguemgang Valley, Odaesan National Park. Fifteenth plots(size is $20m{\times}20m$) were set up and the results analyzed by DCA which is one of the ordination technique showed that the plant communities were divided into seven groups which area community I(Quercus variabilis-Pinus densiflora community), II(Pinus densiflora community), III(Pinus densiflora-Quercus variabilis community), IV(Pinus densiflora-Quercus serrata community), V(Quercus serrata community), VI(Pinus densiflora-Deciduous broad-leaved plant community), VII(Cornus controversa-Carpinus laxiflora community). Shannon diversity index per $400m^2$ was to 0.7777 to 1.1440 and the age of Pinus densiflora 86 years old, Quercus variabilis was ranged from 66 to 87 years old, Quercus serrata was ranged from 51 to 62 years old, Carpinus laxiflora was 94 years old. In 2013, the succession trend was predicted Pinus densiflora${\rightarrow}$Quercus variabilis, Quercus serrata ${\rightarrow}$Cornus controversa, Carpinus laxiflora. The ecological sucession progress has declined power of the Pinus densiflora and the increased power of the deciduous broad-leaved and Quercus spp. in Soguemgang Valley, Odaesan National Park. Quercus serrata and Quercus variabilis communities that judged Pinus densiflora were progressing by direction of landform. The southern slopes vegetation were progressing for Quercus variabilis, the northern slopes vegetation were progressing for Quercus serrata. In flat Valley, mainly native species of Cornus controversa, Carpinus laxiflora are predicted ecological succession for deciduous broad-leaved tree community.

Characteristics of Naturalized Plants in the Gwangyang Steel Works (광양제철소 내의 귀화식물상의 특성)

  • Oh, Hyun-Kyung;Kim, Dal-Ho;Kim, Do-Gyun;Nam, Woong
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.12 no.3
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    • pp.9-20
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    • 2009
  • The naturalized plants in the Gwangyang Steel Works were listed 70 taxa; 18 families, 51 genus, 66 species, 3 varieties and 1 form. by field survey. The naturalized plants divided into pattern by survey of annual plants ratio is 31 taxa (44.3%) by life form spectrum and perennials is 23 taxa (32.9%), biennials is 13 taxa (18.5%), two trees (Robinia pseudoacacia, Alianthus altissima) and one shrub (Amorpha furticosa) were founded. According to analysis results form place of origin, Europe covered 26 taxa (37.1%), North America covered 23 taxa (32.8%). Naturalized degree 3 plants, as common but not abundant, founded as 24 taxa (35.0%) were hold most highly ratio, naturalized degree 1 plants founded as 3 taxa (4.0%) were hold lowest. Introduction period 1 covered 31 taxa (44.3%) have had highest score and period 2 covered 11 taxa (15.7%) have had lowest scores. In addition, the urbanization index based on 271 taxa was 25.8% and 2 taxa (Solanum carolinense, Ambrosia artemisiaefolia) is growing in the Gwangyang Steel Works by ecosystem disturbing wild plants. Meanwhile, Ambrosia artemisiaefolia have confirmed into several tens~hundred in the Gwangyang Steel Works were damage the human body of plants develop an allergy to pollen. Solanium carolinense have composed several large communities about $10m{\times}10m$ ($100m^2$) and hold a dominant position, so management plan of the sequel of monitoring them might be required.

Information System for Architectural Rock & Aggregate in Major Countries and It's Implication (석재·골재 자원정보관리의 해외 사례와 시사점)

  • Deahyung Kim;Yujeong Kim;Yong-Kun Choi
    • Economic and Environmental Geology
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    • v.57 no.2
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    • pp.119-128
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    • 2024
  • In Australia & Canada, architectural rock and aggregate are one of the mineral resources, and related data and information provided integrated with them. In these countries, the provided data and information, through the information system of local government and national geological survey organizations, are interactive maps, geological and thematic maps, exploration data set, 3 dimension geological models, minning rights status, survey reports and related papers etc. However, in case of Korea, aggregate and architectural rock are not assigned as the kind of mineral resources in accordance to domestic mining law, and related geological data and information are not provided from comprehensive mineral information system established in public geoscience organizations. And the administrative and informative management are conducted separately through the different governmental organizations such as Ministry of construction, Korea forest service, geoscience institute & Korea Mine & Reclamation Corporation. For securing the supply of architectural rock and aggregate resources, and for the convenience of their development & utilization, the unified information system and governance reform for the related industry is needed.

The Assessment of pH Variation for Neutralized Acidic Areas using Lysimeters by Seasons (라이시미터를 이용한 중화처리된 산성화경사지의 계절별 pH 용탈특성 평가)

  • Oh, Seungjin;Oh, Minah;Park, Chan-O;Jung, Munho;Lee, Jai-Young
    • Journal of the Korean Geosynthetics Society
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    • v.14 no.4
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    • pp.79-86
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    • 2015
  • Korean territories has formed about 70% of mountainous areas that have acidified serious level to average pH 4-5. There are a number of abandoned metal mines about 1,000 in Korea. However, mine tailings and waste rock included heavy metals are exposed to long-term environment without prevention facility or treatment system. Thus, ongoing management and monitoring of soil environment are required. Most of abandoned mine scattered in forest areas of slopes. Soil erosion due to continuous rainfall in the slopy areas can cause the secondary pollution by the influence eutrophication of water system and the productivity loss of the plant. Therefore, this study would like to estimate pH leaching rate by artificial rainfall using waste neutralization-agent in lysimeter. Moreover, the potentially of secondary pollution related to precipitation is figured out through the experiments, and the optimal planting methods would examinate after neutralizing treatment in soil. Experiments composed three kinds of lysimeter; lysimeter 1 had filled only acidic soil, lysimeter 2 had neutralized soil, and lysimeter 3 had planting plants after neutralized soil. In the results, lysimeter 2 showed the lowest pH leaching, and there is not specific relativity with pH leaching of the seasonal characteristics.

Evaluation of Forest Watershed Hydro-Ecology using Measured Data and RHESSys Model -For the Seolmacheon Catchment- (관측자료와 RHESSys 모형을 이용한 산림유역의 생태수문 적용성 평가 -설마천유역을 대상으로-)

  • Shin, Hyung Jin;Park, Min Ji;Kim, Seong Joon
    • Journal of Korea Water Resources Association
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    • v.45 no.12
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    • pp.1293-1307
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    • 2012
  • This study is to evaluate the RHESSys (Regional Hydro-Ecological Simulation System) simulated streamflow (Q), evapotranspiration (ET), soil moisture (SM), gross primary productivity (GPP) and photosynthetic productivity (PSNnet) with the measured data. The RHESSys is a hydro-ecological model designed to simulate integrated water, carbon, and nutrient cycling and transport over spatially variable terrain. A 8.5 $km^2$ Seolma-cheon catchment located in the northwest of South Korea was adopted. The catchment covers 90.0% forest and the dominant soil is sandy loam. The model was calibrated with 2 years (2007-2008) daily Q at the watershed outlet and MODIS (Moderate Resolution Imaging Spectroradiometer) GPP, PSNnet and 3 year (2007~2009) daily ET data measured at flux tower using the eddy-covariance technique. The coefficient of determination ($R^2$) and the Nash-Sutcliffe model efficiency (ME) for Q were 0.74 and 0.63, and the average $R^2$ for ET and GPP were 0.54 and 0.93 respectively. The model was validated with 1 year (2009) Q and GPP. The $R^2$ and the ME for Q were 0.92 and 0.84, the $R^2$ for GPP were 0.93.